Cardiac biomarkers and health-related quality of life in new hemodialysis patients without symptomatic cardiac disease

BACKGROUND Health Related Quality of Life (HRQOL) is impaired in hemodialysis patients and cardiac biomarkers are elevated, but their relationship is uncertain. OBJECTIVES To determine whether the cardiac biomarkers, troponin T and N terminal pro-B type natriuretic peptide (NT-proBNP), predict deterioration in the physical domains of HRQOL. DESIGN A prospective cohort study of patients in a randomized controlled clinical trial of correction of anemia with erythropoietin. SETTING Multiple hemodialysis centers located throughout Canada and Europe. PARTICIPANTS Patients who started maintenance hemodialysis within the previous 3-18 months, with no clinical evidence or prior history of symptomatic cardiac failure or ischemic heart disease, and left ventricular volume < 100 ml/m(2). MEASUREMENTS PREDICTOR Baseline concentrations of Troponin T and NT-proBNP. OUTCOMES Physical function and vitality scores using the SF-36 questionnaire and fatigue scores using the FACIT questionnaire at baseline and after 24, 48, and 96 weeks follow-up. METHODS Univariate analysis of the association between baseline variables and baseline HRQOL scores and change in scores over time was undertaken using linear regression. Multivariate models were created using multiple linear regression, and it was pre-specified that these include the variables which were associated with the outcome at a p < 0.05 in the univariate regression. RESULTS Baseline median (interquartile range) physical function score was 70 (50-85), vitality 55 (40-75), and fatigue 73 (58-86). The 75th percentile for Troponin T was 0.05 ng/mL and for NT-proBNP 652 ng/mL. High Troponin T levels were significantly associated with deterioration in the 3 physical domains, independent of other risk factors, whereas high NT-proBNP were not associated. In multivariate models baseline Troponin T > 0.05 ng/mL were significantly associated with the change from baseline to 96 weeks follow-up for SF-36 vitality and FACIT-fatigue scores, and approached statistical significance for SF-36 physical function (0.056). LIMITATIONS Not possible to confirm whether Troponin T associations were independent of subsequent cardiac events. CONCLUSIONS In hemodialysis patients without prior symptomatic cardiac disease and without a dilated left ventricle at baseline, elevated baseline Troponin T levels, but not NT-pro BNP, were independently associated with deterioration in the physical domains of HRQOL.