The Breathtaking Scope of ICD-10-CM Revisions for 2011

The Centers for Medicare and Medicaid Services just released a 2011 version of ICD-10-CM. A quick look at the "ICD-10-CM 2010 to 2011 Addenda" reveals a breathtaking scope of change.

First, the "Addenda" document (misnamed, since it also includes things removed and edited, not just added) for the tabular index totals 185 pages in a file nearly 1MB in size. Second, the changes span every chapter of ICD-10-CM.

Worse still, is that numerous codes have undergone a change in meaning, something decried by experts in medical informatics over 16 years ago.

Here is an example:

C64.1 Malignant neoplasm of right kidney, except renal pelvis

is now:

C64.1 Malignant neoplasm of left kidney, except renal pelvis

The update also deletes codes, which also militates against best practices in medical terminology management. Deleted codes include C64.0, C65.0, C66.0.

Anyone trying to update software applications that take advantage of particular codes for logic-based processing will surely have to review all 185 pages very carefully to esnure that their logic remains consistent. DRGs will have to be reviewed as well.

These substantial changes just 1.5 years prior to the deadline to switch will increase the cost and complexity of the switch. Another unwelcome development in the long, sad saga of ICD-10-CM.

Absurd arguments for ICD-10-CM

Sometimes, the arguments in favor of ICD-10-CM border on the absurd. In the January, 2011 issue of Healthcare IT News, the increased "specificity" of ICD-10-CM is highlighted as improving cost savings and disease management. What evidence are we given? The following list of codes:

I'm sure that there are hundreds of billions of dollars to be saved in the health care system, now that we can only code dolphin and sea lion bites better.

Dr. Joel Diamond, in his Health Interoperability Blog, documents similarly absurd arguments here. One proponent of ICD-10-CM said we'd be better off because we would be able to document not just "sports injury", but also whether the injured party was struck by a basketball, baseball, or football.

Busy clinicians trying to take care of sick patients are the ones we will rely on to code this additional specificity, however. Do we really want to distract them from patient care to find the code for dolphin vs. sea lion bites, or strikings by basketball vs. baseball? Is this really the best use of six-figure talent?

Story on ICD-10 contains inaccuracies

A story about 3M consulting services to assist hospitals with the transition to ICD-10 contains several gross inaccuracies.

First, it mentions "ICD-10 concepts and terms". ICD-10 does not have concepts and terms, nor does its predecessor ICD-9-CM. It has codes, categories, and titles. The use of the phrase "concepts and terms" is highly misleading as it suggests that ICD-10 is a concept-based terminology. Although I have issues with those as well, they are lightyears of ahead of ICD-10's archaic structure. So the implication is that ICD-10 is something much better than it really is.

Second, the story lists 4 purposes for ICD-coding of diagnosis, and lists the single most important one, reimbursement, last. Were it not for reimbursement and bureaucratic requirements, no one would assign ICD codes for clinical care, quality, or epidemiological purposes.

In summary, this article misleadingly paints a much more favorable picture of ICD-10 than is warranted by the facts.

ICD-10-CM is NOT a nomenclature

In this article about the lengths to which organizations must go to 'upgrade' to ICD-10-CM, the author refers to ICD-10-CM as a 'nomenclature'.

ICD-10-CM, as its formal name indicates, is a classification, not a nomenclature. Its formal name is the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), as listed on the web site of the government agency that created it from ICD-10.

For example, ICD-10-CM code K83.8 refers to Other specified diseases of the biliary tract. This class of diseases includes multiple individual diseases such as: adhesions of biliary tract, atrophy of biliary tract, hypertrophy of biliary tract, and ulcer of biliary tract.

A nomenclature, by contrast, would have codes for each of these diseases that ICD-10-CM lumps together under the single code K83.8.

So, unfortunately, misinformation about ICD-10-CM continues. Were it truly a nomenclature, and a good one, then it would truly be a worthwhile upgrade.

ICD-10-CM and Windows ME: A Switching Analogy

Much of the lack of resistance to the switch to ICD-10-CM is based on the presumption that since it is the next "version", it simply must be better. Proponents deride the arguments against the switch as being analogous to the question "MS-DOS works fine, why Windows?"

However, a better operating-system analogy would be "Windows 98 works fine, why Windows ME?"

As those who upgraded to Windows ME can attest, the upgrade was a complete disaster. PC World rated Windows ME as the fourth worst tech product of all time.

Analogously, ICD-10-CM is the last upgrade for the archaic, "statistical classification" architecture of terminologies. ICD-11 will use modern approaches to terminology.

In this sense ICD-10-CM is very much like Windows ME, in that Windows ME was the last MS-DOS based Microsoft OS before Microsoft converted its home OS to the newer, Windows NT architecture.

How ironic.

As naysayers against ICD-10-CM, we are saying that we should skip ICD-10-CM, which is the Windows ME of disease classification. It is the proponents of ICD-10-CM who are arguing for the perpetuation of ancient technology, not the naysayers.

The cost of the switch, briefly revisited

Prior efforts to estimate of the cost of switching from ICD-9-CM to ICD-10-CM compared the cost to that of Y2K remediation. In a post last year, we also highlighted the comparison.

