Statistical analysis
EVENTS
We calculated the sample size to minimize the estimation bias. For doing so, it is recommended to have a minimum of five and seven outcome events per independent variable (intervention, age, gender and Charlson Index) (Peduzzi et al., J Clin Epidemiol 1996). This means that for a 95% confidence interval (alpha error: 0.05), we need a minimum number of 28 events. Based on these considerations, sample size was calculated using the formula
Descriptive data were shown as mean (standard deviation) and frequency (%) for continuous or categorical variables, respectively. The comparisons between groups were assessed using Mann–Whitney test and We used multivariate logistic models to assess the effect of the intervention on adverse outcomes. We used age, gender and Charlson IndexThe significance level was established at 