title: Acute renal failure is prevalent in patients with thrombotic thrombocytopenic purpura associated with low plasma ADAMTS13 activity.
abstract: BACKGROUND
  Among patients with thrombotic microangiopathies, acute kidney injury (AKI) is the hallmark of hemolytic uremic syndrome (HUS) and is largely underestimated in patients with thrombotic thrombocytopenic purpura (TTP).
  
  
  OBJECTIVE
  We sought to report AKI features and outcomes in patients with TTP.
  
  
  METHODS
  We conducted a retrospective study of 92 patients with TTP assessed by low ADAMTS13 activity (< 10%) between 2001 and 2013. A logistic regression identified variables independently associated with AKI.
  
  
  RESULTS
  Among the 92 patients, 54 (58.7%) presented with AKI, including 25 (46.3%) with stage 3 AKI. Fourteen (27.4%) patients had a nephrotic-range proteinuria and 21 (45.6%) had hemoglobinuria. Hematuria and leucocyturia were detected in 19 (41.3%) and 16 patients (36.4%), respectively. Renal replacement therapy (RRT) was required in 14 patients (25.9%). Six months after TTP remission, RRT-free patients had median (IQR) MDRD (Modification of Diet in Renal Disease formula estimating the glomerular filtration rate) of 93 mL min(-1) per 1.73 m(2) (68.8-110) and three patients required long-term dialysis. Mild or moderate chronic renal disease occurred in 23/54 (42.6%) AKI patients. By multivariate analysis, serum level of complement component 3 at admission was the only factor independently associated with AKI (OR per 0.25 unit decrease of C3, 0.85; CI, 1.82-8.33; P = 0.001).
  
  
  CONCLUSIONS
  In patients with TTP, AKI is present in more than half the patients, and half of those will have lasting renal effects. Further studies to better understand the pathophysiology of renal involvement in patients with TTP and to identify a subset of patients with TTP syndrome overlapping HUS are warranted.
authors.affiliation: Medical Intensive Care Unit, Saint-Louis Hospital, Assistance Publique-Hôpitaux de Paris and Paris Diderot University, Paris, France.
authors.forename: L
authors.initials: L
authors.lastname: Zafrani
authors.forename: E
authors.initials: E
authors.lastname: Mariotte
authors.forename: M
authors.initials: M
authors.lastname: Darmon
authors.forename: E
authors.initials: E
authors.lastname: Canet
authors.forename: S
authors.initials: S
authors.lastname: Merceron
authors.forename: D
authors.initials: D
authors.lastname: Boutboul
authors.forename: A
authors.initials: A
authors.lastname: Veyradier
authors.forename: L
authors.initials: L
authors.lastname: Galicier
authors.forename: E
authors.initials: E
authors.lastname: Azoulay
mesh_terms: D051722:ADAM Proteins / Q000097:blood*; D000071120:ADAMTS13 Protein; D058186:Acute Kidney Injury / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology / Q000628:therapy; D000328:Adult; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D003176:Complement C3 / Q000032:analysis; D015536:Down-Regulation; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D015994:Incidence; D007668:Kidney / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010297:Paris / Q000453:epidemiology; D015995:Prevalence; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood / Q000175:diagnosis / Q000201:enzymology* / Q000453:epidemiology; D020127:Recovery of Function; D017582:Renal Replacement Therapy; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C038245:C3 protein, human; D003176:Complement C3; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human
keywords: ADAMTS13 protein, human; acute kidney injury; complement system proteins; renal replacement therapy; thrombotic thrombocytopenic purpura