Purpose: This study aimed to assess the cost-effectiveness and -utility of different frequencies of monitoring viral load of HIV-positive children initiating antiretroviral treatment (ART) in a resource-limited setting.
Method: An agent-based simulation model of virological and immunological outcomes of HIV-infected children on ART was built and directly informed by a longitudinal cohort study of 304 HIV-infected children starting ART in Thailand between October 2001 and May 2009. Rates of virological failure, suppression, and rebound, as well as CD4 progression, on first- and second-line ART were captured in the cohort and represented by the model. The model simulated expected clinical outcomes of CD4 percentage (CD4%) and viral load over time among children on ART according to different frequencies of viral load monitoring and initiation of second-line therapies where appropriate. Cost-utility, expressed as cost per quality adjusted life-years (QALYs) saved, and cost-effectiveness, expressed as cost per year of virological failure averted was calculated across 11 monitoring frequencies.
Result: Compared with the status quo, of no viral load monitoring, all frequencies of monitoring and access to second-line ART led to significant reductions in the number of children failing ART after 10 years. A single screening during the first year of ART led to an estimated 43.9% reduction in ART failures after 10 years, with repeated viral load monitoring leading to an average 75.1% reduction. The cost per year of virological failure averted, including antiretroviral drug costs, ranged from US$2,332 (IQR: US$2,311−US$2,365) for a one-off screening 30 weeks after the initiation of ART to US$4,098 (IQR: US$4,057−US$4,134) for screening children every 6 months. Most individuals initiated first-line treatment with a low CD4% and recovered immunologically regardless of monitoring frequency; therefore only a modest gain in QALYs was observed. The incremental cost per QALY gained, attributed to monitoring alone, ranged from US$1,109 (IQR: US$859−US$1,557) for a one-off screening during the first year of ART to US$15,817 (IQR: US$13,961−US$19,855) for screening children every 6 months.
Conclusion: Even very infrequent viral load monitoring is likely to provide substantial clinical benefit to HIV-infected children on ART and be moderately cost-effective. Without access to second-line drugs and regular viral load monitoring the current efficiency of first-line therapies is likely to be compromised, ultimately leading to a reduction in future drug options for Thailand’s population.
Candidate for the Lee B. Lusted Student Prize Competition