Objectives We aimed to identify individual and sexual partnership characteristics associated with partner notification (PN) among people with STI. We hypothesised that PN would be less likely in more casual sexual partnerships and in partnerships with intimate partner violence (IPV).

Methods We conducted an observational study among the first 330 patients with STI enrolled in a trial of a behavioural intervention to reduce STI incidence, at a clinic in a poor, Cape Town community. We included 195 index patients (those reporting STI symptoms), and conducted longitudinal analyses using participant-completed questionnaires on the day of diagnosis and 2 weeks later. Using partnership data for five recent sexual partners, we assessed factors associated with reported PN with logistic regressions, adjusting for repeated measurements on the same participant for each partner.

Results The sample included 99 males with 303 partners and 96 females with 158 partners. Males reported perpetrating IPV in 46.2% of partnerships. Females reported being IPV victims in 53.2% of partnerships. Males notified 58.1%, females 75.4% of partners during the 2 weeks following diagnosis. Type of partner was an independent correlate of PN for males and females, with the odds of PN lower in more casual partnerships. For males, reporting physical IPV perpetration in the partnership was an independent correlate of PN. For females, there was no association between IPV victimisation in a partnership and PN.

Conclusions Efforts to decrease the pool of infectious partners need to have a strong focus on the promotion of PN in casual relationships and one-night stands. IPV was not identified as a barrier to PN. In future, we need to investigate the association between IPV with an objective measure of PN success such as partner testing or treatment, or index patient reinfection.

Clinical trial registration PACTR201606001682364; Pre-results.