The American Hospital Association estimates that the cost of Y2K was $8 billion for hospitals. Compare that to the Health and Human Services (HHS) estimate for switching to ICD-10-CM of $1.6 billion.

Now comes the experience of someone who lived through Y2K and now is preparing his hospital for the government-mandated switch.

Stanley Padfield, system director for health information management at four-hospital Lee Memorial Health System, Cape Coral, Fla, considers the cost of the switch to be higher than that of Y2K remediation.

An article describing Padfield's experience notes:

Padfield says tackling the ICD-10 challenge will prove more difficult than Y2K “because there are a lot more variables involved.” Plus, providers that fail to adequately prepare risk not getting paid promptly by Medicare and other payers.

So, the early experience is already that the ICD-10-CM switch will cost hospitals more than the $8 billion they spent on Y2K. Which dwarfs the HHS low-ball figure of $1.6 billion for the entire health care system to switch.

Even the optimistic RAND report that analyzed the cost of the switch could not come up with more than $7.7 billion in benefits to the switch.

So the early signs are that the costs of the ICD-10-CM switch to the health care system will far exceed the benefits.

Background on disease classification and coding

The Encyclopedia of Public Health on Answers.com has two, concise articles on classification of disease and its history.

For a concise overview on the general task of classifying diseases and the reasons for it, see the Classification of Disease entry.

For a history of disease classification and the International Statistical Classification of Diseases and Related Health Problems (now the official name for ICD, including ICD-10), see this article.

A "monstrous task", "like a heart transplant."

These are the words of those who are starting to investigate the true cost and effort of switching to ICD-10-CM, as quoted in an article about the Healthcare Financial Management Association's annual Healthcare Finance Conference.

Orlando Health has found that the switch will affect 90% of all of its information systems. Integris Health of Oklahoma City has found that the switch will require "changes in data flow," "broad testing," and "intensive staff education".

The American Health Information Management Association (AHIMA), cheerleader for the switch to ICD-10-CM, recommends that you "establish a multi-disciplinary planning team involving all departments" now as a first step for making the transition.

If we're going to expend such resources to switch, why are we adopting a system whose core structure and framework is from the era of punchcards and paper charts?

In other words, if we're going to do a heart transplant, shouldn't we put in a good heart?

Diagnosis classification GEMs

The Center for Medicare and Medicaid Services (CMS) is sponsoring a conference call to discuss "ICD-10-CM/PCS Implementation and General Equivalence Mappings (Crosswalks)".

The purpose of the call is to discuss "...the General Equivalence Mappings that have been created to assist in converting policies, edits, and trend data from ICD-9-CM to ICD-10-CM/PCS."

In other words, to help the switch to ICD-10-CM from ICD-9-CM go more smoothly, CMS is betting on "General Equivalence Mappings" to help people convert their ICD-9-CM encoded data to ICD-10-CM encoded data. A transition plan might therefore involve continuing to code with ICD-9-CM and then converting those codes to ICD-10-CM. (!)

Sounds easy, right?

That is doubtful.

First, we want to point out the irony of this policy. We were told over and over that we'd get better data from ICD-10-CM coding and the sooner the better. Now, we're being told we can continue coding along merrily in ICD-9-CM and just convert our data to ICD-10-CM afterwards. How could that possibly result in better data?

Furthermore, to use the General Equivalence Mappings (or GEMs), you need to know the following facts, taken from the materials CMS posted for the conference call:

- ICD-9 and ICD-10 codes are quite different

- One ICD-9 Diagnosis Code may be represented by multiple ICD-10 codes

- One ICD-10 Diagnosis Code may be represented by multiple ICD-9 codes

- A few ICD-10 codes have no predecessor ICD-9 codes

- Some payers found GEM detail daunting, therefore they developed a "reimbursement mapping" which is much simpler. It is not clear when to use this mapping vs. GEMs.

- There may be multiple translation alternatives for a source system code (the code being looked up), all of which are equally plausible. This is true of both the ICD-10 to ICD-9-CM GEMs and the ICD-9-CM to ICD-10 GEMs.

- A one-to-one mapping does not imply that the two codes refer to the same disease!

- There are instances where there is not a mapping between an ICD-9-CM code and an ICD-10 code. In these instances, CMS has flagged the code with a "no map" flag.

- Each GEM has FIVE flags:
        1. The "approximate" flag
        2. The "no map" flag
        3. A flag to indicate a one-to-many mapping
        4. and 5. Two flags to "further clarify one-to-many mappings".

- CMS et al. developed GEMs "...independently without reference to Medicare data."

- The ultimate goal of the GEMs, and the primary basis on which they are maintained and evaluated, is whether a given patient record receives the SAME Medicare Severity Diagnosis Related Group. Essentially, this means that the improved diagnostic precision of ICD-10-CM is irrelevant to how Medicare will reimburse hospital stays.

- The net effect of the switch and the GEMs on "trend data" (for example, the incidence of hypertension or type 2 diabetes mellitus over time) is not known, and CMS will monitor the effect after the switch.

Why are we switching again?

Final rule for ICD-10-CM survives Obama administration review

HHS' final rule mandating ICD-10-CM has passed muster with the Obama administration. The rules will proceed unaltered, and thus the final compliance date for ICD-10-CM is Oct 1, 2013.

