The association of polypharmacy with functional decline in elderly patients undergoing cardiac surgery

Abstract

Aims: Identifying preoperative risk factors in older patients becomes more important to reduce adverse functional outcome. This study investigated the association between preoperative medication use and functional decline in elderly cardiac surgery patients and compared polypharmacy as a preoperative screening tool to a clinical frailty assessment. Methods: This sub-study of the Anaesthesia Geriatric Evaluation study included 518 patients aged ≥70 years undergoing elective cardiac surgery. The primary outcome was functional decline, defined as a worse health-related quality of life or disability 1 year after surgery. The association between polypharmacy (i.e. ≥5 prescriptions and <10 prescriptions) or excessive polypharmacy (i.e. ≥10 prescriptions) and functional decline was investigated using multivariable Poisson regression. Discrimination, calibration and reclassification indices were used to compare preoperative screening tools for patient selection. Results: Functional decline was reported in 284 patients (55%) and preoperative polypharmacy and excessive polypharmacy showed higher risks (adjusted relative risk 1.57, 95% confidence interval [CI] 1.23–1.98 and 1.93, 95% CI 1.48–2.50, respectively). Besides cardiovascular medication, proton-pump inhibitors and central nervous system medication were significantly associated with functional decline. Discrimination between models with polypharmacy or frailty was similar (area under the curve 0.67, 95% CI 0.61–0.72). The net reclassification index improved when including polypharmacy to the basic model (17%, 95% CI 0.06–0.27). Conclusion: Polypharmacy is associated with functional decline in elderly cardiac surgery patients. A preoperative medication review is easily performed and could be used as screening tool to identify patients at risk for adverse outcome after cardiac surgery.