Introduction
Patients with community-acquired pneumonia (CAP) undergo a dysregulated host response
that is related to mortality. MicroRNAs (miRNAs) participate in this response, but their
expression pattern and their role as biomarkers in CAP have not been fully characterized.
Methods
A prospective observational study was performed in a cohort of 153 consecutive patients
admitted to hospital with CAP. Clinical and analytical variables were collected, and the main
outcome variable was 30-day mortality. Small RNA was purified from plasma of these
patients obtained on the first day of admission, and miRNA expression was analyzed by RTPCR.
Univariate and multivariate analyses were carried out through the construction of a
logistic regression model. The proposed model was compared with established prognostic
clinical scales using ROC curve analysis.
Results
The mean age of the patients included was 74.7 years [SD 15.9]. Their mean PSI was 100.9
[SD 34.6] and the mean modified Charlson index was 2.9 [SD 3.0]. Both miR-146a and miR-
16-5p showed statistically significant association with 30-day mortality after admission due
to CAP (1.10 vs. 0.23 and 51.74 vs. 35.23, respectively), and this association remained for
miR-16-5p in the multivariate analysis adjusted for age, gender and history of bronchoaspiration
(OR 0.95, p = 0.021). The area-under-the-curve (AUC) of our adjusted multivariate
model (AUC = 0.954 95%CI [0.91–0.99]), was better than those of prognostic scales such
as PSI (AUC = 0.799 [0.69–0.91]) and CURB-65 (AUC = 0.722 [0.58–0.86]).
Conclusions
High levels of miR-146a-5p and miR-16-5p upon admission due to CAP are associated with
lower mortality at 30 days of follow-up. Both miRNAs could be used as biomarkers of good
prognosis in subjects hospitalized with CAPThis work has been funded by the Carlos
III Health Institute (ERDF, European Regional
Development Fund), by the Spanish Society of
Pneumology and Thoracic Surgery and by the
Ministry of Science, Innovation and Universities of
Spain