Resources Repository
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ArticlePublication 2020Bayes' Theorem, COVID-19, and Screening Tests
This article reviews the implications of increased testing for COVID-19 using reverse transcriptase polymerase chain …
This article reviews the implications of increased testing for COVID-19 using reverse transcriptase polymerase chain reaction (rRT-PCR) through the application of Bayes’ Theorem for three hypothetical, stylized case scenarios. The scenarios involve three patients with a low, moderate, and high pre-test probability of COVID-19 infection. The category of low probability would include "asymptomatic individuals in a presumed low prevalence environment" and might vary from 10 to 20%. The category of moderate probability would include "individuals…
Test Performance | Health/Medicine | Probability/Bayes | Infectious Diseases | Clinical Care -
Tools/ModelsInteractive, Teaching Resource 2020Interactive Graphic: Interpreting a COVID-19 Test Result
Currently, the most common diagnostic test for COVID-19 relies on reverse transcriptase polymerase chain reaction …
Currently, the most common diagnostic test for COVID-19 relies on reverse transcriptase polymerase chain reaction (RT-PCR), and most often uses samples obtained from the respiratory tract by nasopharyngeal swab. This interactive graphic demonstrates the influence of the prior probability of COVID-19, the test sensitivity (i.e., the probability of a positive test conditional on disease presence), and the test specificity (i.e., the probability of a negative test conditional on disease absence) on the post-test probability of…
Test Performance | Health/Medicine | Probability/Bayes | Infectious Diseases | Clinical Care | Science/Technology | High School | College | Graduate | Doctoral | Professional | Graphics/Visualization | Quantitative Literacy -
ArticlePublication 2020Interpreting COVID-19 Test Results: A Bayesian Approach
This article considers the following question with respect to interpreting the results of polymerase chain reaction …
This article considers the following question with respect to interpreting the results of polymerase chain reaction (PCR) assays from nasal and pharyngeal swabs for COVID-19 to inform clinical decision making: "While a positive result in an acutely ill patient is straightforward, how should physicians interpret negative tests in patients with suspected COVID-19 infection?" Using an assumption of near-perfect specificity of PCR assays for COVID-19, the authors acknowledge the uncertainty of test sensitivity. They consider two clinical scenarios…
Test Performance | Health/Medicine | Probability/Bayes | Infectious Diseases | Science/Technology | Global -
ArticlePublication 2020Translating Population Evidence to Individual Patients
In this paper, the authors describe the differences in population level outcomes compared to individual …
In this paper, the authors describe the differences in population level outcomes compared to individual patients and discuss ways that these are differences. The authors cover topics including the difference between relative and absolute risk and benefit. They use an example of the decision to start anticoagulation in new-onset atrial fibrillation to discuss translating population level evidence to treatment of an individual. These options include generalizability, subgroup analysis, prediction rules, following response to therapy, and even…
Test Performance | Health/Medicine | Evidence Synthesis | Health Systems | Clinical Care -
ArticlePublication 2020Clinical Decision Making: Using a Diagnostic Test
This article is part of a 6-part series on clinical decision making. The authors use …
This article is part of a 6-part series on clinical decision making. The authors use two clinical examples to review the principles of interpreting diagnostic test results. They outline an approach that can be used to determine how to select and apply tests and their results to the practice of internal medicine. Topics covered in the two case studies include sensitivity and specificity, positive predictive and negative predictive value of tests, and how to estimate…
Test Performance | Health/Medicine | Probability/Bayes | Clinical Care -
ArticlePublication 2020Expanding Oral Disease Treatment is Cost Effective
This study developed a stochastic microsimulation model of oral health conditions, type-2 diabetes (T2D), T2D-related …
This study developed a stochastic microsimulation model of oral health conditions, type-2 diabetes (T2D), T2D-related microvascular diseases, and CVD, to project the cost-effectiveness of expanding periodontal treatment coverage among patients with T2D and periodontitis. Previous randomized trials found that treating periodontitis improved glycemic control in patients with type 2 diabetes (T2D), thus lowering the risks of developing T2D-related microvascular diseases and cardiovascular disease (CVD). The micro-simulation model parameters were obtained from the nationally representative National…
Microsimulation | Health/Medicine | Mathematical Models | Calibration/Validation | Cost-Effectiveness Analysis | Chronic Disease/Risk | North America | Graduate -
ArticlePublication 2019Measuring Progress Towards Universal Health Coverage
This article, published in BMJ Global Health, aims to estimate the 2015 national and subnational …
This article, published in BMJ Global Health, aims to estimate the 2015 national and subnational universal health coverage (UHC) service coverage status for Ethiopia. The UHC service coverage index is constructed from the geometric means of component indicators: first, within each of four major categories and then across all components to obtain the final summary index. The authors estimate UHC service coverage at the subnational level using a variety of surveys and routinely collected administrative…
Test Performance | Health/Medicine | Health Systems | Sub-Saharan Africa -
ArticlePublication 2019Decision-Making for Universal Access to Tuberculosis Diagnosis In India
The authors evaluated the costs of centralized and decentralized testing for tuberculosis with Xpert MTB/RIF …
The authors evaluated the costs of centralized and decentralized testing for tuberculosis with Xpert MTB/RIF (Xpert), a WHO-endorsed test. They used an agent-based simulation of TB transmission in a hypothetical representative region in India to assess the impact and cost-effectiveness of various strategies to provide universal access to diagnosis and drug susceptibility testing (DST) for tuberculosis. The authors found that decentralization was most favorable compared to centralized testing when volume at decentralized facilities was high,…
Microsimulation | Health/Medicine | Cost-Effectiveness Analysis | Infectious Diseases | Asia & Pacific -
ArticlePublication 2019POC Diagnosis of TB With Truenat Assay: CEA for India's Public Sector
Using a microsimulation model, the authors compared four TB diagnostic strategies for HIV-negative adults with …
Using a microsimulation model, the authors compared four TB diagnostic strategies for HIV-negative adults with presumptive TB in order to evaluate the potential cost-effectiveness of strategies that incorporate Truenat, a molecular assay that rapidly detects TB and rifampicin-resistance. They projected life expectancy, costs, incremental cost-effectiveness ratios (ICERs), and 5-year budget impact of deploying Truenat POC in India's public sector. Used at the point-of-care in India, Truenat for TB diagnosis should improve linkage-to-care, increase life expectancy,…
Microsimulation | Health/Medicine | Cost-Effectiveness Analysis | Infectious Diseases | Asia & Pacific