Table 3.

Multivariate Cox Proportional Hazards Model: ATV/r Treatment Discontinuation and Time to Virologic Failure

Covariatea	Hazard ratiob	95% CI	p-value
ATV/r treatment discontinuation
Gender: females vs. males	1.54	1.28, 1.85	<0.001
Baseline detectable viremia ≥500 copies/ml, yes vs. no	1.04	0.88, 1.24	0.630
Germany vs. France	1.17	0.96, 1.42	0.129
Sweden vs. France	1.39	1.11, 1.75	0.004
Protease inhibitors vs. no protease inhibitorsc	3.21	2.67, 3.86	<0.001
NRT inhibitors vs. no NRT inhibitorsc	1.43	1.05, 1.95	0.023
Non-NRT inhibitors vs. no non-NRT inhibitorsc	2.22	1.76, 2.80	<0.001
Other antiretrovirals vs. no other antiretroviralsc	1.77	1.01, 3.13	<0.048
Time to virologic failure
Gender: females vs. males	1.06	0.85, 1.33	0.612
Baseline detectable viremia ≥500 copies/ml, yes vs. no	2.93	2.36, 3.64	<0.001
Germany vs. France	0.95	0.76, 1.20	0.674
Sweden vs. France	1.63	1.25, 2.13	<0.001
Protease inhibitors vs. no protease inhibitorsc	1.96	1.56, 2.47	<0.001
NRT inhibitors vs. no NRT inhibitorsc	1.97	1.27, 3.07	0.003
Non-NRT inhibitors vs. no non-NRT inhibitorsc	1.51	1.09, 2.11	0.014
Baseline CD4 count, <200 cells/μl vs. ≥200 cells/μl	1.56	1.26, 1.98	<0.001

^aNumber (%) of patients used in the model, 1262 (98%).

^bCovariate adjusted hazard ratio of time to discontinuation or virologic failure. Only significant variables (p-value <0.05) were included with the exception of gender and detectable viremia, which were known to be significant and so have been forced into the model. The model was rerun with only those variables kept in the final model using backward elimination, thus maximizing the number of patients used in the analysis.

^cUse as the last concomitant therapy (that is the last class of treatment recorded in combination with ATV/r before discontinuation).

CI, confidence interval; NRT, nucleoside reverse transcriptase.