Mortality in ANCA-associated vasculitis: a meta-analysis of observational studies

Objective To determine the magnitude of all-cause mortality risk in patients with antineutrophil cytoplasmic antibodies-associated vasculitis (AAV) compared with the general population through a meta-analysis of observational studies. Methods We searched Medline and Embase databases from their inception to April 2015. Observational studies that met the following criteria were assessed by two researchers: (1) clearly defined AAV identified by either the American College of Rheumatology 1990 classification criteria or the 2012 Chapel Hill Consensus Conference disease definitions, and (2) reported standardised mortality ratios (SMR) and 95% CI. We calculated weighted-pooled summary estimates of SMRs (meta-SMRs) for all-cause mortality using random-effects model, tested for publication bias and heterogeneity. Results Ten studies met the inclusion criteria, comprising 3338 patients with AAV enrolled from 1966 to 2009, and a total of 1091 observed deaths. Overall, we found a 2.7-fold increased risk of death in patients with AAV when compared with the general population (meta-SMR: 2.71 (95% CI 2.26 to 3.24)). Analysis on studies that included only granulomatosis with polyangiitis cases also indicated a similar mortality risk (meta-SMR: 2.63 (95% CI 2.02 to 3.43)). There was no significant publication bias or small-study effect. Subgroup analyses showed that mortality risks were higher in older cohorts, with a trend towards improvement over time (ie, those with their midpoint of enrolment periods that were between 1980-1993 and 1994-1999, vs 2000-2005). Conclusion Published data indicate there is a 2.7-fold increase in mortality among patients with AAV compared with the general population.