Influence of Patient Literacy on the Effectiveness of a Primary Care–Based Diabetes Disease Management Program

CONTEXT: Low literacy is an important barrier for patients with diabetes, but interventions to address low literacy have not been well examined. OBJECTIVE: To examine the role of literacy on the effectiveness of a comprehensive disease management program for patients with diabetes. DESIGN, SETTING, AND PARTICIPANTS: Analysis of the influence of literacy on glycemic control and systolic blood pressure using data from a randomized controlled trial (conducted from February 2001 through April 2003) of a comprehensive diabetes management program. Participants were 217 patients aged 18 years or older with type 2 diabetes and poor glycemic control (glycosylated hemoglobin HbA1c levels > or =8.0%) and presenting to a US academic general internal medicine practice. INTERVENTIONS: All communication to patients was individualized and delivered to enhance comprehension among patients with low literacy. Intervention patients received intensive disease management from a multidisciplinary team. Control patients received an initial management session and continued with usual care. MAIN OUTCOME MEASURES: Achievement of goal HbA1c levels and systolic blood pressure at 12-month follow-up for control and intervention patients stratified by literacy status. RESULTS: Complete 12-month data were available for 193 patients (89%). Among patients with low literacy, intervention patients were more likely than control patients to achieve goal HbA1c levels (< or =7.0%) (42% vs 15%, respectively; adjusted odds ratio OR, 4.6; 95% confidence interval CI, 1.3 to 17.2; P = .02). Patients with higher literacy had similar odds of achieving goal HbA1c levels regardless of intervention status (24% vs 23%; adjusted OR, 1.0; 95% CI, 0.4 to 2.5; P = .98). Improvements in systolic blood pressure were similar by literacy status. CONCLUSIONS: Literacy may be an important factor for predicting who will benefit from an intervention for diabetes management. A diabetes disease management program that addresses literacy may be particularly beneficial for patients with low literacy, and increasing access to such a program could help reduce health disparities.