Supplementary Material for: Factors Influencing the Efficacy of Low-dose Spironolactone in Adults with CKD and Type 2 Diabetes: A Post-hoc Analysis

Introduction: We previously reported the efficacy and safety of low-dose (12.5 mg/day) spironolactone for chronic kidney disease (CKD) with diabetes. Few studies have examined the characteristics of patients who may have reduced urinary albumin-creatinine ratio (UACR) on mineralocorticoid receptor antagonists. In this study, we aimed to identify the clinical characteristics of patients prone to benefit from UACR reduction with low-dose spironolactone.
Methods: This was a post-hoc analysis of a previous trial and included 55 patients assigned to the spironolactone group. Univariate regression analysis was performed to determine the association between the change in UACR after 24 weeks of low-dose spironolactone administration and baseline exploratory parameters. Multiple regression analysis was conducted on the associated parameters, and regression models were created for analysis. A similar analysis was performed for changes in serum potassium levels and estimated glomerular filtration rate (eGFR) after 24 weeks of spironolactone administration.
Results: In the univariate analysis, baseline UACR, triglyceride levels, and eGFR were associated with changes in UACR. The regression coefficient estimates were significant for baseline UACR, triglyceride levels, and eGFR (p = 0.002, 0.017, and 0.003, respectively). The reduction in UACR was greater with higher baseline UACR and triglyceride levels, and lower baseline eGFRs. The increase in serum potassium levels due to low-dose spironolactone administration showed a negative correlation with baseline serum potassium levels and no correlation with baseline eGFR, suggesting its safety.
Conclusions: It may not be too late to start treatment with low-dose spironolactone, even in patients with relatively advanced CKD with diabetes.