Elevated serum leptin levels are associated with low muscle strength and muscle quality in male patients undergoing chronic hemodialysis

OBJECTIVES: Low muscle strength and poor muscle quality are highly prevalent in patients with chronic hemodialysis (HD), which lead to an increased risk of poor clinical outcomes. Leptin dysregulation is common in HD patients. Given that leptin receptors are abundant in skeletal muscle, there may be a link between leptin and muscle strength. The cross-sectional study aimed to explore the correlation of serum leptin levels with muscle strength and muscle quality in patients with chronic HD. MATERIALS AND METHODS: A total of 118 chronic HD patients were included in this study. Basic characteristics, handgrip strength, body composition were assessed, and blood samples for serum leptin levels and other biochemical test were obtained. We defined skeletal muscle index (SMI) as skeletal muscle mass/height(2) (kg/m(2)) and muscle quality as handgrip strength divided by mid-arm muscle circumference (MAMC). Patients were classified into tertile groups, according to sex-specific leptin levels. RESULTS: We observed that patients in the higher leptin tertile tend to have a higher body weight, body mass index (BMI), body fat mass, MAMC, and SMI, while the handgrip strength and muscle quality were significantly lower. Bodyweight (r = 0.30; P = 0.001), BMI (r = 0.45; P = 0.001), body fat mass (r = 0.57;P < 0.001), and SMI (r = 0.22; P = 0.018) were positively and handgrip strength (r = −0.27; P = 0.003) and muscle quality (r = −0.35;P < 0.001) were negatively correlated with serum leptin levels, respectively. After adjusting multiple confounding factors, logarithmically transformed serum leptin levels were independently associated with handgrip strength (β = −3.29, P = 0.005) and muscle quality (β = −0.14, P = 0.009). However, gender-stratified models showed the associations were observed only in male, but not in female. CONCLUSION: We concluded that higher serum leptin levels are associated with low handgrip strength and poor muscle quality in male patients on chronic HD. Further studies are needed to clarify the gender differences and to evaluate the casual relationship between circulating leptin levels and muscle strength.