From September 2010 to March 2011, clinicians referred 445 men to the study. Of these men, 26 declined to participate (fig 1). Nineteen men were found to be ineligible, mainly because they were not planning to reside within Victoria during the study period. Of the 400 men who were recruited and randomised, 200 were assigned to HIV rapid testing and 200 to conventional testing. Among the 200 men randomised to rapid testing, five had a diagnosis of with HIV (two at baseline), six were lost to follow-up, and 189 (94.5%) completed 18 months of follow-up. Among the 200 men randomised to conventional testing five had a diagnosis of HIV (three at baseline), 14 were lost to follow up, and 181 (90.5%) completed 18 months of follow-up (fig 1). The 10 men with a diagnosis of HIV were censored at the date of their positive result. Five were positive at enrolment (overall baseline prevalence 1.25%, (95% confidence interval 0.4% to 2.9%) and five were incident cases (overall incidence 0.9% a year, 0.3% to 2.1%). Table 1 compares the characteristics of men in the intervention and control arms.
Fig 1 Screening, enrolment, randomisation, and follow-up of men who have sex with men in study of effect of provision of rapid HIV testing on frequency of tests
Table 1 Characteristics of men who have sex with men at enrolment in study of effect of rapid point of care HIV tests on frequency of HIV testing in public health service in Australia. Figures are medians unless stated otherwise
Men assigned to the rapid test arm had 469 tests during 288 person years of follow-up while men in the conventional test arm had 396 tests during 278 person years of follow-up. After enrolment, the incidence of HIV testing in the rapid and conventional test arms over 18 months was 1.63 and 1.42 tests a year, respectively, representing an incidence rate ratio of 1.15 (95% confidence interval 0.96 to 1.38; P=0.12) (table 2). When we included only the first HIV test after enrolment in a post hoc analysis, the rate of HIV testing in the rapid test arm was higher than in the conventional test arms. The rate was 1.32 tests a year (161 tests/122 person years) in the rapid test arm and 1.01 tests a year (141 tests/140 person years) in the conventional test arm, representing an incidence rate ratio of 1.32 (10.5 to 1.65; P=0.02; table 2, fig 2). When we excluded the first HIV test after enrolment, the rate of subsequent HIV testing was the same in both arms, at 1.86 tests a year in the rapid arm and 1.83 tests a year in the conventional arm (1.01, 0.86 to 1.20; P=0.90).
Table 2 Incidence rate of HIV testing over time among men who have sex with men according to allocation to rapid HIV test or conventional HIV test in public health service in Australia
Fig 2 Kaplan-Meier estimates showing probability over time of first HIV test undertaken after baseline testing. Curve shows proportion of tests as they occur over 18 months
The rate of testing for syphilis, chlamydia, and gonorrhoea at the study clinic did not differ significantly between study arms. The rates of syphilis testing in the intervention and control arms were 1.42 and 1.32 tests a year, respectively (incidence rate ratio 1.13, 95% confidence interval 0.95 to 1.35; P=0.18), while the rates of testing for chlamydia and gonorrhoea were 1.56 and 1.42 a year, respectively (1.11, 0.90 to 1.36; P=0.33).
Unconfirmed reactive tests, representing false positive results, were more common with rapid tests than with conventional serology (9/596, 1.5% (95% confidence interval 0.6% to 2.8%) v 1/534, 0.2% (0% to 1.0%); P=0.02). Of 417 tests performed in the study clinic after enrolment in the rapid test arm, 396 (95%) were rapid tests and 21 (5%) were conventional tests. Reasons for the performance of conventional tests among participants in the rapid test arm included declined rapid testing after a previous false positive rapid test result (n=5), declined rapid testing without providing a reason (n=6), and clinic staff were unaware of the study (n=5).
At the baseline visit, men in the intervention arm were asked about their preference for HIV testing after they had experienced the finger prick test. Most men (167/190, 88%, 95% confidence interval 82% to 92%) said they preferred rapid tests over conventional HIV testing. The final study questionnaire was completed by 270/390 (69%) of the men who remained HIV negative throughout the study: 142/195 (73%) in the rapid test arm and 128/195 (66%) in the conventional serology arm (P=0.10). Compared with men randomised to rapid tests, men with access only to conventional serology were more likely to feel that the wait for the test result was too long (75/128 (59%) v 13/142 (9%), P<0.001), to report anxiety because of the wait (81/128 (63%) v 63/142 (44%), P=0.002), and to report delaying their next test because of anxiety over the wait (30/127 (24%) v 19/142 (13%), P=0.03). More men randomised to rapid tests reported that obtaining their HIV test result was convenient (105/141 (74%) v 52/128 (41%), P<0.001).