2.3 Statistical analysis
For the study, we compared the bronchiolitis admissions of the 2022-2023
season with the previous five seasons.
Descriptive statistics were produced for demographic and clinical
features. Mean and
standard deviation (SD) are presented for normally distributed
variables; median and
interquartile range (IQR) for non-normally distributed variables.
Numbers and percentages
are presented for categorical variables.
Differences in the frequency of categorical variables were assessed by
chi-square or
Fisher’s exact tests. Continuous variables were assessed by U-Mann
Whitney or Kruskal
Wallis tests where appropriate.
To assess the trend of bronchiolitis episodes across seasons, incidence
(calculated as the
number of bronchiolitis per 1000 hospitalizations) was evaluated over
the study years. On the other hand, the need for respiratory support was
calculated as rate*100 bronchiolitis.
Pearson’s (or Spearman rho where appropriate) correlation coefficient
was calculated to define whether the difference in the incidence of
bronchiolitis, respiratory support, and HFNC use was merely apparent.
This study was conducted in accordance with the Helsinki Declaration.
According to Italian
legislation, the study did not need ethical approval, as it was a purely
observational retrospective study on routinely collected anonymous data.
Furthermore, it was not possible to request informed consent for
participation in the study, given the nature of the study. In any case,
consent to completely anonymous use of clinical data for
research/epidemiological purposes is requested during clinical routine
at the time of admission/diagnostic procedure.
3. Results :