Low muscle mass in COVID-19 critically-ill patients: Prognostic significance and surrogate markers for assessment.

INTRODUCTION: Low muscle mass is a common condition in the critically ill population and is associated with adverse clinical outcomes. The primary aim of this study was to analyze the prognostic significance of low muscle mass using computed tomography (CT) scans in COVID-19 critically ill patients. A second objective was to determine the accuracy and agreement in low muscle mass identification using diverse markers compared to CT as the gold standard. METHODS: This was a prospective cohort study of COVID-19 critically ill patients. Skeletal muscle area at the third lumbar vertebra was measured. Clinical outcomes (intensive care unit [ICU] and hospital length of stay [LOS], tracheostomy, days on mechanical ventilation [MV], and in-hospital mortality) were assessed. Phase angle, estimated fat-free mass index, calf circumference, and mid-upper arm circumference were measured as surrogate markers of muscle mass. RESULTS: Eighty-six patients were included (mean age ± SD: 48.6 ± 12.9; 74% males). Patients with low muscle mass (48%) had a higher rate of tracheostomy (50 vs 20%, p = 0.01), prolonged ICU (adjusted HR 0.53, 95%CI 0.30-0.92, p = 0.024) and hospital LOS (adjusted HR 0.50, 95% CI 0.29-0.86, p = 0.014). Bedside markers of muscle mass showed poor to fair agreement and accuracy compared to CT-assessed low muscle mass. CONCLUSION: Low muscle mass at admission was associated with prolonged length of ICU and hospital stays. Further studies are needed to establish targeted nutritional interventions to halt and correct the catabolic impact of COVID-19 in critically ill patients, based on standardized and reliable measurements of body composition.

Obestatin and adropin in Prader-Willi syndrome and nonsyndromic obesity: Associations with weight, BMI-z, and HOMA-IR.

The roles of obestatin and adropin in paediatric obesity are poorly understood. We compared obestatin and adropin concentrations in younger (n = 21) and older children (n = 14) with Prader-Willi syndrome (PWS) and age and BMI-z-matched controls (n = 31). Fasting plasma obestatin and adropin were higher in younger children with PWS than controls; adropin was also higher in older children with PWS. Growth hormone treatment had no effects on obestatin or adropin in PWS. The ratio of ghrelin to obestatin declined from early to late childhood but was higher in older PWS than older controls. Adropin correlated with fasting glucose in the PWS group only. Changes in the ratio of ghrelin to obestatin may suggest changes in the processing of preproghrelin to ghrelin and obestatin during development and differential processing of preproghrelin in PWS.

Sarcopenia and cachexia in the era of obesity: clinical and nutritional impact.

Our understanding of body composition (BC) variability in contemporary populations has significantly increased with the use of imaging techniques. Abnormal BC such as sarcopenia (low muscle mass) and obesity (excess adipose tissue) are predictors of poorer prognosis in a variety of conditions or clinical situations. As a catabolic illness, a defining feature of cancer is muscle loss. Although the conceptual model of wasting in cancer is typically conceived as involuntary weight loss leading to low body weight, recent studies have shown that both sarcopenia and cachexia can be present with obesity. The combination of low muscle and high adipose tissue (sarcopenic obesity) is an emerging abnormal BC phenotype prevalent across the body weight, and hence BMI spectra. Sarcopenia and sarcopenic obesity in cancer are in most instances occult conditions, which have been independently associated with higher incidence of chemotherapy toxicity, shorter time to tumour progression, poorer outcomes of surgery, physical impairment and shorter survival. Although the mechanisms are yet to be fully understood, the associations with poorer clinical outcomes emphasise the value of nutritional assessment as well as the need to develop appropriate interventions to countermeasure abnormal BC. Sarcopenia and sarcopenic obesity create diverse nutritional requirements, highlighting the compelling need for a more comprehensive and differentiated understanding of energy and protein requirements in this heterogeneous population.