Table 2.

Adjusted hazard ratios (with 95% confidence intervals) for clinical and programmatic outcomes by nucleoside reverse transcriptase inhibitor backbone for antiretroviral therapy in Lusaka, Zambia (July 1, 2007 to January 31, 2009)

	≤ 90 days	> 90 days	Overall
Drug substitution
TDF + FTC	Ref	Ref	Ref
ZDV + 3TC	6.92 (5.31 – 9.03)	1.08 (0.84 - 1.40)	2.74 (2.30 - 3.28)
d4T + 3TC	2.91 (2.05 - 4.13)	1.34 (1.01 - 1.76)	1.92 (1.55 - 2.38)
Mortality
TDF + FTC	Ref	Ref	Ref
ZDV + 3TC	0.80 (0.57 - 1.13)	0.67 (0.40 - 1.12)	0.81 (0.62 - 1.06)
d4T + 3TC	0.97 (0.63 - 1.50)	1.18 (0.66 - 2.11)	1.03 (0.74 - 1.43)
Programmatic failure
TDF + FTC	Ref	Ref	Ref
ZDV + 3TC	1.00 (0.84 - 1.19)	0.96 (0.82 - 1.13)	0.99 (0.88 - 1.11)
d4T + 3TC	1.10 (0.88 - 1.38)	1.21 (0.99 - 1.46)	1.11 (0.96 - 1.28)

All analyses adjusted for age, sex, body mass index, CD4 count, hemoglobin, World Health Organization clinical stage, serum creatinine, tuberculosis co-infection at enrollment, and third antiretroviral agent. Previous drug substitution and adherence also included in the post-90 day analysis. TDF = tenofovir, FTC = emtricitabine, ZDV = zidovudine, d4T = stavudine, 3TC = lamivudine.