Killing two birds with one stone: Eliminating tuberculosis while saving money

A study led by a team at the RI-MUHC suggests that expanding the use of preventive tuberculosis treatments would be economically viable, particularly in low-income countries where there are also many people living with HIV.

It is estimated that one in four people in the world is infected with tuberculosis (TB) either in its active or latent form. In its fight to eradicate the disease, the World Health Organization (WHO) has established a strategy that focuses on preventive treatment for TB, particularly targeting vulnerable groups such as people infected with the human immunodeficiency virus (HIV) and close contacts of people who have tuberculosis. However, this strategy, which requires some investment, has not yet been deployed to its full potential.

From this perspective, the team of Dr. Kevin Schwartzman, Director of the Division of Respiratory Medicine at the McGill University Health Centre (MUHC) and Senior Scientist in the Translational Research Program in Respiratory Diseases at the Research Institute of the MUHC (RI-MUHC), conducted an economic evaluation of preventive treatments based on their efficacy when offered to certain at-risk populations. The results of their study, recently published in PLOS Medicine, indicate that in addition to reducing the occurrence of the disease and saving lives, this strategy would result in a reduction in the costs associated with TB.

“Until recently, in many countries, the use of preventive treatment in at-risk groups was considered too expensive and too complicated to undertake," says Dr. Schwartzman, also a professor in the Department of Medicine at McGill University. “But we know that to stop the tuberculosis epidemic, we need to not only treat people with the disease, but also offer preventive treatment to people with dormant infection, so they don't get sick and continue to spread the bacteria."

An economic approach

The research team calculated the net costs and cost-effectiveness of various existing and potential preventive drug regimens, called “minimal” or “optimal”, as assessed by a WHO-commissioned expert panel. The “minimal” regimen reflected the best preventive regimens used primarily in higher-income countries, with respect to duration and efficacy, while the “optimal” regimen reflected desired characteristics of newer preventive regimens now being developed and tested. The team estimated how much it would cost to provide these regimens to people living with HIV and people living in the same household as people with TB, in various epidemiological settings, and what benefits would result. To do this, the research team conducted TB transmission simulations to project morbidity and mortality levels and disease-related costs from 2020 to 2035. These projections were conducted for Brazil and South Africa, settings with different levels of TB transmission, HIV-TB co-infection and rifampin-resistant TB, an antibiotic-resistant TB that is particularly difficult to treat.

In Brazil, where the transmission rate of TB is relatively low, as is the number of people living with HIV, expanding optimal preventive treatment to target groups would reduce the number of years of full health lost due to premature mortality, disability and TB-related health problems by nine per cent.

In South Africa, where TB has a high transmission rate and HIV has a higher prevalence, the use of optimal preventive treatments for the target populations would reduce the number of years of full health lost by 38 per cent.

Furthermore, in both countries it would be cost-effective to offer a preventive treatment regimen to the targeted groups, whether minimal or optimal; however, an optimal regimen would in fact generate cost savings.

“Even with a higher initial cost, an optimal regimen – one with shorter duration and better efficacy – would yield additional cost savings and health gains in a variety of epidemiologic settings,” says Dr. Schwartzman. “This is why we need to invest in research and development of new TB treatment regimens.”

The study was conducted in collaboration with researchers from McGill University, Imperial College London in the United Kingdom, the Institut de recherche pour le développement de Montpellier in France, the Federal University of Rio de Janeiro in Brazil, and the WHO Global TB Program.