Objective: To assess accelerated partner therapy (APT) as a contact tracing intervention for people with chlamydia.
Design: Cross-over cluster-randomised controlled trial.
Setting: 17 sexual health clinics (clusters) in the United Kingdom, 2018-2019.
Participants: Heterosexual people aged over 16 years with a positive Chlamydia trachomatis test result and/or clinical diagnosis of pelvic inflammatory disease, cervicitis, non-gonococcal urethritis or epididymo-orchitis, and reporting one or more contactable sexual partner in the past six months, and their sexual partners.
Interventions: Clusters were assigned by random permutation to either (a) usual care: health care professional advises the index patient to tell their sex partner(s) to attend clinic for sexually transmitted infection (STI) screening and treatment, or (b) usual care plus the offer of APT: healthcare professional assesses sex partner(s) by telephone, then sends or gives the index patient antibiotics and STI self-sampling kits for their sex partner(s). After a two-week washout period, clinics crossed over to the opposite exposure. Each period lasted 6 months.
Main outcome measures: The primary outcome was the proportion of index patients with a positive C. trachomatis test 12-24 weeks after treatment. Secondary outcomes included proportions and types of sex partners treated.
Analysis: Intention-to-treat, fitting random effects logistic regression models.
Results: All clinics completed both periods. Overall, 1536 and 1724 recruited index patients provided data in intervention and control phases respectively. In total, 4807 sex partners were reported, of whom 1636 (34%) were committed/established partners. Overall, 293/1536 (19.1%) of index patients chose APT for a total of 305 partners, of whom 248 accepted. In intervention and control phases, 666 (43%) and 800 (46%) of index patients were tested for C. trachomatis at 12-24 weeks; 31 (4.7%) and 53 (6.6%) were positive, adjusted odds ratio (aOR) 0.66 (95% CI 0.41 to 1.04, p=0.07). Among index patients with treatment status recorded, the proportion with ≥1 sex partner treated was 775 (88.0%) in the intervention and 760 (84.6%) in the control phase, aOR 1.27 (95% CI 0.96 to 1.68, p=0.10). Seven adverse events of low severity were recorded.
Conclusions: APT can be safely offered as a contact tracing option for people with C. trachomatis and might reduce the risk of repeat infection. Future research should find ways to increase uptake and develop alternative interventions for one-off partners.
Accelerated partner therapy contact tracing for people with chlamydia: The LUSTRUM cluster cross-over randomised controlled trial
