Should countries implementing an artemisinin-based combination malaria treatment policy also introduce rapid diagnostic tests?

Abstract

Background: Within the context of increasing antimalarial costs and or decreasing malaria transmission, the importance of limiting antimalarial treatment to only those confirmed as having malaria parasites becomes paramount. This motivates for this assessment of the cost-effectiveness of routine use of rapid diagnostic tests (RDTs) as an integral part of deploying artemisinin-based combination therapies (ACTs).

Methods: The costs and cost-effectiveness of using RDTs to limit the use of ACTs to those who actually have Plasmodium falciparum parasitaemia in two districts in southern Mozambique were assessed. To evaluate the potential impact of introducing definitive diagnosis using RDTs (costing $0.95), five scenarios were considered, assuming that the use of definitive diagnosis would find that between 25% and 75% of the clinically diagnosed malaria patients are confirmed to be parasitaemic. The base analysis compared two ACTs, artesunate plus sulfadoxine/pyrimethamine (AS+SP) costing $1.77 per adult treatment and artemether-lumefantrine (AL) costing $2.40 per adult treatment, as well as the option of restricting RDT use to only those older than six years. Sensitivity analyses considered lower cost ACTs and RDTs and different population age distributions.

Results: Compared to treating patients on the basis of clinical diagnosis, the use of RDTs in all clinically diagnosed malaria cases results in cost savings only when 29% and 52% or less of all suspected malaria cases test positive for malaria and are treated with AS+SP and AL, respectively. These cut-off points increase to 41.5% (for AS+SP) and to 74% (for AL) when the use of RDTs is restricted to only those older than six years of age. When 25% of clinically diagnosed patients are RDT positive and treated using AL, there are cost savings per malaria positive patient treated of up to $2.12. When more than 29% of clinically diagnosed cases are malaria test positive, the incremental cost per malaria positive patient treated is less than US$1. When relatively less expensive ACTs are introduced (e.g. current WHO preferential price for AL of $1.44 per adult treatment), the RDT price to the healthcare provider should be $0.65 or lower for RDTs to be cost saving in populations with between 30 and 52% of clinically diagnosed malaria cases being malaria test positive.

Conclusion: While the use of RDTs in all suspected cases has been shown to be cost-saving when parasite prevalence among clinically diagnosed malaria cases is low to moderate, findings show that targeting RDTs at the group older than six years and treating children less than six years on the basis of clinical diagnosis is even more cost-saving. In semi-immune populations, young children carry the highest risk of severe malaria and many healthcare providers would find it harder to deny antimalarials to those who test negative in this age group.

Figure 1

Total cost of antimalarials and RDTs: comparing clinical and definitive diagnosis.

Figure 2

Incremental costs (or cost savings) associated with use of RDTs when malaria is confirmed in varying proportions of patients for two ACTs (artesunate plus sulfadoxine-pyrimethamine and artemether-lumefantrine); excluding 'other recurrent costs'.

Figure 3

Incremental costs of using RDTs per malaria positive patient treated (base case): based on total costs of RDT and antimalarials (artesunate plus sulfadoxine-pyrimethamine and artemether-lumefantrine) when all suspected malaria cases are tested.

Figure 4

Impact of changes in age distribution of suspected malaria cases on incremental cost per malaria patient treated.

Figure 5

Impact of changes in age distribution of suspected malaria cases on incremental costs of RDTs + antimalarials (excluding other recurrent costs).

Figure 6

Impact of changes in price of RDTs on Incremental cost per patient treated and total incremental costs.

Figure 7

Multi-way sensitivity analyses: Incremental cost per malaria patient treated.