| 1. |
- Ball, Frank, et al.
(författare)
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Seven challenges for metapopulation models of epidemics, including households models
- 2015
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Ingår i: Epidemics. - : Elsevier BV. - 1755-4365 .- 1878-0067. ; 10, s. 63-67
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers metapopulation models in the general sense, i.e. where the population is partitioned into sub-populations (groups, patches,...), irrespective of the biological interpretation they have, e.g. spatially segregated large sub-populations, small households or hosts themselves modelled as populations of pathogens. This framework has traditionally provided an attractive approach to incorporating more realistic contact structure into epidemic models, since it often preserves analytic tractability (in stochastic as well as deterministic models) but also captures the most salient structural inhomogeneity in contact patterns in many applied contexts. Despite the progress that has been made in both the theory and application of such metapopulation models, we present here several major challenges that remain for future work, focusing on models that, in contrast to agent-based ones, are amenable to mathematical analysis. The challenges range from clarifying the usefulness of systems of weakly-coupled large sub-populations in modelling the spread of specific diseases to developing a theory for endemic models with household structure. They include also developing inferential methods for data on the emerging phase of epidemics, extending metapopulation models to more complex forms of human social structure, developing metapopulation models to reflect spatial population structure, developing computationally efficient methods for calculating key epidemiological model quantities, and integrating within- and between-host dynamics in models.
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| 2. |
- Calderone, Dario, et al.
(författare)
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Efficacy and Safety of Aspirin for Primary Cardiovascular Risk Prevention in Younger and Older Age : An Updated Systematic Review and Meta-analysis of 178,310 Subjects from 21 Randomized Studies.
- 2022
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Ingår i: Thrombosis and haemostasis. - : Georg Thieme Verlag KG. - 2567-689X .- 0340-6245. ; 122:03, s. 445-455
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The efficacy and safety of aspirin for primary cardiovascular disease (CVD) prevention is controversial. The aim of this study was to investigate the efficacy and safety of aspirin in subjects with no overt CVD, with a focus on age as a treatment modifier.METHODS AND RESULTS: Randomized trials comparing aspirin use versus no aspirin use or placebo were included. The primary efficacy outcome was all-cause death. The primary safety outcome was major bleeding. Secondary ischemic and bleeding outcomes were explored. Subgroup analyses were conducted to investigate the consistency of the effect sizes in studies including younger and older individuals, using a cut-off of 65 years. A total of 21 randomized trials including 173,810 individuals at a mean follow-up of 5.3 years were included. Compared with control, aspirin did not reduce significantly the risk of all-cause death (risk ratio: 0.96; 95% confidence interval: 0.92-1.00, p = 0.057). Major adverse cardiovascular events were significantly reduced by 11%, paralleled by significant reductions in myocardial infarction and transient ischemic attack. Major bleeding, intracranial hemorrhage, and gastrointestinal bleeding were significantly increased by aspirin. There was a significant age interaction for death (p for interaction = 0.007), with aspirin showing a statistically significant 7% relative benefit on all-cause death in studies including younger patients.CONCLUSION: The use of aspirin in subjects with no overt CVD was associated with a neutral effect on all-cause death and a modest lower risk of major cardiovascular events at the price of an increased risk in major bleeding. The benefit of aspirin might be more pronounced in younger individuals.
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| 3. |
- Laudani, Claudio, et al.
