The toe‒brachial pressure index as a predictor of mortality in hemodialysis patients

Abstract

The usefulness of the toe‒brachial index (TBI) as a prognostic factor in patients undergoing maintenance hemodialysis (HD) is unknown. This study aimed to investigate patient survival 5 years after the measurement of the ankle‒brachial index (ABI), TBI, and skin perfusion pressure (SPP) in 157 patients undergoing HD, and to identify prognostic factors among the variables evaluated in this study. Analysis with the Cox proportional hazards model revealed that the TBI is an independent prognostic factor among patients undergoing HD (p＜0.001). Receiver operating characteristic (ROC) curves indicated that the optimal TBI cut‒off point for predicting mortality was 0.56, which resulted in an area under the ROC curve of 0.91, demonstrating that the TBI had greater predictive ability than the other examined parameters. When the calculated TBI cut‒off value was used to divide the patients into the TBI≥0.7 group, the 0.7＞TBI≥0.56 group, the TBI＜0.56 group, and zero TBI sign, no differences in survival were observed between the 0.7＞TBI≥0.56 group and the TBI≥0.7 group. Survival was significantly lower in the TBI＜0.56 group than in the 0.7＞TBI≥0.56 group (p＜0.001), and was also significantly lower in zero TBI sign than in the TBI＜0.56 group (p＝0.020). Cardiovascular events were not a cause of death in the TBI≥0.56 group, but accounted for 40％ of deaths in the TBI＜0.56 group and zero TBI sign. The TBI is more useful as a prognostic factor in patients undergoing HD than the ABI and SPP.