Cardiovascular Biomarkers in Nocturnal Hemodialysis and Their Association With Physical Performance.

Introduction: The cardiovascular biomarkers troponin T, N-terminal pro-B-type natriuretic peptide, and fibroblast growth factor 23 are elevated in hemodialysis patients and associated with an increased cardiovascular mortality risk. Nocturnal hemodialysis improves the fluid status in hemodialysis patients. Therefore, we investigated whether nocturnal hemodialysis (7-8 h sessions) was associated with lower levels of troponin T, N-terminal pro-B-type natriuretic peptide, and fibroblast growth factor 23 in comparison to conventional hemodialysis. Second, we investigated whether these biomarkers were independently associated with physical performance in hemodialysis patients.

Methods: A prospective cohort of 33 hemodialysis patients was compared to 32 patients who voluntarily switched from conventional hemodialysis to nocturnal hemodialysis. First, we studied the difference between the two cohorts in change over 12 months of troponin T, N-terminal pro-B-type natriuretic peptide, and fibroblast growth factor 23 with linear mixed models. Second, the associations between these biomarkers and physical-activity monitor, six minute walk test, and physical component summary score were assessed at baseline, 6 and 12 months.

Findings: N-terminal pro-B-type natriuretic peptide increased 122% during conventional hemodialysis, whereas it decreased 31% during nocturnal hemodialysis (p = 0.001). In conventional hemodialysis, fibroblast growth factor 23 rose numerically by 19% (23%-66%) in 12 months, while a decline of 44% (21%-58%) was found in nocturnal hemodialysis patients (p = 0.17). Troponin T did not differ between groups. Regarding physical performance, a higher N-terminal pro-B-type natriuretic peptide (per 1000 ng/L) and fibroblast growth factor 23 (per 1000 RU/mL) were associated with lower physical component summary scores of -0.02 (p = 0.02) and -0.04 (p = 0.05), respectively. Troponin T was not associated with physical performance.

Discussion: Our findings showed that nocturnal hemodialysis was associated with a decrease in N-terminal pro-B-type natriuretic peptide. This suggested that nocturnal hemodialysis diminished volume overload and thereby myocardial stretch. Additionally, lower levels of N-terminal pro-B-type natriuretic peptide and fibroblast growth factor 23 were found to be associated with better self-reported physical performance scores.