title: Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS): a 24-year clinical experience with 178 patients.
abstract: BACKGROUND
  Thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome (TTP-HUS) are related and uncommon disorders with a high fatality and complication rate if untreated. Plasma exchange therapy has been shown to produce high response rates and improve survival in patients with many forms of TTP-HUS. We performed a retrospective cohort study of 178 consecutively treated patients with TTP-HUS and analyzed whether clinical or laboratory characteristics could predict for important short- and long-term outcome measures.
  
  
  RESULTS
  Overall 30-day mortality was 16% (n = 27). 171 patients (96%) received plasma exchange as the principal treatment, with a mean of 8 exchanges and a mean cumulative infused volume of 42 +/- 71 L of fresh frozen plasma. The rate of complete response was 65% or 55% depending on whether this was defined by a platelet count of 100,000/microl or 150,000/microl, respectively. The rate of relapse was 18%. The Clinical Severity Score did not predict for 30-day mortality or relapse. The time to complete response did not predict for relapse. Renal insufficiency at presentation was associated with a decreased risk of relapse, with each unit increase in serum creatinine associated with a 40% decreased odds of relapse. 72% of our cohort had an idiopathic TTP-sporadic HUS, while 17% had an underlying cancer, received a solid organ transplant or were treated with a mitomycin-based therapy. The estimated overall 5-year survival was 55% and was significantly better in those without serious underlying conditions.
  
  
  CONCLUSIONS
  Plasma exchange therapy produced both high response and survival rates in this large cohort of patients with TTP-HUS. The Clinical Severity Score did not predict for 30-day mortality or relapse, contrary to our previous findings. Interestingly, the presence of renal insufficiency was associated with a decreased risk of relapse. The most important predictor of mortality was the presence or absence of a serious underlying disorder.
authors.affiliation: Division of Hematology and Oncology, UC Davis School of Medicine, Sacramento, CA, USA. mlevandovsky1@yahoo.com
authors.forename: Mark
authors.initials: M
authors.lastname: Levandovsky
authors.forename: Danielle
authors.initials: D
authors.lastname: Harvey
authors.forename: Primo
authors.initials: P
authors.lastname: Lara
authors.forename: Ted
authors.initials: T
authors.lastname: Wun
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000150:complications* / Q000175:diagnosis / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010949:Plasma; D010951:Plasma Exchange; D010976:Platelet Count; D011379:Prognosis; D011697:Purpura, Thrombotic Thrombocytopenic / Q000150:complications* / Q000175:diagnosis / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome