Mortality and Predictors of Mortality in a Cohort of Brazilian Type 2 Diabetic Patients

Abstract

OBJECTIVE—To investigate mortality rates and predictors of mortality in Brazilian type 2 diabetic patients.

RESEARCH DESIGN AND METHODS—A prospective follow-up study was carried out with 471 type 2 diabetic outpatients. Primary end points were all-cause, diabetes-related, and cardiovascular deaths. Excess mortality in this cohort was evaluated by calculating standardized mortality ratios (SMRs) in relation to those of the Rio de Janeiro population. Predictors of mortality were assessed by Kaplan-Meier survival curves and by uni- and multivariate Cox survival analyses.

RESULTS—During a median follow-up of 57 months (range 2–84 months), 121 (25.7%) patients died, 91 (75.2%) from diabetes-related causes and 44 (36.4%) from cardiovascular diseases. After adjusting for age and sex, the all-cause SMR was 3.36 (95% confidence interval [CI] 2.81–4.02) and the cardiovascular SMR was 3.28 (CI 2.44–4.41). In the Cox multivariate analysis, the predictors of mortality were older age, increased 24-h proteinuria, preexisting vascular disease, presence of frequent ventricular premature contractions and prolonged maximum heart rate−corrected QT interval on baseline electrocardiogram, and decreased serum HDL cholesterol. The use of β-blockers was a protective factor. In Kaplan-Meier curves, these variables were capable of distinguishing subgroups of patients with significantly different prognoses.

CONCLUSIONS—Brazilian type 2 diabetic patients had a more than threefold excess mortality than the general population, largely because of increased cardiovascular mortality risk. Several clinical, laboratory, and electrocardiographic predictors of mortality were identified that could possibly be modified to decrease the mortality burden of type 2 diabetes in Brazil.