Diabetes in tropical Africa: a prospective study, 1981-7. II. Course and prognosis

Abstract

Objective: To determine the clinical course of diabetes mellitus in tropical Africa.

Design: Continuing care and follow up until 31 March 1989 of all newly diagnosed diabetic patients registered at one hospital between 1 June 1981 and 31 May 1987.

Setting: Muhimbili Medical Centre, Dar es Salaam, Tanzania.

Subjects: 1250 Newly diagnosed diabetic patients seen over a six year period. 272 (21.8%) Had diabetes requiring insulin, 825 (66.0%) diabetes not requiring insulin, and 153 (12.2%) diabetes of uncertain type.

Main outcome measures: Survival rates during each year of follow up.

Results: 205 (16.4%) Patients were known to have died, 126 (61.5%) in hospital and 79 (38.5%) in the community. At least a further 71 patients were likely to have died. The five year survival rates (95% confidence intervals) for patients with diabetes requiring and not requiring insulin were 71% (62% to 80%) and 84% (80% to 89%) respectively for known deaths and 60% (51% to 69%) and 82% (77% to 86%) respectively for known plus probable deaths. 49 (3.9%) Patients died at the time of presentation. Severe diabetic ketoacidosis and infection were responsible for most deaths in patients with diabetes requiring insulin. Infection was responsible for 24% of deaths in patients with diabetes not requiring insulin and was the main cause of death in the group with uncertain type of diabetes. Cardiovascular and renal causes were responsible for 24% of hospital deaths of patients with diabetes not requiring insulin. Diabetes requiring insulin, young age, and ketonuria at presentation were associated with a significantly worse five year survival on multivariate analysis. On univariate analysis underweight, female sex, low educational background, and manual occupations were additional factors with a worse prognosis.

Conclusion: Diabetes in sub-Saharan Africa is, in many patients, a serious disease with a poor prognosis. Most deaths, however, are due to preventable causes. More effort is therefore required to increase public awareness of diabetes and to improve patient detection, management, and follow up.