Scandinavian Journal of Clinical and Laboratory Investigation

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Calprotectin is superior to procalcitonin as a marker and predictor of 30-day mortality in intensive care patients

Anders Larsson, Jonas Tydén, Joakim Johansson, Miklos Lipcsey, Maria Bergquist, Kim Kultima & Aleksandra Mandic-Havelka

To cite this article: Anders Larsson, Jonas Tydén, Joakim Johansson, Miklos Lipcsey, Maria Bergquist, Kim Kultima & Aleksandra Mandic-Havelka (2020) Calprotectin is superior to procalcitonin as a sepsis marker and predictor of 30-day mortality in intensive care patients, Scandinavian Journal of Clinical and Laboratory Investigation, 80:2, 156-161, DOI: 10.1080/00365513.2019.1703216 To link to this article: https://doi.org/10.1080/00365513.2019.1703216

© 2019 The Author(s). Published by Informa Published online: 14 Dec 2019. UK Limited, trading as Taylor & Francis Group

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Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=iclb20 SCANDINAVIAN JOURNAL OF CLINICAL AND LABORATORY INVESTIGATION 2020, VOL. 80, NO. 2, 156–161 https://doi.org/10.1080/00365513.2019.1703216

ORIGINAL ARTICLE Calprotectin is superior to procalcitonin as a sepsis marker and predictor of 30-day mortality in intensive care patients

Anders Larssona, Jonas Tyden b, Joakim Johanssonb, Miklos Lipcseyc, Maria Bergquistc, Kim Kultimaa and Aleksandra Mandic-Havelkad aDepartment of Medical Sciences, , University Hospital, Uppsala, Sweden; bDepartment of Surgical and Perioperative Sciences, Anaesthesiology and Critical Care Medicine (Ostersund),€ Umeå University, Umeå, Sweden; cDepartment of Surgical Sciences, Anaesthesiology and Intensive care, Hedenstierna laboratory, Uppsala University, Uppsala, Sweden; dDepartment of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden

ABSTRACT ARTICLE HISTORY Sepsis is the most frequent cause of death in the intensive care unit (ICU). A rapid and correct diagno- Received 7 November 2019 sis and initiation of therapy is crucial for improving patient outcomes. The aim of this study was to Revised 2 December 2019 compare the performance of calprotectin with the more widely used sepsis biomarker procalcitonin Accepted 8 December 2019 (PCT) in ICU patients. The performance of calprotectin and PCT as sepsis and prognostic markers for KEYWORDS 30-d mortality was compared in a prospective, observational study in an eight-bed ICU. We investi- Calprotectin; procalcitonin; gated concentrations of the biomarkers in plasma collected at admission from all ICU patients admit- sepsis; intensive care; ted during a year (2012–2013, n ¼ 271) together with simplified acute physiology 3 scores (SAPS3) and SAPS3; SOFA sequential organ failure assessment (SOFA) scores. The receiver operating characteristic (ROC) analysis showed a higher area under the curve (AUC) value for calprotectin (0.79) than for PCT (0.49) when used as a sepsis marker. The calprotectin concentrations at admission were higher in non-survivors than in survivors at day 30. In our study, calprotectin was superior to PCT for distinguishing between ICU patients with sepsis and non-sepsis patients. Calprotectin also had higher predictive ability regard- ing 30-d mortality.

Introduction Biomarkers have an important role in detection of sepsis and estimation of the severity of the condition. Biomarkers Infections cause the deaths of more than 10 million people are to distinguish between bacterial, viral and fungal infec- per year [1] and sepsis affects between 3 and 10 per 1000 tions as the different types of infections require different people annually in industrialized countries [2]. Sepsis is the types of treatments. A widely used biomarker is C-reactive most frequent cause of admission to intensive care units protein (CRP) that has been used for many years, but CRP (ICUs) and the most common cause of death in ICUs [3]. is mainly an marker and the specificity in sep- The sepsis incidence and prevalence have been increasing sis has been challenged [9]. Procalcitonin (PCT) is together continuously over the last years [4]. Early identification of with CRP the most widely used sepsis biomarkers. PCT has sepsis and initiation of treatment is essential to minimize been proposed as a more specific [10] and better prognostic mortality and morbidity. [11] marker than CRP, but this has also been questioned A problem is that sepsis often is associated with non-spe- [12]. There is thus a continuous need for better sep- cific symptoms and is, therefore, difficult to diagnose [5]. At sis biomarkers. the same time, any delay in treatment increases the mortal- granulocytes react to bacterial infections and ity [6]. are one of the first-responders to bacterial infections. When One tool used to diagnose sepsis is sequential organ fail- the neutrophil is activated it releases calprotectin, one of the ure assessment (SOFA) score. It is considered a good pre- most abundant proteins in the neutrophil . dictor of outcome when used during the first few days in Calprotectin consists of two subunits, and . the ICU [7], but it does not aid in identifying patients S100A8 has a molecular weight of 10.8 kDa, while S100A9 before they need to be admitted to the ICU. has a molecular weight of 13.2 kDa. This biomarker Although SOFA helps to identify patients with increased increases within hours in response to bacteria or endotoxin risk of death, and it is a part of the current sepsis defini- [13]. Determination of serum calprotectin has been pro- tions [8], it is by no means specific for infection or sepsis. posed as a valuable marker of acute appendicitis [14],

