Chemsex and diagnoses of syphilis, gonorrhoea and chlamydia among men who have sex with men in the UK: a multivariable prediction model using causal inference methodology.

Multipartner chemsex may drive the association between chemsex and bacterial STI diagnoses and thus should be the focus of future tailored chemsex interventions. Additionally, PrEP acceptability among MSM and particularly chemsex participants has generated an emergent group suitable for such interventions.