Is polypharmacy always hazardous? A retrospective cohort analysis using linked electronic health records from primary and secondary care

Payne, R. A., Abel, G. A., Avery, A. J., Mercer, S. W. and Roland, M. O. (2014) Is polypharmacy always hazardous? A retrospective cohort analysis using linked electronic health records from primary and secondary care. British Journal of Clinical Pharmacology, 77(6), pp. 1073-1082. (doi:10.1111/bcp.12292)

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Publisher's URL: http://dx.doi.org/10.1111/bcp.12292

Abstract

Aim Prescribing multiple medications is associated with various adverse outcomes, and polypharmacy is commonly considered suggestive of poor prescribing. Polypharmacy might thus be associated with unplanned hospitalisation. We sought to test this assumption.

Methods Scottish primary care data for 180,815 adults on long-term clinical conditions and numbers of regular medications were linked to national hospital admissions data for the following year. Using logistic regression (age, gender and deprivation adjusted), we modelled the association of prescribing with unplanned admission for patients with different numbers of long-term conditions.

Results Admissions were commoner in patients on multiple medications, but admission risk varied with number of conditions. For patients with one condition, the odds ratio for unplanned admission for 4-6 medications was 1.25 (95% CI 1.11-1.42) vs. 1-3 medications, and 3.42 (95% CI, 2.72-4.28) for ≥10 medications vs. 1-3 medications. However, this effect was greatly reduced for patients with multiple conditions; amongst patients with ≥6 conditions, those on 4-6 medications were no more likely to have unplanned admissions than those taking 1-3 medications (OR 1.00 (95% CI 0.88-1.14)), and those taking ≥10 medications had a modestly increased risk of admission (OR 1.50 (95% CI 1.31-1.71)).

Conclusions Unplanned hospitalisation is strongly associated with number of regular medications. However, the effect is reduced in patients with multiple conditions, with only the most extreme levels of polypharmacy associated with increased admissions. Assumptions that polypharmacy is always hazardous and represents poor care should be tempered by clinical assessment of the conditions for which those drugs are being prescribed.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mercer, Professor Stewart
Authors: Payne, R. A., Abel, G. A., Avery, A. J., Mercer, S. W., and Roland, M. O.
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > General Practice and Primary Care
Journal Name:British Journal of Clinical Pharmacology
Journal Abbr.:Br. J. Clin. Pharmacol.
Publisher:Wiley
ISSN:0306-5251
ISSN (Online):1365-2125
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