Motor subtypes and other risk factors associated with drooling in Parkinson's disease patients

Objective To explore the relationship between motor subtypes and drooling, and other risk factors associated with drooling in a large cohort of Chinese patients with Parkinson's disease (PD). Methods A total of 586 PD patients were enrolled in this study. Unified Parkinson's disease rating scale (UPDRS) and Hoehn & Yahr stage (H & Y stage) scale, Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Hamilton Rating Scale for Depression-24 item (HRSD), and Mini-Mental State Examination (MMSE) were applied to all subjects. Salivary subscores of UPDRS part II were used to evaluate drooling. Constipation was diagnosed using the Rome III criteria. Results The prevalence of drooling in this cohort is 54.6% (320/586). Non-TD subtype PD patients tend to have higher daily levodopa-equivalent dose (LED), H & Y stage, UPDRS I, UPDRS II, and UPDRS III scores, HRSD score and ESS score, a higher percentage of levodopa treatment, drooling, dyskinesia, and constipation. After adjusting for confounders, non-TD subtype, male sex, UPDRS III score, ESS and PSQI scores, and constipation were still associated with drooling, with corresponding Odds ratios and 95% confidence intervals (95% CIs) were 1.865 (95% CI, 1.137-3.060), 1. 951 (95% CI, 1.326-2.869), 1.024 (95% CI, 1.002-1.046), 1.064 (95% CI, 1.024-1.105), 1.058 (95% CI, 1.000-1.119), and 1.603 (95% CI, 1.092-2.353), respectively. Conclusion Drooling is common, even in mild-to-moderate PD patients. PD patients with non-TD subtype are at a higher risk of drooling. Male sex, motor severity, excessive daytime sleepiness, poor nighttime sleep, and constipation are also associated with drooling in patients with PD.