Aims: To assess the long-term (20 years) mortality, with causes of death, in a cohort of Type 1 diabetic patients resident in Soweto, South Africa.
Methods: A cohort of Type 1 diabetic patients attending the Diabetic Clinic of Baragwanath Hospital, Soweto were studied in 1982. They were followed over the subsequent 20 years, the final investigation being in 2002. Numbers dying during the period were recorded, as well as year of death and cause. The complication status of survivors was also assessed.
Results: Of the original cohort of 88 Type 1 patients, 21 died during the follow-up period. There were 39 lost to follow-up, giving a crude 20 years' mortality of 43%. Kaplan-Meier analysis showed mortality hazard of 33%. Of those dying, most (9/21) were as a result of renal failure. Other causes were hypoglycaemia (6), ketoacidosis (2), infection (2) and undetermined (2). Of the survivors, comparing data at 0 and 20 years' follow-up, there was a significant increase in rates of retinopathy (P<0.02) and hypertension (P<0.005), but not of other complications.
Conclusions: This is the first long-term outcome study of Type 1 diabetes in sub-Saharan Africa. Although the mortality was substantial, it is similar to equivalent studies of United States (US) Afro-Americans with Type 1 diabetes. The major cause of death was renal failure related to diabetic nephropathy, and reflects lack of adequate facilities for renal replacement therapy. Despite the deprivation, poverty, political upheaval and recent AIDS epidemic in Soweto, Type 1 diabetes carries a reasonable long-term prognosis, and survivors are generally free of debilitating complications.