Problems with myocardial infarction definitions REPLY

LETTERS TO THE EDITOR Problems with myocardial infarction definitions (DECEMBER 2013) TO THE EDITOR : In the December 2013 Cleveland Clinic Journal of Medicine, Tehrani and Seto provide a review of the updated definitions of myocardial infarction (MI). 1 A key concept incorporated into the structured definitions is that cardiac biomarkers must be interpreted in a clinical context. 2 This in turn helps bet- ter align the laboratory and clinical findings with the pathophysiologic processes. However, there is another dimension to the definitions that is sometimes overlooked and requires careful attention: translation of the definitions into codes and comparable databases. Accurate and consistent coding according to the International Statistical Classification of Diseases, ninth edition (ICD-9), and the ICD-10 is critically vital to the appropriate analysis of data, research, quality measurement, and reimbursement of services related to MI. Unfortunately, there is no straightforward translation of the defini- tions into ICD-9 codes, and the challenge is further confounded when it comes to ICD- 10, which will be implemented in October The ICD-10-CM Index to Diseases does not yet recognize this nomenclature. ST- elevation MI is the default for the unspeci- fied term “acute MI.” Non-ST-elevation MI requires more explicit documentation and is classified based on whether it occurs during or after a variety of procedures. Type 2 MI is particularly challenging because of the sev- eral possible ways to code the condition—for example, as acute subendocardial MI (I21.4), demand ischemia (I24.8), or acute MI, unspecified (I21.9). Coding guidelines are as- sumed to standardize the approach to coding these conditions, but there is no guarantee that comparability of the data will endure biases of code assignment. Although extreme precision in disease capture by coding may not exist, other clinical conditions have better correlations with coding classifica- tions, such as stages of chronic kidney disease ranging from stage 1 through end-stage renal disease (N18.1 through N18.6). Furthermore, ICD-10 codes are insufficient to clearly dis- tinguish the type of acute MI. 3 While the concept of acute MI applies when the stated date of onset is less than 8 weeks in ICD-9, 4 it changes to 4 weeks in ICD-10. “Acute” can reference an initial or a subsequent MI in ICD-10, but it does not de- fine the time frame of the MI. 5 This is different than in ICD-9, where the concept of “subse- quent” refers to a “subsequent episode of care.” On the surface, these variations may not seem significant. However, the discrimina- tory efforts to better define a patient’s clini- cal condition using the new definitions may get diluted by the challenges of the coding process. The implications on comparability of quality metrics and reporting are not to be underestimated and need to be assessed on a national level. SAMER ANTONIOS, MD Via Christi Health, Kansas Assistant Professor, Department of Internal Medicine, University of Kansas— Wichita ◾ ◾ REFERENCES 1. Tehrani DM, Seto AH. Third universal definition of myo- cardial infarction: update, caveats, differential diagnoses. Cleve Clin J Med 2013; 80:777–786. 2. Thygesen K, Alpert JS, Jaffe AS, et al. Third universal definition of myocardial infarction. J Am Coll Cardiol 3. Alexandrescu R, Bottle A, Jarman B, Aylin P. Current ICD10 codes are insufficient to clearly distinguish acute myocardial infarction type: a descriptive study. BMC Health Serv Res 2013; 13:468. 4. ICD-9-CM Addenda, Conversion Table, and Guidelines. www.cdc.gov 5. WEDI Strategic National Implementation Process (SNIP). Acute Myocardial Infarction Issue Brief. www.wedi.org. Accessed February 3, 2014. doi:10.3949/ccjm.81c.03001 IN REPLY : We thank Dr. Antonios for his com- ments regarding the current shortcomings of the ICD-9 and ICD-10 coding systems in describing the acute MI types as defined in the universal definition. We share his con- cern that accurate and consistent coding of MIs may be difficult when the definition CONTINUED ON PAGE 144 C L E V E L A N D C L I N I C J O U R N A L O F M E D I C I N E V O L U M E 8 1 • N U M B E R 3 M A R C H 2 0 1 4 Downloaded from www.ccjm.org on July 7, 2014. For personal use only. All other uses require permission.