Nutritional Factors and Weight Loss Predict Tracheostomy‐Free Survival in Multiple System Atrophy

Abstract

BACKGROUND: Multiple system atrophy (MSA) leads to progressive weight loss and nutritional decline, yet the prognostic significance of specific nutritional factors remains unclear. OBJECTIVES: This study aimed to examine the prognostic value of nutritional parameters, including prognostic nutritional index (PNI), and the annual rate of body mass index (BMI) decline (∆BMI), in patients with MSA. METHODS: We retrospectively analyzed 215 patients with MSA diagnosed according to the 2022 Movement Disorder Society Criteria. Baseline clinical and nutritional parameters included onset age, motor subtype, orthostatic hypotension (OH), Unified MSA Rating Scale (UMSARS) Part I-item 2 and Part IV scores, PNI, and BMI. ∆BMI was calculated post-diagnosis. Survival length was defined as the time from diagnosis to death or tracheostomy. Factors associated with survival were assessed using log-rank and Cox proportional hazards analyses. RESULTS: The mean survival after diagnosis was 3.3 (SD 2.0) years. Log-rank tests showed significant associations of the MSA-P subtype, lower PNI, greater ∆BMI, higher UMSARS Part I-item 2 and Part IV scores, and OH with shorter survival. In multivariate Cox models, lower PNI (HR 2.12; 95% CI 1.14-3.94; p = 0.018), greater ∆BMI (HR 2.90; 95% CI 1.58-5.31; p < 0.001), and higher UMSARS Part I-item 2 scores (HR 1.59; 95% CI 1.10-2.30; p = 0.014) independently predicted shorter survival. CONCLUSIONS: Nutritional decline, as assessed by PNI and ∆BMI, predicts shorter survival in MSA independently of the severity of dysphagia. These findings emphasize the importance of monitoring nutritional status alongside swallowing function to improve clinical outcomes.