Table 2.

Validity of ICD-9 codes for acute myocardial infarction events during follow up.

Coding algorithm	Validated events	PPV (95% CI)	NPV (95% CI)	Sensitivity (95% CI)	Specificity (95% CI)
All 410.xx codes	41	80% (66–90%)	99% (98–100%)	90% (78–96%)	99% (98–100%)
Exclude 410.x2 codes	41	80% (66–89%)	99% (98–100%)	87% (75–94%)	99% (98–100%)
Exclude subjects with previous MI at baseline	40	80% (66–89%)	99% (98–100%)	91% (81–96%)	99% (98–100%)

Validation criteria for acute myocardial infarction are listed in Supplemental Table 1. CI = confidence interval, NPV = negative predictive value, PPV = positive predictive value.