Abstract
BACKGROUND: Correct and consistent condom use is the most effective method to reduce transmission of sexually transmitted infections (STIs). OBJECTIVE: To compare the HIS-UK intervention to usual condom information and distribution care for effect on chlamydia test positivity. METHODS: Trial design A 3-parallel arm randomised controlled trial (1:1:1 allocation, two intervention arms vs. control). Randomisation using permuted blocks of varying lengths, with stratification by site, ethnicity and sexual-partnering risk. Repeated measures design with monthly follow-up to six months post-randomisation. Setting Sexual health services in seven NHS Trusts and one university medical centre. Telephone and video consultations, online and in participants' homes in England, UK. Participants Target sample of 2231 men and people with penises, aged 16-25, at risk of STIs. Intervention HIS-UK delivered (1) face-to-face by health professionals (proHIS) or (2) digitally (eHIS). Two-weeks self-practice and experimentation using the HIS-UK condom kit. Primary health outcome Chlamydia test positivity by six-months. Secondary outcomes Frequency of unprotected sexual intercourse, reported condom use errors and problems, attitudes and use experience. Analyses Chlamydia test positivity by six months analysed by logistic regression. Secondary outcomes analysed using linear mixed effects models with fixed effects and a random effect for the repeated measures, and generalised estimating equations with a logit link, adjusting for fixed effects and specifying an autoregressive-1 correlation structure. RESULTS: Seven hundred twenty-five participants (proHIS:241, eHIS:243, control:241) randomised. 575 participants completed all baseline activities, 189 (32.9%) reached six-months post-randomisation. The absolute difference in chlamydia test positivity between arms was -4.9 percentage points at six months (7.9% HIS-UK, 12.8% control). The odds of chlamydia test positivity during follow-up were 55% lower for HIS-UK participants (p=.261). HIS-UK showed a positive impact on recent condom use over time (p<.001). Significant reductions in condom errors and problems among HIS-UK participants were observed (p=.035). Lubricant use increased among HIS-UK participants, with evidence of an intervention-by-time interaction (p=.051), and a decline in poor condom fit and feel reports, but without intervention effect. CONCLUSIONS: This study provides valuable insights into the potential of HIS-UK to enhance sexual health practices among at-risk populations at-risk of STI transmission. TRIAL REGISTRATION: ISRCTN registration: 11400820 (23/10/2019).