Measures of prevalence: which healthcare registers are applicable?

This study analyses the applicability of some of the registers used within the healthcare system for estimations of disease prevalence. The study focuses on the diagnoses of asthma, diabetes mellitus, chronic bronchitis/emphysema, hypertensive disease, and cerebrovascular disease.

The study population comprised all inhabitants (n=20,037) in the municipality of Tierp on 31 December 1996. Diagnostic information was collected from primary healthcare and occupational healthcare in the municipality of Tierp and from inpatient and outpatient units at the hospitals in Uppsala County. The proportion of registered patients in the different registers was calculated in relation to the total number of patients who had been registered during 1996 with the selected diagnoses.

In the primary healthcare register, between 67% (cerebrovascular disease) and 85% (asthma) of all patients with selected diagnoses could be identified. A search on the inpatient care register (Hospital Discharge Register) led to the identification of between 8% (hypertensive disease) and 53% (cerebrovascular disease) of the patients.

For all of the examined diagnoses, most patients could be identified in the primary healthcare register. Register data from both primary healthcare and inpatient and outpatient care at hospital are needed to make reasonable estimates of prevalence.