Table 2.

Serum RPR and serum TPPA reactivity associated with S-NS

	S-NS n (%)	N-NS n (%)	OR	P		S-NS n (%)	N-NS n (%)	OR	P
Serum RPR titers					Serum RPR titers
Negative	6(3.2)	68(38.2)	1.0 (Ref.)
1:1	17(9.0)	38(21.3)	5.070	0.002	≥1:1 (vs <1:1)	182(96.8)	110(61.8)	18.752	<0.001
1:2	21(11.2)	36(20.2)	6.611	<0.001	≥1:2 (vs <1:2)	165(87.8)	72(40.4)	10.562	<0.001
1:4	18(9.6)	13(7.3)	15.692	<0.001	≥1:4 (vs <1:4)	144(76.6)	36(20.2)	12.909	<0.001
1:8	16(8.5)	8(4.5)	22.667	<0.001	≥1:8 (vs <1:8)	126(67.0)	23(12.9)	13.696	<0.001
1:16	24(12.8)	5(2.8)	54.400	<0.001	≥1:16 (vs <1:16)	110(58.5)	15(8.4)	15.325	<0.001
1:32	26(13.8)	7(3.9)	42.095	<0.001	≥1:32 (vs <1:32)	86(45.7)	10(5.6)	14.165	<0.001
1:64	35(18.6)	1(0.6)	396.667	<0.001	≥1:64 (vs <1:64)	60(31.9)	3(1.7)	27.344	<0.001
≥1:128	25(13.3)	2(1.1)	141.667†	<0.001	≥1:128 (vs <1:128)	25(13.3)	2(1.1)	13.497	<0.001
Serum TPPA titers					Serum TPPA titers
≤1:160a	2(1.1)	40(22.5)	1.0 (Ref.)
1:320	5(2.7)	41(23.0)	2.439	0.303	≥1:320 (vs <1:320)	186(98.9)	138(77.5)	26.957	<0.001
1:640	7(3.7)	32(18.0)	4.375	0.078	≥1:640 (vs <1:640)	181(96.3)	97(54.5)	21.592	<0.001
1:1280	18(9.6)	34(19.1)	10.588	0.003	≥1:1280 (vs <1:1280)	174(92.6)	65(36.5)	21.607	<0.001
1:2560	23(12.2)	12(6.7)	38.333	<0.001	≥1:2560 (vs <1:2560)	156(83.0)	31(17.4)	23.117	<0.001
1:5120	21(11.2)	11(6.2)	38.182	<0.001	≥1:5120 (vs <1:5120)	133(70.7)	19(10.7)	20.236	<0.001
1:10240	29(15.4)	5(2.8)	116.000	<0.001	≥1:10240 (vs <1:10240)	112(59.6)	8(4.5)	31.316	<0.001
≥1:20480	83(44.1)	3(1.7)	553.333‡	<0.001	≥1:20480 (vs <1:20480)	83(44.1)	3(1.7)	46.111	<0.001

S-NS symptomatic neurosyphilis, N-NS syphilis/non-neurosyphilis, RPR rapid plasma reagin, TPPA T. pallidum particle agglutination, OR odds ratio, Ref., reference

^aThis group included two S-NS patients and 21 N-NS patients with serum TPPA titers of 1:160 and 19 N-NS patients with serum TPPA titers of 1:80

^† P for trend <0.001

^‡ P for trend <0.001