Geographic and social factors are related to increased morbidity and mortality rates in diabetic patients.

AIMS: To investigate differences in metabolic control, access to healthcare, clinical outcomes and mortality rates in people from different cultural and ethnic backgrounds living in different geographical areas within central London.
METHODS: Out of a cohort of 610 patients living within the Greater London boundary and having a first visit to St Thomas' hospital in 1982-1985, 332 patients (54%) were reviewed in 1995, 186 patients (30%) died between 1982 and 1995 and 92 patients (16%) were lost to follow-up. The patients' corresponding 'electoral wards' were ascertained in relation to postcodes of residence (Mapinfo). Each electoral ward has a Jarman 'Underprivileged Area Score' (UPA) so that patients can be clustered into prosperous, intermediate or deprived areas.
RESULTS: Patients living in deprived areas (n = 181) were older (61.3 years (95% confidence interval (CI) 59.5-63.1) vs. 58.6 years (95% CI 55.1-62.1), P = 0.01) and had a higher body mass index (29.2 kg/m2 (95% CI 28.4-30.0) vs. 25.7 kg/m2 (95% CI 24.1-27.2), P = 0.003) and worse glycaemic control (HbA1 (%), 10.5 (95% CI 10.1-10.9) vs. 9.1 (95% CI 8.2-10.0), P = 0.003) than patients in prosperous areas (n = 59). Patients in deprived areas were more likely to be Caucasian (P < 0.005), and were less likely to be insulin-treated (P = 0.004). Smoking was more prevalent in deprived areas (P = 0.02). The prevalence of microvascular complications was related to geographical location and the age-sex adjusted mortality rate was significantly higher in deprived than prosperous areas (2.6 vs. 1.91 per 100 person-years).
CONCLUSIONS: Environmental factors affect diabetes outcomes; increased morbidity and mortality rates in diabetic patients are related to socio-economic and ethnic status.