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

Abstract

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).

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.

Trial registration: ClinicalTrials.gov NCT00261521.

Figures

Figure 1

Distribution of baseline troponin T levels (A) and NT-proBNP (B) levels in hemodialysis patients without prior symptomatic cardiac disease. Troponin T levels are expressed in units of ng/mL and NT-proBNP in units of pg/mL).

Figure 2

Serial HRQOL scores for SF-36 domains physical function and vitality, and for FACIT fatigue, in hemodialysis patients without symptomatic cardiac disease.