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.