Malnutrition is a common phenomenon, particularly in those at an increased risk of muscle mass and function losses. In this systematic review and meta-analysis, we aimed to explore the association of malnutrition with sarcopenia in middle-aged and older adults and the prognostic association of malnutrition and sarcopenia vs.

sarcopenia alone on all-cause mortality. PubMed, Scopus, Web of Science, and Cochrane Library were searched from inception until January 2024.

A meta-analysis using a random-effect model was employed, utilizing the Mini Nutritional Assessment (MNA) malnutrition tool as a continuous and categorical variable. The study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42024501521).

Malnutrition was significantly associated with a greater risk of sarcopenia (continuous: k = 12, odds ratio (OR): 1.38, 95% CI 1.18 – 1.61, I = 94.8%, P < 0.01; categorical: k = 37, OR: 2.99, 95% CI 2.26 – 3.96, I = 78.3%, P < 0.01). Sarcopenia and malnutrition was associated with a higher risk of mortality compared to sarcopenia alone (k = 5, hazard ratio (HR): 4.04, 95% CI 1.36 – 11.94, I = 92.8%, P < 0.01).

Meta-regression showed age, sex, and number of adjustments did not explain heterogeneity among studies. The included studies had moderate risk of bias.

Malnutrition is associated with a higher odds of sarcopenia and their combined presence is a better predictor of all-cause mortality compared to sarcopenia alone, further highlighting the importance of applying interventions to counteract these two closely related phenomena.