The accuracy of myocardial infarction diagnosis in medical insurance claims

We attempted to assess the accuracy of the International Classification of Diseases (ICD) codes for myocardial infarction (MI) in,medical insurance cl aims, and to investigate the reasons for any inaccuracy. This study was des igned as a preliminary study to establish a surveillance system for cardiov ascular diseases in Korea. A sample of 258 male patients who were diagnosed with MI from 1993 to 1997 was selected from the Korea Medical Insurance Co rporation cohort (KMIC cohort: 183,461 people). The registered medical reco rd administrators were trained in the survey technique, and gathered data b y investigating the medical records of the study subjects from March 1999 t o May 1999. The definition of MI for this study included symptoms pursuant to the diagnostic criteria of chest pain, electrocardiogram (ECG) findings, cardiac enzyme and results of coronary angiography or nuclear scan. We ask ed the record administrators for the reasons of incorrectness for cases whe re the final diagnosis was 'not MI'. The accuracy rare of the ICD codes for MI in medical insurance claims Nas 76.0% (196 cases) of the study sample, and 3.9% (ten cases) of che medical records were not available due to hospi tal closures, non-computerization or missing information. Nineteen cases (7 .4%) were classified as insufficient due to insufficient records of chest p ain, ECC findings, or cardiac enzymes. The major reason of inaccuracy in th e disease code for MI in medical: insurance claims was 'to meet the review criteria of medical insurance benefits (45.5%)'. The department responsible for the inaccuracy was the department of inspection for medical insurance benefit of the hospitals.