BACKGROUND: A medication review can be defined as a structured evaluation of a patient's medication conducted by healthcare professionals with the aim of optimising medication use and improving health outcomes. Optimising medication therapy though medication reviews may benefit hospitalised patients.

OBJECTIVES: We examined the effects of medication review interventions in hospitalised adult patients compared to standard care or to other types of medication reviews on all-cause mortality, hospital readmissions, emergency department contacts and health-related quality of life.

SEARCH METHODS: In this Cochrane Review update, we searched for new published and unpublished trials using the following electronic databases from 1 January 2014 to 17 January 2022 without language restrictions: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP). To identify additional trials, we searched the reference lists of included trials and other publications by lead trial authors, and contacted experts.

SELECTION CRITERIA: We included randomised trials of medication reviews delivered by healthcare professionals for hospitalised adult patients. We excluded trials including outpatients and paediatric patients.

DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, extracted data and assessed risk of bias. We contacted trial authors for data clarification and relevant unpublished data. We calculated risk ratios (RRs) for dichotomous data and mean differences (MDs) or standardised mean differences (SMDs) for continuous data (with 95% confidence intervals (CIs)). We used the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach to assess the overall certainty of the evidence.

MAIN RESULTS: In this updated review, we included a total of 25 trials (15,076 participants), of which 15 were new trials (11,501 participants). Follow-up ranged from 1 to 20 months. We found that medication reviews in hospitalised adults may have little to no effect on mortality (RR 0.96, 95% CI 0.87 to 1.05; 18 trials, 10,108 participants; low-certainty evidence); likely reduce hospital readmissions (RR 0.93, 95% CI 0.89 to 0.98; 17 trials, 9561 participants; moderate-certainty evidence); may reduce emergency department contacts (RR 0.84, 95% CI 0.68 to 1.03; 8 trials, 3527 participants; low-certainty evidence) and have very uncertain effects on health-related quality of life (SMD 0.10, 95% CI -0.10 to 0.30; 4 trials, 392 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS: Medication reviews in hospitalised adult patients likely reduce hospital readmissions and may reduce emergency department contacts. The evidence suggests that mediation reviews may have little to no effect on mortality, while the effect on health-related quality of life is very uncertain. Almost all trials included elderly polypharmacy patients, which limits the generalisability of the results beyond this population.