A clinic-based intervention to incorporate syphilis testing with routine HIV bloodwork among HIV-positive men who have sex with men (MSM) attending 4 hospital-based HIV clinics in Toronto and Ottawa will be conducted. The objectives are to determine to what degree the intervention: (1) increases the detection rate of untreated syphilis; (2) increases the proportion of men who undergo syphilis testing at least annually (increased screening coverage); (3) reduces the interval between syphilis tests (increased screening frequency); and (4) reaches men at highest risk according to sexual behaviours. The main hypotheses are that the intervention will increase screening coverage to a minimum of 85% of men undergoing syphilis testing annually, increase screening frequency to a median of 3 tests per person per year, and increase the case detection rate by 75% or more.
The design of this study is a cluster-randomized controlled trial with stepped wedge design that will gradually introduce the intervention across clinics. This pragmatic approach incorporates a concurrent comparison group, allows for assessment of time trends, will be well-powered, and will generate more generalizable results due to its inclusion of multiple clinics. The intervention will be operationalized as standing orders for syphilis serology when there is an order for HIV viral load and/or CD4 cell count. Data sources include (1) syphilis tests submitted to the Public Health Ontario Laboratory; (2) a standardized clinical worksheet and medical chart review to validate diagnoses for screen test positives; and (3) data collected from a subset of patients via their participation in the ongoing Ontario HIV Treatment Network (OHTN) Cohort Study. The latter follows adults in HIV care and collects data using chart reviews and annual face-to-face interviews including measures of sexual behaviour.
