Impact and Cost-effectiveness of Regular Self-digital Anorectal Examination on Syphilis Among Gay, Bisexual, and...

Rising syphilis incidence among Australian gay, bisexual, and other men who have sex with men (GBMSM) requires new early detection strategies. Regular self-digital anorectal examination (self-DARE) may facilitate syphilis identification, potentially reducing transmission. We evaluated its population-level impact and cost-effectiveness in controlling syphilis among Australian GBMSM.

We developed an integrated transmission-dynamic and health-economic model, calibrated with 2012-2022 Australian GBMSM data. Over a 10-year period (2025-2034), we compared the base case with two scenarios: recommending self-DARE to men with higher sexual activity ("only high group") or to all individuals ("both groups"). We assessed changes in incidence, incremental cost-effectiveness ratios (ICERs), and benefit-cost ratios.

The base case projected 110 501 new infections over 10 years. The "only high group" strategy averted 57 115 infections (51.7%) and was cost saving (negative ICER), with a benefit-cost ratio of 2.5. The "both groups" strategy averted more infections (58 216; 52.7%) but was less economically efficient (benefit-cost ratio: 1.6), though also cost-saving. Sensitivity analyses indicated that improving self-DARE sensitivity enhanced its performance.

Self-DARE could effectively and cost-effectively reduce syphilis among GBMSM, particularly when focused on men with higher sexual activity. Further empirical research is needed to confirm its feasibility and effectiveness.