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.