Patient- and population-level health consequences of discontinuing antiretroviral therapy in settings with inadequate HIV treatment availability

Table 1 Selected data for the individual-level model

Variable	Base case value	Reference(s)
Initial cohort characteristics
Mean age (SD) (yrs)	36.9 (9.2)	Touré et al. [18]
Gender distribution	70% female	Touré et al. [18]
Mean CD4 count (SD) (cells/μL)	140 (116)	Touré et al. [18]
Median HIV RNA (IQR) (log₁₀ copies/mL)	5.3 (4.8–5.8)	Seyler et al. [19]
First- and second-line antiretroviral efficacy*
HIV RNA suppression at 24 weeks	80.2%	Messou et al. [22]
CD4 count increase at 24 weeks (cells/μL)†	+152	Messou et al. [22]
Probability of discordant response	5%	Grabar et al. [16]
Loss to follow-up
18-month cumulative loss to follow-up	15%	Touré et al. [18]
Probability of returning to care if WHO stage IV event	50%	Assumption

SD standard deviation, WHO World Health Organization, NNRTI non-nucleoside reverse transcriptase inhibitor, PI protease inhibitor, IQR interquartile range.
*First-line antiretroviral therapy (ART) efficacy data were derived from the ACONDA cohort, in which 52% received an initial ART regimen of stavudine, lamivudine, and nevirapine; 22% received stavudine, lamivudine, and efavirenz; and 20% received zidovudine, lamivudine, and efavirenz (with the remaining 6% receiving other regimens). We assumed a dosing scheduled in accordance with WHO recommendations — 300 mg once daily (zidovudine), 150 mg twice daily (lamivudine), 30 mg twice daily (stavudine), 600 mg once daily (efavirenz), and 200 mg once daily (nevirapine). In the absence of data, we assumed that second-line ART suppression rates were identical to that for first-line ART.
†For first-line ART, CD4 count increases were 76 (standard deviation (SD) 19) cells/μL per month for months 1–2 and 4 (SD 1) cells/μL per month thereafter. We assumed similar CD4 response for second-line ART.