Ozmen Sehmus, Kaplan Mehmet Ali, Kaya Halil, Akin Davut, Danis Ramazan, Kizilkan Berfin, Yazanel Orhan
Departments of Nephrology, Dicle University of School of Medicine, Diyarbakir, Turkey.
Scand J Urol Nephrol. 2009;43(2):171-6. doi: 10.1080/00365590802502228.
Glomerular filtration rate (GFR) is the main tool used to diagnose, treat and follow up renal diseases. Age, gender, ethnicity and obesity all affect the relationship between serum creatinine, muscle mass/body weight and GFR. This study aimed to investigate the role of lean body mass for GFR estimation in patients with chronic kidney disease (CKD) with various body mass indices.
In total, 110 Caucasian adult subjects with CKD referred for GFR measurement by (99m)Tc-DTPA renography were enrolled in the study. The patients were categorized according to body mass index values: <18.5 kg/m(2) (underweight), 18.5-24.9 kg/m(2) (normal), 25-29.9 kg/m(2) (overweight) and >30 kg/m(2) (obese). Lean body mass (LBM) and fat mass were measured by leg-to-leg bioimpedance. Predictive factors were identified by linear regression analysis in each group.
GFR measured by DTPA, creatinine clearance, Cockcroft and Gault, and Modification of Diet in Renal Disease (four-variable) equations was 37+/-27, 42+/-30, 42+/-27, and 49+/-35 ml/min/1.73 m(2), respectively. The predictive role of 1/SCr, age, serum albumin, amount of proteinuria, LBM and fat mass was investigated all groups. None of the factors was significant in underweight and healthy weight groups except for 1/serum creatinine (SCr). LBM/SCr was an independent predictive factor for both overweight and obese groups. 1/SCr accounted for 96.2% of the variability in measured GFR for underweight subjects but only 58.1% of the variability in GFR of obese subjects.
The formulae derived from SCr should be used cautiously in overweight and obese subjects. LBM measured by bioimpedance was an independent predictive factor of GFR in obese/overweight subjects and added clinically important diagnostic value to 1/SCr. It needs to be investigated as a parameter in further studies attempting to develop formulae for estimating GFR in larger obese and overweight populations.
肾小球滤过率（GFR）是用于诊断、治疗和随访肾脏疾病的主要工具。年龄、性别、种族和肥胖都会影响血清肌酐、肌肉量/体重与GFR之间的关系。本研究旨在探讨瘦体重在不同体重指数的慢性肾脏病（CKD）患者GFR估算中的作用。
共有110名因进行（99m）Tc-DTPA肾动态显像测量GFR而转诊的成年白种CKD患者纳入本研究。患者根据体重指数值进行分类：<18.5kg/m²（体重过轻）、18.5 - 24.9kg/m²（正常）、25 - 29.9kg/m²（超重）和>30kg/m²（肥胖）。通过双腿生物电阻抗测量瘦体重（LBM）和脂肪量。在每组中通过线性回归分析确定预测因素。
通过DTPA测量的GFR、肌酐清除率、Cockcroft和Gault公式以及肾脏病饮食改良（四变量）公式分别为37±27、42±30、42±27和49±35ml/min/1.73m²。在所有组中研究了1/SCr、年龄、血清白蛋白、蛋白尿数量、LBM和脂肪量的预测作用。除了1/血清肌酐（SCr）外，体重过轻和体重正常组中没有因素具有显著性。LBM/SCr是超重和肥胖组的独立预测因素。1/SCr占体重过轻受试者测量GFR变异性的96.2%，但仅占肥胖受试者GFR变异性的58.1%。
在超重和肥胖受试者中应谨慎使用由SCr推导的公式。通过生物电阻抗测量的LBM是肥胖/超重受试者GFR的独立预测因素，并为1/SCr增加了重要的临床诊断价值。在进一步研究试图为更大的肥胖和超重人群开发GFR估算公式时，需要将其作为一个参数进行研究。
