Literacy and health outcomes: a cross-sectional study in 1002 adults with diabetes

BACKGROUND: Inconsistent findings reported in the literature contribute to the lack of complete understanding of the association of literacy with health outcomes. We evaluated the association between literacy, physiologic control and diabetes complications among adults with diabetes. METHODS: A cross-sectional study of 1,002 English speaking adults with diabetes, randomly selected from the Vermont Diabetes Information System, a cluster-randomized trial of a diabetes decision support system in a region-wide sample of primary care practices was conducted between July 2003 and March 2005. Literacy was assessed by the Short-Test of Functional Health Literacy in Adults. Outcome measures included glycated hemoglobin, low density lipoprotein, blood pressure and self-reported complications. RESULTS: After adjusting for sociodemographic characteristics, duration of diabetes, diabetes education, depression, alcohol use, and medication use we did not find a significant association between literacy and glycemic control (beta coefficent,+ 0.001; 95% confidence interval [CI], -0.01 to +0.01; P = .88), systolic blood pressure (beta coefficent, +0.08; 95% CI, -0.10 to +0.26; P = .39), diastolic blood pressure (beta coefficent, -0.03; 95% CI, -0.12 to +0.07, P = .59), or low density lipoprotein (beta coefficent, +0.04; 95% CI, -0.27 to +0.36, P = .77. We found no association between literacy and report of diabetes complications. CONCLUSION: These findings suggest that literacy, as measured by the S-TOFHLA, is not associated with glycated hemoglobin, blood pressure, lipid levels or self-reported diabetes complications in a cross-sectional study of older adults with diabetes under relatively good glycemic control. Additional studies to examine the optimal measurement of health literacy and its relationship to health outcomes over time are needed.