Statistical Analyses
Results are expressed as absolute numbers with percentages for
categorical variables and medians with interquartile ranges (IQR)
(median [IQR25; IQR75]) for
continuous variables. For categorical variables comparisons were
performed using Chi-square tests between the three groups and in the
case of a significant difference, the groups were compared two by two
using Fisher’s exact tests. For quantitative variables comparisons were
performed using the Kruskal-Wallis test with Dunn’s post-test.
Correlations between parameters were performed using the Spearman test.
Univariate multinomial logistic regression was used to identify the
association between parameters and exacerbation frequency and the Odds
ratio with its 95% confidence interval was determined. Then, parameters
significantly associated with exacerbation frequency were included in a
stepwise multiple multinomial logistic regression analysis to identify
parameters independently and significantly associated with exacerbation
frequency (15,16). Analyses were performed using SPSS software 29.0 (IBM
Corp., Armonk, NY). A p-value < 0.05 was considered
significant.