Supplementary Material for: The burden of chronic kidney disease of undetermined etiology (CKDu) in a tertiary care public hospital in north India

Introduction: Chronic kidney disease of undetermined aetiology (CKDu) is an important public health problem. Indian data is mostly based on studies from rural regions in south and eastern India. We examined the burden and profile of CKDu in patients attending a tertiary care hospital in north India.
Methods: We assessed records of consecutive new CKD patients registered in nephrology clinic from January 2015 till June 2022. Patients were classified as CKDu based on predefined inclusion and exclusion criteria. Clinical and laboratory parameters at presentation and kidney biopsy when done were noted.
Results: Records of 32369 patients with CKD were screened, 29663 were included (2706 excluded due to inadequate data). 370 (1.2%) patients were categorized as CKDu. Mean age was 41±14.7 years, 58.1% being males. 158 (42.7%) patients were in CKD stage 3, 89 (24.1%) in stage 4, 84(22.7%) in stage 5 and 39(10.5%) were dialysis dependent at presentation. 232(62.7%) patients had proteinuria

引言：病因未明的慢性肾脏病（CKDu）是一项重要的公共卫生问题。印度相关数据主要基于印度南部和东部农村地区的调查研究。本研究旨在探讨印度北部一家三级护理医院就诊患者中CKDu的负担及其特征。
方法：本研究评估了2015年1月至2022年6月期间在肾病诊所登记的连续新发慢性肾脏病患者的病历。患者根据既定的纳入和排除标准被分类为CKDu。记录了患者就诊时的临床和实验室参数，以及进行肾脏活检时的情况。
结果：共筛查了32369例慢性肾脏病患者病历，其中29663例被纳入研究（2706例因数据不足被排除）。370例（占比1.2%）患者被归类为CKDu。平均年龄为41±14.7岁，其中58.1%为男性。158例（占比42.7%）患者处于CKDu 3期，89例（占比24.1%）处于4期，84例（占比22.7%）处于5期，39例（占比10.5%）在就诊时依赖透析。232例（占比62.7%）患者出现蛋白尿。