Clinical and economic impact of adverse drug reactions in hospitalised patients: prospective matched nested case-control study in Ethiopia.

Objectives: The purpose of this study was to assess the clinical and economic impact of adverse drug reactions (ADRs) among patients admitted to the University of Gondar Comprehensive Specialized Hospital (UoGCSH).

Design And Setting: A prospective nested case-control study was conducted at the UoGCSH among admitted adult patients with (cases) and without ADRs (controls) between May and October 2022.

Participants: All eligible adult patients admitted in the medical ward of the UoGCSH during the study period were included in this study.

Main Outcome Measures: The outcome variables were the clinical and economic outcomes. Length of hospital stay, visits to intensive care units (ICU) and in-hospital mortality were used to measure and compare clinical outcomes in patients with and without ADRs. The economic outcome was also assessed using direct medical-related costs and compared for the two groups. Paired samples t-test and McNemar tests were used to compare measurable outcomes between the two groups. A p value <0.05 at the 95% CI was considered statistically significant.

Results: Out of a total of 214 eligible enrolled patients, 206 (103 with and 103 without ADRs) with a 96.3% response rate were included in the cohort. The length of hospital stay was much longer in patients with ADRs than without ADRs (19.8 vs 15.2 days, p<0.001). Similarly, ICU visits (11.2% vs 6.8%, p<0.001) and in-hospital mortality (4.4% vs 1.9%, p=0.012) were significantly higher in patients with ADRs compared with those without ADRs. Patients with ADRs were significantly charged with higher direct medical costs compared with those without ADRs (6237.2 vs 5256.3 Ethiopian birr; p<0.001).

Conclusion: This study concluded that ADRs had a significant impact on patients' clinical and medical costs. Healthcare providers should strictly follow the patients to minimise ADR-related clinical and economic adverse outcomes.