Mechanisms Linking Low Health Literacy to Homebound Incidence: A Mediation Analysis Through the Development of...

Health literacy is a critical determinant of health, yet its role in functional decline leading to homebound status remains unexplored.

To examine this association and the mediating role of chronic conditions.

A counterfactual approach using single- and multiple-mediator causal models. CPT codes for home or residence services were used as an indication of homebound status.

A longitudinal cohort of 130,195 adults aged 55 to 84 from EHR in a statewide health data system (2016-2025), regardless of payer.

Mediating effects of COPD, heart failure, pulmonary hypertension, respiratory failure, type II diabetes, chronic kidney disease (CKD), and dementia were examined in the association of health literacy scores (1 to 5) and becoming homebound.

Health literacy both directly and indirectly impacted the risk of becoming homebound (n = 427; 0.3%). When all chronic conditions were analyzed jointly, each 1-unit decrease in health literacy score increased the likelihood of becoming homebound by 56% (95% CI: 37%-85%). Of this total effect, 29.9% was mediated by chronic conditions, while the remaining 70.1% represented the direct effect of health literacy unexplained by chronic conditions. Of the 29.9% percentage mediated (PM), respiratory failure (PM 1.2%; CI: 0.2%-2%), stroke (PM 2.6%, CI: 1.2%-3.9%), and dementia (PM 25%, CI: 14.4%-35.7%) had statistically significant share. Separate analyses modeling each mediator identified COPD (PM 5.2%, CI: 2.2%-8.2%), heart failure (PM 0.9%, CI: 0.1%-1.7%), respiratory failure (PM 3.6%, CI: 1.8%-5.4%), stroke (PM 7.9%, CI: 3.6%-12.1%), CKD (PM 2.8%, CI: 1.2%-4.4%), and dementia (PM 37.8%, CI: 23.4%-52.1%) as significant mediators.

Low health literacy increased the risk of becoming homebound. Mediation through chronic conditions was present but limited, with dementia as the strongest mediator. The strong direct effect highlights the importance for health literacy-informed interventions to prevent functional decline and homebound status.