Abstract
Aim: To develop an assessment tool to predict invasive
mechanical ventilation (IMV) among influenza-related pneumonia (Flu-p)
patients within 14 days of admission.
Methods: In total, 1107 Flu-p patients from five teaching
hospitals were retrospectively enrolled from January 2012 - December
2019 and used to develop a predictive model.
Results: Overall, 10.6% (117/1107) of patients underwent IMV
within 14 days of admission. Multivariate regression analyses revealed
that the following factors were associated with IMV: early neuraminidase
inhibitor use (-2 points), lymphocytes <
0.8×109/L (1 points), multi-lobar infiltrates (1
point), age ≥ 65 years old (2 points), systemic corticosteroid use (2
points), PaO2/FiO2 < 300 mmHg
(2 points), respiratory rate ≥ 30 breaths/min (3 points), and arterial
PH < 7.35 (3 points). A total score of six points was used to
identify patients at risk of IMV. This model had a sensitivity of
88.79%, a specificity of 87.55%, and exhibited better predictive
performance than the ROX index (AUROC = 0.927 vs 0.688, p< 0.001), modified ROX index (AUROC = 0.927 vs 0.747, p< 0.001), and HACOR scale (AUROC = 0.927 vs 0.524, p< 0.001).
Conclusions: Flu-IV scores can be used to reliably predict
14-day IMV rates in Flu-p patients.
- Key notes
- We developed an easy-to-use predictive tool (Flu-IV score) for early
assessing the risk of IMV in patients with Flu-p.
- The Flu-IV score included eight variables, and a total score of six
points was used to identify patients at risk of IMV.
- The model exhibited better predictive performance than the ROX index,
modified ROX index , and HACOR scale.
Key words: Influenza; Pneumonia; Invasive mechanical
ventilation; Prediction rule
Introduction
Influenza is a common viral respiratory disease that affects between 5%
and 10% of the population of the world each year, resulting in 3-5
million severe infections and between 290,000 and 650,000 annual deaths
attributable to influenza-related illness [1]. Owing to the
significant morbidity and mortality associated with disease, influenza
is considered by many researchers to be one of the greatest threats to
global public health at present [2].
Influenza-related pneumonia (Flu-p) is a severe form of influenza
infection associated with over 50% of influenza-relate hospitalization
and mortality [3]. Flu-p can progress from relatively mild disease
to more severe cases that can cause ARDS or respiratory failure such
that patients must often undergo invasive mechanical ventilation (IMV)
within 3-10 days following initial symptom onset [4-5]. The need for
IMV is linked to higher rates of patient morbidity and mortality
[6], and evaluating a given patient’s odds of requiring IMV is thus
a valuable prognostic approach. However, the risk factors associated
with the need for IMV have not been fully clarified. Certain assessment
tools have been established in an effort to gauge the odds of IMV in
individuals suffering from acute hypoxemic respiratory failure,
including the ROX index (pulse oximetry/FiO2 to
respiratory rate) [7], modified ROX index
(PaO2/FiO2 to respiratory rate) [8],
and HACOR scale (heart rate, respiratory rate, arterial pH,
PaO2/FiO2 and Glasgow Coma Scale)
[9]. These tools, however, are not specific to Flu-p patients, nor
have any studies specifically examined their predictive power in
individuals suffering from Flu-p, and there is thus a clear need for the
development of a reliable tool that can predict the requirement for IMV
in Flu-p patients at an early time point prior to the onset of potential
respiratory failure.
As such, we performed the present retrospective multicenter study with
the goal of developing an accurate and easy-to-use assessment tool
capable of predicting the odds of a given Flu-p patient undergoing IMV
within 14 days of admission.
Materials and methods