Prevalence and Factors Associated with Drooling in Parkinson's Disease: Results from a Longitudinal Prospective Cohort and Comparison with a Control Group

Abstract

Introduction: Drooling in Parkinson's disease (PD) is frequent but often goes underrecognized. Our aim was to examine the prevalence of drooling in a PD cohort and compare it with a control group. Specifically, we identified factors associated with drooling and conducted subanalyses in a subgroup of very early PD patients. Patients and Methods. PD patients who were recruited from January 2016 to November 2017 (baseline visit; V0) and evaluated again at a 2-year ± 30-day follow-up (V2) from 35 centers in Spain from the COPPADIS cohort were included in this longitudinal prospective study. Subjects were classified as with or without drooling according to item 19 of the NMSS (Nonmotor Symptoms Scale) at V0, V1 (1-year ± 15 days), and V2 for patients and at V0 and V2 for controls.

Results: The frequency of drooling in PD patients was 40.1% (277/691) at V0 (2.4% (5/201) in controls; p < 0.0001), 43.7% (264/604) at V1, and 48.2% (242/502) at V2 (3.2% (4/124) in controls; p < 0.0001), with a period prevalence of 63.6% (306/481). Being older (OR = 1.032; p = 0.012), being male (OR = 2.333; p < 0.0001), having greater nonmotor symptom (NMS) burden at the baseline (NMSS total score at V0; OR = 1.020; p < 0.0001), and having a greater increase in the NMS burden from V0 to V2 (change in the NMSS total score from V0 to V2; OR = 1.012; p < 0.0001) were identified as independent predictors of drooling after the 2-year follow-up. Similar results were observed in the group of patients with ≤2 years since symptom onset, with a cumulative prevalence of 64.6% and a higher score on the UPDRS-III at V0 (OR = 1.121; p = 0.007) as a predictor of drooling at V2.

Conclusion: Drooling is frequent in PD patients even at the initial onset of the disease and is associated with a greater motor severity and NMS burden.

Figure 1

(a) Percentage of patients (the whole cohort and the group with no more than 2 years since symptom onset (PD ≤ 2 y) and controls reporting drooling at different visits: V0, V1, and V2. (b) Prevalence of drooling during the follow-up period in all patients and in the PD ≤ 2 y group who completed the three visits (V1, V2, and V3) and percentage of cases presenting drooling in only 1 visit, 2 visits, and all visits. PD cohort vs. controls at V0, p < 0.0001; PD cohort vs. controls at V2, p < 0.0001; PD ≤ 2 y group vs. controls at V0, p < 0.0001; PD ≤ 2 y group vs. controls at V2, p < 0.0001. PD: Parkinson's disease. PD ≤ 2 y group: patients with ≤2 years since symptom onset.

Figure 2

(a) Number of patients reporting drooling at V0, V1, and V2 when they were divided in patients with vs. without dysphagia and with vs. without hypomimia (the whole cohort). A comparison between the percentage is shown for each analysis. (b) Number of patients from the PD ≤ 2 y group reporting drooling at V0, V1, and V2 when they were divided in patients with vs. without dysphagia and with vs. without hypomimia. A comparison between the percentage is shown for each analysis. PD: Parkinson's disease. PD ≤ 2 y group: patients with ≤2 years since symptom onset.

Figure 3

(a) Mean score on each domain of the PDQ-39 at the baseline in PD patients from the entire cohort with vs. without drooling; p < 0.0001 for all analysis except for “emotional well-being” (p = 0.001), “stigmatization” (p = 0.129), and “pain and discomfort” (p = 0.063). (b) Mean score on each domain of the EUROHIS-QOL8 at the baseline in PD patients from the entire cohort with vs. without drooling; “quality of life,” p = 0.005; “health status,” p = 0.178; “energy,” p = 0.183; “autonomy for ADL,” p = 0.011; “self-esteem,” p = 0.033; “social relationships,” p = 0.032; “economic capacity,” p = 0.020; “habitat,” p = 0.046. EUROHIS-QOL8, EUROHIS-QOL 8-item index; PD, Parkinson's disease; PDQ-39, 39-item Parkinson's disease quality of life questionnaire.