Cost-related nonadherence can be explained by a general nonadherence framework.

BACKGROUND

A conceptual framework has been developed specifically for cost-related nonadherence (CRNA) that differs from models proposed for general medication nonadherence.

OBJECTIVE

This study aimed to demonstrate that CRNA studies are best explained by a conceptual framework developed for general medication nonadherence.

METHODS

A systematic literature review was conducted using MEDLINE via PubMed, CINAHL, ScienceDirect, and Google Scholar databases from 2008 to 2020. Articles were considered for inclusion if they were research studies, used a self-reported measure for CRNA, and provided self-reported data on factors associated with CRNA.

RESULTS

A total of 58 studies were identified and included in the review. Factors related to financial pressures were consistently associated with CRNA corresponding to conceptual frameworks for both CRNA and general medication nonadherence. However, noneconomic factors, classified as moderators in the CRNA framework (i.e., patient factors, disease factors, clinician factors), consistently demonstrated independent effects, often with similar strength of association compared with economic factors. Overall, the pattern of risk factors identified in CRNA studies was consistent with general nonadherence except for indicators of poor health. Poor health was often associated with an increased risk of CRNA, whereas the inverse association is generally observed in general nonadherence studies (i.e., nonadherence higher in primary prevention vs. secondary prevention). However, the apparent disagreement was likely caused by the general population studied rather than a unique causal pathway for CRNA.

CONCLUSION

Financial difficulties are extremely common among people who take prescription medications. However, current evidence is insufficient to support a conceptual framework that differs from general medication nonadherence.