Improved survival in granulomatosis with polyangiitis: A general population-based study.

BACKGROUND

Granulomatosis with polyangiitis (GPA) is associated with an increased risk of mortality; however, recent mortality trends in GPA are unknown. We evaluated this issue in a general population context.

METHODS

Using data collected between 1992 and 2013 by The Health Improvement Network in the United Kingdom, we identified individuals diagnosed as incident cases of GPA and up to 10 non-GPA controls matched on sex, age, year of birth, and year of GPA diagnosis. The cohort was divided into two based on the year of diagnosis (i.e., 1992-2002 and 2003-2013) to evaluate changes in mortality. We calculated hazard ratios for death using a Cox-proportional hazards model and the rate differences using an additive hazard model, while adjusting for potential confounders.

RESULTS

We identified 465 cases of GPA (mean age: 60 years, 52% male). The early cohort (1992-2002) GPA patients had considerably higher mortality rates than the late cohort (2003-2013) (i.e., 72.0 vs. 35.7 cases per 1000 person-years), as compared with a moderate improvement in the comparison cohorts between the two periods (19.8 vs. 17.0 cases per 1000 person-years). The corresponding absolute mortality rate difference was 52.2 (95% CI: 25.1-79.2) cases and 18.7 (95% CI: 8.3-29.1) cases per 1000 person-years (p for interaction = 0.025). The resulting HRs for mortality were 4.34 (95% CI: 2.72-6.92) and 2.41 (95% CI: 1.74-3.34), respectively (p for interaction = 0.043).

CONCLUSION

This population-based study suggests that survival of GPA patients has improved considerably over the past 2 decades, affirming the benefits of recent trends in the management of GPA and its complications.