Mortality rates due to diabetes in a selected Urban South Indian population - the Chennai Urban Population Study [CUPS - 16]

Abstract

Objective: The aim of this study was to determine the mortality rate in diabetic and non-diabetic subjects in urban south India. Methods: The Chennai Urban Population Study is an ongoing epidemiological study in Chennai [formerly Madras, in south India]. All individuals . 20 years of age living in two residential colonies in Chennai were invited to participate in the study. Of the total 1399 eligible subjects, 1262 individuals responded [90.2%] at baseline, and of these, 1140 individuals [90.3%] could be followed annually from 1997 to 2003-04. Mortality rates and causes of death were the main outcome measures. Results: The median follow up period was six years. The overall mortality rate was higher in diabetic compared to non-diabetic subjects [18.9 vs.5.3 per 1000 person-years, p=0.004]. Mortality due to cardiovascular [diabetic subjects, 52.9%; non-diabetic subjects, 24.2%,p=0.042] and renal causes[diabetic subjects, 23.5%; non-diabetic subjects, 6.1%,p=0.072] was higher among diabetic subjects whereas mortality due to gastrointestinal [12.1%], respiratory [9.1%], lifestyle related [6.1%] and unnatural causes [18.2%] were observed only among non-diabetic subjects. Hazards ratio [HR] for all cause mortality for diabetes was 3.6, [95% Confidence Interval [CI]: 2.02-6.53, p<0.001] and this remained significant even after adjusting for age [HR:1.9, 95% CI:1.04-3.45, p=0.038]. Light grade physical activity was associated with higher mortality rate [p=0.008], but the significance disappeared when adjusted for age. Smoking was also associated with increased mortality. Conclusions: In urban India, mortality rates are two fold higher in people with diabetes compared to nondiabetic subjects. Cardiovascular and renal diseases are the commonest causes of death among diabetic subjects.