title: A proteinuria cut-off level of 0.7 g/day after 12 months of treatment best predicts long-term renal outcome in lupus nephritis: data from the MAINTAIN Nephritis Trial.
abstract: BACKGROUND
  Although an early decrease in proteinuria has been correlated with good long-term renal outcome in lupus nephritis (LN), studies aimed at defining a cut-off proteinuria value are missing, except a recent analysis performed on patients randomised in the Euro-Lupus Nephritis Trial, demonstrating that a target value of 0.8 g/day at month 12 optimised sensitivity and specificity for the prediction of good renal outcome. The objective of the current work is to validate this target in another LN study, namely the MAINTAIN Nephritis Trial (MNT).
  
  
  METHODS
  Long-term (at least 7 years) renal function data were available for 90 patients randomised in the MNT. Receiver operating characteristic curves were built to test the performance of proteinuria measured within the 1st year as short-term predictor of long-term renal outcome. We calculated the positive and negative predictive values (PPV, NPV).
  
  
  RESULTS
  After 12 months of treatment, achievement of a proteinuria <0.7 g/day best predicted good renal outcome, with a sensitivity and a specificity of 71% and 75%, respectively. The PPV was high (94%) but the NPV low (29%). Addition of the requirement of urine red blood cells ≤5/hpf as response criteria at month 12 reduced sensitivity from 71% to 41%.
  
  
  CONCLUSIONS
  In this cohort of mainly Caucasian patients suffering from a first episode of LN in most cases, achievement of a proteinuria <0.7 g/day at month 12 best predicts good outcome at 7 years and inclusion of haematuria in the set of criteria at month 12 undermines the sensitivity of early proteinuria decrease for the prediction of good outcome. The robustness of these conclusions stems from the very similar results obtained in two distinct LN cohorts.
  
  
  BACKGROUND
  NCT00204022.
authors.affiliation: Rheumatology Department , Cliniques Universitaires Saint-Luc, Pôle de Pathologies Rhumatismales Inflammatoires et Systémiques, Université catholique de Louvain , Bruxelles , Belgium.
authors.forename: Farah
authors.initials: F
authors.lastname: Tamirou
authors.affiliation: Rheumatology Department , Cliniques Universitaires Saint-Luc, Pôle de Pathologies Rhumatismales Inflammatoires et Systémiques, Université catholique de Louvain , Bruxelles , Belgium.
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Lauwerys
authors.affiliation: Division of Rheumatology , Russell/Engelman Research Center, University of California, San Francisco , San Francisco, California , USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Dall'Era
authors.affiliation: The Feinstein Institute for Medical Research , Manhasset, New York , USA.
authors.forename: Meggan
authors.initials: M
authors.lastname: Mackay
authors.affiliation: Ohio State University, Wexner Medical Center , Columbus, Ohio , USA.
authors.forename: Brad
authors.initials: B
authors.lastname: Rovin
authors.affiliation: Department of Autoimmune Diseases , Hospital Clinic, Universitat de Barcelona , Barcelona, Catalonia , Spain.
authors.forename: Ricard
authors.initials: R
authors.lastname: Cervera
authors.affiliation: Rheumatology Department , Cliniques Universitaires Saint-Luc, Pôle de Pathologies Rhumatismales Inflammatoires et Systémiques, Université catholique de Louvain , Bruxelles , Belgium.
authors.forename: Frédéric A
authors.initials: FA
authors.lastname: Houssiau
keywords: Lupus Nephritis; Outcomes research; proteinuria