Preoperative BMI-adjusted sarcopenia defined by AWGS 2025 is associated with 1-year changes in the patient-reported outcomes of lumbar spinal stenosis surgery.

Abstract

To examine the association between preoperative body mass index (BMI)-adjusted sarcopenia, defined according to the Asian Working Group for Sarcopenia 2025 (AWGS 2025), and 1-year postoperative outcomes in patients undergoing surgery for lumbar spinal stenosis (LSS). This single-center prospective cohort study included 118 patients scheduled for LSS surgery. Handgrip strength was measured using a hand dynamometer, and appendicular skeletal muscle mass was estimated using bioelectrical impedance analysis. BMI-adjusted sarcopenia was defined as low handgrip strength and low BMI-adjusted muscle mass according to AWGS 2025 age- and sex-specific cutoffs. Patient-reported outcomes were assessed preoperatively and at 1 year using the visual analog scale (VAS), Hospital Anxiety and Depression Scale, Oswestry Disability Index (ODI), and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). Multivariable analysis was adjusted for baseline scores and covariates. BMI-adjusted sarcopenia was present in 16 patients (13.6%). Compared with non-sarcopenia, sarcopenia had higher 1-year low back pain VAS (between-group difference, 8.5 mm) and ODI (10.8 points), and lower JOABPEQ walking ability (23.8 points) and social life function (18.4 points). Multivariable analysis showed that BMI-adjusted sarcopenia was independently associated with smaller 1-year improvements in ODI (B = 9.59; 95% CI, 1.50 to 17.68), JOABPEQ walking ability (B = - 22.22; 95% CI, - 39.64 to - 4.79), and social life function (B = - 13.57; 95% CI, - 26.65 to - 0.49). Preoperative BMI-adjusted sarcopenia was independently associated with 1-year changes in disability and disease-specific quality of life after surgery for LSS.