Health literacy and adherence to treatment in different districts in Chile

The relationship between health literacy and adherence has been described in medical literature, especially for patients with non-communicable diseases (NCDs). However, the relevance that an individual's local context can have has not been considered. This study aimed to examine the association of both concepts at a population level and estimate the correlation between health literacy and adherence to pharmacological treatment in adults from 14 districts in different regions in Chile. A cross-sectional study was carried out in 14 districts from 3 different regions of Chile. Sampling was carried out by volunteers. Three questionnaires were applied: sociodemographic; Morisky-Green-Levine (MMAS-4) and the Short Assessment of Health Literacy for Spanish Adults test (SAHLSA-50). Data were analyzed descriptively, and a Multilevel Poisson Regression model was fitted to evaluate the relationship between health literacy and adherence to pharmacological treatment, considering the districts as fixed intercepts. A total of 1,336 persons were surveyed; 811 self-reported as having at least 1 NCD. A 83.4% had adequate literacy and 37.1% were adherent to pharmacological treatment, regardless of their health literacy. A 3.6% (variance partition coefficient = 0.036) correlation of adherence to treatment was observed in respondents living in the same district. Those with inadequate health literacy had a 12% greater prevalence of being non-adherent (prevalence ratio 1.12; IC 95% 0.87 - 1.47) when adjusting for individual variables. These results could suggest that the individual's local context does not influence the relation of functional health literacy and adherence to pharmacological treatment in populations with basic and intermediate levels of education. We suggest further studies in this matter.