Using registries in general practice to estimate countrywide morbidity in The Netherlands.

OBJECTIVE: Examining the possibility of using data from registries in general practice in order to present morbidity figures concerning a broad range of major diseases for the Dutch population. STUDY
DESIGN: Qualitative and quantitative analysis of registered diagnoses.
METHODS: Quantitative data from six registries were obtained. In addition, information about the registration process was obtained and discussed with representatives of the registries. Subjects for discussion were the general characteristics of the registries and disease-specific rules.
RESULTS: Some important differences exist in the characteristics of the registries and the disease-specific coding rules for computing incidence and prevalence. However, for most diseases the rules of two or more registries corresponded with each other, so that a selection of registries that measured the occurrence of a particular disease in a similar way could be made. Nevertheless, for some age categories rather large differences between registries were observed. The best estimates for the whole country were calculated as the average incidence and prevalence of the selected registries.
CONCLUSIONS: Data that were originally obtained during patient care can be made usable for public health policy purposes. To further improve the quality of data and to increase the usefulness of these data for public health policy purposes, more efforts are required.