Table 1

Cox regression results: unadjusted and adjusted HRs of characteristics associated with retesting probability (n=48375 individuals with at least one known result and ≥14 days follow-up time)

	Episode 1, n	Episode 2, n	Proportion retest (%)	Unadjusted HR	LCI (95%)	UCI (95%)	p Value	Adjusted HR	LCI (95%)	UCI (95%)	p Value
Total	48375	11550	23.9
Gender
Male	19886	2593	13.0	Ref
Female	28489	8957	31.4	2.37	2.27	2.47	<0.001	2.28	2.18	2.38	<0.001
First test
Negative	44010	10122	23.0	Ref
Positive	4365	1428	32.7	1.31	1.24	1.39	<0.001	1.37	1.29	1.44	<0.001
Age
<15	1817	826	45.5	2.80	2.56	3.05	<0.001	2.33	2.13	2.54	<0.001
16–17	9951	2973	29.9	1.71	1.60	1.82	<0.001	1.60	1.50	1.71	<0.001
18–19	12102	2663	22.0	1.12	1.05	1.20	0.001	1.11	1.04	1.18	0.003
20–21	10104	2123	21.0	1.06	0.99	1.14	0.075	1.07	0.99	1.14	0.072
22–23	8169	1678	20.5	0.98	0.91	1.06	0.630	0.96	0.89	1.03	0.296
24–25	6232	1287	20.7	Ref
Year
2003/04	8160	3413	41.8	1.25	1.16	1.35	<0.001	0.99	0.91	1.07	0.736
2005	7992	2602	32.6	1.08	1.00	1.17	0.042	0.96	0.88	1.04	0.306
2006	8668	2502	28.9	1.12	1.04	1.21	0.003	1.01	0.93	1.09	0.860
2007	9399	2035	21.7	1.16	1.07	1.25	<0.001	1.04	0.96	1.12	0.42
2008/09	14156	998	7.1	Ref
3 month
Yes	18511	5491	29.7	1.22	1.17	1.27	<0.001	1.26	1.21	1.31	<0.001
No	15010	4064	27.1	Ref
Don't know	8964	982	11.0	0.93	0.87	1.00	0.062	1.01	0.93	1.09	0.82
Missing	5890	1013	17.2	1.10	1.02	1.17	0.010	1.11	1.03	1.19	0.004

p, probability; LCI, Lower confidence interval; UCI, Upper confidence interval.