Acute Myocardial Infarction Cohorts Defined by International Classification of Diseases, Tenth Revision Versus Diagnosis-Related Groups: Analysis of Diagnostic Agreement and Quality Measures in an Integrated Health System

Circ Cardiovasc Qual Outcomes. 2021 Mar;14(3):e006570. doi: 10.1161/CIRCOUTCOMES.120.006570. Epub 2021 Mar 3.


Background: Among Medicare value-based payment programs for acute myocardial infarction (AMI), the Hospital Readmissions Reduction Program uses International Classification of Diseases, Tenth Revision (ICD-10) codes to identify the program denominator, while the Bundled Payments for Care Improvement Advanced program uses diagnosis-related groups (DRGs). The extent to which these programs target similar patients, whether they target the intended population (type 1 myocardial infarction), and whether outcomes are comparable between cohorts is not known.

Methods: In a retrospective study of 2176 patients hospitalized in an integrated health system, a cohort of patients assigned a principal ICD-10 diagnosis of AMI and a cohort of patients assigned an AMI DRG were compared according to patient-level agreement and outcomes such as mortality and readmission.

Results: One thousand nine hundred thirty-five patients were included in the ICD-10 cohort compared with 662 patients in the DRG cohort. Only 421 patients were included in both AMI cohorts (19.3% agreement). DRG cohort patients were older (70 versus 65 years, P<0.001), more often female (48% versus 30%, P<0.001), and had higher rates of heart failure (52% versus 33%, P<0.001) and kidney disease (42% versus 25%, P<0.001). Comparing outcomes, the DRG cohort had significantly higher unadjusted rates of 30-day mortality (6.6% versus 2.5%, P<0.001), 1-year mortality (21% versus 8%, P<0.001), and 90-day readmission (26% versus 19%, P=0.006) than the ICD-10 cohort. Two observations help explain these differences: 61% of ICD-10 cohort patients were assigned procedural DRGs for revascularization instead of an AMI DRG, and type 1 myocardial infarction patients made up a smaller proportion of the DRG cohort (34%) than the ICD-10 cohort (78%).

Conclusions: The method used to identify denominators for value-based payment programs has important implications for the patient characteristics and outcomes of the populations. As national and local quality initiatives mature, an emphasis on ICD-10 codes to define AMI cohorts would better represent type 1 myocardial infarction patients.

Keywords: International Classification of Diseases; Medicare; diagnosis-related groups; heart failure; myocardial infarction.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Angiotensin Receptor Antagonists
  • Angiotensin-Converting Enzyme Inhibitors
  • Delivery of Health Care, Integrated*
  • Diagnosis-Related Groups
  • Female
  • Humans
  • International Classification of Diseases
  • Male
  • Medicare
  • Middle Aged
  • Myocardial Infarction* / diagnosis
  • Myocardial Infarction* / therapy
  • Patient Readmission
  • Quality Indicators, Health Care
  • Retrospective Studies
  • United States / epidemiology


  • Angiotensin Receptor Antagonists
  • Angiotensin-Converting Enzyme Inhibitors