title: Patient choice in opt-in, active choice, and opt-out HIV screening: randomized clinical trial.
abstract: OBJECTIVE
  What is the effect of default test offers--opt-in, opt-out, and active choice--on the likelihood of acceptance of an HIV test among patients receiving care in an emergency department?
  
  
  METHODS
  This was a randomized clinical trial conducted in the emergency department of an urban teaching hospital and regional trauma center. Patients aged 13-64 years were randomized to opt-in, opt-out, and active choice HIV test offers. The primary outcome was HIV test acceptance percentage. The Denver Risk Score was used to categorize patients as being at low, intermediate, or high risk of HIV infection.
  
  
  CONCLUSIONS
  38.0% (611/1607) of patients in the opt-in testing group accepted an HIV test, compared with 51.3% (815/1628) in the active choice arm (difference 13.3%, 95% confidence interval 9.8% to 16.7%) and 65.9% (1031/1565) in the opt-out arm (difference 27.9%, 24.4% to 31.3%). Compared with active choice testing, opt-out testing led to a 14.6 (11.1 to 18.1) percentage point increase in test acceptance. Patients identified as being at intermediate and high risk were more likely to accept testing than were those at low risk in all arms (difference 6.4% (3.4% to 9.3%) for intermediate and 8.3% (3.3% to 13.4%) for high risk). The opt-out effect was significantly smaller among those reporting high risk behaviors, but the active choice effect did not significantly vary by level of reported risk behavior. Patients consented to inclusion in the study after being offered an HIV test, and inclusion varied slightly by treatment assignment. The study took place at a single county hospital in a city that is somewhat unique with respect to HIV testing; although the test acceptance percentages themselves might vary, a different pattern for opt-in versus active choice versus opt-out test schemes would not be expected.
  
  
  CONCLUSIONS
  Active choice is a distinct test regimen, with test acceptance patterns that may best approximate patients' true preferences. Opt-out regimens can substantially increase HIV testing, and opt-in schemes may reduce testing, compared with active choice testing.
  
  
  BACKGROUND
  This study was supported by grant NIA 1RC4AG039078 from the National Institute on Aging. The full dataset is available from the corresponding author. Consent for data sharing was not obtained, but the data are anonymized and risk of identification is low.Trial registration Clinical trials NCT01377857.
authors.affiliation: Department of Emergency Medicine, University of California, 505 Parnassus Ave, San Francisco, CA 94143, USA juancarlos.montoy@ucsf.edu.
authors.forename: Juan Carlos C
authors.initials: JC
authors.lastname: Montoy
authors.affiliation: School of Public Health, University of California, 239 University Hall #7360, University of California, Berkeley, CA 94720-7360, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Dow
authors.affiliation: Department of Emergency Medicine, University of California, 1001 Potrero Ave, San Francisco CA 94143, USA.
authors.forename: Beth C
authors.initials: BC
authors.lastname: Kaplan
mesh_terms: D000293:Adolescent; D000328:Adult; D002755:Choice Behavior; D004636:Emergency Service, Hospital; D005260:Female; D015658:HIV Infections / Q000175:diagnosis*; D006784:Hospitals, Teaching; D006786:Hospitals, Urban; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D057240:Patient Preference; D055815:Young Adult