High detection rate and risk factors of melanosis coli in end-stage renal disease patients awaiting kidney transplantation: a single-center retrospective study in China

BackgroundRhubarb-containing Traditional Chinese Medicine (TCM) is widely used to manage renal failure in China. Studies show that anthranoids contained in rhubarb are related to the occurrence of melanosis coli (MC). However, no study on the rate of MC in end-stage renal disease (ESRD) patients has been reported.MethodsWe conducted a retrospective study on 99 ESRD patients who received a colonoscopy as part of pre-transplant work-up between Jan 1, 2017 and July 1, 2020 in a single center in Beijing, China. 200 age- and gender-matched subjects with normal renal function and received a colonoscopy for health screening in the same period were randomly selected as control group. Univariate analysis and multivariate logistic regression were performed in succession to determine the association between ESRD and MC, and also probe the independent MC risk factors in ESRD patients.ResultsAmong the 99 ESRD patients, MC was detected in 19, with a detection rate of 19.2% (95% confidence interval [CI]: 11.3%, 27.1%). In contrast, among 200 control subjects, MC was only detected in 1 subject, with an detection rate of 0.5% (95%CI: 0.5%, 1.5%) (ESRD vs. control: odds ratio [OR] = 47.263, 95% CI: 6.222, 358.981; p=0.000). After adjustment of age, body mass index(BMI), albumin, hemoglobin and Charlson comorbidity index, being ESRD was still associated with the presence of MC (OR = 36.251, 95%CI: 3.435, 382.559, p = 0.003). In ESRD patients, both univariate analysis (OR = 4.358, 95% CI: 1.329, 14.286; p = 0.012) and multivariate logistic regression (OR = 4.916, 95% CI: 1.462, 16.525, p = 0.010) found that past use of Rhubarb-containing TCM was the only independent risk factor of MC. However, when the ESRD patients with above use history were excluded, MC rate in ESRD was still higher than non-ESRD group (8.5% vs. 0.5%; OR = 18.512, 95% CI: 2.019, 169.755; p = 0.000).ConclusionOur work highlights that MC rate is high and rhubarb-containing TCM use might be a risk factor in Chinese ESRD patients. There is a need for arranging high quality studies to examine the development of MC in ESRD, especially those awaiting transplantation.