Southeast Asian J Trop Med Public Health

This study was undertaken to compare cost-effectiveness of three drug regimes for treatment of uncomplicated falciparum malaria in Myanmar. The alternative regimens in this study were chloroquine (CQ), sulphadoxine-pyrimethamine (SP) and mefloquine (MFQ) along with their therapeutic efficacy in Myanmar. The study was performed by modeling a clinical decision tree based on a hypothetical 1,000 adult uncomplicated falciparum malaria cases. Key variables were (i) three drug regimes: CQ, SP and MFQ, (ii) three categories of therapeutic efficacy of each drug: adequate clinical response (ACR), early treatment failure (ETF) and late treatment failure (LTF) according to the 1996 WHO protocol, and (iii) compliance with each drug. In structuring the model, necessary assumptions were made. The cost effectiveness was measured as cost per case cured and cost per case prevented death related to the provided drug, from the provider’s perspective. According to the present price and therapeutic efficacy, SP is the most cost effective drug for a case cured in all three categories of efficacy (US$ 0.12 per case cured in ACR, US$ 0.38 per case cured in ETF and US$ 0.54 per case cured in LTF). For a case prevented death, CQ is most cost effective in all three categories (US$ 0.58 per case prevented death in the ACR, US$ 2.14 per case prevented death in the ETF and US$ 2.51 per case prevented death in the LTF). The lowest cost effective regimen is MFQ for both indicators of effectiveness at the present price and therapeutic efficacy. A sensitivity analysis was performed for sensitive values. Correspondence: Dr Cho-Min-Naing. E-mail: [email protected] CLINICAL DECISION ANALYSIS IN MALARIA DRUG USAGE Vol 31 No. 2 June 2000 239 of all medical and public health services for malaria in the country (Kamol-Ratanakul et al, 1993). Structure of the model A model was constructed incorporating 1,000 hypothetical cases of adult uncomplicated falciparum malaria attending a public malaria clinic in Myanmar. These cases were confirmed by microscopy, the conventional diagnostic service. The decision was modeled by a decision tree, which is illustrated in Fig 1. A clinical decision tree is a schematic display of temporal and logical structure of a clinical situation in which one or more decisions must be made (Weinstein et al, 1980). In this study, the decision node represents the choice among three drug options and has three main branches. The initial decision, represented by the decision node (choice node) at the left of Fig 1 is three drug options for treatment of P. falciparum malaria: CQ (upper branch), SP (middle branch), and MFQ (lower branch). The related consequences depend upon the three categories of therapeutic efficacy, ACR, ETF and LTF. The further chance event modeled with probability of good compliance and poor compliance for the drugs provided. Dynamics of the model Key variables considered in the model and their estimates were as follows: 1. Three alternative treatment modalities were considered; CQ, SP and MFQ in line with their current efficacy categories in Myanmar. 2. States of therapeutic efficacy of antimalarials in Myanmar categorized as ACR, ETF and LTF were considered for model development. Probabilities of therapeutic efficacy of each drug were extracted from an empirical study in Myanmar (Ejov et al, 1999). 3. Since noncompliance is the surrogate index for cure (Honrado et al, 1999), estimates of cure are based on compliance with drugs prescribed formally. In the absence of recent country information on this aspect at the time of study, probabilities of compliance for antimalarial drugs provided were drawn from a literature survey of data from countries with situations similar to that in Myanmar. Table 1 presents the values used in the base case analysis.