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\begin{document}

\title{Role of thoracic and abdominal tomography in identifying a potential
source of infection in patients with acute fever of unknown focus}



\author[1]{ekrem taha sert}%
\author[1]{Kamil Kokulu}%
\affil[1]{Aksaray University Medical School}%


\vspace{-1em}



  
  \date{May 27, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
Objectives: To evaluate the relationship between clinical features
evaluated at admission to the emergency department (ED) and the presence
of infection on thoracic and abdominal tomography (CT) scans in patients
with acute febrile illness without clinical clues. Methods: Patients
aged 18 years and over who presented to ED with acute fever between
January 1, 2020 and December 31, 2020 and underwent CT imaging (thoracic
and abdomen) as a diagnostic test CT) were included in the study
retrospectively. The patients were divided into two groups according to
the presence and absence of a source of infection on CT. The clinical
and demographic data of the patients were evaluated. The effect of
clinical factors on the presence of infection in CT scans was determined
using the logistic regression analysis. Results: Among the 173 patients
included in the study, the CT scans were positive for the source of
infection in 31.2\% (n=54) and negative in 68.8\% (n=119). In the
multiple logistic regression analysis, age [?] 65 years {[}odds ratio
(OR):2.72, 95\% confidence interval (CI):1.15-4.35, p\textless{}0.001),
presence of comorbidity (OR:2.37, 95\% CI:1.08-4.14, p=0.033), and
procalcitonin positivity (PCT) (OR:2.54, 95\% CI:1.29-4.95, p=0.006)
were identified as risk factors for the presence of infection in CT.
Conclusion: Age, presence of comorbidity, and PCT level should be
considered when deciding on the use of CT in determining the source of
infection in acute febrile patients without clinical clues.%
\end{abstract}%



\sloppy


\textbf{Role of thoracic and abdominal tomography in identifying a
potential source of infection in patients with acute fever of unknown
focus}

\textbf{Ekrem Taha Sert\textsuperscript{1}, Kamil
Kokulu\textsuperscript{1},}

\textsuperscript{1}Department of Emergency Medicine, Aksaray University
Medical School, Aksaray, Turkey

\textbf{Corresponding author and request for reprints:}

\textbf{Ekrem Taha Sert, M.D.}

Address: Aksaray \selectlanguage{ngerman}Üniversitesi T\selectlanguage{polish}ı\selectlanguage{english}p Fak\selectlanguage{ngerman}ültesi Dekanl\selectlanguage{polish}ığı \selectlanguage{english}Adana Yolu \selectlanguage{ngerman}Üzeri
E-90 Karayolu 7. Km Merkez / AKSARAY

E-mail: tahaekrem@hotmail.com

Telephone number: +90 544 292 14 95

Fax Number: +90 382 288 29 18

\textbf{Abstract}

\textbf{Aim:} To evaluate the relationship between clinical features
evaluated at admission to the emergency department (ED) and the presence
of infection on thoracic and abdominal tomography (CT) scans in patients
with acute febrile illness without clinical clues.

\textbf{Methods:} Patients aged 18 years and over who presented to ED
with acute fever between January 1, 2020 and December 31, 2020 and
underwent CT imaging (thoracic and abdomen) as a diagnostic test CT)
were included in the study retrospectively. The patients were divided
into two groups according to the presence and absence of a source of
infection on CT. The clinical and demographic data of the patients were
evaluated. The effect of clinical factors on the presence of infection
in CT scans was determined using the logistic regression analysis.

\textbf{Results:} Among the 173 patients included in the study, the CT
scans were positive for the source of infection in 31.2\% (n=54) and
negative in 68.8\% (n=119). In the multiple logistic regression
analysis, age \selectlanguage{english}[?] 65 years {[}odds ratio (OR):2.72, 95\% confidence
interval (CI):1.15-4.35, p\textless{}0.001), presence of comorbidity
(OR:2.37, 95\% CI:1.08-4.14, p=0.033), and procalcitonin positivity
(PCT) (OR:2.54, 95\% CI:1.29-4.95, p=0.006) were identified as risk
factors for the presence of infection in CT.

