Prevalence of low muscle mass and its association with orthostatic hypotension and related symptoms in Parkinson's disease.

Although muscle mass loss is an emerging public health concern, its prevalence, associated factors, and clinical significance in Parkinson's disease (PD) remain unclear. This matched case-control study aimed to investigate the prevalence of low muscle mass (LMM) and to examine its association with orthostatic hypotension (OH) and orthostatic symptoms in 409 PD patients with Hoehn and Yahr stage ≤3, compared with 2045 age-, sex-, and height-matched controls from a nationwide database. OH was defined according to the international consensus. LMM was more prevalent in PD patients than in controls, particularly among men and those aged ≥70 years. Among PD patients, the prevalence of OH did not differ between those with and without LMM. Although LMM was linked to greater orthostatic blood pressure reductions at 30 s after standing, there were no differences in the frequency or severity of orthostatic symptoms according to LMM status. These findings suggest that although mild to moderate PD is associated with an increased risk of LMM, its impact on OH and related symptoms appears to be modest. Further longitudinal studies are needed to clarify the clinical implications of LMM in PD.