Objectives: Sarcopenia is characterized by the loss of muscle mass. Skeletal muscle can produce and secrete different molecules called myokines. Irisin and myostatin are antagonistic myokines, and to our knowledge, no studies of both myokines have been conducted in patients with disease-related malnutrition (DRM). This study aimed to investigate the role of circulating irisin and myostatin in sarcopenia in patients with DRM.
Methods: The study included 108 outpatients with DRM according to the Global Leadership Initiative on Malnutrition criteria. Participants had a mean age of 67.4 ± 3.4 y. Anthropometric data, muscle mass by ultrasound at the rectus femoris quadriceps (RFQ) level, impedancemetry (skeletal muscle mass [SMM], appendicular SMM [aSMM], and aSMM index [aSMMI]), dynamometry, biochemical parameters, dietary intake, circulating irisin and myostatin levels were determined in all patients. Confirmed sarcopenia was diagnosed as criteria of probable sarcopenia (low muscle strength) plus abnormal aSMMI.
Results: Of the 108 patients, 44 presented sarcopenia (41%); 64 did not present with the disorder (59%). The following parameters were worse in patients with sarcopenia:
• Body weight (–6.8 ±2.3 kg; P = 0.01),
• Calf circumference (–2 ±0.3 cm; P = 0.02),
• Phase angle (–0.6 ±0.1º; P = 0.01),
• Reactance (–40.8 ±12.3Ω; P = 0.03),
• SMM (–2.4 ±0.3 kg; P = 0.04),
• aSMM (–2.2 ±0.2 kg; P = 0.03),
• aSMMI (–0.9 ±0.2 kg; P = 0.02),
• Dominant muscle area RFQ (–0.9 ±0.2 cm2; P = 0.04),
• Dominant Y-axis RFQ (–0.3 ±0.1 cm; P = 0.03),
• Dominant X/Y-axis RFQ (0.8 ±0.3 cm; P = 0.04),
• Albumin (–0.8 ±0.1 g/dL; P = 0.04), and
• Prealbumin (–3.6 ±0.7 mg/dL; P = 0.02).
Patients without sarcopenia were stronger than those with the disorder (7.9 ±1.3 kg; P = 0.01). Circulating irisin levels were higher in patients without sarcopenia than those with sarcopenia (651.3 ± 221.3 pg/mL; P =0.01). Myostatin levels were similar in both groups. Finally, logistic regression analysis reported a low risk for sarcopenia (odds ratio, 0.39; 95% confidence interval, 0.19–0.92; P = 0.03) in high irisin median levels as a dichotomic parameter after adjusting for body mass index, sex, energy intake, and age.
Conclusion: The present study reported that low levels of serum irisin were closely associated with sarcopenia in patients with DRM.
