Background: A target of an HbA1c <7% is frequently the cornerstone of clinical guidelines for the care of diabetes globally. Yet, nationally representative NHANES surveys indicate that only 50 to 60% of those with diabetes meet this target. Our aim was to evaluate glucose control when assessed by HbA1c in a national sample of Brazilian adults with diabetes.
Methods: A sub-sample of adults (18 years or older) of the representative Brazilian National Health Survey (2014-2015) was randomly selected for the collection of biological samples. Of these, 8952 (52%) individuals provided samples, and 8541 (50%) have HbA1c results. HbA1c was measured at a NDPG-certified central laboratory. Diabetes was defined by self-report of a physician diagnosis. Given the complex sampling used to select participants and the response rate obtained, we used the rake method of post-stratification survey weights, calculated according to sex, age, and education, to estimate national rates.
Results: Among the 8541 adults, 573 (5.87%; 95% CI: 5.41%-6.33%) reported having received a previous diagnosis of diabetes outside of pregnancy. Of these, only 55.2% (51.1%-59.4%) had HbA1c less than 7%, and 69.5% (65.7%-73.4%) less than the more flexible HbA1c target of 8%. On the other hand, 19.8% (16.5%-23.1%) had HbA1c ≥9.0%, indicating very poor glucose control. Though small sample size limited statistical testing, we found no differences across socio-demographic characteristics except for educational achievement, those of lesser education more frequently presenting worse glucose control (p=0.004).
Conclusion: Our results, showing a glucose control similar to that observed in representative U.S. surveys, highlight the large fraction of cases with very poor control. New strategies are needed to improve glucose control in the entire population of persons living with diabetes.
R.C.P. dos Reis: None. B.B. Duncan: Research Support; Self; Eli Lilly and Company. Research Support; Spouse/Partner; Eli Lilly and Company. M.I. Schmidt: Research Support; Self; Eli Lilly and Company. Research Support; Spouse/Partner; Eli Lilly and Company.