Associations of metabolic score for insulin resistance (METS-IR) with cardiovascular mortality risk in peritoneal dialysis patients

Background Metabolic score for insulin resistance (METS-IR) is considered a simple, reliable, and cost-effective alternative indicator of insulin resistance (IR). Our study aimed to assess whether the METS-IR index was associated with an increased risk of cardiovascular (CV) death in our peritoneal dialysis (PD) cohort. Methods This observational study included 553 patients commencing PD for end-stage renal disease between 2003 and 2017, and they were divided into three groups according to the tertiles of METS-IR. The assessed predictor was the METS-IR index at enrollment. Cox proportional hazards models and competing risk analysis using the Fine-Gray models were used to analyze the association between the METS-IR index and CV mortality, with adjustments of potential confounding factors including medication use, demographic characteristics, comorbidities, PD-related data, and laboratory data. Furthermore, receiver operating characteristic (ROC) curve analysis was used to determine the exploratory cutoff value of the METS-IR index for predicting CV mortality, and the area under the ROC curve (AUC) was calculated. Results During follow-up, the crude CV mortality rate increased significantly, with 16 CV deaths (8.6%) in the first tertile of the METS-IR index, 32 CV deaths (17.4%) in the second tertile, and 41 CV deaths (22.3%) in the third tertile (p < 0.001). In the full adjusted model, patients in tertile 2 were associated with an HR of 1.90 (95% CI, 1.01–3.61) and those in tertile 3 was associated with an HR of 1.91 (95% CI, 1.03–3.55) compared with tertile 1. The exploratory cut-off point of METS-IR index was 33.3 (75.3% sensitivity and 48.3% specificity) with an AUC (95% CI) of 0.617 (0.557–0.677; p < 0.001), indicating modest discrimination. The results from the Fine-Gray model are consistent with those from the Cox model. Conclusions METS-IR can identify PD patients at high risk of CV death. However, METS-IR has limited discriminative ability in predicting CV mortality and further research is needed to validate its potential role in risk stratification.