Prognostic value of C-reactive protein / albumin ratio for amputation and/or mortality after lower extremity revascularization in haemodialysis patients with peripheral artery disease

Abstract

Abstract Background Hypoalbuminemia, a manifestation of protein-energy wasting (PEW) or malnutrition, which is commonly observed in patients with chronic kidney disease, is associated with increasing cardiovascular risk. Recently, C-reactive protein (CRP) / albumin ratio has been developed as a newly surrogate marker of the PEW because the PEW seems to result not only from an inadequate diet but also rather be induced by chronic inflammatory status. The aim of this study was to clarify whether pre-procedural CRP/albumin ratio levels could predict amputation and/or mortality after lower extremity revascularization for peripheral artery disease (PAD) in patients on haemodialysis (HD). Methods A total of consecutive 1,850 HD patients successfully undergoing lower extremity revascularization (494 bypass surgery and 1,356 endovascular therapy) were enrolled in this study. Patients were divided into tertiles according to pre-procedural CRP/albumin ratio levels; low (<0.6, n=619), middle (0.6-3.7, n=609) and high tertile (>3.7, n=622). They were followed up for up to 8-year. The primary endpoint was defined as amputation and/or mortality. Results During follow-up period (median of 53 months), 162 major amputation (8.8%) was performed and 508 patients (27.5%) died. Cumulative incidence rates of amputation and/or mortality at 8-year were 47.4%, 56.2% and 70.0% in low, middle and high tertile of CRP/albumin ratio, respectively (p<0.0001). After adjustment for male, age, traditional risk factors, body mass index, history of coronary artery disease or stroke, procedure (bypass vs. endovascular therapy), infrapopliteal disease and ulcer/gangrene, the CRP/albumin ratio was identified as an independent predictor for amputation and/or mortality [adjusted hazard ratio (aHR) 1.39, 95% confidence interval (CI) 1.12-1.72, p=0.0028 for middle vs. low tertile, and aHR 2.53, 95% CI 2.07-3.09, p<0.0001 for high vs. low tertile, respectively]. Similar results were also observed even for major amputation and mortality, respectively (aHR 2.73, 95% CI 1.77-4.31 for amputation and aHR 2.32, 95% CI 1.82-2.97 for mortality with p<0.0001 for high vs. low tertile in both, respectively, Figure). Conclusion Pre-procedural CRP/albumin ratio could predict both of amputation and mortality after lower extremity revascularization, and could stratify the risk in HD patients with PAD. Measurement of CRP/albumin ratio in such high-risk population may be useful because this newly surrogate marker of the PEW is simple and can be easily obtained in daily practice.