Adverse drug reactions (ADRs) associated with hospital admissions - elderly female patients are at highest risk

Background: ADRs represent a significant problem in drug utilisation. The prevalence of admissions caused by ADRs varies depending on the observational site, studied population, data collection method and the used definitions. Women seem to be more frequently affected than men. Objective: To assess the incidence and quality of ADRs related to hospital admissions, to identify the drugs most commonly involved and to define risk factors and preventive strategies for those ADRs. Material and methods: 3,190 medical records of all newly admitted internal ward patients were assessed in a prospective observational study in an internal hospital over 6 months. Potential ADRs at hospital admission were identified following a list of suspicious symptoms and laboratory results. Cases were evaluated by means of a computer tool and data-base specialized on detecting causality and severity of ADRs. Results: 304 ADRs were identified in 242 patients (7.6%), with 60% directly leading to admission. More women than men encountered an ADR (10 vs. 6%, p < 0.005). Analyzed separately by age groups, this gender difference became significant at an age of 81 years. The most common ADRs were electrolyte imbalances and over-anticoagulation. Diuretics and vitamin K antagonists were significantly correlated with ADRs. 62% of all ADRs were severe or life-threatening. Conclusion: ADRs leading or related to hospital admission are highly prevalent. Older age and female gender are significantly associated with ADR related hospital admissons. Causative drugs are the ones prescribed most frequently. Multidisciplinary preventive strategies and surveillance methods are necessary to ensure better care and patient safety especially for elderly women.