Background: Health literacy (HL) is an important concept for patient education and disease management with heart failure (HF). However, research on HL has predominantly focused on functional HL (ability to read and write). The World Health Organization advocates evaluating comprehensive HL, including the ability to access information (communicative HL) and critically evaluate that information (critical HL).

Objective: We developed an instrument for measuring functional, communicative, and critical levels of HL in patients with HF.

Methods: We evaluated the reliability and validity of those 3 HL scales in a sample of 191 outpatients with HF (mean [SD] age, 66.9 [13.9] years; 64.9% males). Sociodemographic and clinical characteristics, knowledge of HF, a well as motivation to obtain health information were assessed for each patient through a self-administered questionnaire and review of electronic medical records.

Results: We constructed scale items to reflect directly the comprehensive World Health Organization definition of HL. We identified 3 interpretable factors by exploratory factor analysis. Internal consistency was marginally acceptable for total HL (Cronbach [alpha] = 0.71), functional HL ([alpha] = 0.73), communicative HL ([alpha] = 0.68), and critical HL ([alpha] = 0.69); the interclass correlation coefficients of the functional, communicative, and critical HL subscales were 0.882, 0.898, and 0.882, respectively. Low functional, communicative, and critical HL was characteristic of older patients, those with lower socioeconomic status, patients living alone, those without a high school education, and patients lacking HF knowledge.

Conclusions: Our new HL scale was demonstrated to be a reliable, valid instrument for measuring functional, communicative, and critical HL in patients with HF. Exploring a patient's HL level, including the ability to access, understand, and use health information as well as the ability to read and write, may provide better understanding of patients' potential barriers to self-care.