Creatinine index and transthyretin as additive predictors of mortality in haemodialysis patients

Abstract

Malnutrition and inflammation are recognized as important predictors of poor clinical outcome in haemodialysis (HD). This study was designed to estimate the relative contribution of known biological markers of inflammation, malnutrition and muscle mass in the prognosis of HD patients. A total of 187 HD patients (100 women, 87 men, median age 66.7 years [22.3-93.5]) were followed-up yearly for 5 years. At baseline, pre-dialysis values of C-reactive protein (CRP), albumin, transthyretin, total HDL- and LDL-cholesterol and triacylglycerol were determined. Estimation of creatinine index (CI) as muscle mass marker was determined by creatinine kinetic modelling using pre- and post-dialysis creatinine values. During the follow-up period, 89 deaths (53 from cardiovascular causes) were observed. After adjustment for age, gender, dialysis vintage, smoking, diabetes mellitus and hypertension, the highest tertile of CRP and lowest tertile of transthyretin and CI were significantly associated with all-cause mortality (relative risk (RR)=1.98 [1.12-3.47], 2.58 [1.48-4.50], 2.71 [1.42-5.19], respectively). In addition, low CI had an additive value to low levels of transthyretin. In contrast, high cholesterol (RR=0.47 [0.27-0.83], P=0.0091) and vitamin E concentrations (RR=0.46 [0.26-0.80], P= 0.006) showed a protective trend for all-cause mortality. In the multivariate analysis, transthyretin appeared as the most predictive biological marker of non-CV mortality (RR=3.78 [1.30-10.96], P=0.014), and CI of CV mortality (RR=2.61 [1.06-6.46], P=0.038), respectively. Discussion. These results confirm that uraemic malnutrition constitutes an important risk factor for mortality in HD. Beyond transthyretin, CI seems to be an additional marker routinely available and monthly determined in HD patients.