Exploring the intersection between orthostatic hypotension and daytime sleepiness in Parkinson disease

Introduction Daytime sleepiness, reported in about 50% of patients with Parkinson disease (PD), is associated with high morbidity, poor quality of life and increased risk for accidents. While an association between dysautonomia and daytime sleepiness in early, de-novo PD has been reported, our understanding of the role of medications, cognitive status and disease duration on this relationship is inadequate. Methods Data were analyzed from the prospective Cincinnati Cohort Biomarkers Program. The primary outcome of interest was daytime sleepiness, as measured by the Epworth Sleepiness Scale (ESS). The primary exposure variable was orthostatic hypotension (OH) with a sub-analysis for the neurogenic OH (nOH) subtype. Regression analyses were carried out adjusting for the following covariates: age, sex, disease duration, education, comorbidities, anti-cholinergic burden, levodopa equivalent dose (LEDD), motor subscore of the Movement disorder society-unified Parkinson disease rating scale, Hoehn and Yahr stage (H&Y), Beck Depression Inventory, and Beck Anxiety Inventory. Results Data on 456 subjects with PD were analyzed. OH was strongly associated with ESS scores, particularly in those with anticholinergic medication use after adjusting for all covariates (RC, 4.30; p<0.001). This adjusted association was more pronounced in men with early disease duration, early H&Y stage, no cognitive decline, and LEDD≤750 mg. Similar results were noted with nOH. Conclusions OH is associated with daytime sleepiness to a greater extent in male patients with early disease and magnified by such prescribing practices as anticholinergic medication use and dopaminergic dosage in early PD. This relationship is independent of cognitive decline.