Prognostic value of troponin T in hemodialysis patients is independent of comorbidity

Abstract

Patients on long-term hemodialysis have a high mortality. Various clinical and biochemical markers are of prognostic value. Cardiac troponin T (cTnT) is a sensitive and specific marker for myocardial damage. Asymptomatic dialysis patients have a high prevalence of cTnT concentrations above the diagnostic threshold for myocardial damage. There is controversy over whether this represents a false positive cTnT or an underlying pathology with a poor outcome. It is not known whether cTnT reflects comorbidity in these patients. A cohort of 73 long-term hospital hemodialysis patients had cTnT estimated once prior to a mid-week dialysis. Samples were analyzed using the second-generation cTnT assay from Boehringer Mannheim on an Elecsys 1010 analyzer. The standard diagnostic threshold for myocardial damage of 0.1 ng/mL was used. A commonly employed measure of comorbidity (Khan) was applied at the time cTnT was measured. Patients were followed for 15 months. Mortality was used as the clinical end point. Kaplan-Meier survival analysis was employed and differences between groups were assessed using the Cox-Mantel log-rank test. Of the 73 patients, 20 were positive for cTnT and 53 were negative, at the cut-off of 0.1 ng/mL. At fifteen months, 65% of the positive patients were dead, whereas only 15% of the negative patients were dead. Survival analysis confirmed that this difference was statistically significant (P < 0.00001), and that the effect of cTnT on survival was independent of comorbidity. There is a high prevalence of positive cTnT in stable hemodialysis patients. A single estimation of cTnT in this group has significant prognostic value, independent of comorbidity.