Table 2. Cox regression models analyzing time to viral suppression and time to virological failure. Models were stratified for the administered PI.

	Viral Suppression					Virological failure
Characteristics	univariable HR(95% CI)	P	multivariable HR (95% CI)	P		univariable HR(95% CI)	P	multivariable HR(95% CI)	P
Minor PI mutation
No	Ref		Ref			Ref		Ref
Yes	1.1 (0.9–1.2)	.364	1.1 (1.0–1.3)	.196		1.0 (0.6–1.6)	.935	0.9 (0.5–1.6)	.765
Sex
Male	Ref		Ref			Ref		Ref
Female	1.3 (1.1–1.6)	.001	1.3 (1.1–1.5)	.003		0.6 (0.3–1.3)	.188	0.5 (0.2–1.2)	.142
Ethnicity
White	Ref		Ref			Ref		Ref
Other	1.3 (1.0–1.6)	.020	1.1 (0.9–1.5)	.250		1.2 (0.5–3.0)	.724	1.2 (0.5–3.3)	.690
Age (per 10 years)	1.0 (0.9–1.0)	.366	1.0 (0.9–1.1)	.670		0.9 (0.7–1.2)	.363	0.9 (0.6–1.2)	.374
Transmission category
Other	Ref		Ref			Ref		Ref
IDU	1.0 (0.8–1.2)	.806	0.9 (0.7–1.1)	.188		1.2 (0.7–2.0)	.551	1.5 (0.9–2.7)	.145
CD4 cell count
<200 cells/µl	Ref		Ref			Ref		Ref
200–350 cells/µl	1.2 (1.1–1.4)	.009	1.1 (1.0–1.3)	.103		0.7 (0.3–1.2)	.170	0.6 (0.3–1.2)	.125
>350 cells/µl	1.4 (1.2–1.7)	<.001	1.3 (1.1–1.6)	.001		1.2 (0.7–2.3)	.496	1.3 (0.6–2.5)	.500
HIV-1 RNA
<10,000 copies/mL	Ref		Ref			Ref		Ref
10,000–99,999 copies/mL	0.7 (0.6–0.8)	<.001	0.7 (0.6–0.9)	.001		1.3 (0.6–3.0)	.513	1.6 (0.7–4.0)	.279
>100,000 copies/mL	0.4 (0.4–0.5)	<.001	0.5 (0.4–0.5)	<.001		1.6 (0.7–3.7)	.259	2.3 (0.9–5.8)	.081
Year of ART start	1.0 (1.0–1.0)	.321	1.0 (1.0–1.0)	.325		0.9 (0.8–1.1)	.536	1.0 (0.8–1.2)	.994
NRTI mutation
No	Ref		Ref			Ref		Ref
Yes	1.0 (0.7–1.4)	.828	0.7 (0.5–1.1)	.106		3.7 (1.6–8.5)	.002	6.1 (2.5–15.0)	<.001

Abbreviations: HR, hazard ratio; CI, confidence interval; PI, protease inhibitor; ART, antiretroviral therapy; NRTI, nucleoside reverse transcriptase inhibitor.