title: Overall survival, renal survival and relapse in patients with microscopic polyangiitis: a systematic review of current evidence.
abstract: OBJECTIVE
  There are limited data on the long-term prognosis of microscopic polyangiitis (MPA). A systematic review was performed to estimate the survival, renal survival and relapse rates in patients with MPA.
  
  
  METHODS
  Articles included in MEDLINE and EMBASE databases were reviewed. Randomized or non-randomized trials, cohort, case-control and cases-series studies of patients with MPA diagnosed according to Chapel Hill Consensus Conference definitions, a high rate of biopsy-confirmed diagnosis, follow-up >1 year and follow-up losses <10%. Two independent authors using a predefined questionnaire for evaluating the quality and risk of bias for each study extracted data.
  
  
  RESULTS
  Eighteen studies for MPA prognosis (n = 940) and six for MPA outcomes after transplantation (n = 65) were included. Survival rates were 77-100% at 1 year, 46-80% at 5 years and 60-80% at 10 years. Higher mortality density occurred within the first months after diagnosis. Vasculitis was the cause of death in 32-50% of patients. Relapses were detected in 19-39% of cases (median time to relapse 15-43 months). Renal graft survival was 85-94% at 1 year and 51-87% at 5 years. Age, renal involvement and immunosuppressive treatment were related to mortality. Lower relapse rate was achieved with 12 vs 6 CYC pulses.
  
  
  CONCLUSIONS
  Evidence regarding MPA prognosis is weak. MPA mortality is mainly concentrated in the first months after diagnosis. Fewer than 50% of deaths are related to MPA activity. MPA long-term prognosis is less severe, although relapses are frequent. End-stage renal failure is a frequent complication of MPA, and renal transplantation could be an effective therapy in these patients. Early diagnosis, early initiation of a tailored therapy according to risk factors and a longer follow-up of the patients are needed.
authors.affiliation: Department of Internal Medicine, Hospital Universitaro de Salamanca, Hospital Los Montalvos s/n, E-37192 Salamanca, Spain. lcorral@saludcastillayleon.es
authors.forename: Luis
authors.initials: L
authors.lastname: Corral-Gudino
authors.forename: María
authors.initials: M
authors.lastname: Borao-Cengotita-Bengoa
authors.forename: Javier
authors.initials: J
authors.lastname: Del Pino-Montes
authors.forename: José L
authors.initials: JL
authors.lastname: Lerma-Márquez
mesh_terms: D002423:Cause of Death; D016206:Databases, Bibliographic; D006801:Humans; D016030:Kidney Transplantation / Q000401:mortality*; D055953:Microscopic Polyangiitis / Q000175:diagnosis / Q000401:mortality*; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D012008:Recurrence; D015996:Survival Rate; D013997:Time Factors