title: Association of low serum complement C3 with reduced patient and renal survival in antimyeloperoxidase-associated small-vessel vasculitis.
abstract: OBJECTIVE
  This study aimed to determine the value of hypocomplementemia in predicting the renal and patient survival of patients with antineutrophil cytoplasmatic antibody-associated vasculitis (AAV).
  
  
  METHODS
  A retrospective analysis of 30 consecutive patients who were diagnosed with AAV and followed at our hospital from 1996 to 2011 was performed. Renal outcome was determined by the Modification of Diet in Renal Disease equation. Disease outcome measures included patient survival and accrual of chronic kidney disease (CKD) defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) from the date of diagnosis. Logistic regression analysis was used to identify predictors of survival.
  
  
  RESULTS
  At presentation, 6 (20%) patients had a low C3 level, which was significantly associated with older age (p = 0.009), higher C-reactive protein (p = 0.02), a lower eGFR (p = 0.03), and anti-MPO antibody positivity (p = 0.03). A low C3 level at presentation was significantly associated with a reduced eGFR at the last study visit (p = 0.015, OR = 11; 95% CI 1.27-95.15). During a mean follow-up of 9.0 ± 6.2 years, 8 (26.6%) patients had accrued CKD that was significantly associated with low C3 levels at presentation (p = 0.002, OR = 22; 95% CI 2.36-204.7). Mortality was significantly associated with low serum C3 levels at presentation (p = 0.02).
  
  
  CONCLUSIONS
  We found that a low serum C3 level at the time of diagnosis was significantly associated with reduced renal and patient survival in patients with anti-MPO AAV. Our results suggest a role for complement activation in the pathogenesis of AAV.
authors.affiliation: Rheumatology Unit, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel.
authors.forename: Yair
authors.initials: Y
authors.lastname: Molad
authors.forename: Ana
authors.initials: A
authors.lastname: Tovar
authors.forename: Shachaf
authors.initials: S
authors.lastname: Ofer-Shiber
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D000906:Antibodies / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D003176:Complement C3 / Q000172:deficiency* / Q000378:metabolism; D003404:Creatinine / Q000097:blood; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
chemical_list: D000906:Antibodies; D003176:Complement C3; D002097:C-Reactive Protein; D003404:Creatinine; D009195:Peroxidase