Diabetes and Cause-Specific Mortality in Mexico City

Background: Most large prospective studies of diabetes and mortality have focused on high-income countries where patients have reasonably good medical care and glycemic control and diabetes less than doubles all-cause mortality. Few have been done in middle-income countries where obesity and diabetes may be common and glycemic control, poor. <br/>Methods: In 1998-2004, a prospective study in Mexico City recruited 50,000 men and 100,000 women aged ≥35 years, recorded previously diagnosed diabetes, stored blood, and tracked 12-year disease-specific mortality through January 1, 2014 (diabetes coded as the underlying cause only for deaths from acute diabetic crises). Mortality rate ratios (RRs, with versus without diabetes) were estimated after excluding people with other chronic diseases. <br/>Results: At recruitment, obesity was common, and diabetes prevalence rose steeply with age (>20% by age 60). Participants with diabetes had poor glycemic control (mean HbA1c 9.0 [SD2.5]); few were taking other risk-reducing medication. Previously diagnosed diabetes was associated with all-cause mortality RRs of 5.4 (95% CI 5.0-6.0) at ages 35-59, 3.1 (2.9-3.3) at ages 60-74 and 1.9 (1.8-2.1) at ages 75-84, accounting for one-third of all deaths at ages 35-74 years; the largest absolute excesses involved renal (RR 20.1 [17.2-23.4]), cardiac (RR 3.7 [3.2-4.2]), and infectious (RR 4.7 [4.0-5.5]) disease, as well as acute diabetic crises (8% of all deaths with diabetes). Marked excesses of stroke and peripheral artery disease, but not cirrhosis, cancer, or COPD were present. <br/>Conclusions: In this study, diabetes was common in overweight individuals from a middle-income country and carried a far worse prognosis than found in similar patients from high-income countries.