Clinical correlates of physical performance and sarcopenia in Parkinson's disease: a cross-sectional study.

Low physical performance was observed in 39% of mild-to-moderate Parkinson's disease patients evaluated in the ON medication state.

• Total sample included 127 patients with idiopathic PD at Hoehn & Yahr stages I-III.
• Mean age was 66 years; 41.7% were female.
• Low physical performance was defined by the Short Physical Performance Battery (SPPB).
• 50 patients (39%) met criteria for low physical performance.

Positive sarcopenia screening by SARC-F (score ≥ 4) was strongly associated with low physical performance.

• Odds ratio for SARC-F ≥ 4 and low SPPB: OR 1.67 (95% CI: 1.30–2.15; p < 0.001).
• SARC-F emerged as an independent predictor of poor physical performance in multivariable logistic regression models.
• Both Enter and Best Subsets logistic regression models were used.

Postural instability and gait difficulty (PIGD) was significantly associated with low physical performance and emerged as an independent predictor in multivariable models.

• PIGD was significantly associated with low SPPB in bivariate analysis (p < 0.001).
• PIGD emerged as an independent predictor of poor physical performance in multivariable logistic regression.
• PIGD is a recognized motor subtype in Parkinson's disease reflecting gait and balance impairment.

Reduced mean handgrip strength was significantly associated with low physical performance in bivariate analyses.

• Patients with low physical performance had mean handgrip strength of 26 ± 10 kgf versus 30 ± 10 kgf in those with normal performance (p = 0.02).
• Muscle strength was assessed using handgrip dynamometry.
• This association was identified in bivariate comparisons but was not reported as an independent predictor in multivariable models.

The Ishii score was significantly associated with low physical performance in bivariate analysis.

• Ishii score was associated with low SPPB performance (p = 0.009) in bivariate analyses.
• The Ishii score is a sarcopenia screening tool used alongside SARC-F as part of the EWGSOP2 evaluation framework.
• Both SARC-F and Ishii scores were noted to help identify risk of functional decline.

The best subset multivariable model combining SARC-F and PIGD showed good discriminative accuracy for predicting low physical performance.

• Area under the curve (AUC) for the combined SARC-F and PIGD model = 0.82.
• The model was derived using Best Subsets logistic regression.
• This combination of sarcopenia screening and motor subtype classification provided the strongest predictive model.

Sarcopenia was evaluated using a multicomponent approach following the revised EWGSOP2 consensus.

• Screening included SARC-F questionnaire and Ishii score.
• Muscle strength was assessed by handgrip dynamometry.
• Body composition and appendicular lean mass were evaluated by whole-body dual-energy X-ray absorptiometry (DXA).
• All patients were evaluated in the ON medication state at mild-to-moderate disease stages (Hoehn & Yahr I-III).