title: Re-examination of 30-day survival and relapse rates in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome.
abstract: OBJECTIVE
  Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are characterized by microangiopathic hemolytic anemia and thrombocytopenia. Interestingly, markedly different survival rates have been reported despite increases in survivability. We studied TTP-HUS 30-day mortality and relapse rates of patients who received TPE at our institution and compared them to published data.
  
  
  METHODS
  Retrospective study analyzed 30-day mortality and relapse rates attributed to TTP-HUS from 01/01/2008 to 12/31/2012 and compared them to comparable literature reporting mortality and survival. Studies describing other etiologies for TPE and different mortality time interval were excluded.
  
  
  RESULTS
  Fifty-nine patients were analyzed and all were initially treated with TPE and corticosteroids. Eleven patients were classified as not having TTP-HUS due to testing or clinical reassessment which ruled in other etiologies, and 18/59 patients had ADAMTS13 activity <10%. Of remaining patients, 36/48 (75%) were diagnosed as idiopathic and 12/48 (25%) as secondary TTP-HUS. Patients received a mean of 12 TPEs (range 1-42); 42/48 (87.5%) patients had ADAMTS13 activity measured; complete response obtained in 39/48 (81.2%) patients (platelet count >100 x 10(9)/L); partial response in 4/48 (8%); and 5/48 (10.4%) did not have increases in platelet counts (2/5 of these patients died within the study period). Forty percent of patients obtained platelet counts >150 x 10(9)/L. Overall 30-day mortality for our patient cohort was 6.7% (4/59). Comparison of our mortality rate to combined data of five published studies of 16% (92/571) showed a significant difference, p = 0.04. Our relapse rate was 18.6% (11/59) similar to previous reports.
  
  
  CONCLUSIONS
  Wide differences in mortality may be due to grouping of two distinct pathologic entities under TTP-HUS; and presence of confounding factors in the patient populations under study such as co-morbidities, promptness of TPE initiation, delay in diagnosis and therapeutic practice.
authors.affiliation: Department of Pathology, University Hospitals Case Medical Center, Cleveland, Ohio, United States of America; Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America.
authors.forename: Cassiana E
authors.initials: CE
authors.lastname: Bittencourt
authors.affiliation: Department of Pathology, University Hospitals Case Medical Center, Cleveland, Ohio, United States of America; Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America.
authors.forename: Jennifer P
authors.initials: JP
authors.lastname: Ha
authors.affiliation: Department of Pathology, University Hospitals Case Medical Center, Cleveland, Ohio, United States of America; Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Maitta
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000188:drug therapy / Q000401:mortality* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010951:Plasma Exchange; D010976:Platelet Count; D011697:Purpura, Thrombotic Thrombocytopenic / Q000188:drug therapy / Q000401:mortality* / Q000628:therapy; D012008:Recurrence; D012074:Remission Induction; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D000305:Adrenal Cortex Hormones