Costs and beliefs: Understanding individual- and neighborhood-level correlates of medication nonadherence among Mexican Americans with type 2 diabetes.

Abstract

High rates of medication nonadherence observed in disadvantaged populations are often attributed to socioeconomic factors. Little is known, however, about how a person's neighborhood environment may contribute to nonadherence beyond what can be explained by a lack of individual resources to pay for medications. This study considered the reasons patients reported for deviating from their medication regimens to understand how individual-level and neighborhood-level indicators of socioeconomic status (SES) may each influence adherence behavior. Cross-sectional data were collected between 2006 and 2011 from a sample of Mexican American patients with type 2 diabetes (N = 749) treated at university-affiliated clinics in Southern California. Measures included individual-level SES (years of education, health insurance type, and household income), neighborhood deprivation, and medication nonadherence (for reasons related to cost and reasons related to beliefs about medications). Neighborhood deprivation was assessed using the Neighborhood Socioeconomic Status Index (Dubowitz et al., 2011), a validated aggregate of census tract-level indicators linked to each participant's home address. RESULTS from multilevel logistic regression models revealed that individual-level SES was associated with nonadherence related to cost (annual household income < $20,000 vs. > $40,000, p = .001; Medicare vs. commercial health insurance, p < .001), whereas neighborhood deprivation was associated with nonadherence related to beliefs about medications (p = .011). Findings from this study suggest that an individual's lack of resources may contribute to nonadherence related to cost, whereas elements of the broader social environment may promote nonadherence related to negative beliefs about medications.