摘要Background:This study compared the validity of the creatinine-to-cystatin C ratio(CCR),sarcopenia index(SI),and relative skeletal mus-cle index(RSMI)as predictors of sarcopenia in patients with colorectal cancer(CRC)and explored their impact on the patient prognosis.Methods:We retrospectively studied patients with CRC who underwent surgical intervention at the Department of Colorectal and Anal Sur-gery,situated within the First Affiliated Hospital of Guangxi Medical University.The investigation spanned from January 2015 to December 2017,encompassing a cohort of patients subject to surgical management for CRC during this period.Pearson's correlation analysis was employed to evaluate the relationships between the CCR,SI,RSMI,and skeletal muscle index(SMI)and the patient prognosis.Receiver operating charac-teristic(ROC)curves were generated to evaluate the predictive precision of these biomarkers and ascertain the optimal cutoff values.Multivar-iate logistic regression analysis was conducted to pinpoint the independent factors linked with sarcopenia.Survival analyses,contingent on dif-ferent surrogate markers of muscle mass and sarcopenia,were performed utilizing the Kaplan-Meier method alongside the log-rank test.Results:We enrolled 815 patients with CRC(522 male and 293 female patients)who were eligible for the analysis.In accordance with the guidelines set forth by the International Consensus on Sarcopenia,sarcopenia was diagnosed in a collective total of 503 patients.A Pearson's correlation co-efficient(r)analysis demonstrated that the CCR,SI,and RSMI were positively correlated with the SMI.In both male and female patients,the RSMI(male:r=0.400,P＜0.001;female:r=0.640,P＜0.001)was more strongly correlated with the SMI than with the CCR(male:r=0.203,P＜0.001;female:r=0.192,P＜0.001)or SI(male:r=0.335,P＜0.001;female:r=0.285,P＜0.001).In male patients,the areas under the ROC curves(AUC)for the CCR,SI,and RSMI were 0.596[(95％confidence interval(CI)=0.545-0.647)],0.648(95％CI=0.599-0.698),and 0.681(95％CI=0.629-0.733),respectively.In female patients,the AUC for the CCR,SI,and RSMI were 0.615(95％CI=0.551-0.680),0.660(95％CI=0.598-0.722),and 0.772(95％CI=0.719-0.825),respectively.A multivariable logistic regression analysis demonstrated that the CCR remained an influential factor for sarcopenia after correcting for confounding[odds ratio(OR)=0.993,95％CI=0.986-1.000,P=0.038)].The SI and RSMI also remained influential factors for sarcopenia after correcting for confounding factors(OR=0.983,95％CI=0.972-0.994,P=0.002;and OR=0.401,95％CI=0.320-0.502,P＜0.001,respectively).The groups characterized by low CCR and SI demon-strated notably reduced overall survival compared with their counterparts with high CCR and SI(P=0.007 and P=0.001,respectively),whereas the RSMI and sarcopenia did not exhibit a significant correlation with survival(P=0.608 and P=0.062,respectively).Conclusions:The CCR,SI,and RSMI all have predictive value for sarcopenia in patients with CRC.The RSMI was a better predictor of sarcopenia than either the CCR or SI in both male and female patients with CRC.However,the RSMI did not have any significant value for predicting the prog-nosis of patients with CRC.Subsequent prospective investigations are warranted to elucidate a superior marker or amalgamation thereof,capable of accurately prognosticating sarcopenia and the overall prognosis in individuals diagnosed with CRC.Such studies should aim to meticulously eval-uate a comprehensive array of potential markers,considering their individual and collective predictive value in delineating the clinical trajectory of CRC patients.By conducting rigorous prospective analyses,researchers can strive to uncover novel insights into the complex interplay between sarco-penia and CRC outcomes,thereby facilitating the development of more precise prognostic models and tailored therapeutic approaches.