Impact of suspected adverse drug reactions on mortality and length of hospital stay in the hospitalised patients: a meta-analysis.

Purpose: To estimate the risk of mortality and length of stay in hospitalised patients who have experienced suspected adverse drug reactions (ADRs) as compared to patients who did not experience suspected ADRs.

Methods: A systematic literature search was conducted on databases for observational and randomised controlled studies conducted in any inpatient setting that reported deaths and/or length of hospital stay in patients who had suspected ADRs and did not have suspected ADRs during hospitalisation. PRISMA guidelines were strictly followed during the review. The methodological quality of included studies was assessed using a tool designed by Smyth et al. for the studies of adverse drug reactions. The meta-analytic summary of all-cause mortality was estimated using odds ratio-OR (95% CI) and length of stay using mean difference-MD (95% CI). Both outcomes were pooled using a random effect model (DerSimonian and Laird method). Subgroup and meta-regression were performed based on study variables: study design, age group, study ward, study region, types of suspected ADRs (ADR-suspected ADRs that lead to hospitalisation and ADR-suspected ADRs that occur following hospitalisation), study duration, sample size and study period. The statistical analysis was conducted through the 'Review manager software version 5.4.1 and JASP (Version 0.14.1)'.

Results: After screening 475 relevant articles, 55 studies were included in this meta-analysis. Patients having suspected ADRs had reported significantly higher odds of all-cause mortality [OR: 1.50 (95% CI: 1.21-1.86; I = 100%) than those patients who did not have suspected ADRs during hospitalisation. Study wards, types of suspected ADRs and sample size were observed as significant predictors of all-cause mortality (p < 0.05). Patients having suspected ADRs had reported significantly higher mean difference in hospital stay [MD: 3.98 (95% CI: 2.91, 5.05; I = 99%) than those patients who did not have suspected ADRs during hospitalisation. Types of suspected ADRs and study periods were observed as significant predictors of length of stay (p < 0.05).

Conclusion: Suspected ADRs significantly increase the risk of mortality and length of stay in hospitalised patients.

Systematic Review Registration: CRD42020176320.