Table 2. Association between the slope of the ratio of the post-treatment RPR titer compared to the baseline titer and other characteristics using linear regression analysis.

	Univariable			Multivariable
	Coefficient		P-value	Coefficient		P-value
Age (per 10 years)	0.23	(0.067–0.39)	0.006	0.23	(0.090–0.37)	0.002
CD4 counts (per 100μL)	0.066	(−0.017 to 0.15)	0.12
HIV-RNA <50 copies/mL	0.67	(0.19–1.16)	0.008
Late syphilis*	0.37	(−0.09 to 0.82)	0.12
History of syphilis	0.45	(0.12–0.78)	0.008	0.36	(0.07–0.65)	0.02
RPR titer at diagnosis (per 10R.U.)	0.0060	(−0.00036 to 0.012)	0.06
RPR titer at treatment initiation (per 10R.U.)	0.0020	(−0.0078 to 0.012)	0.69
Ratio of RPR titer at treatment initiation/diagnosis (per every 10-fold increase)	−0.57	(−0.90 to −0.25)	0.001	−0.52	(−0.81 to −0.22)	0.001
TPLA titer (per 100T.U.)	0.00054	(−0.00072 to 0.0018)	0.40
Amoxicillin therapy	−0.27	(−0.63 to 0.08)	0.13

Coefficients are shown in log2 scale. Abbreviations: RPR, rapid plasma reagin; R.U., RPR unit; TPLA, Treponema pallidum latex-agglutination; T.U., titer unit.

*compared with early syphilis.