Hs-cTnT Predicts Mortality in Suspected Infection Patients
Hs-cTnT Predicts Mortality in Suspected Infection Patients
Introducion To assess the prognostic and discriminative accuracy of high-sensitivity cardiac troponin T (hs-cTnT) for prediction of inhospital mortality in emergency department (ED) patients with suspected infection.
Methods Prospective observational derivation study in ED patients with suspected infection. Prognostic performance of hs-cTnT (divided in four quartiles because of non-linearity) for prediction of inhospital mortality was assessed using multivariable logistic regression, correcting for predisposition, infection, response and organ failure (PIRO) score as a measure of illness severity and quality of ED treatment as quantified by the number of 'Surviving Sepsis Campaign' goals achieved. Discriminative power of hs-cTnT was assessed by receiver operator characteristics with area under the curve (AUC) analysis.
Results Hs-cTnT (median (IQR) was 57 (25–90) ng/L (n=23) in non-survivors, significantly higher than the 15 (7–28) ng/L in survivors (n=269, p<0.001). Additionally, the lowest quartile of hs-cTnT was a perfect predictor of survival because zero death occurred. Therefore, the second quartile was used as a reference category in the multivariable logistic regression analysis showing that hs-cTnT was an independent predictor of inhospital mortality: Corrected ORs were 2.2 (95% CI 0.4 to 12.1) and 5.8 (1.2 to 27.3) for the 3rd and 4th quartile compared with the 2nd hs-cTnT quartile. The AUCs of hs-TnT was 0.81 (0.74 to 0.88), similar to the AUC of 0.78 (0.68 to 0.87) of the PIRO score (p>0.05). Overall negative predictive value of hs-cTnT was 99%.
Conclusions In ED patients with suspected infection, the routinely used biomarker hs-cTnT is an independent predictor of inhospital mortality with excellent discriminative performance. Future studies should focus on the additional value of hs-cTnT to existing risk stratification tools.
Risk stratification of emergency department (ED) patients with a suspected infection is important for rapid initiation of adequate ED treatment and for disposition to the most optimal level of care. Erroneous disposition to a ward instead of an intensive care unit (ICU) affects patient outcome, and unnecessary admissions to a ward or ICU has a negative impact on hospital finances. The Mortality in ED Sepsis (MEDS), and the more recently developed Predisposition, Infection, Response and Organ-failure (PIRO) score have been developed for risk stratification of ED patients with a suspected infection. However, in populations meeting the criteria for early goal-directed therapy, prognostic performance might be limited. Moreover, both the MEDS and PIRO score were less useful for guidance of adequate disposition, while still 13% of ED patients with severe sepsis and septic shock are erroneously disposed to a normal ward, resulting in a higher mortality and longer hospital length of stay. Hence, the currently used MEDS and PIRO score may be strengthened by additional diagnostic tools. In a preliminary study, Kennedy et al identified seven clinical characteristics predicting an unanticipated transfer from ward to ICU. However, their model had moderate discrimination with an area under the curve (AUC) of only 0.73. In the present study, we therefore aimed to find a simple biomarker that could improve current risk stratification of ED patients with a suspected infection.
Impaired cardiac function has been suggested to be a crucial factor in the development of septic shock. During sepsis, cardiac cell wall integrity can be compromised by global hypoperfusion, and the release of endotoxins, cytokines, or reactive oxygen species, with subsequent release of troponins into the circulation. Therefore, cardiac troponin, well known for its role in risk stratification of patients with possible acute coronary syndrome, might also be a suitable biomarker for risk stratification of ED sepsis patients, with the potential to identify ED sepsis patients who need intensive care with inotropic or vasoactive medication or mechanical ventilation. Previous studies, using various types of troponin assays, showed conflicting results with regard to the prognostic performance of cardiac troponins in severely septic patients that needed ICU admission. However, none of these studies included patients with less severe sepsis stages.
The role of high-sensitivity cardiac troponin T (hs-cTnT) for risk stratification of ED patients with suspected infection has never been explored. An ED population consists of a broad severity range of the sepsis syndrome, ranging from low-risk patients who could be discharged home to septic shock patients who require ICU admission. This will affect prognostic properties of hs-cTnT. More importantly, in ED patients with septic shock, it will be clear for the ED physician that aggressive treatment and ICU admission is warranted, but especially in patients with intermediate risk, a more accurate risk stratification tool would be of great value. If hs-cTnT is an independent predictor of mortality in ED patients with a suspected infection, this routinely used biomarker could also have the potential to guide adequate disposition in less severe stages of sepsis, with the additional advantage that it is much simpler than the PIRO score.
The purpose of the present study was therefore to take the two necessary steps to investigate the potential of hs-cTnT for use in risk stratification of ED patients with a suspected infection.
First, the accuracy and discriminative performance of hs-cTnT for prediction of inhospital was assessed. Second, the association of hs-cTnT with disposition pattern and MEDS and PIRO score was assessed.
