Table 1.

Study design and characteristics of the study population among 20 studies included in the systematic review

First author	Study design	Study time period	Study location	Number of study subjects	Study population	Male sex (%)	Men who have sex with men (%)	HIV prevalence (%)	Primary syphilis (%)	Secondary syphilis (%)	Early latent syphilis (%)	Late latent syphilis (%)	Tertiary or neuro-syphilis (%)
Dionne-Odom	R cohort	2002–2008	Lusaka, Zambia and Kigali, Rwanda	1321	HIV-serodiscordant couples	40	NR	70.6	NR			NR	NR
Fiumara	R cohort	NR	Boston, Massachusetts (US)	128	University hospitals	64	NR	NR	0	0	0	100	NR
Ghanem (2007) [23]	R cohort	1992–2000	Baltimore, Maryland (US)	297	STD clinic	44	NR	43.4	62.6			37.4	0
Ghanema (2008) [24]	R cohort	1990–2006	Baltimore, Maryland (US)	180	University HIV clinic	67.2	NR	100	26.8b			55.4b	17.8b
Goemenb	P cohort	NR	Kinshasa, Zaire	193	Women’s health center	0	0	37	NR			NR	NR
Jinno	R cohort	2006–2011	Los Angeles, California (US)	560	Urban HIV clinics	99	96.7	100	14	26	60	0	0
Knautec	R cohort	1999–2008	Zurich, Switzerland	264	University and general hospitals	92	NR	42	34	50	13d		3
Li	R cohort	2000–2010	Beijing, China	501	University hospital	50.9	NR	0	17.4	51.1	31.5	0	0
Longe	P cohort	2003	Lima, Peru	96	Neighborhood venues	NR	NR	15.6	NR			NR	NR
Malonef	R cohort	1985–1991	San Diego, California (US)	100	Naval Medical Center	99e	NR	100	3.6	16.1	17.9	53.6	8.9
Manavig	P cohort	2003–2005	Birmingham UK	261	STD clinics	76f	38.3	38.3	0	0	100	0	0.4
Reidner	P RCT	2000–2003	Myeba Region, Tanzania	328	High risk populations	28.4	NR	52.1	7.6	0	92.8	0	0
Rolfs	P RCT	1991–1994	NR	541	NR	70.8	12.8	18.7	25.7	46.8	27.5	0	HIV+: 61 %
													HIV-: 40 %
Romanowski	R cohort	1981–1987	Alberta, Canada	882	Provincial public health records	17	21.1	NR	68.3	18.3	4.3	0	NR
Seña	P RCT	2000–2009	Birmingham New Orleans, Los Angeles, Baltimore, Durham, Raleigh, Indianapolis, (US); Antana-narivo Tamatave, Madagascar	465	STD clinics	61.7	3.0	0	24.7	46.9	28.4	0	0
Tittesh	R cohort	1987–2010	Vienna, Austria	249	University STD-outpatient clinic	83.1		31.7	26.1	73.9	0	0	0
Tong	R cohort	2005–2010	Xiamen, China	1327	University hospital	58.9	NR	0	22.0	27.1	31.4i		19.5d
Tsai	R cohort	2007–2013	Taiwan	394	HIV care hospitals	100	94.9	100	8.9	55.3	35.8	0	0
Wuj	P cohort	2009–2013	Taiwan	174	University hospital	99.7	97.0	100	17.6	53.7	28.7	0	0
Yang	P cohort	2007–2012	Taiwan	573	HIV care hospitals	NR	94.1	100	8.9	57.8	33.3	0	0

R retrospective, P prospective, RCT randomized controlled trial, NR not reported

^a Demographics and serological outcome data were reported for 180 patients; however, syphilis stages were reported for 231 cases of syphilis

^b Demographics were reported for 193 patients; however, serological outcome data were reported for 120 patients

^c Demographics and syphilis stages were reported for 264 patients; however, serological outcome data were reported for 214 patients

^d This value is the total percentage of latent syphilis patients. This study did not distinguish between early latent and late latent patients

^e Demographics were reported for 96 patients; however, serological outcome data were reported for 76 patients

^f Demographics and syphilis stages were reported for 100 patients; however, serological outcome data were reported for 56 patients

^g Demographics and syphilis stages were reported for 371 patients; however, serological outcome data were reported for 261 patients

^h Demographics and syphilis stages were reported for 379 patients; however, serological outcome data were reported for 249 patients

ⁱ This value is the total percentage of latent syphilis patients. This study did not distinguish between early latent and late latent patients

^j Demographics and syphilis stages were reported for 296 patients; however, serological outcome data were reported for 174 patients