Lower health literacy is associated with poorer health status and outcomes in chronic obstructive pulmonary disease

Abstract

Background: Limited health literacy is associated with poor outcomes in many chronic diseases, but little is known about health literacy in chronic obstructive pulmonary disease (COPD).

Objective: To examine the associations between health literacy and both outcomes and health status in COPD. PARTICIPANTS, DESIGN AND MAIN MEASURES: Structured interviews were administered to 277 subjects with self-report of physician-diagnosed COPD, recruited through US random-digit telephone dialing. Health literacy was measured with a validated three-item battery. Multivariable linear regression, controlling for sociodemographics including income and education, determined the cross-sectional associations between health literacy and COPD-related health status: COPD Severity Score, COPD Helplessness Index, and Airways Questionnaire-20R [measuring respiratory-specific health-related quality of life (HRQoL)]. Multivariable logistic regression estimated associations between health literacy and COPD-related hospitalizations and emergency department (ED) visits.

Key results: Taking socioeconomic status into account, poorer health literacy (lowest tertile compared to highest tertile) was associated with: worse COPD severity (+2.3 points; 95 % CI 0.3-4.4); greater COPD helplessness (+3.7 points; 95 % CI 1.6-5.8); and worse respiratory-specific HRQoL (+3.5 points; 95 % CI 1.8-4.9). Poorer health literacy, also controlling for the same covariates, was associated with higher likelihood of COPD-related hospitalizations (OR = 6.6; 95 % CI 1.3-33) and COPD-related ED visits (OR = 4.7; 95 % CI 1.5-15). Analyses for trend across health literacy tertiles were statistically significant (p < 0.05) for all above outcomes.

Conclusions: Independent of socioeconomic status, poor health literacy is associated with greater COPD severity, greater COPD helplessness, worse respiratory-specific HRQoL, and higher odds of COPD-related emergency health-care utilization. These results underscore that COPD patients with poor health literacy may be at particular risk for poor health-related outcomes.

Figure 1.

Median health literacy scores by educational attainment and annual household income. p < 0.001 for difference by category, for both education and income (Kruskal-Wallis test). *Refused to provide income (N = 14; 5 % of subjects).

Figure 2.

Median health literacy scores associated with COPD-related emergency utilization. p < 0.01 for difference, for both ED visits and hospitalizations (Kruskal-Wallis test).