Desmeules Simon, Lévesque Renée, Jaussent Isabelle, Leray-Moragues Hélène, Chalabi Lofti, Canaud Bernard
Institut de recherche et formation en dialyse, Nephrologie, CHU-Lapeyronie, Montpellier, France
Nephrol Dial Transplant. 2004 May;19(5):1182-9. doi: 10.1093/ndt/gfh016. Epub 2004 Feb 19.
No single measurement adequately defines protein-energy malnutrition. In the dialysis population, somatic protein mass, a useful marker of protein malnutrition, is estimated using the creatinine index (CI), lean body mass (LBM) or both, but the clinical usefulness of these indices remains uncertain. Moreover, calculating these indices requires formal creatinine kinetics or urine and dialysate collection. A simpler method to estimate the creatinine generation rate (G(Cr)) probably might widen its use.
We evaluated the usefulness of creatinine-based indices for predicting mortality in a cohort of 226 French haemodiafiltration patients using the Cox proportional hazards method. We also proposed simple yet precise formulas to calculate post-dialysis creatinine (Cr(post)) concentrations and derive creatinine generation rates (G(Cr)) from readily available measures. These formulas were developed using a large database containing more than 10 000 measured Cr(post) and G(Cr) values based on formal creatinine modelling. A single set of monthly values was used to evaluate the validity of the formulas.
When adjusted for comorbidities, sex and Kt/V, CI and LBM/body weight (LBM/BW) were better predictors of 5 year all-cause mortality than urea-based indices [survival relative risk (RR) = 0.24, P<0.01 for CI<22 mg/kg/day; RR = 0.33, P<0.02 for LBM/BW<0.75]. When the cohort was divided according to gender, similar results were found in males, but not in females. The different formulas allowed adequate prediction of Cr(post) and G(Cr) and classification of patients with good accuracy (CI<22: sensitivity = 94%, specificity = 82%; LBW/BW<0.75: sensitivity = 89%, specificity = 90%).
In a haemodiafiltration population, CI and LBM are excellent predictors of long-term survival. In anuric Caucasian haemodialysis patients, CI and LBM can be estimated from biochemical and anthropometric measurements without relying on formal modelling.
没有单一的测量方法能够充分界定蛋白质 - 能量营养不良。在透析人群中，躯体蛋白质量是蛋白质营养不良的一个有用指标，可通过肌酐指数（CI）、瘦体重（LBM）或两者来估算，但这些指标的临床实用性仍不确定。此外，计算这些指标需要正式的肌酐动力学或尿液及透析液收集。一种更简单的估算肌酐生成率（G(Cr)）的方法可能会扩大其应用范围。
我们使用Cox比例风险法评估了基于肌酐的指标对226名法国血液滤过患者队列中死亡率的预测效用。我们还提出了简单而精确的公式，用于计算透析后肌酐（Cr(post)）浓度，并从易于获得的测量值中推导肌酐生成率（G(Cr)）。这些公式是利用一个包含超过10000个基于正式肌酐模型的测量Cr(post)和G(Cr)值的大型数据库开发的。使用单组月度值来评估公式的有效性。
在对合并症、性别和Kt/V进行校正后，与基于尿素的指标相比，CI和LBM/体重（LBM/BW）是5年全因死亡率的更好预测指标[CI<22 mg/kg/天时生存相对风险（RR）=0.24，P<0.01；LBM/BW<0.75时RR = 0.33，P<0.02]。当根据性别对队列进行划分时，在男性中发现了类似结果，但在女性中未发现。不同的公式能够充分预测Cr(post)和G(Cr)，并以较高的准确率对患者进行分类（CI<22：敏感性=94%，特异性=82%；LBW/BW<0.75：敏感性=89%，特异性=90%）。
在血液滤过人群中，CI和LBM是长期生存的优秀预测指标。在无尿的白种人血液透析患者中，无需依赖正式模型，通过生化和人体测量学测量即可估算CI和LBM。
