Effect of renal function on serum cardiac troponin T--Population and individual effects.

BACKGROUND: Elevations of serum cardiac troponin T (cTnT) have been described in patients with end stage chronic kidney disease (CKD) although the mechanism is unknown, whether from increased production or decreased clearance. Less is known about cTnT in short term changes in renal function and in lesser degrees of renal impairment.

OBJECTIVES: This study aimed to investigate the effect of renal function changes on cTnT within individuals and characterise the distribution of cTnT according to renal function in the population.

DESIGN AND METHODS: A hospital laboratory database extract was performed for paired creatinine and cTnT results. cTnT was compared with estimated glomerular filtration rate (eGFR) at the population level. In individuals who had undergone repeat testing, changes in cTnT were compared with corresponding changes in creatinine.

RESULTS: At the population level, 17,113 cTnT and creatinine measurements from 10,418 patients demonstrated rising cTnT with falling eGFR, with no eGFR threshold for this effect. Of these, 3108 pairs of results were obtained from patients who had undergone repeat testing. The median retesting interval was 15 h (interquartile range: 7-25 h). Within individuals, the magnitude of changes in cTnT approximated 33% of changes in creatinine.

CONCLUSIONS: At the population level, moderate reductions in GFR (30-59 mL/min/1.73 m(2)) corresponded to a median cTnT above the 14 ng/L upper reference limit. The modest association between changes in cTnT and creatinine within individuals in the short term further highlights the need for caution when interpreting troponin elevations in this setting.