Effect of sexual dimorphism on muscle strength in cachexia

BACKGROUND Reduced muscle strength is a cardinal feature in cachexia. We investigated whether weight loss is associated differently with muscle strength in men and women in a large cohort of hospitalized patients. METHODS One thousand five hundred hospitalized patients (whereof 718 men, mean age 57.6 ± 16.0 years, mean body mass index (BMI) 24.6 ± 4.8 kg/m²) were included in the study. Non-edematous involuntary weight loss was determined with Subjective Global Assessment; isometric maximal muscle strength was evaluated by hand grip strength. Mid-upper arm circumference and triceps skinfold were used to calculate arm muscle area. Interrelationship between sex and weight loss was evaluated by regression analysis performed with the general linear model (GLM) allowing adjustment for continuous and categorical variables and corrected for age, arm muscle area (AMA), BMI, and diagnosis category (benign/malignant disease) as potentially confounding covariates. RESULTS Both men and women exhibited a significant stepwise decrease of hand grip strength with increasing weight loss. Age, sex, moderate and severe weight loss, BMI, and AMA were significant predictors of hand grip strength. The GLM moreover revealed a significant sex × weight loss effect, since grip strength was similarly decreased in moderate weight loss in men and women when compared to control patients without weight loss (8.5% in men and 10.5% in women, not significant (n.s.)), but the further reduction of grip strength in severe weight loss was significantly different between men and women (10.6% vs. 4.1%, P = 0.033). CONCLUSIONS Our findings indicate sex-specific differences in muscle strength response to weight loss.