Low plantar skin perfusion pressure predicts long-term atherosclerotic vascular events and mortality in maintenance haemodialysis patients

Background and aims: End-stage renal disease is associated with an increased risk of atherosclerotic vascular disease (AVD). We investigated whether low plantar skin perfusion pressure (SPP), a useful indicator of peripheral arterial disease (PAD), predicts systemic AVD events and mortality in outpatients undergoing maintenance haemodialysis (HD). Methods: A total of 206 HD patients were enrolled and followed for 5 years. They were divided into 3 groups according to measured SPP: group 1 (G1), SPP >70 mmHg (n = 123); G2, SPP 50–70 mmHg (n = 61); and G3, SPP <50 mmHg (n = 22). Results: During the follow-up period (median, 4.2 years), 56 AVD events (27.2%) and 68 deaths (33.0%) occurred. In G1, G2, and G3, the event-free survival rates were 74%, 55% and 19%, respectively, for AVD events (p < 0.01) and 73%, 54% and 26%, respectively, for mortality (p < 0.01). A Cox multivariate analysis showed that lower SPP was an independent predictor for AVD events [hazard ratio (HR) 3.12, 95% confidence interval (CI) 1.45–6.77, p < 0.01 for G3 vs. G1] and mortality (HR 3.06, 95% CI 1.57–5.98, p < 0.01 for G3 vs. G1). Furthermore, the addition of the SPP value to a model with established risk factors improved the predictability of increasing the net reclassification improvement (NRI; 0.463, p < 0.01) and integrated discrimination improvement (IDI; 0.039, p < 0.01) for AVD events. Similar results were obtained for mortality. Conclusions: Low plantar SPP can stratify risk and improve the predictability of both systemic AVD events and mortality in the maintenance HD population.