Hospitals, physicians, clinical laboratories, health plans, the federal government itself, state governments, nursing homes, and more will all now spend an estimated $1 billion to upgrade from a bad disease coding system to a slightly less bad, but unnecessarily more complicated, one.

Final ICD-10-CM rule likely on hold for review

The Obama administration has held for review all rules that either have not been published or have not yet taken legal effect. The latter condition applies to the final ICD-10-CM rule, because it does not take effect till March 17.

It's a long shot, but perhaps the review will lead the Obama administration to realize what a mistake the ICD-10-CM switch is.

The 318 ICD-10-CM codes for diabetes mellitus

In a previous post, we pointed out that despite the fact that there are very few known subtypes of diabetes mellitus, ICD-10-CM has approximately 290 codes for diabetes mellitus, not counting gestational diabetes mellitus.

In the 2009 release of ICD-10-CM, we count a total of 318 codes for diabetes mellitus, including gestational diabetes mellitus. The reason for the large number of codes is that ICD-10-CM combines multiple disease classes into a single code.

For example, the ICD-10-CM code E11.621 Type 2 diabetes mellitus with foot ulcer, contains two disease classes: diabetes mellitus and foot ulcer. For sure, this code implicitly means that the former caused the latter (note that this causal relationship is inaccessible to the computer), but that augments our point. Nothing is its own cause and thus these two diseases are distinct.

We provide here on Google docs the 318 codes and their text strings, in a spreadsheet format that anyone can at least copy-and-paste into their own spreadsheet or database table. An easy way to demonstrate the needless complexity caused by combination codes.

It's final: ICD-10-CM by Oct 1, 2013

The Department of Health and Human Services issued today a final rule (warning: pdf) mandating the adoption of ICD-10-CM as a code set under the Health Insurance Portability and Accountability Act (HIPAA). It pushed back the deadline from Oct 1, 2011 (from its proposed rule last August) to Oct 1, 2013.

At approximately the same time, the National Center for Health Statistics released a new, 2009 version of ICD-10-CM that is available here. Instead of the 23MB, 2,392 page PDF file of the 2007 format, we now have an 8.8MB, 2,369 page PDF file. A trimming of 1% on the page count, and a shrinking of over 50% in file size.

The health care industry now has a little more than 4.5 years to find every usage of ICD-9-CM codes in all of its systems, and upgrade and test them to use ICD-10-CM. All the effort spent on that, will not be spent on adopting electronic medical records, devising and participating in pay for performance programs, improving patient safety, automating the reporting of notifiable diseases, chronic disease management, quality initiatives, adopting other information technology standards for true interoperability, and the list goes on.

ICD-10-CM fails every basic requirement demanded of modern technology, terminology, and ontology, and yet it--and previously ICD-9-CM which also fails to meet these requirements--are the only code sets the government has mandated the industry adopt en masse. We suppose it's not surprising coming from a government bureaucracy. But it still is senseless.

Myth: It is practical to assign ICD-10-CM codes manually

The proposed rule to mandate the switch to ICD-10-CM states:

It would be impractical to attempt to manually assign SNOMED–CT codes. The number of terms and level of detail in a reference of clinical terminology such as SNOMED CT cannot be effectively managed without automation,...

By implication, then, it would be practical to assign ICD-10-CM codes manually. Otherwise this supposed disadvantage of SNOMED-CT would not be a factor in HHS' decision to reject SNOMED-CT.

Let us examine this claim further.

ICD-10-CM, by all accounts we have seen--including the proposed rule itself, contains approximately 68,000 codes.

First, we think the very notion that the human brain can cope with 68,000 codes and reliably and manually assign a few of them correctly to patient visits or hospitalizations has no face validity.

Second, even with the manual assignment of the 13,000 codes of ICD-9-CM, there is and has been tremendous variability and low reliability. The Department of Veterans Affairs (VA) conducted a study that found substantial variability in assignment of ICD-9-CM codes:

Based on this study, OHI concluded that the coding of the primary and secondary diagnoses varied widely. The implications of this variability has to be considered when assessing the validity of health services research, health care program planning, quality assurance, utilization review, and resource allocation for VA Medical Centers based on ICD-9-CM codes or DRG information.

While OHI was not evaluating the coding "error rate" in this study, the coding variability observed in the study was comparable to error rates noted in earlier Institute of Medicine (IOM) studies. We found a 60.6 percent agreement in the primary diagnosis code among the original coders and our expert coder. The IOM studies documented a 65.2 percent agreement on the principal diagnosis code, in 1977, and a 63.4 percent agreement on the principal diagnosis code of the records analyzed in 1980. Thus, in all three studies there was approximately a 2/3's agreement in the coding of the medical record.

Even among the expert coders, there was a 19 percent disagreement on the primary diagnosis code. Since our expert coders were highly qualified, this high rate of disagreement caused OHI to question the reliability of the selection of the primary diagnosis and, thus, the accuracy of coded information.

