Modelling approaches for tuberculosis: are they realistic?
Authors: Sachin Atre
Journal: The Lancet Global Health (2017)

The Article by Nicolas Menzies and colleagues (November, 2016),1Menzies NA Gomez GB Bozzani F et al.Cost-effectiveness and resource implications of aggressive action on tuberculosis in China, India, and South Africa: a combined analysis of nine models.Lancet Glob Health. 2016; 4: e816-e826Summary Full Text Full Text PDF PubMed Scopus (58) Google Scholar based on a modelling approach, concludes that most tuberculosis control interventions in South Africa, China, and India are highly cost-effective. In this regard, I have a different viewpoint. Such modelling approaches are useful in countries where the data are reliable and predictions are precise. However, when applied to low-income or high-burden countries they face a fundamental problem that the reality substantially differs from the basic assumptions. The models rarely account for political determinants such as investments in the health sector, political disruptions, migration, poverty, and poor regulation of the private sector including private pharmacies, which are at the root of existing tuberculosis and emerging anti-tuberculosis drug resistance in the world. India, which carries the highest global burden of tuberculosis, only spends less than 1·5% of gross domestic product on health and a significant gap exists in the required and actual receipt of funding support.2Bloom BR Rethinking how to address the world's largest infectious killer in the world's largest country.J Public Health Pol. 2016; 37: 300-303Crossref PubMed Scopus (3) Google Scholar, 3Atre S Murray M Management and control of multidrug-resistant tuberculosis (MDR-TB): Addressing policy needs for India.J Public Health Pol. 2016; 37: 277-299Crossref PubMed Scopus (13) Google Scholar, 4The Global Fund To Fight AIDSTB and Malaria: Renewal score card IndiaTuberculosis.www.theglobalfund.org/ProgramDocuments/IND/Common/IDA-T-13_GSC_0_en/Google Scholar The ground-level staff handling the tuberculosis programme work are contractual and frequently face salary issues, which has a negative influence on their work performance. Some high-burden countries still do not have a mandatory tuberculosis notification policy and its enforcement remains weak in others.5Uplekar M Atre S Wells W et al.Mandatory TB notification in high incidence countries: Policy and practice.Eur Respir J. 2016; https://doi.org/10.1183/13993003.00956-2016Crossref PubMed Scopus (24) Google Scholar Many countries face temporary drug shortages and several behavioural factors are at the interface between the patient and the health system, which substantially influence tuberculosis diagnosis, treatment, and outcomes. Existing mathematical models rarely seem to capture these real-world scenarios, and one might see its reflection in the increased global burden of tuberculosis.6WHOGlobal tuberculosis report 2016.http://apps.who.int/iris/bitstream/10665/250441/1/9789241565394-eng.pdf?ua=1Date: 2016Google Scholar I declare no competing interests. Cost-effectiveness and resource implications of aggressive action on tuberculosis in China, India, and South Africa: a combined analysis of nine modelsExpansion of tuberculosis services seems cost-effective for high-burden countries and could generate substantial health and economic benefits for patients, although substantial new funding would be required. Further work to determine the optimal intervention mix for each country is necessary. Full-Text PDF Open AccessModelling approaches for tuberculosis: are they realistic? – Authors' replyIn his Correspondence on our paper,1 Sachin Atre describes factors that could reduce the impact of intensified tuberculosis control, and questions the usefulness of mathematical modelling that ignores these challenges. On these points we wholeheartedly agree. As part of this modelling collaboration, we took steps to ensure that modelled strategies reflected real-world constraints—to the extent possible, assumptions about uptake, retention, quality, and other factors influencing policy outcomes were based on empirical programme experience, and stakeholders from national tuberculosis control programmes were involved throughout to define realistic policy scenarios and review modelled results. Full-Text PDF Open Access