CONTACT Anders Larsson [email protected] Department of Medical Sciences, Uppsala University, Entrance 61, 2nd floor, Akademiska Hospital, Uppsala S-751 85, Sweden ß 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. SCANDINAVIAN JOURNAL OF CLINICAL AND LABORATORY INVESTIGATION 157

Table 1. Patient clinical and demographics data. Sepsis Trauma Miscellaneous Other medical (n ¼ 77, 28%) (n ¼ 32, 12%) (n ¼ 80, 30%) (n ¼ 82, 30%) Age, years 72 (28–90) 50 (21–96) 70 (23–95) 63 (19–93) Female sex, n (%) 21 (27) 5 (16) 26 (33) 40 (49) SAPS3 score 63 (41–105) 47 (29–74) 60 (32–108) 52 (30–85) Max SOFA 7 (3–20) 4 (0–18) 7 (1–17) 5 (0–17) Mortality at 30 d, n (%) 16 (21) 3 (9) 25 (31) 18 (22) Continuous parameters are presented as median and (range) unless otherwise stated. rheumatoid [15,16] and sepsis [17–20]. Early release PCT was analyzed by a commercial sandwich ELISA of calprotectin and rapid test turn-around-times suggest that (DY8350-05, R&D Systems, Minneapolis, MN). Calprotectin calprotectin can become a useful biomarker with widespread was measured with particle enhanced turbidimetric assay clinical use. (PETIA) methodology using calprotectin reagents from The aim of this study was to compare the performance Gentian AS (Moss, Norway) and a Mindray BS380 chemis- of calprotectin and PCT as markers for sepsis and 30-d try analyzer (Mindray, Shenzhen, China). mortality in a large cohort of ICU patients. SOFA scoring Materials and methods Simplified acute physiology 3 scores (SAPS3) were recorded Study population on admission [21]. Sequential organ failure assessment (SOFA) scores were also recorded on admission and then This is a prospective observational study in an eight-bed on the two following days [22]. Sepsis was defined accord- county hospital mixed ICU at Ostersund€ hospital, a 300-bed ing to Sepsis-3 as suspected infection and a SOFA >2on hospital in Sweden. The study was approved by the regional admission [8]. ethical review board in Linkoping€ and has been performed in accordance with the ethical standards of the 1964 Declaration of Helsinki and its later amendments. Verbal Statistical analysis consent was provided by the patient or next of kin if the Data are presented as median (IQR) or as number of patient was not able to provide the consent. Consent was observations (percent of total number of observations). documented on the patient’s inclusion sheet. Verbal as Mann–Whitney U test or Kruskal Wallis with Dunn’smul- opposed to written consent was chosen as many of the ICU tiplecomparisontestwereusedtocomparetwoormore patients were not able to write due to severity of illness. groups respectively. Logistic regression was performed with This procedure was approved by the ethics review board. the diagnosis of Sepsis vs. Trauma and Sepsis vs. OMCs, All patients admitted to the ICU, Ostersund€ ’s hospital and 30-d mortality as dependent variables with PCT or cal- between 1 February 2012 and 31 January 2013 were protectin as sole predictors. Area under the curve (AUC) screened for inclusion in the study. Inclusion criteria were of the receiver operating characteristic (ROC) was calcu- admission to the ICU and presence of or need for an arter- lated. Best cut-off was defined at the maximal distance ial catheter to be inserted. Patients transferred from other from ROC curve and the diagonal. In the same model after ICUs and age less than 18 years were exclusion criteria. adjusting for age, sex, illness severity (SAPS3) and extent Final diagnosis was set retrospectively by chart review. of organ failure (SOFA), we also assessed if the biomarker SOFA scoring was recorded daily. The patients were div- in the models was an independent predictor of sepsis or ided into four main groups. Sepsis group; Trauma group, death and the magnitude of such an effect expressed as presumed to have inflammation without infection on admis- odds ratio. STATISTICA software version 13.2 (StatSoft, sion; Other medical conditions (OMC) group, presumed to Tulsa, OK) and GraphPad Prism version 7.0 for Windows have medical conditions without inflammation on admis- (GraphPad Software Inc., La Jolla, CA) were used for cal- sion; and the remaining patients were designated to the culations and figures. p < .05 was considered significant Miscellaneous group. The OMC group consisted of condi- where relevant. tions normally treated by internal medicine doctors while the miscellaneous group consisted of patients treated by other specialties, mainly surgeons. Results Calprotectin and procalcitonin as markers for sepsis Blood sampling and biomarker analyses A total of 271 patients were included in the study. Basic Blood samples were collected in ethylenediaminetetraacetic demographic data for the patient group is presented in acid (EDTA) tubes on admission to the ICU and on the two Table 1. Of the total number of patients, there were 77 following days. The samples were drawn from the arterial patients with sepsis, 33 with trauma, 78 with OMCs and 83 catheter. After centrifugation, the plasma was stored at with miscellaneous conditions as discharge diagnoses. 80 C until analyzed. Mortality at 30 d was 20% for sepsis patients, 9% for trauma 158 A. LARSSON ET AL.

