Cost-effectiveness of COVID rapid diagnostic tests for patients with severe/critical illness in low- and middle-income countries: A modeling study.

Background: Rapid diagnostic tests (RDTs) for coronavirus disease (COVID) are used in low- and middle-income countries (LMICs) to inform treatment decisions. However, to date, it is unclear when this use is cost-effective. Existing analyses are limited to a narrow set of countries and uses. The aim of this study is to assess the cost-effectiveness of COVID RDTs to inform the treatment of patients with severe illness in LMICs, considering real world practice. Methods and findings: We assessed the cost-effectiveness of COVID testing across LMICs using a decision tree model, differentiating results by country income level, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) prevalence, and testing scenario (none, RDTs, polymerase chain reaction tests—PCRs and combinations). LMIC experts defined realistic care pathways and treatment options. Using a healthcare provider perspective and net monetary benefit approach, we assessed both intended (COVID symptom alleviation) and unintended (treatment side effects) health and economic impacts for each testing scenario. We included the side effects of corticosteroids, which are often the only available treatment for COVID. Because side effects depend both on the treatment and the patient's underlying illness (COVID or COVID-like illnesses, such as influenza), we considered the prevalence of COVID-like illnesses in our analyses. We found that SARS-CoV-2 testing of patients with severe COVID-like illness can be cost-effective in all LMICs, though only in some circumstances. High influenza prevalence among suspected COVID cases improves cost-effectiveness, since incorrectly provided corticosteroids may worsen influenza outcomes. In low- and some lower-middle-income countries, only patients with a high index of suspicion for COVID should be tested with RDTs, while other patients should be presumed to not have COVID. In some lower-middle-income and upper-middle-income countries, suspected severe COVID cases should almost always be tested. Further, in these settings, negative test results in patients with a high initial index of suspicion should be confirmed through PCR and, during influenza outbreaks, positive results in patients with a low initial index of suspicion should also be confirmed with a PCR. The use of interleukin-6 receptor blockers, when supported by testing, may also be cost-effective in higher-income LMICs. The cost at which they would be cost-effective in low-income countries ($162 to $406 per treatment course) is below current prices. The primary limitation of our analysis is substantial uncertainty around some of the parameters in our model due to limited data, most notably on current COVID mortality with standard of care, and insufficient evidence on the impact of corticosteroids on patients with severe influenza. Conclusions: COVID testing can be cost-effective to inform treatment of LMIC patients with severe COVID-like disease. The optimal algorithm is driven by country income level and health budgets, the level of suspicion that the patient may have COVID, and influenza prevalence. Further research to better characterize the unintended effects of corticosteroids, particularly on influenza cases, could improve decision making around the treatment of those with COVID-like symptoms in LMICs. Gabrielle Bonnet and team assess the cost-effectiveness of COVID testing across low-and-middle-income countries, differentiating results by country income level, SARS-CoV-2 prevalence and different testing scenarios. Author summary: Why was this study done?: The main role of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) testing has evolved from transmission reduction to informing the treatment of patients with most vulnerability or most severe illness. SARS-CoV-2 testing availability and use remains inconsistent in some low- and middle-income countries (LMICs), and understanding the cost-effectiveness of testing in such contexts may help guide priority setting and inform guidelines for health professionals. Research on the cost-effectiveness of SARS-CoV-2 testing in LMICs is limited. To our knowledge, no paper has considered both presumptive and symptomatic coronavirus disease (COVID) treatment as alternatives to testing, or has considered a range of treatment options reflective of LMIC contexts. What did the researchers do and find?: We used a decision tree model, health payer provider perspective and net monetary benefit approach to assess the cost-effectiveness of testing to support treatment for patients with severe/critical COVID-like illness in 129 LMICs, based on treatment pathways reported by experts working in LMICs. In low-income and the poorest of lower-middle-income countries, only patients with a high index of suspicion for COVID should be tested with rapid diagnostic tests. In the wealthiest among lower-middle-income countries and in upper-middle-income countries, testing of suspected severe COVID cases is almost always recommended. Polymerase chain reaction (PCR) confirmation of negative test results in patients with a high index of suspicion and, during influenza epidemics/outbreaks, of positive test results in patients with a low index of suspicion, is recommended. What do these findings mean?: COVID testing of patients with severe, COVID-like symptoms in LMICs can be cost-effective, provided sufficiently specific clinical screening algorithms can be used. Policymakers should consider both our study's results regarding variability between countries at a similar income level and its sensitivity analysis, particularly regarding country-specific factors, alongside other considerations such as local feasibility and equity, to inform national level decision-making. The main limitation of the study is uncertainty on some parameters, including current COVID case fatality risks and the impact of corticosteroids on patients with influenza. [ABSTRACT FROM AUTHOR]