\textbf{Conclusion:} Age, presence of comorbidity, and PCT level should
be considered when deciding on the use of CT in determining the source
of infection in acute febrile patients without clinical clues.

\textbf{Keywords:} Acute fever, Emergency department, Infection,
Tomography

\textbf{What's already known about this topic?}

Fever is one of the most common symptoms of patients presenting to the
emergency department. Acute fever may be due to the source of infection,
as well as various other causes, including pulmonary embolism,
intracranial hemorrhage, drugs, and malignancy.

\textbf{What does this article add?}

Infectious diseases can also progress to serious conditions, such as
sepsis, which can sometimes be fatal. Therefore, it is crucial to
determine the cause of fever to initiate appropriate treatment. However,
there is still no consensus among clinicians regarding the use of CT in
patients with acute fever without clinical clues. Therefore, in this
study, we examined the use of CT in the identification of sources of
infection in patients with acute fever of unknown origin. We
investigated whether there was any predictor of the source of infection
in thoracic and abdominal CT scans undertaken to explore the etiology of
fever.

\textbf{Review criteria: how did you gather, select and analyze the
information you considered in your review?}

The data of the study were obtained from the hospital electronic
database. Clinical, biochemical and radiological imaging reports were
collected and analyzed.

\textbf{Message for the clinic: what is the `take-home' message for the
clinician?}

While CT can be the gold standard method to obtain important findings in
the presence of appropriate indications, it can also have negative
results in terms of patient and cost-effectiveness when used incorrectly
and inappropriately. We found that the most important risk factors
affecting the presence of infection in CT were age, presence of
comorbidity, and PCT positivity. The presence of one or more of the
identified risk factors can assist clinicians in deciding on the use of
CT in patients with acute fever without clinical clues.

\textbf{1. INTRODUCTION}

Fever is one of the most common symptoms of patients presenting to the
emergency department (ED).\textsuperscript{1} It is an important
diagnostic problem that concerns all branches of medicine since it can
be due to infectious or non-infectious
causes.\textsuperscript{2}Infectious diseases can also progress to
serious conditions, such as sepsis, which can sometimes be fatal.
Therefore, it is crucial to determine the cause of fever to initiate
appropriate treatment. In the initial evaluation of patients presenting
to ED with fever, a comprehensive history is taken and a physical
examination is performed followed by necessary diagnostic tests. In this
process, patients with acute fever of unknown focus are particularly
difficult to manage for clinicians.

In recent years, radiological imaging methods, which have been
increasingly developed, have become diagnostically important for most
patients and diseases. In particular, computed tomography (CT) is an
easily accessible imaging method found in almost all EDs in today's
conditions. The use of CT in EDs has significantly increased due to the
increase in accessibility to the device, shortening of examination times
with technological developments, and medicolegal
reasons.\textsuperscript{3} Studies have reported that CT plays a
beneficial role in determining the source of infection in patients with
sepsis of unknown origin.\textsuperscript{4} However, there is still no
consensus among clinicians regarding the use of CT in patients with
acute fever without clinical clues. Therefore, in this study, we
examined the use of CT in the identification of sources of infection in
patients with acute fever of unknown origin. We investigated whether
there was any predictor of the source of infection in thoracic and
abdominal CT scans undertaken to explore the etiology of fever.

\textbf{2. MATERIALS AND METHODS}

\textbf{2.1. Patient selection}

This study retrospectively reviewed the records of patients who
presented to the ED of our hospital with the complaint of high fever
between January 1, 2020 and December 31, 2020. The case presentations
were classified using the International Classification of Disease-10
coding system. Accordingly, the patients diagnosed with the R50-50.9
codes in this system (fever with chills, fever of other and unknown
origin, persistent fever, and unspecified fever) were screened, and of
these patients, those aged 18 and over who underwent thorax and abdomen
CT imaging as a diagnostic test were included in the sample. Patients
with incomplete records, cases in which CT findings were not reported by
a radiologist, those with a history of trauma, those who used empirical
antibiotics, and those under the age of 18 years were excluded from the
study. Local ethics committee approval was obtained for the study
(ethics committee number: 2021/01-79).

