Improving the Quality and Safety of Drug Use in Hospitalized Elderly : Assessing the Effects of Clinical Pharmacist Interventions and Identifying Patients at Risk of Drug-related Morbidity and Mortality

Abstract: Older people admitted to hospital are at high risk of rehospitalization and medication errors. We have demonstrated, in a randomized controlled trial, that a clinical pharmacist intervention reduces the incidence of revisits to hospital for patients aged 80 years or older admitted to an acute internal medicine ward. The aims of this thesis were to further study the effects of the intervention and to investigate possibilities of targeting the intervention by identifying predictors of treatment response or adverse health outcomes.The effect of the pharmacist intervention on the appropriateness of prescribing was assessed, by using three validated tools. This study showed that the quality of prescribing was improved for the patients in the intervention group but not for those in the control group. However, no association between the appropriateness of prescribing at discharge and revisits to hospital was observed.Subgroup analyses explored whether the clinical pharmacist intervention was equally effective in preventing emergency department visits in patients with few or many prescribed drugs and in those with different levels of inappropriate prescribing on admission. The intervention appeared to be most effective in patients taking fewer drugs, but the treatment effect was not altered by appropriateness of prescribing.The most relevant risk factors for rehospitalization and mortality were identified for the same study population, and a score for risk-estimation was constructed and internally validated (the 80+ score). Seven variables were selected. Impaired renal function, pulmonary disease, malignant disease, living in a nursing home, being prescribed an opioid and being prescribed a drug for peptic ulcer or gastroesophageal reflux disease were associated with an increased risk, while being prescribed an antidepressant drug (tricyclic antidepressants not included) was linked with a lower risk. These variables made up the components of the 80+ score. Pending external validation, this score has potential to aid identification of high-risk patients.The last study investigated the occurrence of prescription errors when patients with multi-dose dispensed (MDD) drugs were discharged from hospital. Twenty-five percent of the MDD orders contained at least one medication prescription error. Almost half of the errors were of moderate or major severity, with potential to cause increased health-care utilization.