GDF15 and Parkinson disease: Although elevated serum GDF-15 levels have been reported in Parkinson's disease (PD), their association with clinical features has not been fully characterized.<h4>Methods</h4>We evaluated serum GDF-15 concentrations in 40 patients with PD and analyzed their relationships with clinical measures, including motor severity (MDS-UPDRS), quality of life (PDQ-39), sleep disturbances (PDSS-2), autonomic symptoms (SCOPA-AUT), and cognitive function (MoCA-J).<h4>Results</h4>Higher serum GDF-15 levels were associated with older age and greater symptom burden across multiple domains.