A prospective observational pilot study of adverse drug reactions contributing to hospitalization in a cohort of middle-aged adults aged 45–64 years

Abstract

Our objective was to determine the prevalence, severity and preventability of adverse drug reactions (ADRs), ADRs causing or contributing to hospitalization (cADRs) and preventable ADRs (pADRs) in middle-aged patients aged 45–64 years presenting acutely to hospital. This was a prospective observational pilot study. The sampling frame was middle-aged patients in the acute medical unit of an Irish university teaching hospital. In total, 100 patients using three or more medicines were screened for ADRs present at hospitalization. Potential ADRs were assessed for causality, preventability, severity and relationship to hospitalization using validated tools and clinician assessment. The associations between ADRs and potentially inappropriate prescribing (PIP) and polypharmacy (five or more medicines) were investigated using Pearson’s χ2 test. Multivariate logistic regression analyses examined associations between ADRs and sex, age, polypharmacy, comorbidity and PIP. Of the 100 patients, 21 experienced 23 ADRs. The prevalence of cADRs and pADRs was 14% and 11% of patients, respectively. Over one-half of ADRs identified (n = 14) were sufficiently severe to prompt presentation to hospital for urgent medical review. PIP was associated with the occurrence of any ADR (adjusted odds ratio 3.49; 95% confidence interval 1.22–9.93) but not with cADR. Excessive polypharmacy (ten or more medicines) (χ2 = 5.73, p = 0.02), but not polypharmacy, was associated with any ADR occurrence. One in five patients had an ADR and experienced short-term morbidity as a result. For 11 patients, the ADR was preventable. These findings illustrate that middle-aged patients are vulnerable to medicine-related harm. Additional research in larger studies is needed to more comprehensively describe the prevalence and risk factors for ADRs in middle-aged patients.