Since DPP-4 inhibitors prevent the degradation of substance P involved in swallowing reflex, DPP-4 inhibitors were expected to prevent dysphagia and aspiration pneumonia.
The aim of the study was to investigate SP in PD patients in order to gain further insights into the underlying pathophysiology of PD-related dysphagia and to evaluate the potential of SP as a biomarker for early dysphagia.