Muscle mass determined from urinary creatinine excretion rate, and muscle performance in renal transplant recipients

Abstract

Background Muscle mass, as determined from 24‐h urinary creatinine excretion rate (CER), is an independent predictor for mortality and graft failure in renal transplant recipients (RTR). It is currently unknown whether CER is comparable with healthy controls after transplantation and whether it reflects muscle performance besides muscle mass. We aimed to compare urinary CER and muscle performance between RTR and healthy controls and to investigate whether urinary CER is associated with muscle performance in RTR. Methods We included RTR, transplanted between 1975 and 2016 in the University Medical Center Groningen. Healthy controls were subjects screened for kidney donation. CER was calculated from a 24‐h urine collection. Muscle performance was assessed by handgrip strength, sit‐to‐stand test, and 2‐min walk test. Statistical analyses were performed using linear regression analyses. Results We included 184 RTR (mean age 56.9 ± 11.9 years, 54% male recipient) and 78 healthy controls (age 57.9 ± 9.9, 47% male recipient). RTR were at a median time of 4.0 (1.1–8.8) years after transplantation. Mean CER was lower in RTR compared to healthy controls (11.7 ± 4.0 vs. 13.1 ± 5.2 mmol/24 h; P = 0.04). Significantly poorer results in muscle performance were found in RTR compared to controls for the handgrip strength (30.5 [23.7–41.1] N vs. 38.3 [29.3–46.0] N, P < 0.001) and the 2‐min walk test (151.5 ± 49.2 m vs. 172.3 ± 12.2 m, P < 0.001) but not for the sit‐to‐stand (12.2 ± 3.3 m vs. 11.9 ± 2.8 m, P = 0.46). In RTR, CER was significantly associated with handgrip strength (std. β 0.33; P < 0.001), independent of adjustment for potential confounders. In RTR, CER was neither associated with the time used for the sit‐to‐stand test (std. β −0.09; P = 0.27) nor with the distance covered during the 2‐min walk test (std. β 0.07; P = 0.40). Conclusions Muscle mass as measured by CER in RTR is lower compared to controls. CER is positively associated with muscle performance in RTR. The results demonstrate that CER does not only reflect muscle mass but also muscle performance in this patient setting. Determination of CER could be an interesting addition to the imaging technique armamentarium available and applied for evaluation of muscle mass in clinical intervention studies and observational studies.

Malnutrition according to GLIM criteria in stable renal transplant recipients: Reduced muscle mass as predominant phenotypic criterion

“…Given the high rate of obesity in our cohort (27%), the prevalence of low muscle mass by use of BIA is probably underestimated in this study population. In addition to the recommended body c Due to incomplete 24-h urine samples or missing data the number (N) available for analysis for creatinine clearance was N ¼ 536, for proteinuria N ¼ 502, for 24-h creatinine excretion N ¼ 534, for 24-h sodium excretion rate N ¼ 534, for 24-h potassium excretion rate N ¼ 520 and for protein intake (24-h urea excretion) N ¼ 501. composition measures, when applied properly, 24-h urinary CER is a reliable non-invasive method to assess muscle mass in the general population and RTR [21,22,59]. However, validated age-and gender specific cut-off values for low muscle mass based on 24-h CER are not yet available, which hampers its clinical use for the diagnosis of malnutrition.…”

“…Furthermore, while standard anthropometric measurements, such as weight and height, are routinely performed at outpatient visits, the assessment of muscle mass, for example with dual energy x-ray absorptiometry (DEXA) or bio-electrical impedance analysis (BIA) as recommended by GLIM, is usually not part of routine care due to practical and time constraints [26]. In several renal transplant care centers, however, 24-h urine samples are routinely collected during outpatient visits, enabling measurement of 24-h urinary creatinine excretion rate (CER), which has shown to be a reliable marker of muscle mass in RTR [21,22]. Therefore, it is worthwhile to explore its potential value for the assessment of reduced muscle mass in diagnosing malnutrition in this population.…”

Malnutrition screening on hospital admission: impact of overweight and obesity on comparative performance of MUST and PG-SGA SF

“…Therefore, other methods for bedside measurement, such as ultrasound, are gaining interest, but require further investigation [56]. Moreover, 24-h urine collections allow assessment of muscle mass from excretion of creatinine, but are only available in specific settings [57][58][59]. Thus, although additional body composition assessment is required to make an adequate diagnosis of malnutrition, its application in daily practice remains challenging.…”

Female Specific Association of Low Insulin-Like Growth Factor 1 (IGF1) Levels with Increased Risk of Premature Mortality in Renal Transplant Recipients

“…To this regard, a large and growing group of patients that might be worthwhile studying is that of renal transplant recipients (RTR), in which protein-energy wasting is always lurking [17][18][19]. In fact, it has been found that the risk of premature mortality in this population is 6-7 times higher compared to the general population [20], and this risk was particularly high in RTR with low muscle mass, as reflected by low 24 h urinary creatinine excretion [21,22]. Recent studies furthermore suggested that 24 h urinary creatinine excretion may be a noninvasive, easily accessible, inexpensive, and direct measurement of total body muscle mass [19], while this measure is often not included in clinical studies to complement the imaging technique armamentarium which is applied for evaluation of muscle mass in observational and clinical intervention studies [23][24][25].…”