Context: Little is known about the effects of low health literacy among patients with heart failure, a condition that requires self-management and frequent interactions with the health care system.
Objective: To evaluate the association between low health literacy and all-cause mortality and hospitalization among outpatients with heart failure.
Design, setting, and patients: Retrospective cohort study conducted at Kaiser Permanente Colorado, an integrated managed care organization. Outpatients with heart failure were identified between January 2001 and May 2008, were surveyed by mail, and underwent follow-up for a median of 1.2 years. Health literacy was assessed using 3 established screening questions and categorized as adequate or low. Responders were excluded if they did not complete at least 1 health literacy question or if they did not have at least 1 year of enrollment prior to the survey date.
Main outcome measures: All-cause mortality and all-cause hospitalization.
Results: Of the 2156 patients surveyed, 1547 responded (72% response rate). Of 1494 included responders, 262 (17.5%) had low health literacy. Patients with low health literacy were older, of lower socioeconomic status, less likely to have at least a high school education, and had higher rates of coexisting illnesses. In multivariable Cox regression, low health literacy was independently associated with higher mortality (unadjusted rate, 17.6% vs 6.3%; adjusted hazard ratio, 1.97 [95% confidence interval, 1.3-2.97]; P = .001) but not hospitalization (unadjusted rate, 30.5% vs 23.2%; adjusted hazard ratio, 1.05 [95% confidence interval, 0.8-1.37]; P = .73).
Conclusion: Among patients with heart failure in an integrated managed care organization, low health literacy was significantly associated with higher all-cause mortality.