Table 2.

Tests for acquired drug resistance and number of episodes of virological failure^* and corresponding rates per 1000 person-years 6 months after ART initiation. HIV-CAUSAL Collaboration 2000–2015.

Baseline characteristics		Tests for acquired drug resistance		Tests detecting acquired drug resistance		Virological failure episodes*
		N	Tests/1000 person-years	N	Tests/1000 person-years	N	Episodes/1000 person-years
Overall		2672	20.1	794	6	1874	14.1
CD4 count, cells/mm3	<100	449	28.9	207	13.3	227	14.8
	100 – 200	433	23.5	138	7.5	254	13.8
	200 – 350	750	19.3	216	5.6	546	14.1
	350 – 500	487	15.8	111	3.6	403	13
	>500	553	19.1	122	4.2	404	15.3
HIV-RNA, copies/mL	<10000	435	16	111	4.1	425	15.6
	10000 – 100000	1117	18.4	338	5.6	803	13.2
	>100000	1120	25	345	7.7	646	14.4
Sex	Male	1959	18.1	574	5.3	1300	12
	Female	713	29	220	9	574	23.4
Age, years	18 – 35	1318	23.9	382	6.9	953	17.3
	35 – 50	1136	18.3	351	5.7	790	12.8
	>50	218	14	61	3.9	131	8.4
Mode of HIV acquisition	Heterosexual	1087	25.8	367	8.7	778	18.7
	Homo/bi-sexual	1326	16.9	337	4.3	864	11
	Injection drug-use	127	30.1	36	8.5	120	28.5
	Other/unknown	132	17	54	7	102	13.2
Calendar year	2000–2004	1403	24	486	8.3	1104	18.9
	2005–2009	1069	19	264	4.7	609	10.8
	2010 – 2015	200	11.1	44	2.4	162	9
Region of origin	Western countries	524	9.2	181	3.2	602	10.6
	Sub-Saharan Africa	159	28.2	65	11.5	128	22.7
	Rest of the world	137	13.6	55	5.4	109	10.8
	Unknown	1852	30.9	493	8.2	1035	17.2
Ethnicity	White	1288	22.1	312	5.4	849	14.6
	Black	727	38.1	245	12.8	461	24.2
	Other/unknown	657	11.9	237	4.3	564	10.2
Testing for transmitted drug resistance	No	1478	19	508	6.6	1200	15.5
	Yes	1194	11.1	286	5.2	674	12.2

^*Virological failure was defined as the second of two consecutive HIV-RNA≥400 copies/mL preceded by HIV-RNA≤50 copies/mL.