\textbf{2.2. Data collection and processing}

Clinical data were obtained from the hospital electronic database. The
patients' demographic characteristics, vital signs at the time of
admission to ED, examination findings, chronic diseases, and
radiological and laboratory findings were recorded. The CT images
evaluated in the study had been acquired using a 128-slice CT device (GE
Revolution EVO, USA). The CT findings reported by radiologists were used
to evaluate the results. According to the radiologists' CT reports, the
patients were divided into two groups according to whether the source of
infection was positive or negative in these reports.

Acute fever of unknown origin was defined as the absence of a history or
physical examination finding that could explain the possible cause of
fever, absence of non-specific symptoms (such as runny nose, cough,
abdominal pain, diarrhea, pain, and burning sensation when urinating),
normal values of parameters that would suggest an infection in the urine
analysis (bacteriuria, pyuria, and nitrite), and absence of infiltration
on chest X-ray. High fever was accepted as a body temperature that was
measured as 38.3 degC or higher in ED at least once during treatment (5).

\textbf{2.3. Statistical Analysis}

Statistical analysis was performed using the Statistical Package for the
Social Sciences (SPSS Inc. Chicago IL, USA) v. 15.0. Number, percentage
(\%), median, and mean +- standard deviation values were used to define
data. The normal distribution of data was tested with the
Kolmogorov-Smirnov test. Student's t-test was used to compare normally
distributed data, the Mann-Whitney U test to compare non-normally
distributed data, and Pearson's chi-square or Fisher's test to compare
categorical variables. The univariate and multivariate logistic
regression analyses were undertaken to determine the relationship
between the presence of the source of infection and clinical risk
factors in thoracic and abdominal CT. Variables with a p value of
\textless{}0.1 in the univariate logistic regression analysis were
included in the multivariate logistic regression analysis. A p value of
\textless{}0.05 was considered significant in all comparisons.

\textbf{3. RESULTS}

A total of 173 patients with a mean age of 47.6 +- 16.4 years were
included in the study. Of the patients, 57.8\% (n=100) were male and
49.2\% (n=73) were female. The demographic and clinical characteristics
of the patients are given in Table 1. The source of infection was
detected in the thoracic and abdominal CT scans of 31.2\% (n=54) of the
patients. Gender, diastolic blood pressure, respiratory rate, and body
temperature did not statistically significantly differ between the
patients with and without an infection source detected on CT. There was
also no significant difference between these two groups in relation to
the white blood cell (WBC) and C-reactive protein (CRP) levels (Table
2). Of the patients, 41\% (n=71) had one or more comorbidities. In the
single logistic regression analysis, age, systolic blood pressure, heart
rate, procalcitonin (PCT), and presence of comorbidity were evaluated as
risk factors for the presence of infection in the thoracic and abdominal
CT scans. According to the multiple logistic regression analysis, age \selectlanguage{english}[?]
65 years {[}odds ratio (OR):2.72, 95\% confidence interval
(CI):1.15-4.35, p\textless{}0.001), presence of comorbidity (OR:2.37,
95\% CI:1.08-4.14, p=0.033), and PCT positivity (OR:2.54, 95\%
CI:1.29-4.95, p=0.006) were determined as risk factors for the presence
of infection in CT (Table 3).

\textbf{4. DISCUSSION}

As a result of this study, we found that 31.2\% (n=54) of the patients
who underwent thoracic and abdominal CT scans due to acute fever of
unknown focus were positive for the source of infection. There were
significant differences in age, presence or absence of chronic disease,
and PCT level between the patients with and without an infection source
on CT. We determined that the most important risk factors affecting the
presence of infection on CT were age \selectlanguage{english}[?] 65 years, presence of
comorbidity, and PCT positivity.

