Stridor Is an Independent Risk Factor for Mortality and Disease Progression in Patients with Multiple System Atrophy

Background and aim Stridor and sleep apnea syndrome (SAS) are common in multiple system atrophy (MSA). Retrospective cohort studies have yielded conflicting results regarding the consequences of stridor and SAS on the disease course. This study aimed to assess the prognostic significance of stridor and SAS, as well as the potential survival benefits of continuous positive airway pressure (CPAP) therapy. Method Retrospective data from 232 participants with MSA (mean age 65 years old, 51% male) from the three sites of the French Reference Center for MSA were analyzed. Patients underwent video‐polysomnography to confirm the presence of stridor and SAS (AHI >15). Survival analyses adjusted for disease progression, age, sex, MSA subtype, and time since symptom onset were conducted using a joint modeling approach. Disease progression was quantified by the repeated assessments of a six‐item composite score and the total Unified MSA Rating Scale I + II. Results Stridor was independently associated with an increased risk of mortality (hazard ratio [HR] = 2.44 [1.41;4.22]), even after adjusting for disease progression. Stridor was also linked to more severe disease progression over time. In contrast, SAS did not independently predict mortality or disease progression. CPAP therapy initiation was associated with a substantial reduction in mortality risk after adjusting for center and AHI (HR = 0.40 [0.19;0.85], P = 0.017). Discussion Stridor is a critical prognostic factor in MSA, associated with higher mortality and worse disease progression, whereas SAS alone is not associated with a change in mortality. Patients undergoing CPAP therapy have a much better survival among those with stridor.