Effect of Kunxian capsule, a novel Tripterygium wilfordii preparation, on reducing proteinuria and slowing renal function decline in diabetic kidney disease: a 48–week randomized controlled trial

Diabetic kidney disease (DKD), a leading cause of chronic kidney disease, remains a clinical challenge despite renin–angiotensin system blockade. This study evaluated the efficacy and safety of adding Kunxian capsule to standard therapy with irbesartan in patients with DKD. Eighty patients with DKD were randomly assigned to either the experimental group (standard therapy with irbesartan plus Kunxian capsule) or the control group (standard therapy with irbesartan) for 48 weeks. Primary outcomes included the proteinuria remission rate, degree of proteinuria reduction, and median time to remission. Secondary outcomes included the slope of eGFR decline and the incidence of renal composite hard endpoint. Safety was assessed by monitoring adverse events. This trial was registered in ClinicalTrials.gov on March 2, 2021 (No. NCT04981613). In the intention–to–treat analysis, the experimental group had a higher proteinuria remission rate (57.50% vs. 25.00%), a shorter median time to remission (5 months vs. not reached), and a greater reduction in 24–hour urinary protein than the control group. A lower incidence of renal composite hard endpoint was observed in the experimental group (10.00% vs. 32.50%), accompanied by a slower eGFR decline. No significant differences in the incidence of adverse events were observed between the two groups. Inflammatory markers, including C–reactive protein and erythrocyte sedimentation rate, were significantly reduced in the experimental group. Adding Kunxian capsule to standard therapy with irbesartan improved the proteinuria remission rate and attenuated renal function decline in patients with DKD, supporting its potential as a promising adjunctive therapy. Diabetic kidney disease (DKD) is a serious complication of diabetes that can cause proteinuria and progressive loss of kidney function. Although current medications help protect the kidneys, many patients still experience persistent proteinuria and worsening kidney function. In this 48–week clinical trial involving 80 patients, researchers evaluated whether adding Kunxian capsule – a traditional Chinese medicine formulation – to standard therapy with irbesartan could improve outcomes. The results showed that patients who took Kunxian capsule alongside standard therapy with irbesartan achieved a higher rate of proteinuria remission and a greater reduction in proteinuria, experienced a slower decline in kidney function, and had fewer composite renal events compared with those receiving irbesartan alone. These findings suggest that Kunxian capsule may be a promising adjunctive treatment option to help reduce proteinuria and protect kidney function in patients with DKD. What is known: Despite advances in kidney–protective therapies, persistent proteinuria and progressive loss of kidney function remain major clinical challenges in patients with DKD.This study adds: In this 48–week randomized controlled trial, patients receiving standard therapy with irbesartan plus Kunxian capsule had a higher proteinuria remission rate, greater proteinuria reduction, a slower decline in eGFR, and fewer composite renal events than those receiving standard therapy with irbesartan alone.Potential impact: These findings provide prospective clinical evidence supporting Kunxian capsule as a promising adjunctive treatment option for DKD. What is known: Despite advances in kidney–protective therapies, persistent proteinuria and progressive loss of kidney function remain major clinical challenges in patients with DKD. This study adds: In this 48–week randomized controlled trial, patients receiving standard therapy with irbesartan plus Kunxian capsule had a higher proteinuria remission rate, greater proteinuria reduction, a slower decline in eGFR, and fewer composite renal events than those receiving standard therapy with irbesartan alone. Potential impact: These findings provide prospective clinical evidence supporting Kunxian capsule as a promising adjunctive treatment option for DKD.