Cost Effectiveness of Repeat HIV Voluntary Counseling and Testing Strategies in Africa
T Reeves1, J Ostermann2,3, J Bartlett1,2,4,5, N Thielman1,2, D Itemba6, and John Crump*1,2,4,5
1Duke Univ Med Ctr, Durham, NC, US; 2Duke Global Hlth Inst, Durham, NC, US; 3Duke Univ, Durham, NC, US; 4Kilimanjaro Christian Med Ctr, Moshi, Tanzania; 5Kilimanjaro Christian Med coll, Moshi, Tanzania; and 6Kilimanjaro Women`s Group Against AIDS, Moshi, Tanzania
Background: HIV voluntary counseling and testing
(VCT) is promoted to increase serostatus awareness and entry into care and
treatment. However, in Africa there is little guidance on whether and how often
repeat testing should be done for those who test negative. Tanzanian VCT
guidelines recommend a single repeat test after 3 months, a policy suited to
the concept of a single exposure. To inform allocation of VCT resources, we
evaluated the cost-effectiveness of alternative repeat testing strategies under
various HIV incidence scenarios.
Methods: We modeled 20-year survival, HIV treatment
costs, and cost of VCT for 3 hypothetical cohorts of 10,000 persons each with HIV
incidence rates of 0.1% (low), 0.5% (medium), and 2.0% (high), respectively. Estimates
of CD4 count decline, treatment failure, mortality, and cost with and without
treatment from Tanzania were used. Marginal costs per case identified were
compared to first-time testing in a previously untested population. Costs and
benefits were discounted at 3% per year.
Results: Under current Tanzania VCT guidelines with
repeat testing after 3 months the cost per case identified from repeat testing ranges
from US$3908 to $28,666 in high- and low-incidence populations, respectively.
Changing the repeat testing interval to 1 year reduces the cost per case to $2914
at high and $8887 at low incidence. An interval of 5 years reduces cost per case
to as low as $2500 in the high incidence population (table).
Conclusions: While beneficial relative to 1-time
testing, the Tanzania strategy of a single repeat test after 3 months is costly,
particularly in low-incidence populations. At the population level repeat
testing at longer intervals is more cost effective. An extension of repeat
testing intervals in low-incidence populations results in the greatest absolute
reduction in cost per case identified. We suggest that testing policies in
countries with generalized epidemics should advocate not only for universal
testing, but also for regular repeat testing. Our data demonstrate the benefits
of tailoring testing intervals to HIV prevalence and incidence in local populations
and provide guidance on the costs of alternative repeat VCT strategies.