Original articleOutcome prediction using the Mortality in Emergency Department Sepsis score combined with procalcitonin for influenza patientsPredicción del resultado utilizando la puntuación de mortalidad por sepsis en la unidad de urgencias combinada con procalcitonina en los pacientes con gripe
Introduction
Influenza epidemics result in approximately 300,000–650,000 deaths worldwide annually and account for heavy social burdens.1, 2 Although these new estimates indicate that influenza-associated mortality has increased, they might underestimate the true mortality burden.3, 4 Current prevention and treatment strategies are seemingly not adequate to reduce this burden.
At the time of epidemics or a sporadic pandemic, it is of vital importance to stratify severity and predict prognosis, which need not only physician's clinical judgment, but also objective severity scores and indicators, especially in the emergency department (ED). Most but not all patients with severe influenza infections present with pneumonia.5 Even if in patients with influenza pneumonia, the most common pneumonia severity scores, including pneumonia severity index (PSI)6; confusion, urea, respiratory rate, blood pressure, age ≥65 years (CURB-65)7; confusion, respiratory rate, blood pressure, age ≥65 years (CRB-65),8 are powerless in predicting mortality.9, 10, 11 The Mortality in Emergency Department Sepsis (MEDS) score is used to assess the severity of disease and to predict the mortality of patients with suspected infection in the ED.12 But fewer studies have investigated the clinical implication of MEDS for evaluating influenza patients.
In view of the limitations of clinical scores, there has been considerable interest in the development of rapid biomarkers for reliable prognosis prediction.13 Among them, procalcitonin (PCT) is widely used in virtue of its higher predictive capacity for bacterial infection,14 and associated with the severity of illness in patients with pneumonia and appears to be a prognostic marker of morbidity and mortality.15 Particularly notable is in recent years the increase in the number of patients with influenza who are admitted to hospitals with bacterial coinfection or superinfection, causing additional hospitalization and mortality.16, 17 These patients should be identified when developing clinical antibiotic strategies, but classical pathogen cultures are slow and have low sensitivity. PCT has been proved as a reliable single predictor to distinguish individual virus infection and virus-bacterial coinfection.18, 19 However, few studies have focused on whether PCT can directly determine prognosis in influenza patients.
Assessment of illness severity and the risk for clinical deterioration at the time of initial diagnosis are essential for optimal management. The purpose of this study is to investigate the prognostic prediction value of MEDS score, PCT and other relevant biomarkers for influenza patients in the ED.
Section snippets
Study design and patient selection
This study was conducted using clinical and laboratory data collected retrospectively at the ED (including fever clinic) of a university-affiliated urban tertiary teaching hospital. From 2010 to 2018, including 8 epidemic influenza seasons, all consecutive ED (including fever clinic) admitted patients with diagnosis of influenza infection were screened. Medical records were independently reviewed by two physicians. This study was approved by the Institutional Review Board and Medical Ethics
Characteristics of the study population
During the study period, 421 admitted patients with diagnosis of influenza were screened. Of these, 57 (13.5%) were excluded: 25 lacked important medical records, 28 were non-ED (or fever clinic) admission, 2 were less than 15 years old, and 2 were pre-existing thyroid disease. Finally 364 (86.5%) were eligible for enrollment, and of them, 230 (63.2%) fulfilled the CAP criteria, 83 (22.8%) were diagnosed with bronchitis, and 51 (14.0%) with respiratory underlying disease aggravated; 335 (92.0%)
Discussion
Severe influenza is a common potential initiating factor for sepsis, and pathogenic bacteria are usually involved in this process, increasing additional mortality and morbidity by coinfection or superinfection.22 These patients undergo a complex interaction process of initial virus, co-pathogen invasion and host immune response, and the disease may deteriorate unexpectedly and rapidly.23 Identifying severe influenza patients at high risk of mortality is crucial to anticipate prognosis, select
Abbreviations
CAP, community-acquired pneumonia; RT-PCR, reverse transcription polymerase chain reaction; PCT, procalcitonin; CRP, C-reaction protein; MEDS, Mortality in Emergency Department Sepsis; SOFA, Sequential Organ Failure Assessment; ED, emergency department; SD, standard deviation; IQR, inter-quartile range; CI, confidence interval; ROC, receiver operating characteristic; AUC, area under the ROC curve; SEN, sensitivity; SPE, specificity; PPV, positive predictive values; NPV, negative predictive
Funding
None.
Conflict of interest
The authors declare that they have no competing interests.
Acknowledgments
The authors would like to thank the staff of the Microbiology Laboratory, the Analysis Department and the Medical Records Department of Beijing Chao-Yang Hospital for their helpful contributions to the study.
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