A study of ICD-9-CM coding in psychiatry concluded:

The question was addressed how well mental health professionals were able to translate diagnostic formulations into ICD-9-CM codes. This was done with three coder groups and under two conditions. It was found that there was insufficient interrater agreement on the ICD-codes in all groups and conditions. This finding then was related to the inadequacies of the ICD-system itself. It was concluded that current mental health statistics that are based on the ICD-9-CM coding system are without scientific value.

A study of ICD-9-CM coding in intensive care concluded:

In a multicenter database designed primarily for epidemiological and cohort studies in ICU patients, the coding of medical diagnoses varied between different observers. This could limit the interpretation and validity of research and epidemiological programs using diagnoses as inclusion criteria.

Since other nations have already switched to ICD-10 or their own national variant of it (none of which has even half as many as 68,000 codes), what has their experience been with ICD-10? Better coding? No.

One study of the reliability of coding with ICD-10 concluded:

The refinement of the ICD-10 accompanied by innumerous coding rules has established a complex environment that leads to significant uncertainties even for experts. Use of coded data for quality management, health care financing, and health care policy requires a remarkable simplification of ICD-10 to receive a valid image of health care reality.

A study from Canada even compared the quality of coding between ICD-9 and ICD-10 and concluded:

The implementation of ICD-10 coding has not significantly improved the quality of administrative data relative to ICD-9-CM.

So then, manual assignment of ~13,000 ICD-9-CM codes in the U.S. and elsewhere, and the manual assignment of ~13,000-30,000 ICD-10 codes (depending on national variant), have not been "effectively managed".

It brings to mind the old adage, those who live in glass houses should not throw stones.

So what of SNOMED-CT? How many disease codes are we looking at?

The July, 2008 version of SNOMED-CT, by contrast, has 63,731 active disease concepts. ^[1]

SNOMED-CT, therefore, actually has fewer disease codes than ICD-10-CM! It is hard to imagine that manual assignment of SNOMED-CT disease codes could be managed any less effectively than manual assignment of ICD-10-CM disease codes.^[2]

Myth: Busted.


^[1]Because SNOMED-CT, unlike ICD-10-CM, comes in machine-readable format, these kinds of exact counts are easy to make.

^[2]Note that we are not advocating SNOMED-CT for disease coding. And studies conducted thus far have shown lack of reliability in SNOMED-CT disease coding as well.

Could ICD-10-CM reduce the primary care workforce?

On the heels of primary-care opposition to the switch to ICD-10-CM comes news of a survey that shows half of primary-care doctors would quit medicine today if they could. The major reason? Insurance-company and government red tape.

Well, the switch to ICD-10-CM is a big roll of federal-government red tape. Will this additional red tape from the federal government lower the threshold for many primary care physicians to leave medicine?

For starters, we'll let them tell you themselves.

The letter by the American College of Physicians on behalf of its Internist members states: The burden associated with implementing ICD-10-CM is likely to exacerbate the crisis in the primary care workforce.

The letter by the American Academy of Family Physicians (AAFP) was somewhat less pointed but no less clear: CMS must realistically consider whether pressures to rapidly adopt the ICD-10-CM code set outweigh the importance of supporting the already fragile backbone of patient care, primary care medicine.

The survey of primary-care physicians obtained responses from an impressive 12,000 doctors, 4000 of whom took the time to provide written comments. Here are some key findings of the survey:

• 49% of physicians -- more than 150,000 doctors nationwide -- said that over the next three years they plan to reduce the number of patients they see or stop practicing entirely.
• 94% said the time they devote to non-clinical paperwork in the last three years has increased, and 63% said that the same paperwork has caused them to spend less time per patient.
• 82% of doctors said their practices would be "unsustainable" if proposed cuts to Medicare reimbursement were made.
• 60% of doctors would not recommend medicine as a career to young people.
• If they had the financial means, 45% of doctors would retire today.
• Only 6% of physicians described the professional morale of their colleagues as “positive.” 42% of physicians said the professional morale of their colleagues is either “poor” or “very low”.
• 78% of physicians said medicine is either “no longer rewarding” or “less rewarding”.

Instead of throwing these physicians a lifeline, the government is throwing them an anchor (ICD-10-CM). Many will very likely drown (leave practice) as a result.

Internists oppose the switch to ICD-10-CM, too

In yesterday's post, we highlighted the opposition of family physicians to the switch to ICD-10-CM.

It turns out that internists, too, are against the switch. Dr. Yul Ejnes wrote a letter (pdf) on behalf of the American College of Physicians (ACP) opposing the switch. Like the AAFP letter (pdf), Ejnes' letter was in response to the proposed rule to mandate a switch.

Here are some highlights from internists' opposition to the switch:

The College urges the Centers for Medicare and Medicaid Services (CMS) to suspend plans to adopt ICD-10-CM, the diagnosis code portion of the ICD-10 set, for physicians and other outpatient entities. Adoption of this diagnosis code set in the ambulatory setting is unwarranted as the collective costs far out-weigh the benefits...The burden associated with implementing ICD-10-CM is likely to exacerbate the crisis in the primary care workforce.

