Prevalence of diabetes in Brazil over time: a systematic review with meta-analysis

Diabetes is one of the most important epidemic diseases of this century and the number of people with diabetes has more than doubled over the past three decades. Our aim was to estimate the prevalence of diabetes in the adult Brazilian population and analyze the trends for the last three decades through a systematic review with meta-analysis. This review included observational studies published between 1980 and 2015, which were independently identified by two reviewers in five databases. Random effect models were used to estimate the prevalence and trends of diabetes. In total, 50 articles were included in this review. Three different patterns for diabetes diagnosis were identified: self-report (36 studies), fasting glucose (7 studies), and complex diagnosis (fasting glucose, oral glucose tolerance test, and self-report; 7 studies). The prevalence of diabetes was 5.6 % (95 % CI 5.0-6.3; I(2) = 100 %) by self-report, 6.6 % (95 % CI 4.8-8.9; I(2) = 94 %) by fasting glucose, and 11.9 % (95 % CI 7.7-17.8 I(2) = 100 %) by complex diagnosis. In trend analyses, we observed an increase in the prevalence of diabetes over time. The biggest increase was detected in studies using complex diagnosis: 7.4 % (95 % CI 7.1-7.7) in the 1980s to 15.7 % (95 % CI 9.8-24.3) in the 2010s. In conclusion, despite high heterogeneity, this study observed a high prevalence of diabetes in Brazilian adults over time and with a progressive increase in the last 35 years.