Therewere1862 potentialcases initially identified based on ICD-9 codes for CHD (Fig 1). Three hundred twenty potential cases were excluded because the sub- ject did not have CHD; in most of these cases, the ICD-9 code had been used to indicate potential CHD that was not confirmed with diagnostic testing. Ul- timately, 64 116 visits from 856 cases and 7674 controls were included in the primary analysis (Supplemental Table
3). Characteristics of included cases are described in Table 1 with primary diagnostic categories in Table