Unraveling the consequences: COVID-19's devastating effect on the TB care cascade

In a recent pre-print posted to the medRxiv* server, researchers conducted a systematic review to evaluate the impact of coronavirus disease 2019 on the tuberculosis care cascade. They screened 27 studies across North America, South America, Asia, Africa, and Europe.

The study found a significant decrease in tuberculosis screening, hospital enrolment, and treatment success, as well as substantial increases in diagnosis duration during the pandemic compared to the year preceding its onset.

Study: Impact of COVID-19 on the cascade of care for tuberculosis: A systematic review. Image Credit: HelenaNechaeva/Shutterstock.comStudy: Impact of COVID-19 on the cascade of care for tuberculosis: A systematic review. Image Credit: HelenaNechaeva/Shutterstock.com

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Tuberculosis during the pandemic

Tuberculosis (TB) is one of the most ubiquitous and deadly diseases globally, responsible for an estimated 1.8 billion asymptomatic carriers, 10.6 million symptomatic patients, and 1.5 million casualties in 2018.

It mainly impacts low-to-middle-income (LMIC) countries, including China, India, Indonesia, Pakistan, Nigeria, the Philippines, South Africa, and Bangladesh. TB primarily infects the lungs and is characterized by cough, severe weight loss, night sweats, and high fever.

To combat the global TB burden, the 67th World Health Assembly (2014) signed the End TB strategy, aimed at reducing TB mortality by 90% and TB incidence by 80% by 2030. While numerous countries undertook steps to meet End TB goals, the onset of the coronavirus disease 2019 (COVID-19) has severely hampered their efforts. These impacts have hitherto not been quantified within a scientific framework.

One of the most characteristic government responses to the COVID-19 pandemic was the implementation of policies that imposed lockdowns and movement restrictions. Many countries shifted medical priorities towards combating the pandemic, often at the expense of other disease interventions.

In LMICs, COVID-19 is thought to have impacted entire health systems, severely impacting care cascades in diseases such as TB and AIDS, which require constant contact between patients and medical professionals at all infection stages.

The TB care cascade, comprising screening, diagnosis, treatment (onset and subsequent completion), and post-treatment patient monitoring, was adapted from HIV interventions to ensure positive medical outcomes and prevent relapses in TB patients. High TB burden countries, including India and South Africa, have even incorporated the TB care cascade into their national strategic policies.

However, the onset of COVID-19 is thought to have caused global disruptions in these policies, primarily due to patient movement restrictions and the re-deployment of medical caregivers and their allied health professionals to the care of pandemic patients.

While previous research has attempted to document the impacts of the COVID-19 outbreak on TB care cascade components, their results remain contradictory and inconclusive. Scientist postulate that this might be due to the country-specific differences in COVID-19 impacts and responses.

Repercussions of COVID-19 on TB care – a review

In the present pre-print, researchers conducted a systematic review to quantify the impacts of the pandemic on delaying or even reversing the global effort toward the End TB strategy.

Their methodology was modeled after the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and began by screening Scopus, PubMed, CINAHL, COCHRANE, and Ebscohost for previous literature on TB care before and during the pandemic.

Criteria for study inclusion comprised research wherein quantitative changes in TB screen, diagnosis, and treatment were reported for at least one year preceding the pandemic and one year during COVID-19. Reviews, case studies, qualitative publications, and letters to the editor were excluded.

Of the 7,855 records originally found, screening cascades of duplicate removal, title, and abstract screening, and finally, full-text screening yielded 27 publications used in the review.

Two researchers then independently extracted data about changes in the number of patients processed through the TB care cascade and included characterization of the loss to follow-up, potential patients not evaluated, and TB-related or suspected deaths during the pandemic.

Study findings

The 27 studies included in the pre-print review covered seven countries from Africa, 15 from Asia, two from South America, two from North America, and 46 from Europe. Results from the study suggest that the pandemic contributed to significant decreases in TB screening, diagnosis, treatment enrolment, and retention.

Tuberculosis screening decreased by almost 50% in some nations, with multidrug-resistant TB (MDR-TB) reducing by 15%–17%. 

“It is worth noting that decreases in TB and MDR TB screening could have multiple adverse effects on the health system due to lengthened case detection gap, diagnostic delay, and decreased linkage to care. This may result in increasing TB prevalence, community transmission and incidence.”

This study found that clinical TB diagnoses decreased by up to 46% and case notifications by more than 63% during the pandemic. The pandemic caused treatment delays of more than five days, which, when clubbed with reduced treatment success rates (17%), might have had severe repercussions on TB-related morbidity and mortality.

The study has notable limitations – results could not be compared to prior research, as no other reviews or meta-analyses on the implications of COVID-19 on TB care cascades exist. Contextual differences in reviewed studies, some of which have very small sample sizes, prevented statistical meta-analysis from being conducted.

Finally, many studies failed to report temporal population sizes, preventing analysis from standardizing results between nations.

Conclusions

In the present pre-print, researchers utilized PRISMA methodologies to attempt to quantify the impact of the COVID-19 pandemic on the TB care cascade.

Their results suggest significant delays in TB treatment and reductions in all aspects of the cascade (screening, patient enrolment, post-treatment follow-up), which seemingly halted or even reversed global progress toward the World Health Assembly’s End TB plan.

“…findings suggest a need for policies to protect the existing healthcare systems for TB and other communicable, (and, by extension, non-communicable) diseases in future health emergencies.”

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Hugo Francisco de Souza

Written by

Hugo Francisco de Souza

Hugo Francisco de Souza is a scientific writer based in Bangalore, Karnataka, India. His academic passions lie in biogeography, evolutionary biology, and herpetology. He is currently pursuing his Ph.D. from the Centre for Ecological Sciences, Indian Institute of Science, where he studies the origins, dispersal, and speciation of wetland-associated snakes. Hugo has received, amongst others, the DST-INSPIRE fellowship for his doctoral research and the Gold Medal from Pondicherry University for academic excellence during his Masters. His research has been published in high-impact peer-reviewed journals, including PLOS Neglected Tropical Diseases and Systematic Biology. When not working or writing, Hugo can be found consuming copious amounts of anime and manga, composing and making music with his bass guitar, shredding trails on his MTB, playing video games (he prefers the term ‘gaming’), or tinkering with all things tech.

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