Milheiro, Joaquim

Abstract Background and Aims Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are emerging as an essential part of the new standard of care for proteinuria, alongside renin-angiotensin system (RAS) inhibitors in patients with proteinuric chronic kidney disease (CKD). Subgroup analysis of EMPA-KIDNEY and DAPA-CKD trials done in patients with glomerular diseases [IgA Nephropathy (IgAN) and focal and segmental glomerulosclerosis (FSGS)] showed these agents are less effective in reducing proteinuria compared to other agents like Sparsentan, or Double RAS Blockade. Also, the antiproteinuric effects of SGLT2i in patients with glomerular diseases is not well understood. To date, no study has specifically evaluated the effects of body mass index (BMI) on the antiproteinuric efficacy of SGLT2. Here we report the impact of BMI on the antiproteinuric efficacy of SGLT2i in non-diabetic patients with glomerular diseases. Method Single-center retrospective cohort study. Inclusion criteria (1) adult patients with a biopsy-proven glomerular disease or genetic diagnosis [i.e., Collagen IV mutations] from January 1st, 2019, to December 31st, 2023, (2) no Diabetes Mellitus, (3) proteinuria more than 0.75 g/24 h at the time of initiation of treatment despite optimized blood pressure control with renin-angiotensin system (RAS) inhibition at maximum tolerated dose (5) no concomitant use of induction immunosuppression therapy—stable maintenance immunosuppression was allowed. Patients with active neoplasia, no follow-up available after initiation of therapy or kidney transplant were excluded. Baseline was defined as the time of the initiation of SGLT2i. Laboratory values, including proteinuria, serum creatinine, and estimated glomerular filtration rate (eGFR), were obtained at baseline and 6 months. Changes in laboratory values over time were analyzed using the paired t-test and the signed-rank test, depending on the distribution. Weight status was classified based on BMI in three categories: regular (BMI < 25 kg/m2), overweight (25–29.9 kg/m2), and obese (>30 kg/m2). Results We identified 115 non-diabetic patients with glomerular diseases. Median age [IQR] at the time of SGLT2i initiation was 49.1 [35.4, 61.5] years; 74 (64.3%) patients were male, and 96 (83.5%) patients were white, with the second most common ethnicity being Asian with 10 (8.7%) patients. Median BMI for the entire cohort was 28.2 [26.0, 33.1] Kg/m2. Fifty-three (46.1%) patients had IgAN, 22 (19.1%) had secondary FSGS (sFSGS), 3 (2.6%) primary FSGS (pFSGS), and 12 (10.4%) genetic FSGS (gFSGS), with collagen IV mutations as the most common cause of gFSGS. Kidney function and proteinuria over time are presented in Table 1. Significant declines in eGFR [−1.77 ml/min/1.73m2 95% CI: (−4.2, −1.19)] and proteinuria [−0.58 g/24h 95% CI (−0.91, −0.44)] were observed at 6 months in the entire cohort compared to baseline. However, in the subgroup analysis by BMI strata, i.e., <25, 25-29.9, ≥30, the reduction in proteinuria was statistically significant only in overweight and obese patients. The expected early drop in eGFR was not observed in patients with a normal BMI. However, the decline in eGFR progressively increased and was statistically significant in the obese group (Fig. 1). Conclusion The principal finding of the present study is the lack of significant proteinuria reduction in patients with BMI<25 kg/m², which contrasts with the significant reductions observed in overweight and obese patients. SGLT2i's main antiproteinuric mechanism of action involves reducing glomerular hyperfiltration, which is commonly seen in patients with diabetes and obesity. In non-diabetic patients with glomerulopathies, proteinuria may be sustained by mechanisms not dependent on glomerular hyperfiltration, especially in those patients with normal BMI. These findings are crucial to advocate a personalized approach to treatment, challenging the “one-size-fits-all” strategy.

ABSTRACT Background Sodium–glucose co-transporter 2 inhibitors (SGLT2is) are emerging as an essential part of the standard of care for proteinuria in patients with chronic kidney disease. To date, no study has specifically evaluated the effects of body mass index (BMI) on the antiproteinuric efficacy of SGLT2is. Here we report the impact of BMI on the antiproteinuric efficacy of SGLT2is in non-diabetic patients with glomerular diseases. Methods This is a retrospective, multicentre, international observational cohort study that included non-diabetic patients with biopsy-proven glomerular disease and proteinuria >0.5 g/24 h who received SGLT2is between 2016 and 2023. Laboratory values, including proteinuria and estimated glomerular filtration rate (eGFR), were obtained at baseline and after 3–6 months. Changes in laboratory values over time were analysed using the paired signed-rank test. Results A total of 300 patients met the inclusion criteria. The median age was 51.82 years [interquartile range (IQR) 41–62.65], 64.7% were male and 92.7% were white. The most common glomerular disease was immunoglobulin A nephropathy (40.3%). The median eGFR was 52.26 ml/min/1.73 m2 (IQR 36.41–74.01), the median proteinuria was 1.60 g/24 h (IQR 1.15–2.91) and the median serum albumin was 4.08 g/dl (IQR 3.80–4.30). Proteinuria reduction after SGLT2i initiation was significant only in overweight and obese patients (P < .001 versus 0.18). Patients with normal BMI did not experience the expected early decrease in eGFR (P = .16). Conclusions SGLT2is are ineffective in proteinuria reduction in patients with a BMI <25 kg/m2, which contrasts with the significant proteinuria reduction in overweight and obese patients with glomerulopathies.