The association between body composition and orthostatic hypotension in patients with neurodegenerative disorders in parkinsonism-related multidisciplinary clinic.

INTRODUCTION

Orthostatic hypotension (OH) commonly impairs the quality of life and prognosis of patients with neurodegenerative disorders. Since skeletal muscle functions as a peripheral pump for blood pressure stabilization and a reservoir for intracellular water, we investigated its association with body composition in these patients.

METHODS

This prospective cross-sectional study included 86 patients with neurodegenerative disorders from Parkinsonism-related Multidisciplinary Clinic in Peking Union Medical College Hospital (PUMCH), including multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and other atypical parkinsonian syndromes (APS). OH was defined as a sustained reduction in systolic blood pressure of ≥20 mmHg or diastolic blood pressure of ≥10 mmHg within 3 min of active standing. Participants were divided into with OH and without OH (non-OH). Body composition was measured via Bioelectrical Impedance Analysis (BIA). The measured values were normalized to height squared to generating indices such as the fat-free mass index (FFMI) and appendicular muscle mass index (AMI). Clinical scores, levodopa equivalent daily dosage (LEDD), and grip strength were compared between groups. Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia 2019 (AWGS2019) criteria.

RESULTS

The incidence of OH was 45.3%, significantly higher in MSA (58.0%) than in PSP (13.3%). Sarcopenia prevalence did not differ significantly between groups. Elastic net and support vector machine (SVM) analysis identified lower limb extracellular water index (LLEWI) and AMI as the most predictive body composition indicators for OH. Linear regression confirmed AMI as an independent negative predictor of orthostatic systolic blood pressure change (β = -4.69, p = 0.008).

CONCLUSION

Our findings indicate that OH is significantly associated with decreased AMI and lower LLEWI. Measuring these indices may offer valuable insights into OH risk, potentially serving as a more sensitive early indicator than a formal diagnosis of sarcopenia.