Health literacy and therapeutic adherence: a network and mediation analysis in dyslipidemic outpatients

To evaluate the impact of health literacy on medication adherence of hyperlipidemic outpatients, considering age, gender, perceived health, adverse drug reaction and lipid-lowering treatment. To examine the impact of a modifiable factor-health literacy (HL)-on medication adherence (MA), a cross-sectional observational study was conducted in outpatient lipid clinic (January to June 2025). The exposure of interest was HL, assessed using the Brief Health Literacy Screening Items scale. The primary outcome was MA, measured with the Morisky Medication Adherence Scale. 621completed questionnaires were analysed (age 61.2 ± 13.8 years; male 58.1%). Patients had 8 [2-15] years of lipid lowering therapy, their perceived well-being score was 75.8 ± 15.8 while 40.6% reported side effects due to hypolipidemic medications. Subjects with adequate adherence were older (p = 0.030) and showed a higher level of HL (p < 0.001) while patients with adequate literacy showed a higher level of medication adherence (p < 0.001), reported a greater perceived well-being (p = 0.003) and a lower incidence of side effects (p = 0.003). The network analysis revealed that unintentional MA is directly correlated with age (R = 0.141; p < 0.001) and intentional MA (R = 0.362; p < 0.001). Intentional MA is directly correlated with health numerical literacy (R = 0.227; p < 0.001) and inversely correlated with adverse drug reactions (rho = - 0.143; p < 0.001). The parallel mediation model was built showing the indirect effect of age on MA, mediated by HL (indirect effect₁ = - 0.033, 95% CI - 0.060 to - 0.008). Combining the findings from both the network and mediation analyses revealed that HL mediates the relationship between patients' age and MA, with numerical literacy playing a central role. These insights could potentially inform the development of effective health policies.No part of the submitted work has been published or is under consideration for publication elsewhere.