The administrative changes and related costs of ICD-10 adoption at this time will place a significant burden on internal medicine and all other physicians; with the burden especially acute for primary care physicians. This is at a time when physician practices—small primary care practices--are already struggling to meet:

• other regulatory requirements (e.g. other HIPAA related initiatives including implementation of the National Provider Indicator (NPI) and the upcoming adoption of the 5010 transaction standards);
• calls for increased adoption of HIT (e.g. e-prescribing and interoperable electronic health records (EHR) systems) including the recently passed Medicare e-prescribing bonus that transitions into a payment reduction; and
• expectations to participate in various pay-for-quality initiatives such as the Medicare Physician Quality Reporting Initiative (PQRI).

Providing more diagnostic code options is not guaranteed to generate better data or patient care.

Indeed, the problems with ICD-10-CM that we have outlined here make it certain that our data will not be better if we switch.

Two of the major primary care specialties, specialties on which hopes for health care reform are often founded, have weighed in. ICD-10-CM will not help them care for patients. Instead, the switch would burden them unnecessarily and impede their ability to care for patients.

Family physicians oppose switch to ICD-10-CM

Much of the opposition to HHS' proposed rule to adopt ICD-10-CM is about the timeline. They have drunk the ICD-10-CM kool-aid, as it were, and simply ask for more time to make the switch from ICD-9-CM.

However, we recently uncovered opposition to switching at all. On behalf of the American Academy of Family Physicians (AAFP), Dr. Jim King writes a letter in response to the proposed rule.

Here are some highlights of the letter:

The AAFP does not support the transition to ICD-10-CM because we do not find that there is good rationale for making such a significant change.

The purported benefits of the transition to 68,000 ICD-10-CM diagnosis codes are largely based on assumptions and not supported with any real world trial involving practicing physicians in the United States.

Our recommendation that CMS not adopt ICD-10-CM is further supported with the following:

• Enhancement and adoption of electronic health records (EHR) must come first
• ICD-9-CM diagnosis codes meet the needs of patient care
• Biosurveillance and research needs can be met through the mapping of ICD-9-CM to ICD-10-CM
• Disease management programs are not dependent on diagnosis codes
• CMS’s estimates of coding education needs are not accurate
• Changes required for adoption of ICD-10 are substantial
• Lack of resources to support physician adoption

The AAFP is the premier speciality society for family physicians. Dr. King is Chair of the Board of the AAFP.

The AAFP has been at the vanguard of electronic health record (EHR) adoption. They have been a key driving force behind the creation of health care information technology standards, including the continuity of care record and continuity of care document.

This opposition does not therefore come from a small, fringe group. Nor does it come from a group that is backwards in its thinking with respect to health care information technology.

The Centers for Medicare and Medicaid Services would do well to listen to those doctors who are at the forefront of using information technology to improve healthcare. They should drop their plan to switch to ICD-10-CM.

As a postscript, we note that in our third post, we criticized the AAFP for not opposing the switch. We hereby withdraw that criticism!

The blogosphere recognizes the pitfalls of ICD-10-CM

The blogosphere is coming to the realization that ICD-10-CM has substantial problems.

Dr. Wes, in a post on October 25th entitled "Ten Times the Fun," laments:

Imagine, 290 codes just for diabetes! Yeeeee haaaaa! Diabetes with foot ulcers on the right foot gets one code, diabetes with foot ulcers on the left foot gets another code, diabetes with foot ulcers on both feet, but not involving the shins gets another code... I mean, a new code for every nuance of disease! You get the drift! Isn't this SPECIAL? Just think of the COST SAVINGS those clever bureaucrats have found!

Meanwhile, Richard Elmore in a post on his Healthcare Technology News blog on October 29th, entitled "More painful than an insect bite? ICD-10 cost-benefit for healthcare providers," lists all 87 ICD-10-CM codes for diagnoses of insect bites. These 87 codes replace 18 ICD-9-CM codes, a 4.8 fold increase.

Mr. HISTalk linked to Dr Wes' post in his October 27th entry. Mr. HISTalk also linked to Richard Elmore's post in his October 31st entry.

Readers of Mr. HISTalk are similarly not impressed with ICD-10-CM. Comments from Mr. HISTalk readers (not including the comments of yours truly) include the following:

The lists of codes are in general a slavish enumeration of nearly every possible combination of pathology, anatomic location, laterality, and ordinality of visit.

They [NCHS] are distributing it [ICD-10-CM] in a text file to:

1. Reduce the most “arduous” task - writing an upload and deduplication routine
2. Keep a non-Government entity (3M?) on the payroll to “manage” the process for them

Disease classification as patronage?

The blogosphere isn't fooled. ICD-10-CM is a poorly designed and executed boondoggle.

Combination code explosion: An illustration

The Blue Cross Blue Shield Association highlights the complexity of ICD-10-CM in a presentation on its web site.

On slide 9 of the presentation is a nice illustration of how ICD-10-CM takes a single code from ICD-10 and explodes it out into 144 codes. ICD-10-CM is based on ICD-10 from the World Health Organization. Individual member countries may modify ICD-10 within certain constraints. Australia (ICD-10-AM) and Canada (ICD-10-CA) both have made modifications.

Well, when the National Center for Health Statistics modified ICD-10 to create the United States' clinical modification or ICD-10-CM, it frequently took one or a small number of ICD-10 codes and "expanded" them out to a much larger number of combination codes.

