Statistical package for social sciences version 20.0 spss

All computations were performed using the Statistical Package for Social Sciences, version 20.0 (SPSS; IBM Corporation, Somers, NY, USA). Clinical variables are presented as the mean and standard deviations or absolute and relative frequencies, as appropriate. The variability was expressed by using the inter-hospital range (IHR), which represents the highest and lowest mean value from the participant centers. The significance of this variability was explored by the chi-squared test or ANOVA between the different participant centers. The alpha error was set at 0.05.

All computations were performed using the Statistical Package for Social Sciences, version 20.0 (SPSS; IBM Corporation, Somers, NY, USA). Clinical variables are presented as means and standard deviations or absolute and relative frequencies, as appropriate. Quantitative variables were analysed using the unpaired Student’s t-test for independent data, preceded by the Levene test to evaluate homogeneity of variances. Categorical data were compared using the χ² test. The variables associated with exacerbations and mortality during the 1-year follow-up were identified using hierarchical multilevel multivariate logistic regression analysis, as previously described [23 (link)]. The alpha error was set at 0.05.