Cardiac troponin I concentration is commonly increased in nondialysis patients with CKD: experience with a sensitive assay.
BACKGROUND
Cardiac troponin (cTn) concentrations commonly are increased in patients with chronic kidney disease (CKD) in the absence of an acute coronary syndrome. cTn T (cTnT) concentration reportedly is increased more commonly than cTn I (cTnI). Using a sensitive cTnI assay, we studied cTnI concentrations in predialysis patients with CKD who did not have an acute coronary event.


METHODS
Observational cohort study.


METHODS
Nondialysis patients with CKD attending an outpatient clinic.


METHODS
Plasma cTnI was measured using the cTnI-Ultra assay (Bayer HealthCare LLC, Diagnostics Division, Tarrytown, NY), the same manufacturer's standard cTnI assay, and a cTnT assay (Roche Diagnostics PLC, East Sussex, UK).


METHODS
Prevalence of increased cTn concentration, effect of clinical variables on cTnI-Ultra concentration, and independent associations between cTn assays and all-cause mortality by using multiple regression modeling.


RESULTS
Plasma cTnI-Ultra concentration exceeded the upper limit of normal in 33% of patients compared with 18% with the cTnI-standard assay and 43% with the cTnT assay. Age, vascular disease, parathyroid hormone concentration, and left ventricular mass, but not kidney function, had independent effects on plasma cTnI-Ultra concentrations. There were 39 deaths during follow-up. Survival was decreased in patients with baseline cTnI-Ultra concentrations of 0.040 ng/mL or greater (54% versus 83%; P < 0.001), cTnI-standard concentrations of 0.07 ng/mL or greater (55% versus 78%; P = 0.02), and cTnT concentrations of 0.01 ng/mL or greater (59% versus 89%; P < 0.001). Only cTnT concentration was an independent predictor of death.


CONCLUSIONS
Only all-cause mortality was recorded.


CONCLUSIONS
Using a sensitive assay, we found that the prevalence of increased cTnI concentrations in patients with CKD is similar to that observed for cTnT. cTnT concentration, but not cTnI, was independently associated with death.
Lamb
Edmund J
EJ
Clinical Biochemistry, East Kent Hospitals NHS Trust, Canterbury, Kent. edmund.lamb@ekht.nhs.uk
Kenny
Claire
C
Abbas
Nasir A
NA
John
R Ian
RI
Webb
Michelle C
MC
Price
Christopher P
CP
Vickery
Susan
S
D000368:Aged; D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007674:Kidney Diseases / Q000378:metabolism* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D009994:Osmolar Concentration; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood* / Q000378:metabolism; D020107:Troponin T / Q000097:blood / Q000378:metabolism
D019210:Troponin I; D020107:Troponin T