Kumar Vivek, Yadav Ashok Kumar, Yasuda Yoshinari, Horio Masaru, Kumar Vinod, Sahni Nancy, Gupta Krishan L, Matsuo Seiichi, Kohli Harbir Singh, Jha Vivekanand
Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
BMC Nephrol. 2018 Feb 1;19(1):22. doi: 10.1186/s12882-018-0813-9.
Accurate estimation of glomerular filtration rate (GFR) is important for diagnosis and risk stratification in chronic kidney disease and for selection of living donors. Ethnic differences have required correction factors in the originally developed creatinine-based GFR estimation equations for populations around the world. Existing equations have not been validated in the vegetarian Indian population. We examined the performance of creatinine and cystatin-based GFR estimating equations in Indians.
GFR was measured by urinary clearance of inulin. Serum creatinine was measured using IDMS-traceable Jaffe's and enzymatic assays, and cystatin C by colloidal gold immunoassay. Dietary protein intake was calculated by measuring urinary nitrogen appearance. Bias, precision and accuracy were calculated for the eGFR equations.
A total of 130 participants (63 healthy kidney donors and 67 with CKD) were studied. About 50% were vegetarians, and the remainder ate meat 3.8 times every month. The average creatinine excretion were 14.7 mg/kg/day (95% CI: 13.5 to 15.9 mg/kg/day) and 12.4 mg/kg/day (95% CI: 11.2 to 13.6 mg/kg/day) in males and females, respectively. The average daily protein intake was 46.1 g/day (95% CI: 43.2 to 48.8 g/day). The mean mGFR in the study population was 51.66 ± 31.68 ml/min/1.73m. All creatinine-based eGFR equations overestimated GFR (p < 0.01 for each creatinine based eGFR equation). However, eGFR by CKD-EPI was not significantly different from mGFR (p = 0.38). The CKD-EPI exhibited lowest bias [mean bias: -3.53 ± 14.70 ml/min/1.73m (95% CI: -0.608 to -0.98)] and highest accuracy (P: 74.6%). The GFR in the healthy population was 79.44 ± 20.19 (range: 41.90-134.50) ml/min/1.73m.
Existing creatinine-based GFR estimating equations overestimate GFR in Indians. An appropriately powered study is needed to develop either a correction factor or a new equation for accurate assessment of kidney function in the Indian population.
准确估算肾小球滤过率（GFR）对于慢性肾脏病的诊断和风险分层以及活体供体的选择至关重要。种族差异使得最初开发的基于肌酐的GFR估算方程需要针对世界各地的人群进行校正。现有的方程尚未在素食的印度人群中得到验证。我们研究了基于肌酐和胱抑素的GFR估算方程在印度人中的性能。
通过菊粉的尿清除率测量GFR。使用可溯源至IDMS的Jaffe法和酶法测定血清肌酐，用胶体金免疫测定法测定胱抑素C。通过测量尿氮排出量计算膳食蛋白质摄入量。计算eGFR方程的偏倚、精密度和准确性。
共研究了130名参与者（63名健康肾脏供体和67名慢性肾脏病患者）。约50%为素食者，其余每月吃肉3.8次。男性和女性的平均肌酐排泄量分别为14.7mg/kg/天（95%CI：13.5至15.9mg/kg/天）和12.4mg/kg/天（95%CI：11.2至13.6mg/kg/天）。平均每日蛋白质摄入量为46.1g/天（95%CI：43.2至48.8g/天）。研究人群的平均mGFR为51.66±31.68ml/min/1.73m²。所有基于肌酐的eGFR方程均高估了GFR（每个基于肌酐的eGFR方程p<0.01）。然而，CKD-EPI方程得出的eGFR与mGFR无显著差异（p=0.38）。CKD-EPI方程的偏倚最低[平均偏倚：-3.53±14.70ml/min/1.73m²（95%CI：-0.608至-0.98）]，准确性最高（P：74.6%）。健康人群的GFR为79.44±20.19（范围：41.90-134.50）ml/min/1.73m²。
现有的基于肌酐的GFR估算方程高估了印度人的GFR。需要进行一项有足够样本量的研究来开发校正因子或新方程，以准确评估印度人群的肾功能。