Going back to the illustration of combination-code explosion from the BCBSA, ICD-10 has code S42.0 for fracture of the clavicle (the clavicle is also commonly referred to as the collar bone).

Canada chose to expand this code out to eight codes in ICD-10-CA:

1. S42.01 - fracture of sternal end of clavicle
   
2. S42.01 - fracture of shaft of clavicle
   
3. S42.02 - fracture of acromial end of clavicle
   
4. S42.09 - fracture of unspecified part of clavicle
   
5. S47 - multiple fractures of clavicle
   
6. M84.11 - nonunion, shoulder region
   
7. M84.21 - delayed union, shoulder region
   
8. M84.22 - malunion, shoulder region

Below, we list the 144, seven-character ICD-10-CM codes for fracture of the clavicle. The 144 codes add laterality, whether the fracture is displaced and if so in what direction, and information about which encounter and whether there is "routine healing", malunion, and so on. Note that all the four-, five-, and six-character codes beginning with S42.0 (it is typical in ICD not to count the decimal point as a character) are also part of ICD-10-CM. There are 1 four-character, 4 five-character, and 24 six-character codes, for a grand total of 173 codes, although only the 144 seven-character codes will be valid for reimbursement (in all likelihood).

From one code to 173 codes as we go from ICD-10 to ICD-10-CM. Combinatorial explosion.

ICD-10: ~12,000-13,000 codes
ICD-10-AM: ~16,000 codes
ICD-10-CA: ~30,000 codes
ICD-10-CM: >68,000 codes

The 144, seven-character ICD-10-CM codes for fracture of the clavicle (with thanks to the BCBSA):

