Independent and combined effect of bilirubin and smoking on the progression of chronic kidney disease

Jiancheng Wang,1,* Binyan Wang,1,2,* Min Liang,1 Guobao Wang,1 Jianping Li,3 Yan Zhang,3 Yong Huo,3 Yimin Cui,4 Xiping Xu,1,5 Xianhui Qin1 1National Clinical Research Center for Kidney Disease, State Key Laboratory for Organ Failure Research, Renal Division, Nanfang Hospital, Southern Medical University, Guangzhou, 2Institute for Biomedicine, Anhui Medical University, Hefei, 3Department of Cardiology, 4Department of Pharmacy, Peking University First Hospital, Beijing, 5Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China *These authors contributed equally to this work Objective: Whether serum bilirubin and cigarette smoking affect the risk of renal function decline remains inconclusive. We aimed to test the independent and combined effects of bilirubin and cigarette smoking on the progression of chronic kidney disease (CKD) in hypertensive adults. Methods: The study population consisted of 12,633 patients in the renal sub-study of the China Stroke Primary Prevention Trial. The primary outcome was progression of CKD, defined as a decrease in estimated glomerular filtration rate (eGFR) of ≥30% and to a level of