Lean Mass Estimation by Creatinine Kinetics and Dual-Energy X-Ray Absorptiometry in Peritoneal Dialysis

Abstract

Background: Malnutrition is widely prevalent in dialysis. Malnourished patients present depletion of somatic protein stores and a decrease in lean body mass (LBM) that can be measured by different techniques. Aims: (1) To assess the reliability of lean mass measurements obtained by creatinine kinetics (CrK) in a group of stable peritoneal dialysis (PD) patients, using dual-energy x-ray absorptiometry (DEXA) measurements as the reference method; (2) to establish the reproducibility of LBM estimated by CrK in individual patients analyzing repeated measurement in the short term, and (3) to correlate measurements of LBM with laboratory determinations that assess nutritional status. Methods: We performed a cross-sectional evaluation of LBM by DEXA and CrK in 39 PD patients. In 14 patients we performed repeated measurements of LBM by CrK in the short term. Results: No significant difference was found in mean lean mass values estimated by both methods: mean DEXA LBM was 41.7 kg, 36.1 ± 4.5 kg in females and 52.7 ± 6.4 kg in males and mean CrK LBM was 41.08 kg, 37.5 ± 6.1 kg in females and 48.1 ± 8.4 kg in males. A good correlation was found between both techniques (r = 0.71; p < 0.003). The mean difference between the two methods was 0.638 ± 6.95 kg (95% confidence limits: –12.98 and +14.26). A wide scatter of the differences between both methods was seen throughout the range of measurements of LBM. When LBM by CrK was repeatedly (2–3 times) measured in a period of 3–4 months in 14 patients, it had a coefficient of variation (CV) of 15.39% (range 2.89–42.88%), while body weight CV in the same period was 0.69% (range 0–1.9%). Conclusions: CrK is an unsatisfactory method for the assessment of LBM in PD patients.

Assessment of Body Composition in Peritoneal Dialysis Patients Using Bioelectrical Impedance and Dual-Energy X-Ray Absorptiometry

“…Current techniques include SGA, anthropometric measurements, creatinine kinetics [3], DEXA and bioimpedance [10]. Previous reports have suggested that DEXA scanning is more accurate than SGA, anthropometric measurements and creatinine kinetics, particularly in assessing FM [20]. However, for everyday routine clinical practice the choice of a method to detect protein energy wasting by assessing body composition depends upon the balance between practicality, validity and cost.…”

Reproducibility of serial creatinine excretion measurements in peritoneal dialysis

“…Another study suggested that determination of lean body mass as LBM Cr has advantages over its determination by bioimpedance or dual energy X-ray absorptiometry in overhydrated PD patients[36]. However, several studies have reported substantial differences between LBM Cr and other methods used to assess muscle mass and between LBM Cr and other indices of nutrition in PD patients[35,37-42]. Nevertheless, one of these studies did support the monitoring of EX Cr T as a means of assessing changes in muscle mass[37].…”

Normative Values for Body Compartments of Sedentary White People

“…This is another example of the increasingly numerous clinical applications of assessed muscular mass using DXA [32,33]; a technique that has recently been employed on peritoneal dialysis patients [34], on women carrying a silicone mammary prostheses [35] and on young patients suffering from Crohn's disease [36].…”