Assessment of kidney function in the elderly: a population-based study

Introduction: Chronic kidney disease (CKD) affects all age groups, and its prevalence has increased during recent years. CKD is divided into six stages, according to the renal function of patients: 1. Normal renal function without kidney damage; 2. Kidney damage with normal renal function; 3. Mild renal insufficiency; 4. Moderate renal insufficiency or lab tests failure; 5. Severe renal insufficiency or clinical failure; 6. End stage of chronic renal failure. Objective: This study was intended to assess renal function in elderly patients and identifying the presence of factors associated with those changes. Methods: A cross-sectional population-based study was performed. Elderly patients were surveyed between September 2010 and May 2011. Kidney function was assessed by determining of serum creatinine, and estimation of the glomerular filtration rate by the CKD-EPI equation. Results: In all, 822 elderly were surveyed; 61.6% were women; 92.2% were Causasian; and most (61.0%) were aged between 60 and 69 years. With regard to the glomerular filtration rate, 26.2% had a normal rate; 60.2% showed a slight decrease; 13.0% a moderate decrease; 0.5% severe kidney function decline; and 0.1% extreme fall. Increasing age was associated with kidney damage by decreased glomerular filtration rate (p < 0.001). In addition, obesity, hypertension and smoking were factors independently associated with reduced glomerular filtration rates. Conclusion: This study found that the great majority of the surveyed elderly had some mild kidney damage, and 13.6% showed moderate to severe dysfunction.

引言：慢性肾脏病（Chronic Kidney Disease, CKD）可累及各年龄层人群，近年来其患病率呈上升趋势。根据患者肾功能水平，CKD可分为六个阶段：1. 肾功能正常且无肾脏损伤；2. 存在肾脏损伤但肾功能正常；3. 轻度肾功能不全；4. 中度肾功能不全或实验室检查异常；5. 重度肾功能不全或临床衰竭；6. 慢性肾衰竭终末期。研究目的：本研究旨在评估老年患者的肾功能，并识别与肾功能改变相关的影响因素。研究方法：本研究为基于人群的横断面研究。研究对象为2010年9月至2011年5月期间纳入的老年患者。通过检测血清肌酐水平，并采用CKD-EPI公式估算肾小球滤过率，以此评估肾脏功能。研究结果：本研究共纳入822名老年受试者，其中女性占61.6%；高加索人种占92.2%；多数受试者（61.0%）年龄介于60至69岁之间。就肾小球滤过率而言，26.2%的受试者处于正常水平；60.2%出现轻度下降；13.0%出现中度下降；0.5%存在重度肾功能减退；0.1%出现极重度下降。年龄增长与肾小球滤过率降低导致的肾脏损伤显著相关（p < 0.001）。此外，肥胖、高血压及吸烟均为肾小球滤过率降低的独立相关因素。研究结论：本研究发现，绝大多数受访老年患者存在轻度肾脏损伤，13.6%的受试者表现为中度至重度肾功能不全。