Measurement of circulating troponin Ic enhances the prognostic value of C-reactive protein in haemodialysis patients.

BACKGROUND Cardiac Troponin I (cTnI) levels are considered an important diagnostic tool in acute coronary events. They could be of predictive value in haemodialysis (HD) patients. However, the relationship between cTnI and the HD-induced inflammatory state remains unclear. The aim of this study was to explore the prognostic relevance to all-cause and cardiovascular mortalities in HD patients of cTnI, in combination with highly sensitive C-reactive protein (hs-CRP) levels. METHODS We measured cTnI and hs-CRP at baseline (March 10 to November 16, 2001) in 191 HD patients without clinical signs of acute coronary artery disease [median age 66.7 years (range 22.3-93.5), 94 females, 97 males]. We used a cTnI concentration with a total imprecision of 10% (0.03 microg/l), determined in the laboratory, as the analytical threshold value. Patients were followed for mortality until 1 January, 2003 (median follow-up 418 days). The adjusted relative risks (RRs) of death and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models. RESULTS A significant proportion (25.1%) of patients had elevated CTnl, > or =0.03 microg/l; 40.3% of patients had CRP concentrations > or =10 mg/l. During follow-up, 29 patients died, 44.8% due to cardiac causes. Elevated cTnI or CRP levels were associated with increased mortality [RR adjusted for age, sex and duration of dialysis 4.2 (1.9-9.0) for cTnI > or =0.03 microg/l and 3.6 (1.6-8.1) for CRP > or =10 mg/l], cTnI being particularly predictive of cardiovascular death. Moreover, the combination of elevated hs-CRP (> or =10 mg/l) and circulating cTnI (> or =0.03 microg/l) dramatically impaired the HD survival rate [adjusted RR for all-cause mortality 16.9 (4.5-63.8)]. CONCLUSION Circulating cTnI was associated with poor prognosis, especially when combined with elevated CRP, strongly supporting the adoption of regular cTnI testing in HD patients.