OBJECTIVES: This systematic review assessed the relationship between religiosity (R) or spirituality (S) and medication adherence among patients with CVDs.

METHODS: This systematic review was conducted in accordance with the Preferred Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Seven electronic databases (PubMed, MEDLINE, EMBASE, Scopus, Cochrane Central Library, ProQuest Thesis and dissertation, and Google Scholar) were searched with no restriction on year of publication. All searches were completed between August and September 2018. In addition, a manual search of the bibliographies of retrieved articles was conducted. The Crowe Critical Appraisal Tool was used to evaluate the quality of all eligible studies. Due to the heterogeneity observed across the included studies, data synthesis was undertaken using a narrative approach.

RESULTS: Nine included studies were published between 2006 and 2018. The quality of the included studies as assessed by CCAT ranged from 75% to 95%. The agreement between the two reviewers was high (Cohen’s Kappa = 0.850). Most studies were conducted in the USA and recruited patients with hypertension. Five studies showed a positive relationship between R/S and medication adherence, with higher organized religiousness, prayer and spirituality. The other included studies reported a negative or null association.

CONCLUSIONS: There was a paucity of studies concerning the relationship between R/S and medication adherence among patients with CVDs. Some studies have found the relationships between R/S and adherence in patients with hypertension and heart failure.