NDT Advance Access originally published online on July 13, 2004
Nephrology Dialysis Transplantation 2004 19(9):2313-2318; doi:10.1093/ndt/gfh365
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Nephrol Dial Transplant Vol. 19 No. 9 © ERA-EDTA 2004; all rights reserved
Original Article
Measurement of circulating troponin Ic enhances the prognostic value of C-reactive protein in haemodialysis patients
1 Biochemistry Laboratory and 4 Nephrologie, Centre Hospitalier Universitaire de Montpellier, 2 INSERM Unité 500 ‘Epidemiology of chronic diseases and ageing’,3 Centre Hémodialyse Languedoc Méditerranée, 5 AIDER and 6 Renal Research and Training Institute, Montpellier, France
Correspondence and offprint requests to: Professor Jean-Paul Cristol, Biochemistry Laboratory, Hôpital Lapeyronie, 371 Av. Doyen Gaston Giraud, 34295 Montpellier cedex 5, France. Email: jp-cristol{at}chu-montpellier.fr
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 µg/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, 
0.03 µg/l; 40.3% of patients had CRP concentrations 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 0.03 µg/l and 3.6 (1.6–8.1) for CRP 10 mg/l], cTnI being particularly predictive of cardiovascular death. Moreover, the combination of elevated hs-CRP (10 mg/l) and circulating cTnI (0.03 µg/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.
Keywords: cardiovascular disease; haemodialysis; mortality; troponin