title: Reasons for non-enrollment in a cohort study of ARF: the Program to Improve Care in Acute Renal Disease (PICARD) experience and implications for a clinical trials network.
abstract: BACKGROUND
  Acute renal failure (ARF) is associated strongly with in-hospital mortality and morbidity. Previous clinical trials of ARF have been hampered by the heterogeneous population affected, difficulty defining ARF, delays in identification of ARF, and significant comorbid conditions, among other factors.
  
  
  METHODS
  The Program to Improve Care in Acute Renal Disease (PICARD) phase I was a multicenter cohort study aimed to identify clinical characteristics and practice patterns associated with adverse and favorable outcomes in patients with ARF in intensive care units. Although PICARD used no interventions, signed informed consent was required of all study subjects or their proxies.
  
  
  RESULTS
  Signed informed consent was obtained in 645 of 1,243 ARF episodes (52%). The fraction of patients not enrolled and reasons for non-enrollment varied widely across the 5 PICARD centers. Refusal by potential study subjects was infrequent, although the absence of family or proxy (15%) and refusal by family or proxy (18%) accounted for large fractions of non-enrolled subjects. Death (23%) and discharge (11%) before study personnel could evaluate patients were additional important reasons for non-enrollment.
  
  
  CONCLUSIONS
  Understanding reasons for non-enrollment may help rationalize mortality and other outcome differences seen in clinical trials and cohort studies that require informed consent compared with historic reports of "all comers" with ARF.
authors.affiliation: Department of Medicine Research, University of California San Francisco, San Francisco, CA 94118-1211, USA. chertowg@medicine.ucsf.edu
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Chertow
authors.forename: Maria T
authors.initials: MT
authors.lastname: Pascual
authors.forename: Sharon
authors.initials: S
authors.lastname: Soroko
authors.forename: Brandon R
authors.initials: BR
authors.lastname: Savage
authors.forename: Jonathan
authors.initials: J
authors.lastname: Himmelfarb
authors.forename: T Alp
authors.initials: TA
authors.lastname: Ikizler
authors.forename: Emil P
authors.initials: EP
authors.lastname: Paganini
authors.forename: Ravindra L
authors.initials: RL
authors.lastname: Mehta
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000523:psychology* / Q000628:therapy; D000328:Adult; D000368:Aged; D002986:Clinical Trials as Topic / Q000523:psychology; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D003422:Critical Care; D003643:Death; D005190:Family; D005260:Female; D006801:Humans; D007258:Informed Consent; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic / Q000523:psychology; D010351:Patient Discharge; D019727:Proxy; D045808:Refusal to Participate / Q000523:psychology* / Q000706:statistics & numerical data; D012042:Registries / Q000706:statistics & numerical data; D020458:Third-Party Consent; D014481:United States
chemical_list: D003404:Creatinine