Development and external validation of a practical diagnostic support tool, ′ABC2-Screener′, to predict sarcopenia among patients on maintenance haemodialysis: A multicentre cross-sectional study

Background and hypothesis. Sarcopenia is common in patients undergoing maintenance haemodialysis (MHD); however, the current diagnostic support tools for sarcopenia are difficult to implement in dialysis clinics. This study aimed to develop a clinically friendly screening tool to predict sarcopenia using ubiquitous clinical data. Methods. This cross-sectional multicentre study enrolled 373 and 129 patients undergoing MHD in the derivation and external validation cohorts, respectively. The Asian Working Group for Sarcopenia diagnostic criteria were used as a sarcopenia reference standard. Candidate predictors, such as age, sex, body mass index, routine blood tests, and the one-item Clinical Frailty Scale (CFS) version 2.0, were used to develop an original web-based model and a paper-based point score system using backward elimination selection. The two tools were completed using optimism-corrected regression coefficients for each variable, derived by bootstrapping. Their performance was evaluated by examining the discrimination and calibration in the two cohorts. Results. In total, 98 (26.3%) and 44 (34.1%) patients in the derivation and validation cohorts were diagnosed with sarcopenia, respectively. For internal validation, the area under the receiver operating characteristic curve (AUROC) for the original model and the point score system were 0.97 (95% CI: 0.96-0.98) and 0.95 (95% CI: 0.93-0.97), respectively. Calibration plots for the original model showed excellent agreement between the predicted and observed probabilities. In contrast, the point-score-based model underestimated sarcopenia in the moderate-risk range. For external validation, the original model achieved an AUROC of 0.97 (95% CI: 0.95-1.00), while the point score system achieved an AUROC of 0.91 (95% CI: 0.87-0.96). The calibration plots for both models showed similar performances to those of the internal validation. Conclusion. In patients undergoing MHD, our practical diagnostic support tool the ABC2-Screener has good discrimination and calibration abilities and can be easily used at any medical facility. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported by JSPS KAKENHI (grant numbers: JP19KT0021). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethical Review Board of Fukushima Medical University (number: ippan2021-292). All the patients signed an informed consent form. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.