Troponin I levels are less dependent on glomerular filtration rate compared to Troponin T and other cardiac biomarkers
Christian Bjurman1,*, Max Petzold2, Michael Fu1, Ola Hammarsten3
1Department of Medicine, 2Centre for Applied Biostatistics, 3Department of Clinical Chemistry and Transfusion Medicine, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
Introduction: Low Kidney function as measured by Glomerular Filtration Rate (GFR) increases the concentration of cardiac biomarkers. The extent of elevation in relation to different levels of renal dysfunction has not been fully assessed and impairs the diagnostic utility of these biomarkers.
Objectives: To compare the effects of renal insufficiency on levels of multiple cardiac biomarkers. Moreover, to compare creatinine based vs Cystatin C (CysC) based GFR estimates for the prediction of cardiac biomarker levels.
Methods: 489 patients with different degrees of renal function referred for GFR measurement by either Cr51-EDTA or Iohexol clearance (true GFR). Median (IQR) age was 58 (45-65) years and 56% were males. Troponin T (hs-cTnT), Troponin I (hsTnI), N-Terminal pro Brain Natriuretic Peptide (NTproBNP), Copeptin and Human Fatty Acid Binding Protein (HFabp) were measured.
Results: HsTnI increased 132 % between true GFR 90 and 15 ml/min/1.73 m2, whereas hs-cTnT increased 222% according to our normalization functions. On the other hand, when CysC based eGFR was used, Troponin I (hsTnI) increased 173 % and hs-cTnT increased 326% between eGFR 90 and 15 ml/min/1.73 m2. Moreover, hs-cTnT levels and hsTnI levels were higher in patients with circulatory disorders (“I”-diagnoses), for instance at GFRs < 30 ml/min/1.73 m2: hs-cTnT 31 ng/L vs 12 ng/L (p<0.001) and hsTnI 14 ng/L vs 8.9 ng/L (p=0.028) respectively.
Conclusion: Normalized cardiac biomarker levels can be estimated in patients with renal dysfunction. Troponin T och Troponin I levels are influenced more by comorbidities and less by renal dysfunction at decreasing GFRs. CysC based GFR estimates resulted in the steepest rise in predicted cardiac biomarker levels at decreasing GFRs.
Keywords: Biomarker, Cardiovascular, Kidney