Patients more likely to accept ‘opt-out’ HIV screening in ED than other testing offers, study finds

Opt-out consent appeared to be the best of the 3 approaches in terms of overall acceptance, even in patients who were most at-risk, supporting the use of this kind of consent even in settings that use targeted screening, according to an editorial.


When offering rapid HIV screening to patients in the ED, 1 way of asking seems to produce a higher acceptance rate than others, according to a recent study.

Between June 18, 2011, and June 30, 2013, nonclinical staff at an ED offered HIV screening to patients in 3 ways: opt-in (“You can let me, your nurse, or your doctor know if you'd like a test today”), active choice (“Would you like a test today?”), or opt-out (“You will be tested unless you decline”). Results were published online on Jan. 19 by The BMJ.

Researchers included 4,800 patients in the study, which was conducted in the ED of an urban teaching hospital and regional trauma center. They randomized 33.5% of participants to opt-in, 33.9% to active choice, and 32.6% to opt-out test offers.

Patients accepted 51.6% of all test offers. Opt-out testing had the highest acceptance rate (65.9%), followed by active choice (51.3%) and opt-in (38.0%), an unadjusted difference of 27.9% (95% CI, 24.4% to 31.3%) between the opt-out and opt-in arms. Opt-out testing also yielded 14.6% (95% CI, 11.1% to 18.1%) more acceptances than the active choice option.

Researchers included patients with a wide range of demographics, symptoms, and levels of HIV infection risk (as determined by the Denver HIV Risk Score used to further classify each patient's risk for HIV infection as low, intermediate, or high). They did not find risk-specific differences in treatment effects, except for high-risk patients in the opt-out arm. Their analysis showed that the opt-out effect was attenuated in high-risk patients (interaction term between opt-out and high risk, −15.5%; 95% CI, −27.8 to −3.1).

The study authors noted limitations to their work, such as how the proportion of patients who accepted testing may vary in other settings. “However, although the test acceptance percentages themselves might vary, we have little reason to expect a different pattern for opt-in versus active choice versus opt-out test schemes,” they wrote. They also noted that study staff was not blinded to treatment assignments, which could introduce bias.

The researchers concluded that active choice testing, which has been considered a form of opt-in testing, is a distinct category and that “simply asking patients if they would like a test increased test acceptance by 13 percentage points.” However, their version of opt-in screening seems “unrealistic” because it is unlikely that clinicians would tell patients that they test for HIV without actually asking if they want to be tested, according to an accompanying editorial.

Nonetheless, opt-out consent appeared to be the best of the 3 approaches in terms of overall acceptance, even in patients who were most at-risk, supporting the use of this kind of consent even in settings that use targeted screening, according to the editorial. The results of this study, the editorialists wrote, “support the notion that ‘the ask’ is a critical piece of the equation and is probably as important as ‘the test.’”