There is an urgent need for further robust clinical evidence on the risks and benefits of medicines taken by elderly patients, concludes a recent review in The Lancet.

Existing data from clinical trials have limited applicability as they usually exclude frail, older patients, note the researchers from Belgium, the UK and the US. Even when a study is targeted at elderly patients, they add, the enrolled population tends to be highly selective.

The paper published in the 14 July issue of The Lancet is one of two addressing the challenges of prescribing for the elderly. The series co-ordinator is Dr Anne Spinewine, from the Centre for Clinical Pharmacy at the Université catholique de Louvain in Brussels.

The first paper looks at how well appropriate prescribing in the elderly can be measured and optimised. Evidence suggests that the use of drugs in elderly patients is often inappropriate, partly because of the complexities of prescribing for this population, it observes. One study in Europe found that 20% of elderly people cared for at home were taking at least one inappropriate medicine as defined in the lists developed by Beers and colleagues in the US or McLeod et al in Canada.

Appropriate prescribing

The Lancet review sets out to define and categorise appropriate prescribing in the elderly, critically review the instruments available to measure appropriate prescribing (criterion-based and judgment-based processes) and discuss their predictive validity. The researchers also evaluate randomised controlled intervention studies that assess the impact of optimisation strategies on the appropriateness of prescribing in elderly patients, examine the relationship between inappropriate prescribing and poor health outcomes, and suggest directions for future research and practice.

Among the optimisation strategies discussed are geriatric multidisciplinary team care, pharmacist prescribing, and the importance of involving elderly patients and their carers in the prescribing process, difficult though this may be.

Current evidence of a link between inappropriate prescribing and adverse patient outcomes remains “mixed and contradictory”, the authors point out. Further clinical trials, complemented by evidence from well-designed non-experimental studies that evaluate causal effects, would help to resolve the inequity in research geared to elderly patients’ drug use, they suggest.

The researchers also stress the need for “multicentre studies with large samples and outcome measures that are clinically relevant and responsive to the intervention” in order to gauge the effectiveness of the various approaches used to optimise the appropriateness of prescribing in the elderly.

Managing drug interactions

The second Lancet paper addresses the challenge of managing drug interactions in the elderly. It cites one study of 1,601 elderly outpatients in six European countries, 46% of whom had at least one clinically significant drug-drug interaction. In addition, 10% of these interactions were classed as being of high severity.

Computer-based drug interaction software and databases can help to alert doctors and pharmacists to potential difficulties, although these systems have “substantial drawbacks," the authors say. Moreover, any generated recommendations need to be “tempered by a holistic, geriatric, multiprofessional approach that is team-based,” they add.