The key role of Shenyan Kangfu tablets, a Chinese patent medicine for diabetic nephropathy: study protocol for a randomized, double-blind and placebo-controlled clinical trial

Background: Diabetic nephropathy (DN) is a major microvascular complication with diabetes. In China, an estimated 34.7 percent of people diagnosed with diabetes have renal complications and a further 50 percent die of renal failure. Hence, identification of alternative treatments for these patients should be given priority. The Shenyan Kangfu tablet (SYKFT) is a new formulation of an existing and widely acclaimed Chinese herbal tea for treating qi-yin deficiency syndrome. Because a considerable portion of DN patients presenting with symptoms of swelling, fatigue and weak limbs would be diagnosed with qi-yin deficiency syndrome according to the traditional Chinese medicine (TCM) diagnostic criteria, we hypothesize that SYKFT may represent a complementary drug for DN patients with the corresponding syndrome. In view of this, we have designed a trial to assess the efficacy and safety of SYKFT for patients with diabetic nephropathy exhibiting signs of qi and yin deficiency. Methods: This is a multicenter, double-blind, randomized controlled trial (RCT). The total target sample size is planned at 80 participants, with a balanced (1: 1) treatment allocation. The experimental intervention will be SYKFY plus irbesartan (SI regimen) and the control intervention will be a placebo plus irbesartan (PI regimen). Participants will receive two courses of medication treatment each lasting 8 weeks. The primary outcome will be the composite of the quantitative 24-hour urinary protein level and urinary albumin excretion rate (UAER). Changes in urine albumin-to-creatinine ratio (UACR) and DN staging, and TCM symptom improvement will be the secondary outcome measures. Adverse events (AEs) will be monitored throughout the trial. Discussion: This study will be the first placebo-controlled RCT to assess whether SYKFT plus irbesartan will have beneficial effects on enhancing overall response rate (ORR), changing DN staging, improving clinical symptoms, and reducing the frequency of AEs for DN patients with qi-yin deficiency syndrome. The results of this trial will help to provide evidence-based recommendations for clinicians.