Phase angle, muscle mass, and functionality in patients with Parkinson's disease.

Objective: To evaluate the association of phase angle (PA) with clinical and nutritional aspects in patients with Parkinson's disease (PD) treated in an outpatient clinic in northeastern Brazil.

Methods: This is a case series study involving adults and the elderly with PD of both genders. We collected data such as stage, severity, and time of diagnosis of the disease, muscle strength, gait speed, and level of physical activity. We evaluated the nutritional status using body mass index, calf circumference, skeletal appendicular muscle mass index, and the presence of sarcopenia. We obtained the PA through the analysis by electrical bioimpedance. After obtaining the result of the division between reactance and resistance, with later transformation into degrees, we multiplied the result by 180/π.

Results: We evaluated 77 individuals with a mean age of 65.4 ± 8.9 years. 63.6% of them had reduced PA values and 19.7% of them had sarcopenia. Age (rho =  - 0.423; p =  < 0.001) was inversely correlated with PA. Skeletal appendicular muscle mass index (rho = 0.251; p = 0.028), pressure force (rho = 0.240; p = 0.035), and gait speed (rho = 0.323; p = 0.005) showed a direct correlation with age. When adjusted for confounding factors, only age remained associated with PA (p = 0.012).

Conclusion: Most individuals had reduced PA, and only age was associated with this result. Aging is a risk factor for reducing muscle mass and physical disability in PD. Although this study indicates a relationship between PA, age, muscle mass, and functionality, further prospective studies are needed to confirm these findings.