Associations Between Health Literacy, Diabetes Knowledge, Self-Care Behaviors, and Glycemic Control in a Low Income Population with Type 2 Diabetes

Objective: This study assessed associations among health literacy, diabetes knowledge, self-care, and glycemic control in a low income, predominately minority population with type 2 diabetes. Methods: One hundred twenty-five adults with diabetes were recruited from a primary care clinic. Subjects completed validated surveys to measure health literacy, diabetes knowledge, and self-care (medication adherence, diet, exercise, blood sugar testing, and foot care). Hemoglobin A1c values were extracted from the medical record. Spearman's correlation and multiple linear regression were used to assess the relationship among health literacy, diabetes knowledge, self-care, and glycemic control controlling for covariates. Results: Cronbach's alpha was 0.95 for the Revised Rapid Estimate of Adult Literacy in Medicine. The majority of the sample was < 65 years old (50.7%), female (72.5%), and African American (71.4%), had less than a high school education (68.2%) and a household income <$15,000 (64.2%), and reported their health status as worse than last year (73.9%). In adjusted models that examined the associations among health literacy, diabetes knowledge, medication adherence, and self-care, health literacy was only significantly associated with diabetes knowledge (beta = 0.55; 95% confidence interval [CI] 0.29, 0.82). In the final adjusted model for independent factors associated with glycemic control, both diabetes knowledge (beta = 0.12; 95% CI 0.01, 0.23) and perceived health status (beta = 1.14; 95% CI 0.13, 2.16) were significantly associated with glycemic control, whereas health literacy was not associated with glycemic control (beta = -0.03; 95% CI -0.19, 0.13). Conclusions: Diabetes knowledge and perceived health status are the most important factors associated with glycemic control in this population. Health literacy appears to exert its influence through diabetes knowledge and is not directly related to self-care or medication adherence.