Effects of Keluoxin capsule combined with losartan potassium on diabetic kidney disease: study protocol for a randomized double-blind placebo-controlled multicenter clinical trial

BACKGROUND: Diabetic kidney disease (DKD) is one of the most important microvascular complications of diabetes, and its prevalence has increased dramatically in the past few decades. DKD is responsible for considerable morbidity and mortality of patients with diabetes. Keluoxin capsule (KLX) is a Chinese patent medicine that has been used in the clinic to control DKD for years. Previous studies have shown that KLX appears to reduce proteinuria, but the study protocols as well as the primary outcome need to be improved. Thus, we aim to evaluate whether losartan potassium combined with KLX is more effective than losartan potassium in DKD treatment and to provide validated evidence for the application of KLX in the treatment of DKD. METHODS: We will conduct a randomized double-blind placebo-controlled multicenter clinical trial. A total of 252 participants diagnosed with DKD recruited from 18 institutions will be randomly allocated to either a losartan potassium plus KLX (n = 126) or a losartan potassium plus placebo group (n = 126). The participants will be administered KLX or placebo in addition to losartan potassium for 24 weeks. The primary outcome measure will be the decline in estimated glomerular filtration rate (eGFR) (ml/min/1.73 m(2)/year) from baseline within 24 weeks, and the secondary outcomes will be the incidence of serum creatinine doubling, the incidence of end-stage renal disease (ESRD), the proportion of subjects with a progressive decline in eGFR > 30%, the percent change in 24 h urinary total protein (UTP), the change in the urinary albumin/creatinine ratio (UACR), and the total effective rate of the traditional Chinese medicine (TCM) syndrome scale scores. Comparison of the differences in the variables between groups will be performed according to the data revealed by independent t tests, chi-squared tests, Fisher’s exact tests, or Wilcoxon’s tests. All statistical tests will be two-sided, and significance will be considered for p values < 0.05. DISCUSSION: This study will be the first randomized clinical trial to evaluate the efficacy and safety of KLX versus the placebo for the treatment of patients with DKD. The outcome of this trial will provide a basis for prescribing KLX to patients with DKD. TRIAL REGISTRATION: Chinese Clinical Trial Registry (www.chictr.org.cn) ChiCTR1900021113. Registered on January 29, 2019.