Microvascular complications in South African patients with long duration diabetes mellitus
Objective. To determine the prevalence of microvascular complications in South African black and Indian patients with long-duration diabetes mellitus (DM).
Design. A retrospective analysis was undertaken of clinical records of 219 DM patients (132 black, 87 Indian) with longduration DM (over 10 years) attending a diabetes clinic in Durban. Data recorded on each subject included demographic details (age, gender, ethnic group, type of diabetes, age of onset and duration of diabetes), presence of retinopathy, markers of nephropathy and biochemical variables. The prevalence of complications and the clinical and biochemical parameters were evaluated for type 1 and type 2 diabetes and for each ethnic group.
Results. Of the 219 patients, 47 had type 1 DM (36 blacks, 11 Indians) and 172 were classilied a type 2 DM (96 blacks, 76 Indians). The mean age of onset of DM was later in blacks than Indians, both for type 1 (P < 0.05) and type 2 DM (P < 0.01). In patient with type 1 DM, the prevalence of retinopathy was 53.2% (blacks 55.6%, lndians 45.5%}, persistent proteinuria was found in 23.4% (blacks 25%, Indians 1 .2%) and hypertension in 34%. o ethnic difference was found except for the prevalence of hypertension which was higher in blacks than Indians (41.7% v. 9.1%, P < 0.5). Onset of retinopathy from time of diabetes diagnosis occurred earlier in blacks than Indians (13.0 ± 4.6 yr v. 18.0 ± 4.6 yrs, P < 0.05). For the type 2 DM group, retinopathy was found in 64.5% (black v. Indian 68.8 v. 59.2%) and per istent proteinuria in 25% (black v. Indian 30.2 v. 1 .4%). Hypertention was observed in 68% and wa more prevalent in blacks (84.4 v. 47.4%, P < 0.01} There was an earlier onset of retinopathy (P < 0.05) and hypertension (P < 0.01) from time of diabetes diagno is in blacks than Indians. In the type 1 DM group retinopathy was associated with a significantly longer duration of diabetes (P < 0.05) and higher glycated haemoglobin (HbA1) (P < 0.05). For type 2 DM subjects there was a significant association between retinopathy and longer duration of diabetes (P < 0.05) and higher systolic blood pressure (P < 0.05).
Conclusion. This study has shovm that there is a high prevalence of microvascular complications in South African patients with long-duration diabetes mellitus.