#826 Protein-energy wasting and sarcopenia in assessing the outcomes and quality of dialysis
Authors: Al-Barbari Karim , Gerasimchuk Roman , Zemchenkov Alexander , Vishnevskii Konstantin , Rumyantsev Aleksander 
Published: May 2024

Abstract

Background and Aims
Sarcopenia is one of the serious complications of long-term hemodialysis (HD) therapy and is one of the independent predictors of morbidity and mortality in this population. Sarcopenia is associated with low physical activity, depression and low social adaptation. There are few estimates of the sarcopenia prevalence in HD patients, and they fit into the range of 15-30% in the general group and 45-60% among patients over 60 yo. The aim: in a prospective study, to clarify the prevalence, outcomes and risk factors of sarcopenia in comparison with protein and energy wasting (PEW) severity data. The results of the first year follow-up of the first cohort in the ongoing study are presented below.

Method
In the group of 99 prevalent patients of single HD center (vintage 26.4; 21.8-93.3 months; age 55±17 years, HD/HDF for 4-4.5 hours three-time weekly; Kt/V 1.57±0.31), the prevalence of sarcopenia was estimated (muscle mass was assessed anthropometrically and by bioimpedance (BIA), BodyStat 5000). The presence of sarcopenia was assessed by EWGSOP2 criteria, muscle strength - by wrist expander. The reference values for men and women were &gt;27 kg and &gt;16 kg. The PEW degree was assessed by 24-point scale (BMI, arm circumference, skin-fat fold above the triceps, arm muscle circumference, total protein, albumin, transferrin, absolute lymphocytosis; max 3 point for each). Obesity was established at BMI &gt;30 kg/m² or according to the fat mass index &gt;9 kg/m² in men and &gt;13 kg/m² in women. The quality of life was assessed by KDQOL-SF™ after exclusion of patients with significant depression by the Beck scale.

Results
The muscle mass indices calculated anthropometrically (IMMA) and by bioimpedance (IMMB) were well correlated: IMMA=0.15+1.06×IMMB, R²=76%; diagnostic efficacy (in detecting sarcopenia) IMMA to IMMB was 86%. The prevalence of PEW by stage: absent (scores of all assessed scales - 3) – 59%, grade 1 (average score ≥2 and &lt;3) – 32%, grade 2 (average score ≥1 and &lt;2); in one patient, PEW was classified as severe (average score of scales &lt;1). In the univariate and in the multiple adjusted analysis (for age, gender, provided dialysis dose and average ultrafiltration, hemoglobin and phosphate levels), the degree of PEW or the presence of PEW was not associated with the risk of death. At the same time, the phase angle (PA) of bioimpedance had such a link: the PA increase in by 1° was associated with a 24.4% reduction in the risk of death (95%CI 3.9-40.4%; p=0.022), and the inclusion of the same set of variables in the regression analysis model as for the PEW only weakened, but did not eliminated the link (OR decrease by 26.9%; 0.3-46.4%; p=0.048). The risk of death was not associated with obesity.
Sarcopenia was detected in 52% of patients. It was not associated with the presence (severity) of PEW in women, but in men it was 1.48 times more common in the presence of PEW (p=0.049); in the entire group, the higher prevalence of sarcopenia in the presence of PEW (by 34%) did not reach significance (p=0.3). In multiple regression analysis, the presence of sarcopenia was associated with a 1.95-fold higher risk of death (95% CI 1.001-3.809; p=0.050). In the presence of sarcopenia, the quality of life scores were significantly lower for the scales of Physical functioning, Energy, and Physical Composite Score. The higher prevalence of sarcopenia among men than in women remains unexplained. It is possible that uniform thresholds for muscle mass and muscle strength are not suitable for all populations and require clarification.

Conclusion
Sarcopenia is the feature of more than half of HD patients and is significantly associated with an increased risk of death. PEW and sarcopenia, including partially similar indicators in their estimates, turned out to be poorly related in HD patients, and sarcopenia is more closely associated with hard outcomes than PEW. A separate assessment of these conditions and a search for contributing factors for its development/progression are required in prospective studies. One of the key objectifying indicators of the PEW and sarcopenia assessment could be the phase angle of bioimpedance associated with both clinical predictors and outcomes.