Orthostatic Hypotension in Multiple System Atrophy: Related Factors and Disease Prognosis

Background: Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by Parkinsonism, ataxia, and autonomic nervous failure. Orthostatic hypotension (OH) is the main feature of central vascular autonomic failure in MSA. Objective: The study aimed elucidate the effects of OH on cognitive function, disease milestones, and survival. Methods: A total of 444 patients with clinically established MSA were enrolled. Mild and severe OH were defined as a decrease in systolic blood pressure (SBP)/diastolic blood pressure (DBP) >20/10 mmHg and SBP/DBP ≥30/15 mmHg, respectively. Results: In this study, 215 MSA patients presented without OH, 88 had mild OH, and 141 had severe OH. The proportion of MSA-C in the severe OH subgroup was significantly higher than that in the subgroup without OH (95/46 vs. 113/102, p = 0.021). The UMSARS I score and the frequency of supine hypertension (SH) in patients with OH were significantly higher than those in patients without OH (16.22 vs. 16.89 vs. 14.60, p < 0.001; 77/64 vs. 29/59 vs. 32/183, p < 0.001). Factors related to the severity of OH included sex (OR, 0.65; p = 0.031), onset age (OR, 0.98; p = 0.029), and SH (OR, 0.21; p < 0.001). The median survival time of patients with severe OH was significantly lower than that of patients without OH (6.79 vs. 8.13 years, p = 0.001). Consistently, Cox survival analysis found that compared with patients without OH, patients with severe OH had a significantly increased risk of death (OR, 2.22; p < 0.001). Conclusion: Our large cohort study of MSA provides additional evidence for the negative impact of severe OH on survival.