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The impact of response to the results of diagnostic tests for malaria: cost-benefit analysis

BMJ 2008; 336 doi: https://doi.org/10.1136/bmj.39395.696065.47 (Published 24 January 2008) Cite this as: BMJ 2008;336:202
  1. Yoel Lubell, health economist1,
  2. Hugh Reyburn, clinical senior lecturer2,
  3. Hilda Mbakilwa, clinical officer3,
  4. Rose Mwangi, social scientist3,
  5. Semkini Chonya, data manager3,
  6. Christopher J M Whitty, professor of international health2,
  7. Anne Mills, professor of health economics1
  1. 1Health Economics and Financing Programme, Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London WC1E 7HT
  2. 2Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine
  3. 3Joint Malaria Programme, Kilimanjaro Christian Medical Centre, PO Box 2228, Moshi, Tanzania
  1. Correspondence to: Y Lubell yoel.lubell{at}lshtm.ac.uk
  • Accepted 25 October 2007

Abstract

Objective Rapid diagnostic tests for malaria seem cost effective in standard analyses, but these do not take account of clinicians’ response to test results. This study tested the impact of clinicians’ response to rapid diagnostic test or microscopy results on the costs and benefits of testing at different levels of malaria transmission and in different age groups.

Design Cost-benefit analysis using a decision tree model and clinical data on the effectiveness of diagnostic tests for malaria, their costs, and clinicians’ response to test results.

Setting Tanzania.

Methods Data were obtained from a clinical trial of 2425 patients carried out in three settings of varying transmission.

Results At moderate and low levels of malaria transmission, rapid diagnostic tests were more cost beneficial than microscopy, and both more so than presumptive treatment, but only where response was consistent with test results. At the levels of prescription of antimalarial drugs to patients with negative tests that have been found in observational studies and trials, neither test methodis likely to be cost beneficial, incurring costs 10-250% higher, depending on transmission rate, than would have been the case with fully consistent responses to all test results. Microscopy becomes more cost beneficial than rapid diagnostic tests when its sensitivity under operational conditions approaches that of rapid diagnostic tests.

Conclusions Improving diagnostic methods, including rapid diagnostic tests, can reduce costs and enhance the benefits of effective antimalarial drugs, but only if the consistency of response to test results is also improved. Investing in methods to improve rational response to tests is essential. Economic evaluations of diagnostic tests should take into account whether clinicians’ response is consistent with test results.

Footnotes

  • The trial was sponsored by the Gates Malaria Partnership with funds from the Bill & Melinda Gates Foundation. It is part of the Joint Malaria Programme of NE Tanzania, a collaboration between the National Institute for Medical Research in Tanzania, Kilimanjaro Christian Medical Centre, London School of Hygiene and Tropical Medicine, and the University of Copenhagen. Alan Minja, Kereja Mlay, and Rajabu Malahiyo were key hospital staff in each site. Anna Mtei, Emmanuel Mwakasungula, Lilian Ngowi, Boniface Njau, Yustina Mushi, Happiness Manaso, Mary Urio, and Nico Funga collected the outpatient data. Magdalena Massawe, James Kalabashanga, and Hatibu Athumani read research blood films. Thanks to all the patients and staff in study sites for their support and participation.

  • Contributors: HR, CJMW, HM and RM facilitated the trial and data collection; Raimos Olomi contributed to the study design; SC was responsible for data management and primary analysis; YL and AM conducted the economic analysis; YL, HR, CJMW and AM wrote the initial draft; all authors contributed to the writing of the final manuscript. YL and AM are guarantors.

  • Competing interests: None declared.

  • Ethical approval: Ethics committees of the National Institute for Medical Research, Tanzania, and the London School of Hygiene and Tropical Medicine.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Accepted 25 October 2007
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