“…Within the competing prognostication frameworks, there have been a dearth of large-scale external and independent validations, especially ones that compare models (exceptions include Kong et al 7 and Christodoulou et al 8 ). Although AAV is a relatively rare disease, it means that there is a wider need for intercenter, international, and intercontinental collaboration as individual centers will likely not have sufficient patient cohorts to have sufficient power.…”