Introduction of a prognostic biomarker to strengthen risk stratification of acutely admitted patients: rationale and design of the TRIAGE III cluster randomized interventional trial

Utilization of Prognostic Biomarker Soluble Urokinase Plasminogen Activator Receptor in the Emergency Department: A Tool for Safe and More Efficient Decision-making

Introduction:

Risk stratification in the emergency departments (EDs) is in critical need for new applications due to ED overcrowding and hospitalization of older people. We aimed to evaluate the expediency, efficiency and safety of a prognostic biomarker, soluble urokinase plasminogen activator receptor (suPAR), as a tool for the risk assessment of patients arriving at the ED.

Methods:

We performed a comparative cross-sectional study in 2 emergency departments (EDs), suPAR measurements being incorporated into routine blood sampling in the intervention ED. The primary outcome was the number of discharges from the ED. The importance of the outcomes was examined by appropriate multi- or bivariate analysis.

Results:

The absolute and relative number of discharges were similar between the intervention and control groups [121 (55.3%) vs 62 (55.9%)]. No significant differences between the groups were seen in the length of stays in the ED. Patients with low suPAR values were more likely discharged and patients with high suPAR values more likely admitted to hospital. Two admitted patients with low suPAR values could have been discharged safely.

Conclusion:

The utilization of suPAR did not increase the risk for neither positive nor negative outcomes. Low suPAR values could be potential in discharging more patients safely. Instead of unselected patient populations, the benefits of suPAR measurements in the ED could emerge in the assessment of a more precisely determined and selected group of patients.

Promising Novel Biomarkers in Cardiovascular Diseases

Cardiovascular diseases remain the most common causes of death globally, according to the World Health Organization. In recent years, a great number of biomarkers have been investigated, whereas only some have gained value in the diagnosis, prognosis, and risk stratification of different cardiovascular illnesses. As numerous studies have investigated the diagnostic yield of novel biomarkers in various disease entities every year, this review aims to provide an overview of the current status of four promising representatives. In particular, this manuscript refers to soluble suppression of tumorigenicity 2 (sST2), heart-type fatty acid binding protein (H-FABP), growth differentiation factor (GDF-15) and soluble urokinase-type plasminogen activator receptor (suPAR). These markers are of special interest as they are thought to provide an accurate estimate of cardiovascular risk in certain patient populations, especially those with pre-existing diseases, such as obesity or diabetes mellitus. We sought to give an overview of their function, individual diagnostic and predictive value and determination in the laboratory. A review of the literature regarding the aforementioned cardiovascular biomarkers yielded manifold results with respect to their individual diagnostic and prognostic value. Yet, the clinical relevance of these findings remains unclear, warranting further studies to identify their optimal use in clinical routine.

Mortality and major complications after emergency laparotomy: A pilot study of risk prediction model development by preoperative blood-based immune parameters

BACKGROUND

Emergency laparotomy is associated with high risk of postoperative complications and mortality. Preoperative identification of patients at high risk of adverse outcome is important. The immune response to conditions requiring emergency laparotomy is not understood in detail. The present study describes preoperative blood-based immune profiles and their potential value in surgical risk assessment.

METHOD

Patients (N = 100) referred for emergency laparotomy at Hvidovre Hospital were consecutively included from 3 June 2013-11 April 2014. All patients had blood samples collected before surgery and the immune parameters c-reactive protein (CRP), Interleukin-6 (IL-6), Interleukin-10 (IL-10), interferon-γ induced protein 10 kDa (IP-10), tumor necrosis factor α (TNF-α) and soluble urokinase plasminogen receptor activator (suPAR) were determined. Patients were stratified according to major postoperative complications (including death), 30- and 180-day mortality. Using logistic regression models and receiver operating characteristics curves the predictive ability of the immune parameters were estimated.

RESULTS

Major complications were recorded in 45 (45.0%) of the patients, whereas 30-day and 180-day mortalities were 17 (17.0%) and 25 (25.0%), respectively. Concentrations of suPAR and TNF-α were associated with major complications while CRP, IL-6, suPAR and TNF-α were associated with mortality. Adding the combined immune parameters to a regression model including age, sex, American Society of Anesthesiologists physical status and Eastern Cooperative Oncology Group Performance Status significantly improved the predictive ability for major complications, 30-day mortality and 180-day mortality.

CONCLUSION

In emergency laparotomy, preoperative blood-based immune parameters added predictive power to regression models and could be considered in risk prediction model development.

Abnormal routine blood tests as predictors of mortality in acutely admitted patients

BACKGROUND

This study aimed to improve early risk stratification in the emergency department by creating a simple blood test score based on routine biomarkers and assess its predictive ability for 30-day mortality of acutely admitted patients.

