Yield of tuberculosis screening among people with diabetes

Abstract

Diabetes is one of the fastest growing global health issues. Around 10% of the world has diabetes but it is expected that in 2045 there will be 800 million patients, mostly with type 2 diabetes. Because people are getting older and type 2 diabetes risk increases with age, this number increases so quickly. In developing countries, this rise of diabetes is happening even faster. Health systems need to adapt to this development. In 2021, almost half of people with diabetes were unaware they had the condition. This means we need to prevent and better manage chronic conditions such as diabetes. People with diabetes are more at risk of getting infectious diseases, such as tuberculosis. It is also more likely that they will suffer from poor disease and treatment outcomes. About a quarter of the world is infected with tuberculosis. To lower this number, we must prevent the disease from spreading. One suggested strategy is early detection of tuberculosis cases by screening. Since people with diabetes have a higher risk of developing disease and poor outcomes, it might be beneficial to screen them for tuberculosis. In this review, I assess how many cases are found when people with diabetes are screened for tuberculosis. The World Health Organization recommends several screening and diagnostic tests for accurate diagnosis. People can be screened using a tuberculosis-symptom questionnaire, chest-X-ray or bacteriological tests. I searched databases for recent studies that conducted screening programs among people with diabetes and then assessed how many tuberculosis cases these programs yielded. There were large differences among the eight included studies in design of screening programs and tests used. Most studies used a parallel screening program, where two different screening tests are done at the same time, usually chest-X-ray and symptom screening. After, people with possible tuberculosis are referred for bacteriological tests to confirm tuberculosis infection. The yield of screening was very low, but there were differences based on how high the tuberculosis burden is in the country. It ranged from 1 case per 10,000 people screened to 270 per 10,000. This suggests that it is probably not cost-effective and efficient to screen all people with diabetes for tuberculosis. For example, screening could for example only been done in people with diabetes with additional risk factors, such as poorly controlled glucose levels, or in countries where tuberculosis is more common. There are benefits of screening, such as early detection to prevent the disease from spreading and treating infected people adequately. However, there are also disadvantages, such as diagnosing people falsely due to incorrect tests results, which may lead to stress and unnecessary treatment. Screening is also high cost and labor intensive. Due to the low yield and unclear risk-benefit ratio of screening, future research should therefore assess what the best approach is for screening people with diabetes for tuberculosis. It might not be feasible to screen all people with diabetes, but cost-effectiveness studies should compare different approaches to screening, for example based on the risk of tuberculosis and poor outcomes.