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.