METHODS

This was a secondary analysis of data from the TRIAGE II study. It included unselected acutely admitted medical and surgical patients, who had albumin, C-reactive protein, creatinine, haemoglobin, leukocytes, potassium, sodium and thrombocytes levels analysed upon admission. Patients were classified according to the number of biomarker results outside the reference range into four risk groups termed "very low", "low", "intermediate", and "high" with 0-1, 2-3, 4-5 and 6-8 abnormal biomarker results, respectively. Logistic regression was used to calculate odds ratios for 30-day mortality and receiver operating characteristic was used to test the discriminative value. The primary analysis was done in patients triaged with ADAPT (Adaptive Process Triage). Subsequently, we analysed two other cohorts of acutely admitted patients.

RESULTS

The TRIAGE II cohort included 17,058 eligible patients, 30-day mortality was 5.2%. The primary analysis included 7782 patients. Logistic regression adjusted for age and sex showed an OR of 24.1 (95% CI 14.9-41.0) between the very low- and the high-risk group. The area under the curve (AUC) was 0.79 (95% CI 0.76-0.81) for the blood test score in predicting 30-day mortality. The subsequent analyses confirmed the results.

CONCLUSIONS

A blood test score based on number of routine biomarkers with an abnormal result was a predictor of 30-day mortality in acutely admitted patients.

Early Discharge from the Emergency Department Based on Soluble Urokinase Plasminogen Activator Receptor (suPAR) Levels: A TRIAGE III Substudy

Objective

Using biomarkers for early and accurate identification of patients at low risk of serious illness may improve the flow in the emergency department (ED) by classifying these patients as nonurgent or even suitable for discharge. A potential biomarker for this purpose is soluble urokinase plasminogen activator receptor (suPAR). We hypothesized that availability of suPAR might lead to a higher proportion of early discharges.

Design

A substudy of the interventional TRIAGE III trial, comparing patients with a valid suPAR measurement at admission to those without. The primary endpoint was the proportion of patients discharged alive from the ED within 24 hours. Secondary outcomes were length of hospital stay, readmissions, and mortality within 30 days.

Setting

EDs at two university hospitals in the Capital Region of Denmark.

Participants

16,801 acutely admitted patients were included.

Measurements and Main Results

The suPAR level was available in 7,905 patients (suPAR group), but not in 8,896 (control group). The proportion of patients who were discharged within 24 hours of admittance was significantly higher in the suPAR group compared to the control group (50.2% (3,966 patients) vs. 48.6% (4,317 patients), P = 0.04). Furthermore, the mean length of hospital stay in the suPAR group was significantly shorter compared to that in the control group (4.3 days (SD 7.4) vs. 4.6 days (SD 9.4), P = 0.04). In contrast, the readmission rate within 30 days was significantly higher in the suPAR group (10.6% (839 patients) vs. 8.8% (785 patients), P < 0.001). Among patients discharged within 24 hours, there was no significant difference in the readmission rate or mortality within 30 days. Readmission occurred in 8.5% (336 patients) vs. 7.7% (331 patients) (P = 0.18) and mortality in 1.3% (52 patients) vs. 1.8% (77 patients) (P = 0.08) for the suPAR group and control group, respectively.

Conclusion

These post hoc analyses demonstrate that the availability of the prognostic biomarker suPAR was associated with a higher proportion of discharge within 24 hours and reduced length of stay, but more readmissions. In patients discharged within 24 hours, there was no difference in readmission or mortality.

Trial Registration of the Main Trial

This trial is registered with NCT02643459.

Risk assessment models for potential use in the emergency department have lower predictive ability in older patients compared to the middle-aged for short-term mortality - a retrospective cohort study

Background

Older patients is a complex group at increased risk of adverse outcomes compared to younger patients, which should be considered in the risk assessment performed in emergency departments. We evaluated whether the predictive ability of different risk assessment models for acutely admitted patients is affected by age.

Methods

Cohort study of middle-aged and older patients. We investigated the accuracy in discriminating between survivors and non-survivors within 7 days of different risk assessment models; a traditional triage algorithm, a triage algorithm with clinical assessment, vital signs, routine biomarkers, and the prognostic biomarker soluble urokinase plasminogen activator receptor (suPAR).

Results

The cohort included 22,653 (53.2%) middle-aged patients (age 40–69 years), and 19,889 (46.8%) older patients (aged 70+ years). Death within 7 days occurred in 139 patients (0.6%) in middle-aged patients and 596 (3.0%) of the older patients. The models based on vital signs and routine biomarkers had the highest area under the curve (AUC), and both were significantly better at discriminating 7-day mortality in middle-aged patients compared to older patients; AUC (95% CI): 0.88 (0.84–0.91), 0.75 (0.72–0.78), P < 0.01, and 0.86 (0.82–0.90), 0.76 (0.73–0.78), P < 0.001. In a subgroup of the total cohort (6.400 patients, 15.0%), the suPAR level was available. suPAR had the highest AUC of all individual predictors with no significant difference between the age groups, but further research in this biomarker is required before it can be used.

