ICD-10 essentials for busy physicians who would rather be doing something else -- Asthma and COPD

Asthma and COPD are two chronic conditions common enough in the general population that most physicians will want to know the documentation needs for coding in ICD-10. I’ll compare them to documentation for ICD-9.

Asthma coding has changed. Two axes of classification that physicians rarely documented in ICD-9 have been eliminated, and two axes of classification (that hopefully physicians will find useful) have been added in ICD-10. As a result, the total number of asthma and COPD codes is roughly the same in ICD-9 and ICD-10 -- 17 ICD-9 codes and 20 ICD-10 codes.

Here are the two hair-splitting ICD-9 axes of classification that have been eliminated in ICD-10:

  • ICD-10 does not force physicians to categorize asthma as intrinsic or extrinsic. Asthma is just asthma.
  • ICD-10 does not have separate codes for chronic obstructive asthma, as opposed to chronic obstructive bronchitis or plain old chronic obstructive pulmonary disease. COPD is just COPD in ICD-10. More about COPD when we finish with asthma.

Here are the two (hopefully more useful) axes of classification for asthma that have been added to ICD-10:

  • Asthma is categorized by degree of severity — mild, moderate and severe are the terms used in the codes to distinguish the level of severity.
  • Asthma is further categorized as either intermittent or persistent. (Intermittent often means the asthma has an external trigger; therefore, extrinsic/allergic in its cause. But it doesn’t rule out non-allergic asthma that is also intermittent. Let’s face it, asthma causes are not that easy to pin down, and having the classification hinge on the physician’s ability to use mutually exclusive terminology to declare the cause of the asthma doesn’t make sense.

It is probably in your interest to use the ICD-10 terminology in documenting a patient encounter. Unlike the discontinued detail in ICD-9, the ICD-10 codes clearly distinguish the behavior of an illness rather than its cause. They tell how sick a patient is, and therefore how much effort is involved in monitoring and treatment. A patient with severe persistent asthma is clearly distinguishable from a patient with mild persistent asthma. And eventually, if not immediately, those distinctions are going to be used by the (evil) people who use diagnosis codes to calculate what to pay you and to comment on how well you do your job.

You of course have the right to vote against the entire ICD system by not documenting to comply with measures of clinical significance cooked up by a global committee, but at some point it may, literally, cost you. These clinical distinctions will no doubt be used wherever possible to fine-tune payment systems and quality report cards and all the rest of it. It is no secret that the healthcare system is not optimized for the physician’s convenience or preferences on how to best deliver care, but by being a practicing physician in the United States you are playing this game, which includes using ICD codes to eke out all the justifiable credit you can for the work you do.

As an example, here are the ICD-10 asthma codes for a patient with severe persistent asthma, with the ICD-9 codes they replace.

J45.50 Severe persistent asthma, uncomplicated  


493.00 Extrinsic asthma, unspecified 
493.10 Intrinsic asthma, unspecified

J45.51 Severe persistent asthma with (acute) exacerbation  


493.02 Extrinsic asthma with (acute) exacerbation 
493.12 Intrinsic asthma with (acute) exacerbation

J45.52 Severe persistent asthma with status asthmaticus  


493.01 Extrinsic asthma with status asthmaticus 
493.11 Intrinsic asthma with status asthmaticus

Notice you still have the ability to capture acute exacerbation and status asthmaticus. The same is true of all the flavors of asthma mentioned earlier -- severe intermittent, moderate persistent, moderate intermittent, etc. The whole category is perfectly regular.

There is also an unspecified subcategory if you choose not to play the documentation game. If you document only “patient is on prescribed inhalers for asthma” the default code is

J45.909 Unspecified asthma, uncomplicated


Not a lot to say about COPD beyond what I mentioned earlier. As with asthma coding, an axis of classification that wasn’t seen as useful was eliminated.  ICD-10 added a code for a common acute exacerbation that brings a patient with COPD back to seek care — COPD with acute lower respiratory infection such as acute bronchitis or pneumonia. The specific pneumonia or bronchitis code can be coded in addition.

J44.0 Chronic obstructive pulmonary disease with acute lower respiratory infection  

As with ICD-9, there is an ICD-10 code for COPD with exacerbation, which captures “decompensated” COPD, without any additional documentation.

J44.1 Chronic obstructive pulmonary disease with (acute) exacerbation  

491.21 Obstructive chronic bronchitis with (acute) exacerbation 
493.22 Chronic obstructive asthma with (acute) exacerbation

And of course there is an unspecified option, which no longer splits hairs about whether the COPD is predominantly asthma or predominantly bronchitis — it’s just COPD.

J44.9 Chronic obstructive pulmonary disease, unspecified  


491.20 Obstructive chronic bronchitis without exacerbation 
493.20 Chronic obstructive asthma, unspecified 
496 Chronic airway obstruction, not elsewhere classified

Getting rid of dead wood in the classification is one of the benefits of these periodic revisions of the ICD. In the case of asthma and COPD, distinctions of dubious relevance have been abandoned. Even if you could say with absolute certainty that the cause of the patient’s asthma is extrinsic, the fact remains that regardless of the cause there is constriction of airways and inflammation in the lungs that must be treated. Instead of forcing you to declare the underlying cause, the ICD-10 asthma codes give a clearer indication how sick the patient is and therefore supports what you did to treat that patient.

Rhonda Butler is a senior clinical research analyst with 3M Health Information Systems. She is responsible for the development and maintenance of the ICD-10 Procedure Coding System since 2003 under contract to CMS, and for the development and maintenance of the ICD-10 General Equivalence Mappings (GEMs) and Reimbursement Mappings under contract to CMS and the CDC.  She leads the 3M test project to convert the MS-DRGs to ICD-10 for CMS, and is on the team to convert 3M APR-DRGs to ICD-10. Rhonda also writes for the 3M Health Information Systems blog.