Prevalence of polypharmacy and its association with clinical outcomes in kidney transplant recipients : results from the KNOW-KT study

Background: Polypharmacy (PP) is common among kidney transplant recipients (KTRs) due to lifelong immunosuppressive therapy and comorbidity management. However, PP's impact on clinical outcomes remains unclear. In this study, we examine the association between PP and adverse outcomes in KTRs. Methods: We analyzed data of 972 KTRs from the Korean Cohort Study for Outcomes in Patients with Kidney Transplantation (KNOW-KT). Excessive PP (ePP) was defined as ≥10 medications at 1-year posttransplantation. Outcomes included all-cause mortality, graft failure, and cardiovascular events. Inverse probability of treatment weighting (IPTW) was used to balance the baseline characteristics. Results: ePP was present in 49% of the KTRs, averaging 9.8 medications. After IPTW, ePP was not significantly associated with allcause mortality or graft failure. However, ePP was significantly associated with an increased risk of cardiovascular events (hazard ratio [HR], 1.80; 95% confidence interval [CI], 1.07-2.96; p = 0.03). This association remained significant after accounting for death as a competing risk (HR, 3.23; 95% CI, 1.40-7.47; p = 0.006). Subgroup analysis showed that the association between ePP and cardiovascular events was more pronounced in male patients and those receiving lipid-lowering agents. Use of immunosuppressive agents was broadly comparable between groups. Conclusion: ePP is highly prevalent among KTRs and is independently associated with an increased risk of cardiovascular events. This association appears to be primarily attributable to the overall PP burden. These findings highlight the importance of regular medication review and individualized pharmacologic strategies to optimize cardiovascular risk management in this population.