Figure 1

Design of the cost-effectiveness model. *ART cost per quarter calculated as the average cost per ART year ($556) divided by four. This figure represents year one costs and is not subject to discounting. **Added lifetime cost per active ART patient is calculated by subtracting cumulative ART cost accrued during 2 model cycles from an overall cost of $6,118 per death averted, or the lifetime expenditure per patient (discounted at a rate of 3% and accounting for historical rates of second-line ART use). Cost estimates for ART and the switch rate from first to second-line treatment are from a PEPFAR-supported, program-wide cost-effectiveness analysis of 45 public and private-sector centers providing HIV treatment in Zambia between 2004 and 2008.