The effect of nutritional status on respiratory muscle strength in patients with sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown etiology. Fatigue is one of the most commonly reported symptoms, and its cause remains under investigation. Factors such as reduced lung function, diminished respiratory muscle strength, physical deconditioning, and corticosteroid-induced myopathy may contribute to fatigue. The importance of assessing nutritional status in evaluating respiratory system diseases has been increasingly recognized. This study aimed to investigate the impact of nutritional assessment on reduced peripheral muscle strength, respiratory muscle strength, and exercise capacity in patients with sarcoidosis. This prospective, case-control study included 31 sarcoidosis patients who were not receiving systemic corticosteroid therapy and 24 healthy controls matched for age and sex. Participants underwent functional exercise capacity evaluation using the 6-minute walk test (6MWT), respiratory muscle strength assessment via maximum inspiratory (MIP) and expiratory pressures (MEP), peripheral muscle strength measurement using handgrip dynamometry, and pulmonary function tests. Nutritional status was evaluated using the Mini Nutritional Assessment (MNA) questionnaire and body composition analysis via bioelectrical impedance. Despite similar lung function and respiratory muscle strength, sarcoidosis patients demonstrated significantly lower 6MWT distances compared to controls. Body mass index (BMI) and fat mass were higher in sarcoidosis patients, while lean mass, soft tissue mass, skeletal muscle mass, body fluid weight, and peripheral muscle strength were similar between the groups. No significant differences in MIP, MEP, or their predicted percentage values were observed between sarcoidosis patients and controls. Positive correlations were identified between MIP, MEP, and lean body mass. Sarcoidosis patients did not show significant differences in Prognostic Nutritional Index (PNI) values compared to controls. This study highlights the importance of individualized interventions, including lifestyle modifications, nutritional support, and physical rehabilitation, in addressing fatigue in sarcoidosis, alongside treating the underlying inflammation.