Table 1.

Variables, measures, and methods of analysis for ESSAHM trial

Variable/outcome	Hypothesis	Outcome measure	Methods of analysis
1) Primary: syphilis case detection	75 % increase over baseline rate	New, previously untreated syphilis case as a binary measure	GLMM models using SAS PROC GLIMMIX with logit function
2) Secondary: a. screening coverage	Increase to 85 % of men testing annually	Tested one or more times in 6-month study period as a binary measure	GLMM models using SAS PROC GLIMMIX with logit function Compare proportion tested and modify to annualized rates
b. screening frequency	Increase to median of 3 tests per person/year	Number of tests per year as Poisson count outcome data	GLMM models using SAS PROC GLIMMIX with log link function
c. reached men at highest risk for syphilis by examining OHTN Cohort Studya subgroup	Increases in screening coverage and frequency (2a&b) occur in the among men at highest risk for syphilis according to sexual behaviors	Outcome measures for screening coverage and screening frequency	GLMM models using SAS PROC GLIMMIX with logit and log link function

GLMM general linear mixed models

^aOntario HIV Treatment Network Cohort Study, an ongoing clinical HIV cohort taking place at the four participating clinics of the trial [37]. An estimated 40 % of men in HIV care at these clinics are active participants of that cohort