Simple screening tool detects many more cases of tuberculosis

Disease and treatment 21. may 2021 2 min Associate professor, Staff Specialist Christian Morberg Wejse Written by Kristian Sjøgren

A simple screening tool developed in Denmark can detect four times more people with tuberculosis (TB) than previously. The tool can save many lives in low-income countries, says a researcher.

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Although Denmark has fewer cases of TB, some countries have many. Until COVID-19 arrived, the world’s deadliest disease was TB, which is caused by Mycobacterium tuberculosis.

New research in Denmark shows that a simple screening tool detects many more people with TB so that they can get treated – and survive.

The screening tool, developed by researchers at Aarhus University and Aarhus University Hospital and others and tested in Ethiopia and Guinea-Bissau, detects four times as many cases of TB than previous methods, presenting many more opportunities for treating them before TB becomes serious – and may kill them.

“TB is the infectious disease that kills the most people worldwide and so much work still needs to be done to reduce infection. Doctors in many countries need to be better equipped to detect people with TB, and our screening tool can help,” explains a researcher behind the new study, Christian Wejse, Associate Professor, Aarhus University and Staff Specialist, Aarhus University Hospital.

The research results have been published in the International Journal of Infectious Diseases.

TB killed nearly as many people as COVID-19 in 2020

In Denmark, 300–400 people per year develop TB. Fortunately, Denmark has excellent treatment options, but the mortality rate is still 5%.

However, the situation is completely different in countries in Africa and Asia. Globally, ten million people develop TB annually, and 1.3 million people died from it in 2020. This was nearly the same as the number of people dying with COVID-19, which has disrupted the whole world.

One challenge in reducing the number of people dying from TB is access to treatment, but an equally great challenge is diagnosis, and here the new results can be useful.

“Many countries have overburdened healthcare systems with insufficient resources to thoroughly examine people with a slight cough and fever. This normally just triggers a diagnosis of pneumonia and then people can have untreated TB for a long time,” says Christian Wejse.

Difficult to diagnose

Diagnosing TB requires doctors to suspect TB. However, the symptoms do not greatly differ from those of many other diseases: cough, weight loss, shortness of breath and a slight fever. These symptoms are insidious, so doctors need to diagnose by examining a sputum sample, mostly available under a microscope, or by more advanced methods.

However, referral for microscopy is rare in many healthcare systems because of insufficient resources.

“A systematic approach is therefore required to enable doctors to identify signs of TB more rapidly and then refer patients for further investigation,” explains Christian Wejse.

After examination and diagnosis, treatment is long term with four types of antibiotics but is fortunately so inexpensive that most countries can afford it.

Scoring system identifies TB

The new tool systematizes and simplifies diagnosis.

The researchers studied a TB scoring system through a randomized trial with doctors in Ethiopia and Guinea-Bissau in hospitals and clinics.

The doctors examined people who might have TB for nine symptoms and signs, including cough, fever and weight loss. For example, people with very low weight or thin arms get two points and other more discrete symptoms and signs get one point. The doctor then calculates the score, and patients who score 3 or more points are referred for further investigation of TB.

“This score systematically ensures that doctors examine the patients and also investigate some more discrete symptoms and signs that are not usually linked to TB, and more people are therefore referred for further investigation,” says Christian Wejse.

Success in Ethiopia – but not in Guinea-Bissau

The trial in Ethiopia was very successful, with many clinics using the scoring system for 2 years. The system increased the percentage of clinic attendees diagnosed with TB from 1% to 4%.

“This is a very satisfactory result. The study emphasizes that finding the patients with the relevant symptoms and signs and ensuring that they are examined will actually detect more people with TB and ensure that they receive the necessary treatment,” explains Christian Wejse.

However, the results in Guinea-Bissau also showed that a scoring system is not enough. The doctors could not keep up with the number of cases referred for investigation of TB.

“They did not detect more people with TB because they did not examine them further. We therefore conclude that this scoring system can help in countries with a reasonably well-functioning healthcare system that can easily be scaled up , whereas countries with overburdened healthcare systems need more initiatives to detect and treat more people with TB,” concludes Christian Wejse.

Increasing smear positive tuberculosis detection using a clinical score – A stepped wedge multicenter trial from Africa” has been published in the International Journal of Infectious Diseases. In 2015, the Novo Nordisk Foundation awarded a grant to Christian Wejse for the project Clinical Scoring Tool for Point-of-care Diagnosis of Tuberculosis – ClinPOC-TB.

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