Model parameters and data sources.

Distributions of times to event were assumed to be exponential, Weibull or double Weibull, based on the cohort data. Cohort data are from the Khayelitsha and Gugulethu ART programmes in Cape Town, South Africa, unless otherwise specified.
CI, confidence interval; ART, antiretroviral therapy; HR, hazard ratio; ASSA, Actuarial Society of South Africa; LTFU, loss to follow-up; n/a, not applicable.
*)Relative decrease in second-line efficacy per year spent on failing first-line ART.
**)Age-specific mortality rates.
***)Non-HIV related mortality estimated from the ASSA2008 model deducted from cohort data on all-cause mortality.
****)Weighted sum of two Weibull distributions.
*****)Data from Ministry of Health-Centre for Infectious Disease Research in Zambia.