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

Background & Aims: Malnutrition has a negative impact on quality of life and survival in renal transplant recipients (RTR). Therefore, malnutrition detection is important in RTR, but this may be hampered by concomitant presence of weight gain and overweight. Recently, the Global Leadership Initiative on Malnutrition (GLIM) developed a set of diagnostic criteria for malnutrition. We aimed to assess the prevalence of malnutrition according to the GLIM criteria and the distribution of phenotypic criteria in RTR. Additionally, we examined the potential value of 24-h urinary creatinine excretion rate (CER) as alternative measure for the criterion reduced muscle mass.

Methods: We used data from stable outpatient RTR included in the TransplantLines Cohort and Biobank Study (NCT02811835). Presence of weight loss and reduced intake or assimilation were derived from Patient-Generated Subjective Global Assessment (PG-SGA) item scores. Reduced muscle mass was assessed by multi-frequency bio-electrical impedance analysis (MF-BIA) and defined as an appendicular skeletal muscle mass index (ASMI) < 7 kg/m for men and <5.5 kg/m for women, and in additional analysis defined as creatinine-height index (CHI, based on 24 h urine CER) < 80%. Inflammation was present if C-reactive protein (CRP) was >5 mg/L. Malnutrition was defined as presence of at least one phenotypic (weight loss and/or low BMI and/or reduced muscle mass) and one etiologic criterion (reduced intake/assimilation and/or disease burden/inflammation).

Results: We included 599 RTR (55 ± 13 years old, 62% male, BMI 27.2 ± 4.7 kg/m) at a median of 3.1 years after transplantation. According to GLIM criteria, 14% was malnourished, of which 91% met the phenotypic criterion for reduced muscle mass. Similar results were found by using CHI as measure for muscle mass (13% malnutrition of which 79% with reduced muscle mass).

Conclusions: Malnutrition is present in one in 7 stable RTR, with reduced muscle mass as the predominant phenotypic criterion. Assessment of nutritional status, most importantly muscle status, is warranted in routine care, to prevent malnutrition in RTR from remaining undetected and untreated. The diagnostic value of 24-h urinary CER in this regard requires further investigation.