Effect of socioeconomic status on mortality among people with type 2 diabetes: a study from the Scottish Diabetes Research Network Epidemiology Group.

Abstract

The study objective was to describe the effect of socioeconomic status (SES) on mortality among people with type 2 diabetes. We used a population-based national electronic diabetes database for 35- to 84-year-olds in Scotland for 2001-2007 linked to mortality records. SES was derived from an area-based measure with Q5 and Q1 representing the most deprived and affluent quintiles, respectively. Poisson regression was used to estimate relative risks (RRs) for mortality among people with type 2 diabetes compared with the population without diabetes stratified by age (35-64 and 65-84 years), sex, duration of diabetes (< 2 and ≥ 2 years), and SES. Complete data were available for 210,994 eligible individuals (99.4%), and there were 33,842 deaths. Absolute mortality from all causes among people with type 2 diabetes increased with increasing age and socioeconomic deprivation and was higher for men than women. RR for mortality associated with type 2 diabetes was highest for women aged 35-64 years in Q1 with diabetes duration < 2 years at 4.83 (95% CI 3.15-7.40) and lowest for men aged 65-84 years in Q5 with diabetes duration ≥ 2 years at 1.13 (1.03-1.24). SES modifies the association between type 2 diabetes and mortality so that RR for mortality is lower among more deprived populations. Age, sex, and duration of diabetes also interact with type 2 diabetes to influence RR of mortality. Differences in prevalence of comorbidities may explain these findings.