Health Literacy and Hospital Length of Stay: An Inpatient Cohort Study

BACKGROUND: Associations between low health literacy (HL) and adverse health outcomes have been well documented in the outpatient setting; however, few studies have examined associations between low HL and in-hospital outcomes. OBJECTIVE: To compare hospital length of stay (LOS) among patients with low HL and those with adequate HL. DESIGN: Hospital-based cohort study. SETTING: Academic urban tertiary-care hospital. PATIENTS: Hospitalized general medicine patients. MEASUREMENTS: We measured HL using the Brief Health Literacy Screen. Severity of illness and LOS were obtained from administrative data. Multivariable linear regression controlling for illness severity and sociodemographic variables was employed to measure the association between HL and LOS. RESULTS: Among 5540 participants, 20% (1104/5540) had low HL. Participants with low HL had a longer average LOS (6.0 vs 5.4 days, P < 0.001). Low HL was associated with an 11.1% longer LOS (95% confidence interval [CI], 6.1%-16.1%; P < 0.001) in multivariate analysis. This effect was significantly modified by gender (P = 0.02). Low HL was associated with a 17.8% longer LOS among men (95% CI, 10.0%-25.7%; P < 0.001), but only a 7.7% longer LOS among women (95% CI, 1.9%-13.5%; P = 0.009). CONCLUSIONS: In this single-center cohort study, low HL was associated with a longer hospital LOS. The findings suggest that the adverse effects of low HL may extend into the inpatient setting, indicating that targeted interventions may be needed for patients with low HL. Further work is needed to explore these negative consequences and potential mitigating factors. Published online first September 20, 2017. (c) 2017 Society of Hospital Medicine