Estimated effects on unplanned hospitalisations of exposure to high-risk and potentially inappropriate medications in elderly Western Australians: a cross-jurisdictional data linkage approach

[Truncated abstract] The harmful effects of therapeutic drugs, including unplanned hospitalisations, are a significant health problem, especially in the elderly. Older people are major consumers of medication and are more susceptible to adverse drug events (ADEs) due to physiological deterioration and other age-related factors. To address this problem, various lists of medications considered potentially inappropriate in older people have been developed. Among them, the Beers Criteria are by far the most commonly referenced.
Until recently, most Australian statistics on ADE-related hospitalisations have been based on the analysis of external cause codes from the International Classification of Diseases (ICD) found on inpatient discharge summaries. Not only does this classification system lack sufficient detail to permit the identification of individual drugs as causal agents but, given the ambiguous symptoms associated with some adverse drug reactions, it is suspected that a number of patients hospitalised due to harmful drug effects may not be identified as such in hospital records.
The linkage of records from the Australian Pharmaceutical Benefits Scheme (PBS), Medicare Benefits Scheme (MBS) and System for the Payment of Aged Residential Care (SPARC) databases with Western Australian inpatient, death and electoral roll records provided the opportunity to explore alternative methods for estimating the ADE-related hospital admission burden in elderly Western Australians, and to assess the impact of exposure to potentially inappropriate medications (PIMs) from the general Beers list in this population in terms of unplanned hospitalisations.