Social capital and cost-related medication nonadherence (CRN): A retrospective longitudinal cohort study using the Health and Retirement Study data, 2006-2016.

Prescription drug spending and other financial factors (e.g., out-of-pocket costs) partially explain variation in cost-related medication nonadherence (CRN). Indicators of social capital such as neighborhood factors and social support may influence the health and well-being of older adults as they may rely on community resources and support from family and peers to manage conditions. Previous research on the relationship of social capital and CRN has limited evidence and contradictory findings. Hence, our objective is to assess the relationship of social capital indicators (neighborhood social cohesion, neighborhood physical disorder, positive social support, and negative social support) and CRN using a longitudinal design, 2006 to 2016, in a nationally representative sample of older adults in the United States (US). The Health and Retirement Study is a prospective panel study of US adults aged ≥ 50 years evaluated every two years. Data was pooled to create three waves and fitted using Generalized Estimating Equation modelling adjusting for both baseline and timevarying covariates (age, sex, education, race, total household income, and perceived health status). The three waves consisted of 11,791, 12,336, and 9,491 participants. Higher levels of neighborhood social cohesion and positive social support were related with lower CRN (OR 0.92, 95% CI 0.88-0.95 and OR 0.77, 95% CI 0.70-0.84, p<0.01). In contrast, higher levels of neighborhood physical disorder and negative social support were related to higher CRN (OR 1.07, 95% CI 1.03-1.11 and OR 1.46, 95% CI 1.32-1.62, p<0.01). Interventions targeting social capital are needed, reinforcing positive social support and neighborhood social cohesion and diminishing neighborhood physical disorder and negative social support for older adults.