Health Literacy, Health Care Utilization, and Direct Cost of Care Among Linguistically Diverse Patients with Type 2 Diabetes Mellitus

BACKGROUND: Low functional health literacy (HL) has been associated with poor self-management of chronic conditions, including type 2 diabetes mellitus (T2DM), an inefficient use of health services, and higher health care costs. Low functional HL and limited English language proficiency both independently predict poor glycemic control among Latino and Chinese immigrants in the United States, and is more common among patients with diabetes with limited HL. OBJECTIVE: This study investigated the relationship between low functional HL, health care utilization, and costs of health care among a cohort of low-income patients with T2DM whose primary language was English, Spanish, or Cantonese (N = 277). METHODS: Patient data were collected from Medicaid administrative health care records as part of a low-income managed care program administered by the San Francisco Health Plan between April 2009 and March 2011. HL was measured with the Brief Questions Screening Tool for Health Literacy, administered via telephone survey. We used negative binomial regression with robust standard errors to estimate the effect of low functional HL on health care utilization, adjusting for demographic, socioeconomic, and health covariates. Results were reported as rate-ratios (RRs). We used two-part regression models to estimate the marginal difference in cost per patient associated with low functional HL. Utilization and cost models were also estimated, stratified by patient language. KEY RESULTS: We observed a nonsignificant association between low functional HL and lower health care utilization, and lower total health care costs (−$1,493.53, 95% confidence interval [CI]: $3,602 to $615). While we observed a nonsignificant trend for low functional HL and lower utilization and total cost among people who speak English and Cantonese, low functional HL was significantly associated with more outpatient visits among patients who spoke Spanish (RR 1.31, 95% CI 1 to 1.72). CONCLUSIONS: The relationship between low functional HL and health care utilization among this linguistically diverse cohort of patients with T2DM varied by patient language. Further research is needed to determine if lower utilization and costs in certain linguistic subgroups is indicative of barriers to access. [Health Literacy Research and Practice. 2017;1(3):e116–e126.] PLAIN LANGUAGE SUMMARY: This study attempts to understand the relationship between health literacy, health care utilization, and costs of health care among an ethnically and linguistically diverse cohort of low-income patients with type 2 diabetes mellitus. We observed differences that could be due to actual differential effects of low HL by language status, or could be explained by unmeasured differences in health-seeking behaviors, access to care, degree of acculturation, or comorbidities.