Acute fever may be due to the source of infection, as well as various
other causes, including pulmonary embolism, intracranial hemorrhage,
drugs, and malignancy.\textsuperscript{2} Every person experiences fever
many times in their lives. Most causes of acute fever are related to
viral infections but patients may sometimes unexpectedly face serious
conditions, such as sepsis and septic shock.\textsuperscript{6} The
detection of the fever focus quickly and accurately with CT scans is
very important for the initiation of appropriate treatment and
survival;\textsuperscript{4} therefore, the use of CT in ED has
increased in recent years.\textsuperscript{7} However, CT has certain
disadvantages, such as deterioration in kidney function due to contrast
agent use, exposure to radiation, and additional
costs.\textsuperscript{8} Therefore, CT imaging should be performed
after careful benefit/risk assessment of the advantages and
disadvantages of this method. In our study, a source of infection was
detected in CT scans in patients with comorbidities, those aged \selectlanguage{english}[?] 65
years, and those with PCT positivity. If clinical benefit is presumed to
be high in these patients, thoracic and abdominal CT scans can be
performed to detect the focus of fever.

Advances in CT technology have allowed this imaging modality to be used
both as a diagnostic and triage method.\textsuperscript{9} However, this
can raise concerns in terms of the appropriate use of resources. The
reasons for using CT to detect the source of infection in acute febrile
patients without clinical clues in ED are blood parameters, such as WBC,
CRP, and PCT being significantly higher than
normal.\textsuperscript{10,11} and the need to determine whether there
is an occult focus of infection and decide on hospitalization or
outpatient treatment.\textsuperscript{12} In a previous study, PCT was
found to be useful in the diagnosis of infection and had a higher
diagnostic value than CRP in patients admitted to ED due to
fever.\textsuperscript{13} PCT appears to be an earlier and better
marker than inflammatory response parameters, such as CRP and leukocyte
count in sepsis and serious infections.\textsuperscript{14} From these
data, it can be concluded that clinicians often consider CT scans for
possible infectious disease due to increased inflammatory markers. In
the current study, we found that positive PCT was an effective parameter
in detecting possible sources of infection in CT.

Diseases seen in the geriatric population may show a different course
compared to other age groups and have more dramatic results. In the
elderly, one of the most common causes of hospitalization is infections.
The main reasons for this are the weakening of cellular and humoral
immunity with aging, deterioration of physiological functions, such as
the cough reflex, and comorbidities creating predisposition to
infectious diseases. It may not always be possible to identify
infections without delay in the elderly since they mostly progress with
atypical findings in this population.\textsuperscript{15} The presence
of fever in the elderly is a more serious indicator of disease compared
to the younger age group. Delayed diagnosis and treatment and more
severe infections increase morbidity and mortality
rates.\textsuperscript{16} The results of our study indicate that
thoracic and abdominal CT scans should be used more aggressively in
elderly patients with high fever without clinical clues.

\textbf{Study Limitations}

The limitation of our study is that it had a retrospective and
single-center design. Therefore, there is a need for further studies
involving many centers.

\textbf{5. CONCLUSIONS}

While CT can be the gold standard method to obtain important findings in
the presence of appropriate indications, it can also have negative
results in terms of patient and cost-effectiveness when used incorrectly
and inappropriately. We found that the most important risk factors
affecting the presence of infection in CT were age, presence of
comorbidity, and PCT positivity. The presence of one or more of the
identified risk factors can assist clinicians in deciding on the use of
CT in patients with acute fever without clinical clues.

\textbf{Acknowledgements} : The authors thank all the participants in
this study

\textbf{Declaration of conflicting interests}

The author(s) declared no potential conflicts of interest with respect
to the research, authorship, and/or publication of this article.