1. S42.001A Unspecified part of right clavicle, initial encounter for closed fracture
2. S42.001D Unspecified part of right clavicle, subsequent encounter for fracture with routine healing
3. S42.001G Unspecified part of right clavicle, subsequent encounter for fracture with delayed healing
4. S42.001K Unspecified part of right clavicle, subsequent encounter for fracture with nonunion
5. S42.001P Unspecified part of right clavicle, subsequent encounter for fracture with malunion
6. S42.001S Unspecified part of right clavicle, sequalae
7. S42.002A Unspecified part of left clavicle, initial encounter for closed fracture
8. S42.002D Unspecified part of left clavicle, subsequent encounter for fracture with routine healing
9. S42.002G Unspecified part of left clavicle, subsequent encounter for fracture with delayed healing
10. S42.002K Unspecified part of left clavicle, subsequent encounter for fracture with nonunion
11. S42.002P Unspecified part of left clavicle, subsequent encounter for fracture with malunion
12. S42.002S Unspecified part of left clavicle, sequalae
13. S42.009A Unspecified part of unspecified clavicle, initial encounter for closed fracture
14. S42.009D Unspecified part of unspecified clavicle, subsequent encounter for fracture with routine healing
15. S42.009G Unspecified part of unspecified clavicle, subsequent encounter for fracture with delayed healing
16. S42.009K Unspecified part of unspecified clavicle, subsequent encounter for fracture with nonunion
17. S42.009P Unspecified part of unspecified clavicle, subsequent encounter for fracture with malunion
18. S42.009S Unspecified part of unspecified clavicle, sequalae
19. S42.011A Anterior displaced fracture of sternal end of right clavicle, initial encounter for closed fracture
20. S42.011D Anterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with routine healing
21. S42.011G Anterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with delayed healing
22. S42.011K Anterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with nonunion
23. S42.011P Anterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with malunion
24. S42.011S Anterior displaced fracture of sternal end of right clavicle, sequalae
25. S42.012A Anterior displaced fracture of sternal end of left clavicle, initial encounter for closed fracture
26. S42.012D Anterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with routine healing
27. S42.012G Anterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with delayed healing
28. S42.012K Anterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with nonunion
29. S42.012P Anterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with malunion
30. S42.012S Anterior displaced fracture of sternal end of left clavicle, sequalae
31. S42.013A Anterior displaced fracture of sternal end of unspecified clavicle, initial encounter for closed fracture
32. S42.013D Anterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with routine healing
33. S42.013G Anterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with delayed healing
34. S42.013K Anterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with nonunion
35. S42.013P Anterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with malunion
36. S42.013S Anterior displaced fracture of sternal end of unspecified clavicle, sequalae
37. S42.014A Posterior displaced fracture of sternal end of right clavicle, initial encounter for closed fracture
38. S42.014D Posterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with routine healing
39. S42.014G Posterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with delayed healing
40. S42.014K Posterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with nonunion
41. S42.014P Posterior displaced fracture of sternal end of right clavicle, subsequent encounter for fracture with malunion
42. S42.014S Posterior displaced fracture of sternal end of right clavicle, sequalae
43. S42.015A Posterior displaced fracture of sternal end of left clavicle, initial encounter for closed fracture
44. S42.015D Posterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with routine healing
45. S42.015G Posterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with delayed healing
46. S42.015K Posterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with nonunion
47. S42.015P Posterior displaced fracture of sternal end of left clavicle, subsequent encounter for fracture with malunion
48. S42.015S Posterior displaced fracture of sternal end of left clavicle, sequalae
49. S42.016A Posterior displaced fracture of sternal end of unspecified clavicle, initial encounter for closed fracture
50. S42.016D Posterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with routine healing
51. S42.016G Posterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with delayed healing
52. S42.016K Posterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with nonunion
53. S42.016P Posterior displaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with malunion
54. S42.016S Posterior displaced fracture of sternal end of unspecified clavicle, sequalae
55. S42.017A Nondisplaced fracture of sternal end of right clavicle, initial encounter for closed fracture
56. S42.017D Nondisplaced fracture of sternal end of right clavicle, subsequent encounter for fracture with routine healing
57. S42.017G Nondisplaced fracture of sternal end of right clavicle, subsequent encounter for fracture with delayed healing
58. S42.017K Nondisplaced fracture of sternal end of right clavicle, subsequent encounter for fracture with nonunion
59. S42.017P Nondisplaced fracture of sternal end of right clavicle, subsequent encounter for fracture with malunion
60. S42.017S Nondisplaced fracture of sternal end of right clavicle, sequalae
61. S42.018A Nondisplaced fracture of sternal end of left clavicle, initial encounter for closed fracture
62. S42.018D Nondisplaced fracture of sternal end of left clavicle, subsequent encounter for fracture with routine healing
63. S42.018G Nondisplaced fracture of sternal end of left clavicle, subsequent encounter for fracture with delayed healing
64. S42.018K Nondisplaced fracture of sternal end of left clavicle, subsequent encounter for fracture with nonunion
65. S42.018P Nondisplaced fracture of sternal end of left clavicle, subsequent encounter for fracture with malunion
66. S42.018S Nondisplaced fracture of sternal end of left clavicle, sequalae
67. S42.019A Nondisplaced fracture of sternal end of unspecified clavicle, initial encounter for closed fracture
68. S42.019D Nondisplaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with routine healing
69. S42.019G Nondisplaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with delayed healing
70. S42.019K Nondisplaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with nonunion
71. S42.019P Nondisplaced fracture of sternal end of unspecified clavicle, subsequent encounter for fracture with malunion
72. S42.019S Nondisplaced fracture of sternal end of unspecified clavicle, sequalae
73. S42.021A Displaced fracture of shaft of right clavicle, initial encounter for closed fracture
74. S42.021D Displaced fracture of shaft of right clavicle, subsequent encounter for fracture with routine healing
75. S42.021G Displaced fracture of shaft of right clavicle, subsequent encounter for fracture with delayed healing
76. S42.021K Displaced fracture of shaft of right clavicle, subsequent encounter for fracture with nonunion
77. S42.021P Displaced fracture of shaft of right clavicle, subsequent encounter for fracture with malunion
78. S42.021S Displaced fracture of shaft of right clavicle, sequalae
79. S42.022A Displaced fracture of shaft of left clavicle, initial encounter for closed fracture
80. S42.022D Displaced fracture of shaft of left clavicle, subsequent encounter for fracture with routine healing
81. S42.022G Displaced fracture of shaft of left clavicle, subsequent encounter for fracture with delayed healing
82. S42.022K Displaced fracture of shaft of left clavicle, subsequent encounter for fracture with nonunion
83. S42.022P Displaced fracture of shaft of left clavicle, subsequent encounter for fracture with malunion
84. S42.022S Displaced fracture of shaft of left clavicle, sequalae
85. S42.023A Displaced fracture of shaft of unspecified clavicle, initial encounter for closed fracture
86. S42.023D Displaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with routine healing
87. S42.023G Displaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with delayed healing
88. S42.023K Displaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with nonunion
89. S42.023P Displaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with malunion
90. S42.023S Displaced fracture of shaft of unspecified clavicle, sequalae
91. S42.024A Nondisplaced fracture of shaft of right clavicle, initial encounter for closed fracture
92. S42.024D Nondisplaced fracture of shaft of right clavicle, subsequent encounter for fracture with routine healing
93. S42.024G Nondisplaced fracture of shaft of right clavicle, subsequent encounter for fracture with delayed healing
94. S42.024K Nondisplaced fracture of shaft of right clavicle, subsequent encounter for fracture with nonunion
95. S42.024P Nondisplaced fracture of shaft of right clavicle, subsequent encounter for fracture with malunion
96. S42.024S Nondisplaced fracture of shaft of right clavicle, sequalae
97. S42.025A Nondisplaced fracture of shaft of left clavicle, initial encounter for closed fracture
98. S42.025D Nondisplaced fracture of shaft of left clavicle, subsequent encounter for fracture with routine healing
99. S42.025G Nondisplaced fracture of shaft of left clavicle, subsequent encounter for fracture with delayed healing
100. S42.025K Nondisplaced fracture of shaft of left clavicle, subsequent encounter for fracture with nonunion
101. S42.025P Nondisplaced fracture of shaft of left clavicle, subsequent encounter for fracture with malunion
102. S42.025S Nondisplaced fracture of shaft of left clavicle, sequalae
103. S42.026A Nondisplaced fracture of shaft of unspecified clavicle, initial encounter for closed fracture
104. S42.026D Nondisplaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with routine healing
105. S42.026G Nondisplaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with delayed healing
106. S42.026K Nondisplaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with nonunion
107. S42.026P Nondisplaced fracture of shaft of unspecified clavicle, subsequent encounter for fracture with malunion
108. S42.026S Nondisplaced fracture of shaft of unspecified clavicle, sequalae
109. S42.031A Displaced fracture of lateral end of right clavicle, initial encounter for closed fracture
110. S42.031D Displaced fracture of lateral end of right clavicle, subsequent encounter for fracture with routine healing
111. S42.031G Displaced fracture of lateral end of right clavicle, subsequent encounter for fracture with delayed healing
112. S42.031K Displaced fracture of lateral end of right clavicle, subsequent encounter for fracture with nonunion
113. S42.031P Displaced fracture of lateral end of right clavicle, subsequent encounter for fracture with malunion
114. S42.031S Displaced fracture of lateral end of right clavicle, sequalae
115. S42.032A Displaced fracture of lateral end of left clavicle, initial encounter for closed fracture
116. S42.032D Displaced fracture of lateral end of left clavicle, subsequent encounter for fracture with routine healing
117. S42.032G Displaced fracture of lateral end of left clavicle, subsequent encounter for fracture with delayed healing
118. S42.032K Displaced fracture of lateral end of left clavicle, subsequent encounter for fracture with nonunion
119. S42.032P Displaced fracture of lateral end of left clavicle, subsequent encounter for fracture with malunion
120. S42.032S Displaced fracture of lateral end of left clavicle, sequalae
121. S42.033A Displaced fracture of lateral end of unspecified clavicle, initial encounter for closed fracture
122. S42.033D Displaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with routine healing
123. S42.033G Displaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with delayed healing
124. S42.033K Displaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with nonunion
125. S42.033P Displaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with malunion
126. S42.033S Displaced fracture of lateral end of unspecified clavicle, sequalae
127. S42.034A Nondisplaced fracture of lateral end of right clavicle, initial encounter for closed fracture
128. S42.034D Nondisplaced fracture of lateral end of right clavicle, subsequent encounter for fracture with routine healing
129. S42.034G Nondisplaced fracture of lateral end of right clavicle, subsequent encounter for fracture with delayed healing
130. S42.034K Nondisplaced fracture of lateral end of right clavicle, subsequent encounter for fracture with nonunion
131. S42.034P Nondisplaced fracture of lateral end of right clavicle, subsequent encounter for fracture with malunion
132. S42.034S Nondisplaced fracture of lateral end of right clavicle, sequalae
133. S42.035A Nondisplaced fracture of lateral end of left clavicle, initial encounter for closed fracture
134. S42.035D Nondisplaced fracture of lateral end of left clavicle, subsequent encounter for fracture with routine healing
135. S42.035G Nondisplaced fracture of lateral end of left clavicle, subsequent encounter for fracture with delayed healing
136. S42.035K Nondisplaced fracture of lateral end of left clavicle, subsequent encounter for fracture with nonunion
137. S42.035P Nondisplaced fracture of lateral end of left clavicle, subsequent encounter for fracture with malunion
138. S42.035S Nondisplaced fracture of lateral end of left clavicle, sequalae
139. S42.036A Nondisplaced fracture of lateral end of unspecified clavicle, initial encounter for closed fracture
140. S42.036D Nondisplaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with routine healing
141. S42.036G Nondisplaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with delayed healing
142. S42.036K Nondisplaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with nonunion
143. S42.036P Nondisplaced fracture of lateral end of unspecified clavicle, subsequent encounter for fracture with malunion
144. S42.036S Nondisplaced fracture of lateral end of unspecified clavicle, sequalae

