Table 2.

Poisson regression results for assessing temporal trends for HIV and syphilis incidence, in the VCT cohort of men who have sex with men, and transgender women, Silom Community Clinic, Bangkok, Thailand 2005–2015.

Variable	Incident infections	PY	Rate	(95% CI)	RR	(95% CI)	p value (adjusted)
HIV
Overall	347	7157	4.84	(4.35–5.39)
Time (trend)
Overall							<0.001
time_RCS_linear							<0.001
time_RCS_spline							<0.001
Age group (yrs)
30+	80	2707	2.96	(2.35–3.68)	1.0
22–29	189	3319	5.69	(4.91–6.57)	1.92	(1.67–2.22)
18–21	78	1132	6.89	(5.45–8.60)	2.31	(1.95–2.74)	<0.001
Syphilis
Overall	376	8623	4.36	(3.93–4.82)
Time (trend)
Overall							<0.001
time_RCS_linear							<0.001
time_RCS_spline 1							<0.001
time_RCS_spline 2							<0.001
Age group (yrs)
30+	113	3195	3.54	(2.91–4.26)	1.0
22–29	200	4135	4.84	(4.19–5.55)	1.36	(1.20–1.54)
18–21	63	1293	4.87	(3.74–6.23)	1.35	(1.15–1.59)	<0.001

CI: confidence Interval; PY: person-years; RCS: restricted cubic spline; RR: rate ratio; VCT: voluntary counseling and testing.

Note: (1) No estimates are given for the RCS function as they are not directly interpretable; (2) adjusted p value is from model including time represented by RCS and age; and (3) time_RCS_spline is a nonlinear component of RCS.