Sources of disparity in the spectrum of diabetes mellitus at incidence and prevalence.

In a population-based study in Rochester, Minnesota, the clinical characteristics of 1135 patients newly diagnosed with diabetes (1945-69) were compared with those of 810 residents with diabetes mellitus on prevalence day (1 January 1970). The prevalence patients were older and the male: female ratio was reduced from that seen among incidence cases. The prevalence patients were more likely to be on oral agents, had lower fasting blood glucose levels, were less likely to be symptomatic, but were more likely to have macrovascular and microvascular complications. These differences seemed to come about as a result of variation in survival rates among patients with specific characteristics, differential migration of certain groups of patients, and changes in the status of individuals.