Polypharmacy influences the renal composite outcome in patients treated with sodium‐glucose cotransporter 2 inhibitors

Polypharmacy is a serious concern in general practice, especially among elder patients; however, the evidence showing significantly poor renal outcomes is not sufficient. This survey was performed to evaluate the effect of polypharmacy on the incidence of the renal composite outcome among a sample of patients with sodium‐glucose cotransporter 2 inhibitor (SGLT2i) treatment. We assessed 624 Japanese patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease who received SGLT2i treatment for greater than 1 year. The patients were classified as those with concomitant treatment, that was limited to the medications for hypertension, T2DM, and dyslipidemia, with greater than or equal to seven medications (n = 110) and those with less than seven medications (n = 514). Evaluation of the renal composite outcome was performed by propensity score matching and stratification into quintiles. A subgroup analysis of patients of greater than or equal to 62 years of age and less than 62 years of age was also performed. The incidence of the renal composite outcome was larger in patients with greater than or equal to seven medications than in those with less than seven medications in the propensity score‐matched cohort model (6% vs. 17%, respectively, p = 0.007) and also in the quintile‐stratified analysis (odds ratio [OR], 2.23, 95% confidence interval [CI, 1.21–4.12, p = 0.01). The quintile‐stratified analysis of patients of less than 62 years of age—but not those of greater than or equal to 62 years of age—also showed a significant difference (OR, 3.29, 95% CI, 1.41–7.69, p = 0.006). Polypharmacy appears to be associated to the incidence of the renal composite outcome, especially in young patients.