Conclusion

The predictive value was lower in older patients compared to middle-aged patients for all investigated models. Vital signs or routine biomarkers constituted the best models for predicting 7-day mortality and were better than the traditional triage model. Hence, the current risk assessment for short-term mortality can be strengthened, but modifications for age should be considered when constructing new risk assessment models in the emergency department.

Electronic supplementary material

The online version of this article (10.1186/s12877-019-1154-7) contains supplementary material, which is available to authorized users.

Availability of suPAR in emergency departments may improve risk stratification: a secondary analysis of the TRIAGE III trial

Introduction

Soluble urokinase plasminogen activator receptor (suPAR) is a prognostic and nonspecific biomarker associated with short-term mortality in emergency department (ED) patients. Therefore, the blood level of suPAR might be usable for identification of patients at high- and low risk, shortly after arrival at the ED. Here, we investigate the value of adding suPAR to triage and how this may impact on risk stratification regarding mortality.

Methods

The analyses were performed on the TRIAGE III cohort. Patients were triaged in four groups: Red, Orange, Yellow, and Green. Outcome was all-cause mortality within seven days. Discriminative abilities of triage and suPAR on mortality were assessed using the area under the curve (AUC) for receiver operating characteristics (ROC) curves. A suPAR cut-off value was generated using the Youden’s index. Patients were subsequently reclassified one triage level up if the suPAR level was above this cut-off and one level down if the suPAR level was below that value.

Results

The study included 4420 patients with an available triage category and suPAR measurement. suPAR was significantly better in predicting mortality than triage; AUC (95% confidence interval): 0.85 (0.80–0.89) vs. 0.71 (0.64–0.78), P < 0.001. Combining suPAR and triage yielded an AUC of 0.87 (0.82–0-93). The Youden’s cut-off of suPAR was 5.9 ng/mL and reclassified triage using this value resulted in a more accurate risk stratification regarding hospital admission and mortality.

Conclusion

Addition of suPAR to triage potentially improves prediction of short-term mortality. Measurement of suPAR in relation to the triage process may allow a more accurate identification of ED patients at risk.

Trial registration

Clinicaltrials.gov, NCT02643459. Registered 31 December 2015. https://clinicaltrials.gov/ct2/show/NCT02643459?cond=NCT02643459&rank=1.

Electronic supplementary material

The online version of this article (10.1186/s13049-019-0621-7) contains supplementary material, which is available to authorized users.

Use of the prognostic biomarker suPAR in the emergency department improves risk stratification but has no effect on mortality: a cluster-randomized clinical trial (TRIAGE III)

Background

Risk stratification of patients in the emergency department can be strengthened using prognostic biomarkers, but the impact on patient prognosis is unknown. The aim of the TRIAGE III trial was to investigate whether the introduction of the prognostic and nonspecific biomarker: soluble urokinase plasminogen activator receptor (suPAR) for risk stratification in the emergency department reduces mortality in acutely admitted patients.

Methods

The TRIAGE III trial was a cluster-randomized interventional trial conducted at emergency departments in the Capitol Region of Denmark. Eligible hospitals were required to have an emergency department with an intake of acute medical and surgical patients and no previous access to suPAR measurement. Three emergency departments were randomized; one withdrew shortly after the trial began. The inclusion period was from January through June of 2016 consisting of twelve cluster-periods of 3-weeks alternating between intervention and control and a subsequent follow-up of ten months. Patients were allocated to the intervention if they arrived in interventional periods, where suPAR measurement was routinely analysed at arrival. In the control periods suPAR measurement was not performed. The main outcome was all-cause mortality 10 months after arrival of the last patient in the inclusion period. Secondary outcomes included 30-day mortality.

Results

The trial enrolled a consecutive cohort of 16,801 acutely admitted patients; all were included in the analyses. The intervention group consisted of 6 cluster periods with 8900 patients and the control group consisted of 6 cluster periods with 7901 patients. After a median follow-up of 362 days, death occurred in 1241 patients (13.9%) in the intervention group and in 1126 patients (14.3%) in the control group.

The weighted Cox model found a hazard ratio of 0.97 (95% confidence interval, 0.89 to 1.07; p = 0.57). Analysis of all subgroups and of 30-day all-cause mortality showed similar results.

Conclusions

The TRIAGE III trial found no effect of introducing the nonspecific and prognostic biomarker suPAR in emergency departments on short- or long-term all-cause mortality among acutely admitted patients. Further research is required to evaluate how prognostic biomarkers can be implemented in routine clinical practice.

Trial registration

clinicaltrials.gov, NCT02643459. Registered 31 December 2015.

Electronic supplementary material

The online version of this article (10.1186/s13049-018-0539-5) contains supplementary material, which is available to authorized users.