Cost effectiveness calculations for the diagnosis and treatment of tuberculous meningitis.

This study illustrates how cost-effectiveness calculations provide help in decisions involving a choice between introduction of a new diagnostic procedure or a new therapy for a particular clinical problem. This type of problem is critical for areas where financial resources are limiting. Our analysis is centered on the value of diagnosis and treatment in tuberculous meningitis (Tbm) and, because of its importance to developing countries, our epidemiologic data were derived from India. When financial costs are ignored, the introduction of second line therapy (e.g., Rifampin) leads to more cures than does the introduction of even a perfect diagnostic test. However, diagnostic tests (e.g., the Bromide partition test or possibly radioassays) markedly improve case finding and to some extent increase cure rates. All affects vary markedly with the prevalence of tuberculous meningitis in the population under study. For example, net financial savings would occur were a perfect nuclear test available and conventional therapy used at a prevalence of Tbm of 30% whereas there would be a net loss if the prevalence rose to 80%. This study underscores the need for detailed studies on the radiobromide partition test and for the development of new diagnostic tests, perhaps a radioimmunoassay of either the acid fast bacillus or of an antibody to it.