In early Parkinson disease (PD), high levels of uric acid appear to be associated with the tremor-dominant (TD) motor PD subtype, as well as lower fatigue levels and less cognitive impairment, according to a study published in Parkinsonism and Related Disorders.
Patients with early PD who participated in a previous longitudinal analysis on disease progression were enrolled in this study (n=125). Investigators used the Movement Disorder Society Unified Parkinson’s Disease Rating Scale to categorize patients according to motor subtypes, including TD (n=51), postural instability gait difficulty (n=11), and mixed subtype (n=63). In addition, investigators categorized nonmotor symptoms as present or absent.
At baseline, the average serum acid levels among TD, mixed, and postural instability gait difficulty subtypes were significantly different between the groups (mean±SD: 4.96±1.44 mg/dL vs 4.38±1.30 mg/dL vs 5.75±1.17 mg/dL, respectively; P =.0106). When investigators used the TD subtype as a reference, they found that higher serum uric acid levels were significantly less likely to feature the mixed subtype compared with the TD subtype (odds ratio [OR], 0.684; P =.0312).
Higher serum acid levels were associated with less fatigue for patients with PD with nonmotor symptoms (OR, 0.693; P =.0408). In addition, higher levels of serum uric acid were associated with less global cognitive impairment, as assessed by the Montreal Cognitive Assessment (OR, 0.546; P =.0021).
Considering the models used in this study did not produce an area-under-the-curve value of >0.8, the investigators suggest that uric acid levels only are insufficient to be used as a predictor for patient outcomes.
Despite the limitations, the investigators do suggest that uric acid levels may “be an important biomarker for these motor and non-motor features and may be a potential biomarker for disease progression.”
Huang X, Ng SY, Chia NS, et al. Serum uric acid level and its association with motor subtypes and non-motor symptoms in early Parkinson’s disease: PALS study [published online May 14, 2018]. Parkinsonism Relat Disord. doi: 10.1016/j.parkreldis.2018.05.010