Health literacy and blood glucose among Guyanese emergency department patients without diagnosed diabetes: a cross-sectional study

Background: Low health literacy is associated with worse glycemic control among patients with diabetes; the relationship between health literacy and blood glucose among patients without diagnosed diabetes, particularly in resource-limited settings, is not known. Because emergency department patients are at risk for both low health literacy and undiagnosed diabetes, we examined their relationships among emergency department patients at the Georgetown Public Hospital Corporation in Guyana. Methods: We conducted a cross-sectional study across random time blocks from May to August 2012 among Guyanese emergency department patients without a diagnosis of diabetes. Health literacy was assessed by the Single Item Literacy Screener (SILS, range 1-5); low health literacy was defined as SILS >= 3. We examined the relationships among health literacy, random blood glucose (RBG), and point-of-care glycated hemoglobin (HbA1c). Results: Of the 228 enrolled patients, 125 (54%) were female, median age was 43 years (interquartile range 38 to 53), mean body mass index (BMI) was 25.6 kg/m(2) (standard deviation 6.8 kg/m(2)), and 103 (45.2%) had low health literacy. The receiver operating characteristic area under the curve for RBG to detect elevated HbA1c (>= 48mmol/mol) was 0.94 (95% CI: 0.91-0.97). After adjustment for age, sex, BMI, ethnicity, and education, the odds of having HbA1c >= 48 mmol/mol, consistent with undiagnosed diabetes, rose with decreasing health literacy (OR 2.2, 95% CI 1.2-3.8, p = 0.007, per point decrease in literacy). Conclusion: This pilot study of Guyanese emergency department patients without diagnosed diabetes found that low health literacy was common and was associated with higher HbA1c and random blood glucose.