Diabetes mellitus and health service utilization: a case-control study of outpatient visits 8 years after diagnosis.

All incident cases of diabetes mellitus in the age group 15 to 34 years have been prospectively registered in Sweden since January 1983. To analyse the utilization of outpatient services 8 years after disease onset, we selected the cases registered in 1983 and two controls per case from the general population, matched by age, gender, and county of residence. In 1991, retrospective data about utilization patterns during a 3-month period were collected via a mailed questionnaire, returned by 317 (72%) patients with diabetes and 586 (68%) controls. Seventy-four percent of the cases and 19% of the controls reported at least one visit to a hospital outpatient clinic, including accident and emergency departments. The odds ratio for one visit was 14 (95% CI 9.6-20), for two visits 11 (95% CI 7.0-18), and for three or more visits 8.9 (95% CI 5.6-14). Even when specialized diabetes clinics were excluded from the analysis, the cases had higher odds for visits to internal medicine clinics, to ophthalmology clinics, and to gynaecology clinics, but not for visits to surgical clinics or to accident and emergency departments. Of non-hospital outpatient services, only visits to nurse practitioners were reported by a higher percentage of diabetic responders. Twenty-seven percent of patients with diabetes, as compared to 9% of the controls, had visited both hospital and non-hospital outpatient offices. Females were overrepresented among diabetic high-consumers. The results indicate that most young to middle-aged Swedish persons with diabetes are monitored at hospital outpatient offices, but considerable overlap exists between hospital and non-hospital outpatient services. Further research is needed into the determinants of utilization patterns in diabetes, such as gender.