The relationship between positive affect and adherence to treatment regimens: A meta-analysis

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Aims/hypothesis:Medication adherence is a growing public health concern that affects therapeutic outcomes and influences morbidity and mortality, but the role of positive affect in improving patient adherence to medication has not been fully explored. This meta-analysis therefore aimed to examine the association between positive affect and medication adherence. Methods: A systematic literature search was conducted for peer-reviewed studies published in the English language from January 2000 to June 2021 that examined the association between positive affect and medication adherence. The following electronic databases were systematically searched: PubMed, Cochrane Library, Science Direct, Google Scholar, CINAHL and PsycINFO. The search was carried out with no restrictions on study design, medical condition or patient demographics, including age, gender and race/ethnicity. Original studies that reported the relationship between positive affect and medication adherence were included if they met the following inclusion criteria: (1) included subjects of age ≥ 18 years; (2) reported results from properly validated measures of medication adherence, such as self-reported questionnaires, therapeutic drug monitoring and pill counting; and (3) considered positive affect before or while patients were taking medication. The Newcastle–Ottawa Scale was used to assess the methodological quality of the included articles. Statistical analysis was performed with version 5.4 of the Review Manager (RevMan) software, using the random-effect model. Results: Of the 71 identified studies, 5 observational studies met the inclusion criteria and displayed at least moderate methodological quality. The studies included 1,906 participants in total, with sample sizes ranging from 90 to 1,022 participants and mean participant ages of 38 to 66.8 years. The overall effect sizes indicated statistically significant positive associations between medication adherence and high positive affect; the pooled odds ratio was 1.47 (95%, CI 1.13–1.92, Z = 2.87, p = 0.004) with high observed heterogeneity of effect (I2 = 78%, Q statistic p = 0.0010). Subgroup analysis based on the instrument used to measure positive affect and the reported use of illicit drugs showed a positive association between positive affect and medication adherence. Conclusion: this meta-analysis found that positive affect was associated with improved medication adherence.