\textbf{Funding}

The author(s) received no financial support for the research,
authorship, and/or publication of this article.

\textbf{References}

\begin{enumerate}
\tightlist
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\item
  Larson DB, Johnson LW, Schnell BM, Salisbury SR, Forman HP. National
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\item
  Just KS, Defosse JM, Grensemann J, Wappler F, Sakka SG. Computed
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\item
  Durack DT, Street AC. Fever of unknown origin reexamined and
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  Tintinalli's emergency medicine: a comprehensive study guide. 8th ed.
  McGraw-Hill; 2016. p.1039.
\item
  Bellolio MF, Bellew SD, Sangaralingham LR, et al. Access to primary
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\item
  Marshall JC, Innes M. Intensive care unit management of
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\item
  Le Bel J, Hausfater P, Chenevier-Gobeaux C, et al. Diagnostic accuracy
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\item
  Hausfater P, Juillien G, Madonna-Py B, Haroche J, Bernard M, Riou B.
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  de Kruif MD, Limper M, Gerritsen H, et al. Additional value of
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  Carrol ED, Thomson APJ, Hart CA. Procalcitonin as a marker of sepsis.
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  Cagatay AA, Tufan F, Hindilerden F, et al. The causes of acute fever
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  Htwe TH, Mushtaq A, Robinson SB, Rosher RB, Khardori N. Infection in
  the elderly. Infect Dis Clin N Am 2007;21(3):711-43, ix.
\end{enumerate}

\textbf{Table legends}

\textbf{Table 1} . Patient characteristics

\textbf{Table 2.} Baseline characteristics of the patients according to
CT findings and infection source

\textbf{Table 3.} Univariate and multivariate analyses of predictive
factors for the source of infection in CT

\textbf{Table 1} . Patient characteristics\selectlanguage{english}
\begin{longtable}[]{@{}ll@{}}
\toprule
Variable (n = 173) &\tabularnewline
\midrule
\endhead
Age (years) & 47.6 \selectlanguage{ngerman}± 16.4\tabularnewline
Gender, male & 100 (57.8\%)\tabularnewline
Vital sign &\tabularnewline
Systolic BP at ED triage (mmHg) & 121 (110-138)\tabularnewline
Diastolic BP at ED triage (mmHg) & 75 (70-80)\tabularnewline
Pulse at ED triage (bpm) & 116 (92-128)\tabularnewline
Respiratory rate at ED triage (bpm) & 18 (18--21)\tabularnewline
Temperature at ED triage (\selectlanguage{ngerman}°C) & 38.6 (38.3-39.9)\tabularnewline
Oxygen saturation at ED triage (\%) & 94 (90-96)\tabularnewline
Inflammatory biomarkers &\tabularnewline
PCT (ng/mL) & 0.7 (0.5-2.5)\tabularnewline
CRP (mg/L) & 144 (91-245)\tabularnewline
WBC (\selectlanguage{ngerman}× 10\textsuperscript{9}/L) & 15.0 (10.0-24.6)\tabularnewline
Presence of comorbidity & 71 (41.0\%)\tabularnewline
Source of infection (n= 54) &\tabularnewline
Respiratory system infection & 25(46.3\%)\tabularnewline
Intra-abdominal infection & 29(53.7\%)\tabularnewline
\bottomrule
\end{longtable}

BP=blood pressure; ED=emergency department; CRP=C-reactive protein;

PCT=procalcitonin; WBC=white blood cells; CRP reference: \textless{}5
mg/L. PCT reference: \textless{}0.25 ng/mL

