An interactive digital behaviour change intervention to decrease incidence of sexually transmitted infections among users of STI self-sampling websites: a feasibility RCT.

Abstract

Background: Sexually transmitted infections such as chlamydia are common among young people. If left untreated, they can have serious health consequences. Condoms are recommended for prevention, but young people report often not using them for penetrative sex. Use of web-based sexually transmitted infection testing is increasing rapidly, but these services provide little support or advice on how to prevent future infections. 'Wrapped' is a web-based intervention that aims to support young users of web-based sexually transmitted infection testing to use condoms correctly every time they have penetrative sex, thus reducing future sexually transmitted infection incidence.

Objective: To assess whether and how it is possible to carry out a future randomised controlled trial of Wrapped.

Design: A two-arm, parallel-group feasibility randomised controlled trial, with nested qualitative study, in which Wrapped in addition to usual care is tested against usual care alone.

Setting: Participants were recruited from five English local authority areas through one web-based sexually transmitted infection testing service.

Participants: Young people aged 16-24 years with internet access and who were likely to have penetrative sex during the study.

Intervention: Wrapped interactive multimedia intervention. Control: Non-interactive web page with standard information on sexually transmitted infections and details about how to access condoms.

Main outcome measures: Proportion of sampling pool recruited and return of valid chlamydia self-sample at month (M)12. Other outcome measures: return of valid chlamydia self-sample at M3; completion of surveys at baseline, M3, M6 and M12; follow-up by demographic characteristics; and acceptability of intervention and measures.

Results: In total, 230 participants were recruited and randomised to the feasibility randomised controlled trial: 115 to the intervention group and 115 to the control. Of these, 173 (75.2%) self-reported the result of their first sexually transmitted infection test. This sub-sample ('restricted sample') best represents the true nature of the sample at full trial for which the baseline sexually transmitted infection test result is needed. Results which follow are therefore for this sample. Of the sampling pool, 1.5% were recruited. A valid chlamydia self-sample was returned by 75.7% at M12. Based on this information, 3574 participants, derived from a sampling pool of 238,266 service users, were estimated to be necessary to power a future full trial. Return of other follow-up measures was as follows: valid M3 chlamydia self-sample 75.1%, M3 survey 91.3%, M6 survey 90.8% and M12 survey 91.8%. Participants at M12 appeared to broadly represent individuals in the sampling pool with some limited exceptions: a tendency for over-representation of participants who were older (20-24 years), of black ethnicity, and in the least deprived quintile; and for under-representation of participants who were younger (16-19 years), of white ethnicity, and in deprivation quintile 3. There was no evidence of differential attrition by intervention group. Participants reported that trial processes and procedures were acceptable.

Limitations: Study advert was likely not visible to most eligible participants resulting in a low recruitment rate. Qualitative study sample lacked ethnic and gender diversity.

Conclusions: A full trial is feasible. Despite the low recruitment rate, there are sufficiently high numbers of young people accessing web-based sexually transmitted infection testing (585,000 per year based on most recent data) to achieve the required sample. Suggested strategies to address the potential for under- and over-representation of some demographic subgroups at M12 should be implemented.

Future work: A full definitive randomised controlled trial implementing learning from this study.

Study registration: This study is registered as Current Controlled Trials ISRCTN17478654.

Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme (NIHR award ref: NIHR128148) and is published in full in Public Health Research; Vol. 13, No. 9. See the NIHR Funding and Awards website for further award information.