Are Clinical Outcomes Associated With Medication Regimen Complexity? A Systematic Review and Meta-analysis

Background: Current evidence of the influence of the medication regimen complexity (MRC) on the patients' clinical outcomes are not conclusive. Objective: To systematically and analytically assess the association between MRC measured by the Medication Regimen Complexity Index (MRCI) and clinical outcomes. Methods: A search was carried out in the databases Cochrane Library, LILACS, PubMed, Scopus, EMBASE, Open Thesis, and Web of Science to identify studies evaluating the association between MRC and clinical outcomes that were published from January 1, 2004, to April 2, 2018. The search terms included outcome assessment, drug therapy, and medication regimen complexity index and their synonyms in different combinations for case-control and cohort studies that used the MRCI to measure MRC and related the MRCI with clinical outcomes. Odds ratios (ORs), hazard ratios (HRs), and mean differences (WMDs) were calculated, and heterogeneity was assessed using the I-2 test. Results: A total of 12 studies met the eligibility criteria. The meta-analysis showed that MRC is associated with the following clinical outcomes: hospitalization (HR = 1.20; 95% CI = 1.14 to 1.27;I-2 = 0%) in cohort studies, hospital readmissions (WMD = 7.72; 95% CI = 1.19 to 14.25; I-2 = 84%) in case-control studies, and medication nonadherence (adjusted OR = 1.05; 95% CI = 1.02 to 1.07; I-2 = 0%) in cohort studies. Conclusion and Relevance: This systematic review and meta-analysis gathered relevant scientific evidence and quantified the combined estimates to show the association of MRC with clinical outcomes: hospitalization, hospital readmission, and medication adherence.