(författare)
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Short Duration of DAPT Versus De-Escalation After Percutaneous Coronary Intervention for Acute Coronary Syndromes
- 2022
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Ingår i: JACC. - : Elsevier BV. - 1936-8798 .- 1876-7605. ; 15:3, s. 268-277
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of this study was to compare short dual antiplatelet therapy (DAPT) and de-escalation in a network meta-analysis using standard DAPT as common comparator.BACKGROUND: In patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI), shortening DAPT and de-escalating to a lower potency regimen mitigate bleeding risk. These strategies have never been randomly compared.METHODS: Randomized trials of DAPT modulation strategies in patients with ACS undergoing PCI were identified. All cause death was the primary outcome. Secondary outcomes included net adverse cardiovascular events (NACE), major adverse cardiovascular events, and their components. Frequentist and Bayesian network meta-analyses were conducted. Treatments were ranked on the basis of posterior probability. Sensitivity analyses were performed to explore sources of heterogeneity.RESULTS: Twenty-nine studies encompassing 50,602 patients were included. The transitivity assumption was fulfilled. In the frequentist indirect comparison, the risk ratio (RR) for all-cause death was 0.98 (95% CI: 0.68-1.43). De-escalation reduced the risk for NACE (RR: 0.87; 95% CI: 0.70-0.94) and increased major bleeding (RR: 1.54; 95% CI: 1.07-2.21). These results were consistent in the Bayesian meta-analysis. De-escalation displayed a >95% probability to rank first for NACE, myocardial infarction, stroke, stent thrombosis, and minor bleeding, while short DAPT ranked first for major bleeding. These findings were consistent in node-split and multiple sensitivity analyses.CONCLUSIONS: In patients with ACS undergoing PCI, there was no difference in all-cause death between short DAPT and de-escalation. De-escalation reduced the risk for NACE, while short DAPT decreased major bleeding. These data characterize 2 contemporary strategies to personalize DAPT on the basis of treatment objectives and risk profile.
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| 4. |
- Marion, Glenn, et al.
(författare)
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Modelling : Understanding pandemics and how to control them
- 2022
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Ingår i: Epidemics. - : Elsevier BV. - 1755-4365 .- 1878-0067. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- New disease challenges, societal demands and better or novel types of data, drive innovations in the structure, formulation and analysis of epidemic models. Innovations in modelling can lead to new insights into epidemic processes and better use of available data, yielding improved disease control and stimulating collection of better data and new data types. Here we identify key challenges for the structure, formulation, analysis and use of mathematical models of pathogen transmission relevant to current and future pandemics.
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| 5. |
- Thompson, Robin N., et al.
(författare)
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Key questions for modelling COVID-19 exit strategies
- 2020
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 287:1932
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Tidskriftsartikel (refereegranskat)abstract
- Combinations of intense non-pharmaceutical interventions (lockdowns) were introduced worldwide to reduce SARS-CoV-2 transmission. Many governments have begun to implement exit strategies that relax restrictions while attempting to control the risk of a surge in cases. Mathematical modelling has played a central role in guiding interventions, but the challenge of designing optimal exit strategies in the face of ongoing transmission is unprecedented. Here, we report discussions from the Isaac Newton Institute 'Models for an exit strategy' workshop (11-15 May 2020). A diverse community of modellers who are providing evidence to governments worldwide were asked to identify the main questions that, if answered, would allow for more accurate predictions of the effects of different exit strategies. Based on these questions, we propose a roadmap to facilitate the development of reliable models to guide exit strategies. This roadmap requires a global collaborative effort from the scientific community and policymakers, and has three parts: (i) improve estimation of key epidemiological parameters; (ii) understand sources of heterogeneity in populations; and (iii) focus on requirements for data collection, particularly in low-to-middle-income countries. This will provide important information for planning exit strategies that balance socio-economic benefits with public health.
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| 6. |
- Vegvari, Carolin, et al.
(författare)
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Commentary on the use of the reproduction number R during the COVID-19 pandemic
- 2022
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Ingår i: Statistical Methods in Medical Research. - : SAGE Publications. - 0962-2802 .- 1477-0334. ; 31:9, s. 1675-1685
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Tidskriftsartikel (refereegranskat)abstract
- Since the beginning of the COVID-19 pandemic, the reproduction number R has become a popular epidemiological metric used to communicate the state of the epidemic. At its most basic, R is defined as the average number of secondary infections caused by one primary infected individual. R seems convenient, because the epidemic is expanding if R>1 and contracting if R<1. The magnitude of R indicates by how much transmission needs to be reduced to control the epidemic. Using R in a naïve way can cause new problems. The reasons for this are threefold: (1) There is not just one definition of R but many, and the precise definition of R affects both its estimated value and how it should be interpreted. (2) Even with a particular clearly defined R, there may be different statistical methods used to estimate its value, and the choice of method will affect the estimate. (3) The availability and type of data used to estimate R vary, and it is not always clear what data should be included in the estimation. In this review, we discuss when R is useful, when it may be of use but needs to be interpreted with care, and when it may be an inappropriate indicator of the progress of the epidemic. We also argue that careful definition of R, and the data and methods used to estimate it, can make R a more useful metric for future management of the epidemic.
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