Trends in the Sensitivity, Positive Predictive Value, False-Positive Rate, and Comparability Ratio of Hospital Discharge Diagnosis Codes for Acute Myocardial Infarction in Four US Communities, 1987-2000

Abstract

Variations in the validity of hospital discharge diagnoses can complicate the assessment of trends in incidence of acute myocardial infarction (AMI). To clarify trends in the validity of discharge codes, the authors compared event classification based on published Atherosclerosis Risk in Communities (ARIC) Study criteria with the presence or absence of an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) hospital discharge code for AMI (code 410). Between 1987 and 2000, 154,836 coronary heart disease events involving hospitalization in the four ARIC communities had ICD-9-CM codes screened for AMI. The sensitivity of ICD-9-CM code 410 for classifying AMI in men (sensitivity = 0.65, 95% confidence interval (CI): 0.63, 0.66) was statistically significantly greater than that found for women (sensitivity = 0.60, 95% CI: 0.58, 0.62) and was greater in Whites (sensitivity = 0.67, 95% CI: 0.65, 0.68) than in Blacks (sensitivity = 0.50, 95% CI: 0.47, 0.53). The ethnic difference was related to a greater frequency of hypertensive heart disease and congestive heart failure codes encompassing AMI among Blacks as compared with Whites. The authors found that although the validity of ICD-9-CM code 410 to identify AMI was generally stable from 1987 through 2000, differences between Blacks and Whites and across geographic locations support investment in validation efforts in ongoing surveillance studies.

Recent Declines in Hospitalizations for Acute Myocardial Infarction for Medicare Fee-for-Service Beneficiaries

“…Changes in the sensitivity of ICD-9-CM codes for capturing AMIs could potentially explain the observed changes in AMI hospitalization rates. Older studies have suggested that ICD-9 codes have reasonable accuracy for capturing clinically confirmed AMIs, 25,26 but further investigation into current medical coding practices is warranted. Our study did find that cardiac conditions that may have been coded instead of AMI such as unstable angina, heart failure, coronary artery disease, and dysrhythmia have also fallen over time, suggesting that there has not been a dramatic shift in coding hospitalizations away from AMI to these particular conditions.…”

“…46 It is unlikely that the sensitivity of ICD-9-CM codes would decline substantially and consistently over time to explain the overall downward trend in AMI rates. The ability of ICD-9-CM codes to detect AMIs has been shown to vary with race, 25 which may explain some of the differences in AMI rates between white and black patients but is unlikely to alter trends observed within racial categories.…”

Discrepancy between Medical Evidence Form 2728 and Renal Biopsy for Glomerular Diseases

“…We therefore assume that those with nonglomerular diseases would very rarely be labeled as having a glomerular disease requiring a biopsy for diagnosis. The FP rate and PPV is thus conditional on the fact that a patient has a biopsy-confirmed glomerular disease (21).…”

Suboptimal Utilization of Secondary Drug Prevention in Acute Coronary Syndrome: Measurement Issues and Managed Care Opportunities

“…A 2004 validation study published by Rosamond et al evaluated the validity of hospital discharge codes as an identification method for cardiac events by comparing hospital codes with the Atherosclerosis Risk in Communities (ARIC) identification criteria. 5 This study found that 75% of persons identified via ICD-9-CM code 410 had a "definite" or "probable" MI according to the more rigorous ARIC classification scheme. When evaluating ICD-9-CM code 411.xx, only 14% of patients met the ARIC definition for "definite" or "probable" MI.…”