Opt-Out Screening Can Improve Acceptance of HIV Testing

Nicola M. Parry, DVM

January 21, 2016

Compared with active choice testing, opt-out screening can substantially increase HIV testing, and opt-in schemes may reduce testing, a new study has suggested.

"Our study provides evidence that small changes in wording can significantly affect patients' behavior and thus our understanding of their preferences. Specifically, modifying HIV testing defaults led to clinically and statistically significant differences in test acceptance percentages," write Juan Carlos C. Montoy, MD, from the University of California, San Francisco, and colleagues. They published the results of their study online January 19 in the BMJ.

"We found that active choice testing, although previously considered a form of opt-in testing, is a distinct category: compared with a strict opt-in scheme informing patients that they can request a test, simply asking patients if they would like a test increased test acceptance by 13 percentage points," the authors write.

To improve patients' acceptance of HIV testing, the Centers for Disease Control and Prevention revised its HIV screening guidelines in 2006, calling for routine, nontargeted, opt-out testing. Yet, although the centers noted that emergency departments may offer ready access to identify the estimated 20% of HIV-positive people who are undiagnosed, most hospitals have not implemented the opt-out recommendations. In addition, whereas studies of emergency department–based HIV screening have demonstrated that opt-out programs are associated with testing of an increased proportion of patients, they have reported conflicting results, with patients' test acceptance ranging from 29% to 87%.

Dr Montoy and colleagues therefore aimed to evaluate the effect of default test offers on the likelihood of acceptance of an HIV test among patients in an emergency department.

The researchers performed a nonblinded, randomized clinical trial in 4800 patients who visited an emergency department. They included patients aged 13 to 64 years who were able to consent to HIV testing, and excluded those who had previously been diagnosed with HIV or had received an HIV test in the previous 3 months. During the visit, nonclinical staff approached patients on two separate occasions — first to offer them a questionnaire, and again to offer them a rapid screening HIV test — and informed them that the emergency department was offering HIV tests in a nontargeted manner to all patients.

Patients were randomly assigned to opt-in (notifying patients that HIV testing was available but requiring them to ask for it), active choice (directly asking patients whether they would like to be tested), or opt-out (notifying patients that they would be tested unless they declined) HIV test offers.

Patients accepted 51.6% of all offers of HIV tests: 38.0% of those in the opt-in group accepted an HIV test compared with 51.3% in the active choice group (difference, 13.3%; 95% confidence interval [CI], 9.8% - 16.7%; P < .001) and 65.9% in the opt-out group (difference, 27.9%; 95% CI, 24.4% - 31.3%; P < .001). And compared with active choice testing, opt-out testing resulted in 14.6% (95% CI, 11.1% - 18.1%) more test acceptances.

In all groups, patients were more likely to accept testing if they were at intermediate (difference, 6.4%; 95% CI, 3.4% - 9.3%; P < .001) or high (difference, 8.3%; 95% CI, 3.3% - 13.4%; P = .0013) risk for HIV infection. The opt-out effect was significantly smaller (interaction term, −15.5%; 95% CI, −27.8% to −3.1%) for patients at high risk for HIV infection; however, the active choice effect did not significantly vary by level of reported HIV risk behavior.

In an accompanying editorial, Jason S. Haukoos. MD, and Sarah E. Rowan, MD, both from the University of Colorado School of Medicine, Aurora, emphasize that, "the study by Montoy and colleagues represents one of the largest trials to evaluate consent for HIV testing among emergency department patients, and the only one to do it in a randomized fashion but with particular focus on the efficacy of the various consent options."

However, they note that the authors' version of "opt-in" consent seems unrealistic because it is unlikely that clinicians would tell patients that they perform HIV testing without asking them whether they want to be tested. "If this occurs in practice, we believe it should be abandoned," they write.

Nevertheless, Dr Haukoos and Dr Rowan acknowledge the importance of using evidence to guide decisions about the best way to conduct HIV screening to maximize test acceptance and improve HIV diagnosis. "We commend the authors for conducting a large, thoughtful, and methodically rigorous clinical trial to help to improve our understanding of how best to offer an HIV test. Their results support the notion that 'the ask' is a critical piece of the equation and is probably as important as 'the test,' " they conclude.

This work was supported by the National Institute on Aging. The authors and editorialists have disclosed no relevant financial relationships.

BMJ. Published online January 19, 2016. Article full text, Editorial full text


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