Early clinical and programmatic outcomes with tenofovir-based antiretroviral therapy in Zambia

Abstract

Background: In July 2007, amid some controversy over cost, Zambia was the first African country to introduce tenofovir (TDF) as a component of first-line antiretroviral therapy (ART) on a wide scale.

Methods: We compared drug substitutions, mortality, and "programmatic failure" among adults starting TDF-, zidovudine (ZDV)-, and stavudine (d4T)-containing ART. Programmatic failure was defined as death, withdrawal, or loss to follow-up.

Results: Between July 2007 and January 2009, 10,485 adults initiated ART (66% on TDF, 23% on ZDV, 11% on d4T), with a median follow-up time of 239 (interquartile range 98, 385) days. Those starting TDF were more likely to be male and more likely to have indicators of severe disease at baseline. In adjusted Cox proportional hazards models, ZDV- (adjusted hazard ratio [AHR] = 2.74, 95% confidence interval [CI] = 2.30-3.28) and d4T-based regimens (AHR = 1.92, 95% CI = 1.55-2.38) were associated with higher risk for drug substitution when compared with TDF-based regimens. Similar hazards were noted for overall mortality (ZDV: AHR = 0 .81, 95% CI = 0.62-1.06; d4T: AHR = 1.03, 95% CI = 0.74-1.43) and programmatic failure (ZDV: AHR = 0.99, 95% CI = 0.88-1.11; d4T: AHR = 1.11, 95% CI = 0.96-1.28) when compared with TDF.

Conclusions: TDF is associated with similar clinical and programmatic outcomes as ZDV and d4T but appears to be better tolerated. Although further evaluation is needed, these results are encouraging and support Zambia's policy decision.

Figure 1

HIV-infected adults initiating antiretroviral therapy across 18 Lusaka primary care sites from July 1, 2007 to January 31, 2009

Figure 2

Numbers of HIV-infected adults initiated on each of the three primary nucleoside reverse transcriptase inhibitor backbones for antiretroviral therapy from July 1, 2007 to January 31, 2009.

Figure 3

Kaplan-Meier analysis describing over time drug substitution (A), mortality (B), and “program failure” (C), stratified by initially prescribed nucleoside reverse transcriptase inhibitor backbones for antiretroviral therapy. Program failure comprised mortality, program withdrawals, and follow-up losses.

Figure 3

Kaplan-Meier analysis describing over time drug substitution (A), mortality (B), and “program failure” (C), stratified by initially prescribed nucleoside reverse transcriptase inhibitor backbones for antiretroviral therapy. Program failure comprised mortality, program withdrawals, and follow-up losses.

Figure 3

Kaplan-Meier analysis describing over time drug substitution (A), mortality (B), and “program failure” (C), stratified by initially prescribed nucleoside reverse transcriptase inhibitor backbones for antiretroviral therapy. Program failure comprised mortality, program withdrawals, and follow-up losses.