Estimating the epidemiological and economic impact of providing nutritional care for tuberculosis-affected households across India: a modelling study

Abstract

Background: Approximately 20% of global tuberculosis incidence is attributable to undernutrition, increasing to more than a third in India. Targeting nutritional interventions to tuberculosis-affected households is a policy priority, but understanding of epidemiological and economic impacts is limited. We aimed to estimate the population-level epidemiological and economic effect of such an intervention.

Methods: We used a previously published, age-stratified, compartmental transmission model of tuberculosis in India, and incorporated explicit BMI strata linked to disease progression and treatment outcomes. We used results from a recent trial of an intervention in which nutritional support in the form of food baskets was provided to people initiating tuberculosis treatment and to their household contacts (1200 kcal for patients and 750 kcal for contacts) to inform estimates of the impact and costs of nutritional support. We estimated the numbers of cases of tuberculosis disease and deaths due to tuberculosis disease that could be averted from 2023 to 2035 under the intervention scenario.

Findings: Compared with a baseline with no nutritional intervention, at 50% coverage of adults on tuberculosis treatment and their households (around 23% of households affected by incident tuberculosis in India), providing the nutritional support intervention could prevent 361 200 (95% uncertainty interval 318 000-437 700) tuberculosis deaths and 880 700 (802 700-974 900) disease episodes from 2023 to 2035. This would be equivalent to averting approximately 4·6% (4·2-5·5) tuberculosis deaths and 2·2% (2·1-2·4) tuberculosis episodes. The additional health system cost would be US$1349 million (1221-1492), with an incremental cost-effectiveness ratio of $167 (147-187) per disability-adjusted life-year averted. The median number of households needed to treat to prevent one tuberculosis death was 24·4 and to prevent one tuberculosis case was 10·0.

Interpretation: A nutritional intervention for tuberculosis-affected households could avert a substantial amount of tuberculosis disease and death in India, and would be highly likely to be cost-effective on the basis of the tuberculosis-specific benefits alone.

Funding: None.

Translations: For the Bangla and Hindi translations of the abstract see Supplementary Materials section.

Figure 1

Cumulative proportions of tuberculosis disease cases prevented (A) and deaths averted (B) due to a nutritional support intervention in India between 2023 and 2035, assuming 2 years duration of protection, and considering different recipients and coverage of the intervention Intervention recipients considered were all individuals in tuberculosis-affected households (all), only household contacts of people with tuberculosis (contacts), or only patients with tuberculosis (patients). Intervention coverage specifies the proportion of coverage among adults with tuberculosis receiving treatment.

Figure 2

Number of households receiving the nutritional support intervention needed to prevent one person developing tuberculosis disease (A) and one tuberculosis death (B) in India between 2023 and 2035, with varying intervention coverage in adults on treatment NNTs are shown for 50% coverage; for other coverage levels, NNTs were the same to this level of rounding. NNT=number needed to treat.

Figure 3

Incremental cost-effectiveness of the nutritional support intervention for patients with tuberculosis (A) and for patients and their household contacts (B) from a health system perspective at 50% coverage Three willingness-to-pay thresholds are shown, based on 1 × Indian GDP per capita in 2022 ($2411); 23% of Indian GDP per capita ($555); and 17% of Indian GDP per capita ($410). DALYs=disability-adjusted life-years. GDP=gross domestic product.