The clinical characteristics at diagnosis of type 2 diabetes in a multi-ethnic population: the South London Diabetes cohort (SOUL-D)

This study aimed to investigate the clinical features of newly diagnosed type 2 diabetes in an urban multi-ethnic cohort. A population-based cross-sectional design was used. People diagnosed with type 2 diabetes in the preceding 6 months were recruited from primary care practices in three adjacent inner-city boroughs of South London, serving a population in which 20% of residents are of black African or Caribbean ethnicity. Sociodemographic and biomedical data were collected by standardised clinical assessment and from medical records. Multiple logistic regression methods were used to report associations between ethnicity and diabetes-complication status. From 96 general practices, 1,506 patients were recruited. Their mean age was 55.6 (+/- 11.07) years, 55% were men, 60% were asymptomatic at diagnosis and 51%, 38% and 11% were of white, black and South Asian/other ethnicity, respectively. Compared with white participants, black and South Asian/other participants were: younger (mean age 58.9 [+/- 10.09], 52.4 [+/- 11.19] and 51.5 [+/- 10.42] years, respectively; p < 0.0001); less likely to have neuropathy (10.1%, 3.6% and 4.4%; p < 0.0001) or report coronary artery disease (12.7%, 4.8% and 7.3%; p < 0.0001). In logistic regression, compared with white participants, black participants had lower levels of macrovascular complications (OR 0.52, 95% CI 0.32, 0.84; p = 0.01). Male sex was independently associated with microvascular disease (OR 1.69, 95% CI 1.26, 2.28; p < 0.0001). The prevalence of complications at time of diagnosis was lower than expected, especially in black and South Asian/other ethnic groups. However, in multi-ethnic inner-city populations, onset of type 2 diabetes occurred almost 10 years earlier in non-white populations than in white participants, predicating a prolonged morbidity.