The influence of sex on non-motor wearing-off in Parkinson's disease: A WORK-PD post-hoc study

Introduction: The wearing-off phenomenon is characterized by the recurrence of motor and non-motor symptoms of Parkinsonism during a period free from levodopa. It is a pivotal aspect marking the end of the pharmacological "honeymoon" period in Parkinson's disease (PD). A growing body of literature is connecting sex with the likelihood of developing fluctuations. We investigated such an association in a post-hoc analysis of the large WORKPD study. Methods: WORK-PD analyzed the usability of the wearing-off questionnaire 19 (WOQ19) in clinical practice and included cross-sectional data on age, disease duration, time on levodopa, Hoehn and Yahr stage, and WOQ19 scores of 532 PD patients. In the present study, we selected patients with an exposure time to levodopa of at least 1 year. Results: A total of 380 patients were included. Women reported a higher number of wearing-off symptoms than men (6.09 +/- 3.39 vs 4.96 +/- 3.11, p = 0.0006). Sex groups also differed in non-motor symptoms (2 +/- 1.9 vs 1.5 +/- 1.5, p = 0.021), particularly behavioral wearing-off scores being higher in women (p < 0.001). The latter were primarily featured by anxiety-related phenomena. Finally, there was a significant interaction between behavioral symptoms, sex, and age at onset (df = 2, F = 9.79, p < 0.0001), whereas no such interaction was observed with levodopa exposure and motor impairment, unlike motor symptoms. Discussion: Women showed a greater propensity than men to experience wearing-off, particularly non-motor fluctuations on the anxiety spectrum. The latter may demonstrate a lesser reliance on dopamine compared to motor symptoms. This observation could be underpinned by biological variances between genders at the neurotransmitter level.