Dyspnea and dystussia in Parkinson's disease: patient-reported prevalence and determinants

The prevalence of respiratory dysfunction in PD is unknown and a better understanding of determinants contributing to respiratory dysfunction is important to facilitate early recognition and treatment.

To examine the prevalence and determinants of self-reported symptoms of respiratory dysfunction among people with PD.

In a cross-sectional study, we administered a self-completed questionnaire among a sample of 939 persons with PD. Respiratory dysfunction was defined as experiencing at least one of the following symptoms: breathing difficulties, breathlessness/shortness of breath, tightening of the chest, frequent throat clearing, frequent coughing, or coughing difficulties. A principal component analysis (PCA) was used to define composite constructs of respiratory dysfunction. The association with participant-reported determinants was assessed using multivariable logistic regression models (with adjustment for pulmonary diseases and COVID-19 symptoms).

The overall prevalence rate of respiratory dysfunction was 44% in persons with PD (42% after excluding pulmonary diseases or COVID-19). The PCA resulted in two constructs of respiratory dysfunction: 'dyspnea' and 'dystussia' (an impaired cough response), which together explained 68% of the total variance. Female sex (OR = 1.39), higher BMI kg/m² (OR = 1.04), longer disease duration (OR = 1.35), greater self-reported rigidity (OR = 1.16), previous pulmonary disease(s) (OR = 7.12), and anxiety (OR = 1.04) were independently associated with 'dyspnea'. Pulmonary disease(s) (OR = 1.81), COVID-19 symptoms (OR = 2.20), swallowing complaints (OR = 1.48), and speech complaints (OR = 1.02) were independently associated with 'dystussia'.

Dyspnea and dystussia are common manifestations of respiratory dysfunction among people with PD and deserves more awareness in clinical practice. A proactive screening for the determinants of dyspnea and dystussia may contribute to earlier recognition and treatment of respiratory dysfunction.