Skeletal muscle index and hand grip strength as predictors of postoperative recovery in patients with gastrointestinal tumors.

BACKGROUND: Sarcopenia, defined by loss of muscle mass and function, predicts poor cancer outcomes. In gastrointestinal (GI) malignancies, its prognostic role remains underexplored. Skeletal muscle index (SMI) from computed tomography (CT) scans and hand grip strength (HGS) may contribute to preoperative risk assessment. This study aimed primarily to evaluate the association between preoperative SMI and postoperative hospitalization length, and secondarily to assess HGS as a functional measure related to muscle status and its association with SMI and other clinical factors in GI cancer patients. METHODS: A prospective observational cohort study was conducted (2019–2022) at a tertiary hospital in Tehran. Patients with GI malignancies undergoing surgery and preoperative CT scans were included. SMI was measured at the L3 vertebral level using standardized thresholds. The primary outcome was hospitalization length; HGS was secondary. Negative binomial regression was used to evaluate predictors of hospitalization length, and linear regression models were used to examine factors associated with HGS. Univariate and multivariable analyses were performed. RESULTS: A total of 233 patients were included in the study. The mean age was 59.13 ± 12.74 years, and 56.7% were male. Higher SMI was associated with shorter hospitalization length in both univariate and multivariable analyses (Incidence rate ratios [IRRs] = 0.97 and 0.94, respectively; P < 0.001). HGS was not associated with hospitalization length. Psoas muscle diameter showed a small positive association with hospitalization length in the multivariable model (IRR = 1.01; P = 0.032). SMI was positively associated with HGS in univariate analyses for both hands (right hand: β = 0.31; P = 0.027; left hand: β = 0.32; P = 0.016), but this association was not retained after adjustment. Age and psoas muscle diameter remained independent predictors of HGS in both hands. CONCLUSION: Preoperative SMI appears to be a clinically relevant imaging-based marker of postoperative recovery in patients with GI cancers and may contribute to preoperative risk assessment. HGS, evaluated as a functional measure of muscle status, was associated with SMI and selected clinical factors but did not provide comparable prognostic information for hospitalization outcomes. These findings support the complementary but distinct roles of structural (SMI) and functional (HGS) muscle assessments. Further studies are required to validate these findings and clarify their clinical application.