Raised serum cardiac troponin I concentrations predict hospital mortality in intensive care unit patients†

Recent work suggests that increased plasma concentrations of cardiac troponin I (cTnI) are common in critically ill patients and are associated with poor outcome. We measured the frequency of increased plasma cTnI concentrations during patients stay in a mixed medical/surgical intensive care unit (ICU) and compared our findings with hospital mortality. Basic details, organ support, and hospital mortality were recorded for all patients treated in ICU during a 6 month period. cTnI concentrations were sampled daily for all patients, using 0.04 g litre(1) as the upper limit of normal, and 0.12 g litre(1) as an additional stratification point. Of 663 patients, 54 were male, with a mean (sd) age of 60 (18) yr, 65 were surgical patients, and the median Acute Physiology and Chronic Ill Health II (APACHE II) score was 15 (inter-quartile range 1220). Increased cTnI concentrations were found in 345 patients (52) while in ICU. One hundred and twenty patients (18) died in hospital. cTnI concentration 0.04 g litre(1) was associated with reduced odds of hospital survival, independent of age, medical admission, unplanned admission, APACHE II score, mechanical ventilation, and haemofiltration (adjusted odds ratio 0.25, 95 confidence interval 0.080.75, P0.014). Stratification by the degree of cTnI increase revealed an incremental trend towards a lower odds of hospital survival, including for patients with ominor' elevations of cTnI (0.050.12 g litre(1)). Increased serum cTnI concentrations during ICU stay independently predicts hospital mortality, even when the threshold is low. We found a trend towards an association between ominor' elevations in cTnI and higher in-hospital mortality.