Figure 1. The levels of calprotectin and procalcitonin in plasma at admission in in the different patientgroups. p < .05, p < .01 and p < .001.

Figure 2. Calprotectin and procalcitonin in plasma at admission in survivor vs. non-survivor at 30 d. p < .01. patients, 21% for patients with OMC and 23% for patients Calprotectin was an independent predictor for sepsis vs with miscellaneous conditions. The most common diagnoses trauma after adjustment for age, sex, SAPS3 and SOFA in the OMC group were in decreasing order ketoacidosis, scores (Table 3). intoxications, hyponatremia and stroke. In the miscellaneous group, the most common diagnoses were gastrointestinal bleeding, intestinal perforations, cardiac arrest and postoper- Discussion ative pneumonia. When bacteria or virus invade the body, the immune system The levels of plasma calprotectin were higher in sepsis vs. is activated to counter the infection and reduce the damage. trauma patients (p < .001; Figure 1(a)), sepsis vs. OMC The first step in the process is the innate immunity, which (p < .01), sepsis vs. miscellaneous conditions (p < .01) and responds rapidly in a non-specific fashion. The neutrophil is were higher in patients who did not survive to 30 d the first cell to reach the affected location [23]. High neutro- (p < .01, Figure 2(a)). Plasma PCT did not differ signifi- cantly between the groups or for the outcome (Figures 1(b) phil counts are often used as a sign of sepsis, but low neu- and 2(b)). trophil counts may also be found in sepsis patients. Both AUC values for discriminating (Figure 3) sepsis vs. non- low and high neutrophil values are associated with a poor sepsis patients, sepsis vs. trauma patients, sepsis vs. OMC prognosis in patients with suspected sepsis. and survivor vs. non-survivor at 30 d were higher for cal- adhere to the vessel wall and penetrate the blood vessels to protectin than for PCT. reach the site of infection. This extravasation leads to lower Using the best cut-off for calprotectin sensitivity values neutrophil numbers in the circulation [24]. Neutrophil acti- for sepsis vs. non-sepsis patients, sepsis vs. trauma patients, vation markers will be released from the neutrophil when sepsis vs. OMC and survivor vs. non-survivor were equal or activated. The measurement of neutrophil activation above 80% (Table 2), while specificity values were lower. markers may overcome the problem of low values due to Due to low AUC values for PCT cut-off values were not extravasation of the cells. The aim of this study was thus to identified (Figure 3). evaluate the performance of calprotectin, a neutrophil SCANDINAVIAN JOURNAL OF CLINICAL AND LABORATORY INVESTIGATION 159

Figure 3. Receiver operating characteristic curves for plasma calprotectin and procalcitonin. Discrimination between sepsis and non-sepsis, sepsis and other med- ical conditions, sepsis and trauma, as well as death at 30 d are displayed. activation marker, with PCT which is a widely used bio- higher and calprotectin remained an independent predictor marker for sepsis. We found significantly higher calprotectin for sepsis also after adjustment for age, sex, SAPS and max- concentrations in sepsis patients while the PCT concentra- imum SOFA scores. Calprotectin concentrations were higher tions did not distinguish between sepsis patients and the in non-survivors than in survivors while PCT showed no other patient groups. The AUC for calprotectin was also significant difference between the groups. The significance 160 A. LARSSON ET AL.

Table 2. Diagnostic performance of calprotectin and PCT for discrimination patients. Calprotectin had also higher predictive ability between sepsis and other patients. regarding 30-d mortality. Biomarker levels on admission Best cut-off Sensitivity Specificity Sepsis vs. all non-sepsis patients Calprotecin (mg/L) 1.3 81 56 Acknowledgments Procalcitonin (pg/L) n/a n/a n/a Sepsis vs. trauma We thank Ms Carina Br€annstrom€ for technical assistance. Calprotectin (mg/L) 1.3 81 70 Procalcitonin (pg/L) n/a n/a n/a Sepsis vs. other medical conditions Calprotectin (mg/L) 1.3 81 59 Disclosure statement Procalcitonin (pg/L) n/a n/a n/a 30-d mortality The authors have no financial conflicts of interest. Calprotecin (mg/L) 1.1 80 46 Procalcitonin (pg/L) n/a n/a n/a References

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