Association of polypharmacy with incidence of CKD: a retrospective cohort study

Background Polypharmacy is common in patients with chronic kidney disease (CKD) and is associated with a decline in kidney function. However, its impact on patients without CKD has not been adequately elucidated. Therefore, we aimed to investigate the association between polypharmacy and the incidence of CKD. Methods We conducted retrospective cohort study using 1221 participants who were enrolled in the Fukushima Cohort Study with one or more risk factors of CKD, an estimated glomerular filtration rate (eGFR) of >= 60 mL/min/1.73 m(2), and without proteinuria. Participants were categorized into three groups based on the number of medications: non-polypharmacy, 0-4 medications; polypharmacy, 5-9 medications; and hyper-polypharmacy, >= 10 medications. Results The median age was 62 years, 49% were men, the median eGFR was 75.4 ml/min/1.73 m(2), and the median number of medications was 5. Polypharmacy and hyper-polypharmacy were noted in 506 (41%) and 250 (20%) participants, respectively. During follow-up, 288 participants developed CKD and 67 cardiovascular events were observed. Compared to the non-polypharmacy group, the hyper-polypharmacy group had a higher risk of CKD and cardiovascular events. The adjusted hazard ratios were 1.41 (95% CI1.01-1.99) and 2.24 (95% CI1.05-4.78) for the incidence of CKD and cardiovascular events, respectively. Sensitivity analyses yielded similar findings for the restricted cubic spline function models. Conclusions Hyper-polypharmacy is associated with a higher risk of CKD and cardiovascular events.