Comparing outcomes of biopsy-proven anti-neutrophil cytoplasmic autoantibody-associated glomerulonephritis patients treated with cyclophosphamide in the 20th and 21st centuries: a 23-year study

BACKGROUND: Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is a multisystem autoimmune disorder associated with significant morbidity and mortality. Approximately 80–90% of patients have circulating ANCAs. Long-term outcomes appear to be improving. This retrospective study analyses the incidence and patient outcomes over a period of 23 years at a single tertiary centre. METHODS: Outcomes of patients diagnosed with AAV between 1 January 1988 and 31 December 2010 were collected retrospectively. Data including patient demographics, age of diagnosis, dates of starting renal replacement therapy, death and biochemistry results were collected. Patients were divided into two cohorts (1988–99 and 2000–10) and analysed using Stata software (StataCorp, College Station, TX, USA). RESULTS: A complete dataset was obtained for 273 patients. Of these patients, 101 were diagnosed between 1988 and 1999 while 172 were diagnosed between 2000 and 2010. The number of patients diagnosed with AAV increased from 2.2/million in 1988 to 10.3/million in 2010. A higher proportion of patients (56.4%) in the earlier cohort presented with creatinine >500 μmol/L compared with the later cohort (30.2%; P < 0.001). Overall patient survival improved significantly between the two cohorts. Cohort 1 had a median survival of 59 months compared with 125 months for Cohort 2 (P = 0.003). CONCLUSIONS: This study shows that AAV is being diagnosed at an earlier stage, resulting in improved outcomes. This may be because of improvements in the management of AAV and chronic kidney disease.