Association of preoperative ankle reflex with skeletal muscle loss and poorer physical performance 6 months after gastrectomy in elderly patients with gastric cancer.

BACKGROUND: Neuromuscular dysfunction may contribute to postoperative skeletal muscle loss in elderly patients with gastric cancer. However, the association between preoperative ankle reflex and postoperative muscle-related outcomes remains unclear. This study investigated whether reduced or absent preoperative ankle reflexes were associated with appendicular skeletal muscle index (ASMI) and impaired physical performance 6 months after gastrectomy. METHODS: A total of 507 elderly patients with gastric cancer were enrolled. Ankle reflex was assessed within 1 week before surgery and graded from 0 to 4. Reflex status was classified as reduced or absent (grades 0-1), normal (grade 2), or brisk/hyperreflexic (grades 3-4). ASMI was measured before surgery and at 6 months after surgery using bioelectrical impedance analysis. Dominant hand grip strength, 6-m walking speed, and Short Physical Performance Battery (SPPB) scores were assessed 6 months after surgery. The primary outcome was the change in ASMI between the preoperative and 6-month postoperative assessments. The secondary outcomes included ASMI, dominant-hand grip strength, 6-m walking speed, and SPPB score at 6 months after surgery. Five self-reported muscle-related symptoms during follow-up were listed as exploratory outcomes. Multivariable linear and logistic regression models were adjusted for prespecified baseline confounders, and inverse probability weighting (IPTW) was employed as a sensitivity analysis. RESULTS: Patients with ankle reflex grades 0-1 experienced greater ASMI change during the first 6 months after surgery than patients with normal reflexes (adjusted β = 0.311, 95% CI: 0.278-0.344, p < 0.001). At 6 months, they also had lower ASMI (adjusted β = -0.409), lower dominant-hand grip strength (adjusted β = -3.043), slower walking speed (adjusted β = -0.105) and lower SPPB scores (adjusted β = -1.081) (all p < 0.001). Reduced or absent reflexes were associated with higher odds of several exploratory muscle-related symptoms (p < 0.05). IPTW analyses confirmed the associations with all continuous outcomes and with selected exploratory muscle-related symptoms. CONCLUSION: Reduced or absent preoperative ankle reflexes were associated with greater skeletal muscle loss, as well as poorer muscle strength and physical performance, 6 months after gastrectomy in elderly patients with gastric cancer.