Abstract and Introduction
Abstract
Introducion To assess the prognostic and discriminative accuracy of high-sensitivity cardiac troponin T (hs-cTnT) for prediction of inhospital mortality in emergency department (ED) patients with suspected infection.
Methods Prospective observational derivation study in ED patients with suspected infection. Prognostic performance of hs-cTnT (divided in four quartiles because of non-linearity) for prediction of inhospital mortality was assessed using multivariable logistic regression, correcting for predisposition, infection, response and organ failure (PIRO) score as a measure of illness severity and quality of ED treatment as quantified by the number of 'Surviving Sepsis Campaign' goals achieved. Discriminative power of hs-cTnT was assessed by receiver operator characteristics with area under the curve (AUC) analysis.
Results Hs-cTnT (median (IQR) was 57 (25–90) ng/L (n=23) in non-survivors, significantly higher than the 15 (7–28) ng/L in survivors (n=269, p<0.001). Additionally, the lowest quartile of hs-cTnT was a perfect predictor of survival because zero death occurred. Therefore, the second quartile was used as a reference category in the multivariable logistic regression analysis showing that hs-cTnT was an independent predictor of inhospital mortality: Corrected ORs were 2.2 (95% CI 0.4 to 12.1) and 5.8 (1.2 to 27.3) for the 3rd and 4th quartile compared with the 2nd hs-cTnT quartile. The AUCs of hs-TnT was 0.81 (0.74 to 0.88), similar to the AUC of 0.78 (0.68 to 0.87) of the PIRO score (p>0.05). Overall negative predictive value of hs-cTnT was 99%.
Conclusions In ED patients with suspected infection, the routinely used biomarker hs-cTnT is an independent predictor of inhospital mortality with excellent discriminative performance. Future studies should focus on the additional value of hs-cTnT to existing risk stratification tools.
Introduction
Risk stratification of emergency department (ED) patients with a suspected infection is important for rapid initiation of adequate ED treatment and for disposition to the most optimal level of care. Erroneous disposition to a ward instead of an intensive care unit (ICU) affects patient outcome, and unnecessary admissions to a ward or ICU has a negative impact on hospital finances. The Mortality in ED Sepsis (MEDS), and the more recently developed Predisposition, Infection, Response and Organ-failure (PIRO) score have been developed for risk stratification of ED patients with a suspected infection. However, in populations meeting the criteria for early goal-directed therapy, prognostic performance might be limited. Moreover, both the MEDS and PIRO score were less useful for guidance of adequate disposition, while still 13% of ED patients with severe sepsis and septic shock are erroneously disposed to a normal ward, resulting in a higher mortality and longer hospital length of stay. Hence, the currently used MEDS and PIRO score may be strengthened by additional diagnostic tools. In a preliminary study, Kennedy et al identified seven clinical characteristics predicting an unanticipated transfer from ward to ICU. However, their model had moderate discrimination with an area under the curve (AUC) of only 0.73. In the present study, we therefore aimed to find a simple biomarker that could improve current risk stratification of ED patients with a suspected infection.
Impaired cardiac function has been suggested to be a crucial factor in the development of septic shock. During sepsis, cardiac cell wall integrity can be compromised by global hypoperfusion, and the release of endotoxins, cytokines, or reactive oxygen species, with subsequent release of troponins into the circulation. Therefore, cardiac troponin, well known for its role in risk stratification of patients with possible acute coronary syndrome, might also be a suitable biomarker for risk stratification of ED sepsis patients, with the potential to identify ED sepsis patients who need intensive care with inotropic or vasoactive medication or mechanical ventilation. Previous studies, using various types of troponin assays, showed conflicting results with regard to the prognostic performance of cardiac troponins in severely septic patients that needed ICU admission. However, none of these studies included patients with less severe sepsis stages.
The role of high-sensitivity cardiac troponin T (hs-cTnT) for risk stratification of ED patients with suspected infection has never been explored. An ED population consists of a broad severity range of the sepsis syndrome, ranging from low-risk patients who could be discharged home to septic shock patients who require ICU admission. This will affect prognostic properties of hs-cTnT. More importantly, in ED patients with septic shock, it will be clear for the ED physician that aggressive treatment and ICU admission is warranted, but especially in patients with intermediate risk, a more accurate risk stratification tool would be of great value. If hs-cTnT is an independent predictor of mortality in ED patients with a suspected infection, this routinely used biomarker could also have the potential to guide adequate disposition in less severe stages of sepsis, with the additional advantage that it is much simpler than the PIRO score.
The purpose of the present study was therefore to take the two necessary steps to investigate the potential of hs-cTnT for use in risk stratification of ED patients with a suspected infection.
First, the accuracy and discriminative performance of hs-cTnT for prediction of inhospital was assessed. Second, the association of hs-cTnT with disposition pattern and MEDS and PIRO score was assessed.