Longitudinal Troponin T Associated With Mortality in Advanced CKD

Quick Takes

  • This was an observational prospective cohort study of 176 participants aged ≥65 years with an eGFR <20 ml/min/173 m2 not on dialysis who underwent serial cardiac troponin T (cTnT) measurements.
  • Higher and increasing levels of cTnT were associated with worse survival.
  • Clinical implications are unclear. Determining how that additional prognostic information can help clinical management is the most crucial step in the study of biomarkers.

Study Questions:

Are longitudinal changes in cardiac troponin T (cTnT) associated with mortality in patients aged ≥65 years with stage 4-5 chronic kidney disease (CKD)?

Methods:

The EQUAL (European QUALity) study is an ongoing observational multicenter prospective cohort study in patients with stage 4-5 CKD (estimated glomerular filtration rate [eGFR] <20 ml/min/1.73 m2) who are not on dialysis and who are receiving routine medical care. This study leverages a subcohort of EQUAL, which includes 176 patients recruited by five nephology clinics across Sweden who underwent serial cTnT measurements every 6 months. Patients were followed until kidney transplantation (n = 4), death (n = 60), refusal for further participation (n = 4), loss to follow-up (n = 3), or end of follow-up (n = 105). The primary outcome was all-cause mortality.

Results:

The mean age of participants in the subcohort was 75 years. Two thirds were men, and the mean eGFR at baseline was 17.6 ml/min/1.73 m2. There was a total of 927 cTnT measurements (median 6 per patient; interquartile range [IQR], 2-8) collected over a median follow-up of 2.4 years (IQR, 0.7-3.5 years). A total of 60 deaths occurred. Patients in the highest cTnT tertile (47-379) had a 9.1-fold (95% confidence interval [CI], 4.1-20.0) higher risk of death compared with those in the lowest cTnT tertile (10-28). Every standard deviation (SD) increase in cTnT, at any time point, was associated with a 3.3-fold increase (95% CI, 2.5-4.6) in mortality risk. The slope of the cTnT trajectory was also associated with increased mortality risk; if the cTnT slope increased by 1 SD, mortality risk would increase 3.2-fold (95% CI, 2.0-6.0). Adjustment for comorbidities had no significant impact on symptoms.

Conclusions:

Higher and increasing levels of cTnT are associated with worse survival in people aged ≥65 years with an eGFR <20 ml/min/1.73 m2.

Perspective:

This study highlights that evidence of subclinical myocardial injury, as assessed by high-sensitivity cTnT assays in the absence of an acute indication, is prognostic. While this may not be surprising given the wealth of evidence of troponin and outcomes, the advantages in this study are the systematic serial assessment of troponins and the exclusion of participants suffering from acute kidney injury, thus limiting confounding. Clinical implications are unclear. The authors suggest that measuring troponin could impact decision making; however, they do not elaborate on how. Numerous biomarkers are prognostic. Determining how that additional prognostic information can help clinical management is the most crucial step in the study of biomarkers.

Keywords: Acute Kidney Injury, Biomarkers, Geriatrics, Glomerular Filtration Rate, Kidney Transplantation, Metabolic Syndrome, Primary Prevention, Renal Dialysis, Renal Insufficiency, Chronic, Survival, Troponin T


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