Usefulness of a large automated health records database in pharmacoepidemiology

Objectives In the present study, using a large automated health records database, we investigated the incidence of cardio-cerebrovascular events, diabetes new-onset events, and dialysis initiation events in hypertensive patients, and examined the effects of antihypertensive medications on these incidences. Materials and methods We conducted a search of an automated health records database that contained anonymous information from the health insurance claims and the results of laboratory tests at 15 medical facilities across Japan. The study cohort was defined as patients who were diagnosed with hypertension and who visited a medical institution in the registration period. Events were defined by diagnosis, medication history, and laboratory test results. Results We obtained a cohort of 20,686 patients diagnosed with hypertension. The mean (standard deviation, SD) age in the cohort was 67.9 (13.2) years, and the follow-up period was 2.56 (1.42) years. The total incidence rates per 1,000 person-years in the present study population showed good agreement with rates in reported cohort studies: 8.10 (5.6–11.1) for cerebrovascular events, 1.27 (0.5–7.4) for cerebral hemorrhage, 6.57 (4.6–8.9) for cerebral infarction, 0.46 (0.1–1.0) for subarachnoid hemorrhage, and 1.75 (1.6–4.4) for myocardial infarction. The standardized incidence rates of cardio-cerebrovascular events, diabetes new-onset events, and dialysis initiation events were 9.73, 20.94, and 5.99 events/1,000 personyears, respectively. Conclusions In terms of the incidence of the investigated events in hypertensive patients, the study results suggested that the automated health records database data were as valid and reliable as data from other epidemiological studies.