More On Diagnostic Precision

We say that a diagnosis of disease A is more precise than a diagnosis of disease B if disease A is a subtype of disease B. For example, a diagnosis of coronary artery disease is more precise than a diagnosis of heart disease, and a diagnosis of stenosis of the left anterior descending coronary artery is more precise than a diagnosis of coronary artery disease.

One big reason that ICD-10-CM proponents want to switch from ICD-9-CM is that the disease classes of ICD-9-CM are often not at a sufficient level of diagnostic precision to support many "secondary" uses of health care data, such as rewarding doctors and hospitals for improving quality of care, medical research, chronic disease management, and so on.

For sure, ICD-9-CM is not sufficient for patient care, because to treat patients you need to record the individual diseases, not the classes into which they go.

Because ICD-10-CM is also a classification of diseases, as opposed to a set of codes for individual diseases, it is likely that even with ICD-10-CM, we will still be wanting for increased diagnostic precision. Again, for patient care we need to code individual diseases, not disease classes. Thus, no disease classification will ever be sufficient for patient care.

However, already there are even secondary uses of health care data that require higher diagnostic precision than that provided by ICD-10-CM.

At least one researcher wants to study patients with type 1a diabetes mellitus, and thus wishes to exclude patients with type 1b diabetes mellitus from the study. However, ICD-10-CM does not provide codes for these two subtypes of type 1 diabetes mellitus. This researcher will not be helped by ICD-10-CM, but will still have to test all patients with type 1 diabetes mellitus to determine which subtype they have.

We need a disease-coding system, not a disease-classification coding system. We should not switch to ICD-10-CM.