Going beyond the numbers – a call to redefine polypharmacy

‘Polypharmacy’ has often been used to describe the use of multiple medications and has been noted as ‘one of the most pressing prescribing challenges’ 1. There is no accepted definition as to what number of drugs constitutes polypharmacy, with some authorities proposing four or five medications 2–4. Polypharmacy has also been viewed negatively and been described as the ‘administration of more medicines than are clinically indicated, representing unnecessary drug use’ 5. However, there is growing recognition that polypharmacy may be entirely appropriate, as evidence-based guidelines advocate the use of more than one drug in the management of long term conditions, e.g. hypertension 6. This situation may be compounded further by the presence of two or more long term conditions i.e. multimorbidity 7. A recent study by Barnett et al. has shown that 64.9% of those aged over 65 years had a mean of 2.6 multimorbidities and 81.5% of those over 85 years were multimorbid and had a mean of 3.62 long term conditions 7. Although multimorbidity is more prevalent with increasing age, the Barnett study showed 30.4% of those aged between 45 and 64 years were living with two or more chronic conditions (mean of 1.18 morbidities) 7, all of which may require drug treatment. Therefore, polypharmacy is arguably the new paradigm for prescribing 8, being driven by multimorbidity and the plethora of evidence-based guidelines for the management of long term conditions. Aronson has described polypharmacy as having a dual meaning: ‘too many drugs’, or ‘many drugs’, and in the case of the latter, this may be entirely appropriate 9. Hence, there has been a call for a change in emphasis from inappropriate polypharmacy (‘too many drugs’) to the prescribing of appropriate polypharmacy (‘many drugs’). This is the challenge that faces healthcare professionals (HCPs) who care for older people, particularly general practitioners (GPs) who prescribe most of their medication. Payne et al. 10 have contributed a timely paper on the potential hazards of polypharmacy, highlighting that although unplanned hospitalization was strongly associated with the number of regular medicines, the effect was reduced in patients with multiple conditions, with only the most extremes levels of polypharmacy associated with increased admissions. This is an important finding as it goes some way towards dispelling the myth that polypharmacy is not just about numbers of drugs and is not always associated with poor outcomes.

This study made use of Scottish primary care data for just over 180 000 patients (long term clinical conditions and details on regularly prescribed medication) and linked these data with national hospital admissions information for the following year. The study has examined a more inclusive population, ranging in age from 20 years and over. Interestingly, the authors did not attempt to define polypharmacy based on the numbers of drugs, recognizing the lack of consensus as to what constitutes polypharmacy. Rather, they categorized medicines into ranges (e.g. 1–3, 4–6) which allowed for the non-linear effects of increasing the number of medicines. The term polypharmacy was still used to convey the use of multiple medications, but not necessarily in a pejorative way. They employed a list of 40 physical and mental conditions to develop a measure of multimorbidity, which was inclusive of morbidities that had been previously recognized as core to such a measure, those that were included in the United Kingdom (UK) GP contract (the Quality and Outcomes Framework-QOF) and those considered important for health care planning in the context of Scotland. Using the secondary care data, the authors identified one unplanned hospital admission (in the year following a cut-off point for prescribing and clinical information) which was defined as an emergency or urgent according to the condition of the patient as assessed by a doctor. Following linkage between these two datasets, regression analysis revealed, unsurprisingly, that increasing numbers of regular medicines were seen with increasing multimorbidity. Unplanned admissions were more common as the numbers of prescribed medicines increased. However, the strength of the association was greatly reduced in individuals with more conditions. For example, those patients with six or more conditions taking 4–6 medicines, were no more likely to have an unplanned admission than those taking 1–3 medicines. In contrast, those patients with six or more conditions taking no medicines, were more likely to be admitted than those taking 1–3 medicines. This suggests that appropriate drug management using several drugs in those with multiple conditions may prevent unnecessary hospitalizations and highlights the importance of ensuring that all clinical conditions receive appropriate treatment.

As stated in the Discussion of the paper 10, the study ‘highlights the importance of considering polypharmacy in the clinical context for which medications are being prescribed.’ This calls into question the continuing reliance of judging the quality of prescribing on the numbers of drugs alone, although numbers may signal the need for a review. Considering the clinical context requires having access to high quality data, and clearly, dataset linkage should be strongly encouraged to facilitate this type of research. The authors also call for a re-framing of the term ‘polypharmacy’ and we would support this. A Cochrane review published in 2012 4 attempted to go some way to do this, by using the term ‘appropriate polypharmacy’ and sought to identify studies which were effective in improving the appropriate use of polypharmacy and reducing medication-related problems in older people. Ten studies were identified which produced changes in reducing inappropriate prescribing and medication-related problems, but it was unclear if the interventions resulted in significant clinical improvement. Almost all included studies used a number to define polypharmacy.

Going beyond the numbers in terms of polypharmacy seems a natural progression in the light of this study, provided that access to comprehensive, high quality clinical information is guaranteed. Multimorbidity is increasing throughout the population and central to its appropriate management will be the prescribing of multiple long term medications. Clinical guidelines in the future will need to consider the implications of multimorbidity for drug treatment, with the recognition that many drugs may be entirely appropriate, and in that sense, polypharmacy should be strongly encouraged.

Competing Interest Statement

All authors have completed the Unified Competing Interest form at http://www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare no financial relationships with any organizations that might have an interest in the submitted work in the previous 3 years and no other relationships or activities that could appear to have influenced the submitted work.