Data Analysis
Data was analysed using ‘R’ software v4.0.5 for Mac IOS. A frailty model (using Cox proportional-hazards regression) was performed to obtain the procedure-free interval (PFI) with IS use. Co-variables reviewed included patient gender, ANCA status, GPA-associated disease progression, type of surgical procedure and C-M grade.
The mean PFI was calculated for comparisons with our cohort & stipulated SGS-GPA studies. This was based on the number of surgical procedures per patient divided by the stipulated average follow-up period.