Objective: To determine features predictive of differential phenoconversion rates in isolated REM sleep Behavior Disorder (iRBD) to a defined neurodegenerative disease (NDD).
Background: iRBD is strongly associated with progression to overt NDD, usually synucleinopathies. Prior studies have focused on older, male-predominant iRBD cohorts; the disease course of women and early-onset iRBD requires further characterization.
Method: 186 iRBD women were matched by month of polysomnogram diagnosis with 186 iRBD men. Baseline demographic and clinical variables and NDD outcomes (Parkinson disease, multiple system atrophy, pure autonomic failure, dementia with Lewy bodies, Alzheimer disease, or mild cognitive impairment diagnosed by standard criteria) were abstracted via chart review. Kaplan Meier curves compared phenoconversion rates for demographic and clinical predictors. Cox-proportional hazards modeling evaluated factors associated with phenoconversion risk.
Results: Age at iRBD diagnosis was lower in women compared with men (54.9 vs 62.5 years, p <0.0001). 46 patients (12%) including 17 women (9.1%) and 29 men (15.6%) phenoconverted during median 6.3 years, slower in women than men at 10 years (20% vs 27%, p=0.03), with lower conversion in antidepressant users (p<0.001) and patients with psychiatric comorbidity (p=0.03). Only older age at diagnosis (HR 1.1 [1.06-1.13]) was associated with phenoconversion after adjusting for RBD symptom duration, sex, antidepressant use and psychiatric comorbidity. Ten-year conversion rates stratified by age at iRBD diagnosis were: <50 years (2%); 50-60 years (9%); 60-70 years (22%); >70 years (67%).
Conclusion: Older age at iRBD diagnosis is the strongest predictor of phenoconversion risk, independent of sex, antidepressant use, and psychiatric comorbidity. The lower conversion rate in our cohort compared with previous studies may be explained by our focus on iRBD women, who trend younger at diagnosis.
To cite this abstract in AMA style:
C. Alexandres, S. Mccarter, G. Tabatabai, L. Leclair-Visonneau, J. Feemster, T. Gossard, P. Timm, D. Sandness, J. Jagielski, E. Strainis, D. Carvalho, M. Junna, M. Lipford, J. Moore, M. Tippmann-Peikert, M. Silber, B. Boeve, E. ST. Louis. Clinical features and phenoconversion risk in women with isolated REM sleep behavior disorder [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/clinical-features-and-phenoconversion-risk-in-women-with-isolated-rem-sleep-behavior-disorder/. Accessed June 15, 2025.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/clinical-features-and-phenoconversion-risk-in-women-with-isolated-rem-sleep-behavior-disorder/