title: Mycophenolate mofetil versus azathioprine therapy is associated with a significant protection against long-term renal allograft function deterioration.
abstract: BACKGROUND
  To evaluate the association of long-term continuous mycophenolate mofetil (MMF) versus azathioprine (AZA) therapy and renal allograft function, as measured by the slope of reciprocal creatinine, we analyzed 49,666 primary renal allograft recipients reported to the United States Renal Data System between October 31, 1988 and June 30, 1998.
  
  
  METHODS
  The primary study endpoint was defined as a greater than 20% decrease below a 6-month baseline of 1/serum creatinine (SCr) (slope of reciprocal creatinine) at or beyond 1 year after transplantation. A secondary endpoint was defined as reaching an SCr value greater than 1.6 mg/dL. Univariate Kaplan-Meier analysis and multivariate Cox proportional hazard models were used to investigate the risk of reaching the study endpoints. Multivariate analyses were corrected for potential confounding covariates.
  
  
  RESULTS
  According to the Cox proportional hazard model, 12-month continued therapy of MMF versus AZA was associated with a protective effect against declining renal function, as measured by the slope of reciprocal creatinine (relative risk [RR]=0.84, confidence interval 0.78-0.91, P<0.001). For 24-month continued therapy of MMF versus AZA, MMF was associated with a further decreased risk for a decline in renal function (RR=0.66, confidence interval=0.57-0.77, P<0.001). Furthermore, MMF was associated with a protective effect against reaching the SCr threshold of 1.6 mg/dL (RR=0.80, P<0.001) beyond 12 months posttransplantation.
  
  
  CONCLUSIONS
  Continuous use of MMF versus AZA was associated with a protective effect against declining renal function beyond 1 year after transplantation. Further study is needed to confirm that continued MMF therapy is protective against long-term deterioration in renal function.
authors.affiliation: Department of Internal Medicine, University of Florida College of Medicine, Gainesville, FL 32610-0224, USA. meierhu@medicine.ufl.edu.
authors.forename: Herwig-Ulf
authors.initials: HU
authors.lastname: Meier-Kriesche
authors.forename: Bettina J
authors.initials: BJ
authors.lastname: Steffen
authors.forename: Alan M
authors.initials: AM
authors.lastname: Hochberg
authors.forename: Robert D
authors.initials: RD
authors.lastname: Gordon
authors.forename: Michael N
authors.initials: MN
authors.lastname: Liebman
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Morris
authors.forename: Bruce
authors.initials: B
authors.lastname: Kaplan
mesh_terms: D000328:Adult; D001379:Azathioprine / Q000627:therapeutic use*; D003404:Creatinine / Q000097:blood; D005260:Female; D006085:Graft Survival / Q000187:drug effects; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007668:Kidney / Q000187:drug effects / Q000503:physiopathology; D007674:Kidney Diseases / Q000517:prevention & control*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D016019:Survival Analysis; D014184:Transplantation, Homologous
chemical_list: D007166:Immunosuppressive Agents; D003404:Creatinine; D009173:Mycophenolic Acid; D001379:Azathioprine