Nutritional status and frailty in patients receiving maintenance hemodialysis: the role of sarcopenia risk and comorbidity burden

Poor nutritional status and frailty frequently coexist in patients receiving maintenance hemodialysis (MHD), but whether their association varies with disease burden remains unclear. This cross-sectional study included 321 MHD patients at a tertiary hospital in Jiangsu Province, China, between January and March 2026. Nutritional status, sarcopenia risk, and frailty were assessed using the MNA-SF, SARC-F, and FRAIL scales, respectively. Disease burden was quantified using the age-adjusted Charlson Comorbidity Index (aCCI). Mediation and first-stage moderated mediation analyses incorporated aCCI main effects and adjusted for sex, hemoglobin, and dialysis duration, with 5000 bootstrap resamples. Overall, 111 patients (34.6%) were frail. The adjusted indirect association between MNA-SF and FRAIL through SARC-F was − 0.163 (95% confidence interval [CI], − 0.231 to − 0.110). The MNA-SF × aCCI interaction coefficient was − 0.093 (95% CI, − 0.135 to − 0.051), and the index of moderated mediation was − 0.023 (95% CI, − 0.036 to − 0.013). Conditional indirect effects were − 0.124 and − 0.171 at aCCI scores of 4 and 6, respectively. Sensitivity analyses broadly supported these findings. Poorer nutritional status was associated with greater frailty partly through sarcopenia risk, with a stronger indirect association at higher age-adjusted comorbidity burden. Longitudinal studies are needed to establish temporal relationships.