Evaluating the Home-based Intervention Strategy (HIS-UK) to reduce new chlamydia infection among young men aged 16-25 years by promoting correct and consistent condom use: Findings from a randomised controlled trial
Authors: Stone Nicole , Graham Cynthia , Bremner Stephen , McGrath Nuala , Bedford Rowena , Brown Katherine E , Newby Katie , Clarke Amanda , Jackson Louise , Morrison Leanne , Nadarzynski Tom , To Ye 
Published: May 2024

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
725 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.
Compared to control participants, HIS-UK participants showed enhanced and sustained positive condom attitudes, reduced perceived barriers, and increased confidence in condom use, during follow-up; these changes were statistically significant.
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.
Funding
NIHR Public Health Research Programme (17/54/06), with additional excess treatment cost support from Public Health England.
Trial Registration
ISRCTN registration: 11400820 (23/10/2019)
Ethical Review
South Central - Oxford B Research Ethics Committee REC number: 19/SC/0486 (04/11/2019); IRAS ID: 255684 (HRA approval 19/11/2019)