\textbf{Table2.} Baseline characteristics of the patients according to
CT findings and infection source\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
\begin{minipage}[b]{0.22\columnwidth}\raggedright\strut
Variable\strut
\end{minipage} & \begin{minipage}[b]{0.22\columnwidth}\raggedright\strut
Thoracic and abdominal CT findings\strut
\end{minipage} & \begin{minipage}[b]{0.22\columnwidth}\raggedright\strut
Thoracic and abdominal CT findings\strut
\end{minipage} & \begin{minipage}[b]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.24\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.24\columnwidth}\raggedright\strut
Infection-negative (n = 119)\strut
\end{minipage} & \begin{minipage}[t]{0.24\columnwidth}\raggedright\strut
Infection-positive (n = 54)\strut
\end{minipage} & \begin{minipage}[t]{0.24\columnwidth}\raggedright\strut
P-value\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Age\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
44.2 \selectlanguage{ngerman}± 15.2\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
55.1 \selectlanguage{ngerman}± 16.5\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textless{}0.001\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textless{}65 years\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
102 (85.7\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
33 (61.1\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textless{}0.001\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
[?]65 years\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
17 (14.3\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
21 (38.9\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Gender\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.355\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Female\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
53 (44.5\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
20 (37.0\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Male\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
66 (55.5\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
34 (63.0\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Vital sign\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Systolic BP at ED triage (mmHg)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
122 (100-145)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
109 (100-132)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.008\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Diastolic BP at ED triage (mmHg)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
78 (70-82)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
74 (70-80)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.258\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Pulse at ED triage(bpm)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
108 (92-126)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
117 (96-128)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.035\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
RR at ED triage (bpm)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
18 (18--21)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
18 (18--22)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.835\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Temperature at ED triage (\selectlanguage{ngerman}°C)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
38.4 (38.2-39.0)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
38.6 (38.3-39.9)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.791\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Oxygen saturation at ED triage (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
95 (90-96)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
94 (90-96)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.821\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Inflammatory biomarkers\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
PCT (ng/mL)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.5 (0.2-1.3)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
1.6 (0.7-3.9)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.001\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
CRP (mg/L)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
148 (93-224)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
166 (95-254)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.241\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
WBC (\selectlanguage{ngerman}× 10\textsuperscript{9}/L)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
16.7 (10.1-28.4)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
15.1 (10.5-20.7)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.183\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Comorbidities\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.003\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Absent\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
79 (66.4\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
23 (42.6\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
Present\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
40 (33.6\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
31 (57.4\%)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

Data are presented as mean \selectlanguage{ngerman}± standard deviation, median (25\%-75\%
quartiles) or n (\%) BP=blood pressure; RR=respiratory rate;
ED=emergency department; CRP=C-reactive protein; PCT=procalcitonin;
WBC=white blood cell

\textbf{Table 3.} Univariate and multivariate analyses of predictive
factors for the source of infection in CT\selectlanguage{english}
\begin{longtable}[]{@{}lllllll@{}}
\toprule
Variables & Univariate logistic regression & Univariate logistic
regression & Univariate logistic regression & Multivariate logistic
regression & Multivariate logistic regression & Multivariate logistic
regression\tabularnewline
\midrule
\endhead
& OR & 95\% CI & P-value & OR & 95\% CI & P-value\tabularnewline
Age [?] 65 years & 3.28 & 1.48-8.74 & \textless{}0.001 & 2.72 & 1.15-4.35
& \textless{}0.001\tabularnewline
Gender & 1.14 & 0.84-1.57 & 0.355 & & &\tabularnewline
Pulse at ED triage & 1.23 & 1.09-1.47 & 0.035 & & &\tabularnewline
Positive PCT (ng/mL) & 2.92 & 1.47-5.35 & 0.001 & 2.54 & 1.29-4.95 &
0.006\tabularnewline
Systolic BP at ED triage (mmHg) & 1.60 & 1.42-1.78 & 0.008 & &
&\tabularnewline
Presence of comorbidity & 2.68 & 1.20-4.87 & 0.003 & 2.37 & 1.08-4.14 &
0.033\tabularnewline
\bottomrule
\end{longtable}

ED=emergency department; PCT=procalcitonin; BP=blood pressure

\selectlanguage{english}
\FloatBarrier
\end{document}

