ORCID Profile
0000-0001-5672-0443
Current Organisations
The University of Edinburgh
,
University of Oxford
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Publisher: Springer Science and Business Media LLC
Date: 09-06-2021
DOI: 10.1038/S41591-021-01408-4
Abstract: Reports of ChAdOx1 vaccine–associated thrombocytopenia and vascular adverse events have led to some countries restricting its use. Using a national prospective cohort, we estimated associations between exposure to first-dose ChAdOx1 or BNT162b2 vaccination and hematological and vascular adverse events using a nested incident-matched case-control study and a confirmatory self-controlled case series (SCCS) analysis. An association was found between ChAdOx1 vaccination and idiopathic thrombocytopenic purpura (ITP) (0–27 d after vaccination adjusted rate ratio (aRR) = 5.77, 95% confidence interval (CI), 2.41–13.83), with an estimated incidence of 1.13 (0.62–1.63) cases per 100,000 doses. An SCCS analysis confirmed that this was unlikely due to bias (RR = 1.98 (1.29–3.02)). There was also an increased risk for arterial thromboembolic events (aRR = 1.22, 1.12–1.34) 0–27 d after vaccination, with an SCCS RR of 0.97 (0.93–1.02). For hemorrhagic events 0–27 d after vaccination, the aRR was 1.48 (1.12–1.96), with an SCCS RR of 0.95 (0.82–1.11). A first dose of ChAdOx1 was found to be associated with small increased risks of ITP, with suggestive evidence of an increased risk of arterial thromboembolic and hemorrhagic events. The attenuation of effect found in the SCCS analysis means that there is the potential for overestimation of the reported results, which might indicate the presence of some residual confounding or confounding by indication. Public health authorities should inform their jurisdictions of these relatively small increased risks associated with ChAdOx1. No positive associations were seen between BNT162b2 and thrombocytopenic, thromboembolic and hemorrhagic events.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.IJMEDINF.2015.05.003
Abstract: Despite their potential for improving health outcomes, mobile-based home monitoring systems for heart failure have not yet been taken up widely by the patients and providers. To design and iteratively move towards a personalised mobile health monitoring system for patients living with heart failure, according to their health care and usability needs. We present an iterative approach to refining a remote health monitoring system that is based on interactions between different actors (patients, clinicians, social scientists and engineers) and supports the collection of quantitative and qualitative information about user experience and engagement. Patients were provided with tablet computers and commercially available sensing devices (a blood pressure monitor, a set of weighing scales, and a pulse oximeter) in order to complete physiological measurements at home, answer symptom-specific questionnaires, review their personal readings, view educational material on heart failure self-management, and communicate with their health professionals. The system supported unobtrusive remote software upgrades via an application distribution channel and the activation or deactivation of functional components by health professionals during run-time operation. We report early findings from the application of this approach in a cohort of 26 heart failure patients (mean age 72±15 years), their caregivers and healthcare professionals who participated in the SUPPORT-HF (Seamless User-centred Proactive Provision Of Risk-stratified Treatment for Heart Failure) study over a one-year study period (mean patient follow-up duration=270±62 days). The approach employed in this study led to several system upgrades dealing in particular with patient requirements for better communication with the development team and personalised self-monitoring interfaces. Engagement with the system was constantly high throughout the study and during the last week of the evaluation, 23 patients (88%) used the system at least once and 16 patients (62%) at least three times. Designers of future mobile-based home monitoring systems for heart failure and other chronic conditions could leverage the described approach as a means of meeting patients' needs during system use within the home environment and facilitating successful uptake.
Publisher: Elsevier BV
Date: 08-2020
Publisher: BMJ
Date: 23-11-2020
DOI: 10.1136/THORAXJNL-2020-215540
Abstract: Longitudinal studies investigating impact of exogenous sex steroids on clinical outcomes of asthma in women are lacking. We investigated the association between use of hormonal contraceptives and risk of severe asthma exacerbation in reproductive-age women with asthma. We used the Optimum Patient Care Research Database, a population-based, longitudinal, anonymised primary care database in the UK, to construct a 17-year (1 January 2000–31 December 2016) retrospective cohort of reproductive-age (16–45 years, n=83 084) women with asthma. Using Read codes, we defined use, subtypes and duration of use of hormonal contraceptives. Severe asthma exacerbation was defined according to recommendations of the European Respiratory Society/American Thoracic Society as asthma-related hospitalisation, accident and emergency department visits due to asthma and/or oral corticosteroid prescriptions. Analyses were done using multilevel mixed-effects Poisson regression with QR decomposition. The 17-year follow-up resulted in 456 803 person-years of follow-up time. At baseline, 34% of women were using any hormonal contraceptives, 25% combined (oestrogen rogestogen) and 9% progestogen-only contraceptives. Previous (incidence rate ratio (IRR) 0.94, 95% CI 0.92 to 0.97) and current (IRR 0.96, 95% CI 0.94 to 0.98) use of any, previous (IRR 0.92, 95% CI 0.87 to 0.97) and current use of combined (IRR 0.93, 95% CI 0.91 to 0.96) and longer duration of use (3–4 years: IRR 0.94, 95% CI 0.92 to 0.97 5+ years: IRR 0.91, 95% CI 0.89 to 0.93) of hormonal contraceptives, but not progestogen-only contraceptives, were associated with reduced risk of severe asthma exacerbation compared with non-use. Use of hormonal contraceptives may reduce the risk of severe asthma exacerbation in reproductive-age women. Mechanistic studies investigating the biological basis for the influence of hormonal contraceptives on clinical outcomes of asthma in women are required. European Union electronic Register of Post-Authorisation Studies (EUPAS22967).
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 07-2021
DOI: 10.1016/J.JAIP.2021.02.052
Abstract: The impact of hormone replacement therapy (HRT) on clinical outcomes in menopausal women is uncertain. To investigate the association between use of HRT and severe asthma exacerbation in perimenopausal and postmenopausal women with asthma. We used the Optimum Patient Care Research Database, a population-based longitudinal primary care database in the United Kingdom, to construct a 17-year (January 1, 2000, to December 31, 2016) cohort of perimenopausal and postmenopausal (46-70 years, N = 31,656) women. We defined use of HRT, its subtypes, and duration of HRT use. Severe asthma exacerbation was defined as an asthma-related hospitalization, emergency department visits due to asthma, and/or prescription of oral corticosteroids. Analyses were undertaken using multilevel mixed-effects Poisson regression. At baseline, 22% of women were using any HRT, 11% combined HRT, and 11% estrogen-only HRT. Previous, but not current, use of any (incidence rate ratio [IRR]: 1.24, 95% confidence interval [CI]: 1.22-1.26), combined (IRR: 1.28, 95% CI: 1.25-1.31), and estrogen-only HRT (IRR: 1.18, 95% CI: 1.14-1.21), and longer duration (1-2 years: IRR: 1.16, 95% CI: 1.13-1.19 3-4 years: IRR: 1.43, 95% CI: 1.38-1.48 5+ years: IRR: 1.32, 95% CI: 1.28-1.36) of HRT use were associated with increased risk of severe asthma exacerbation compared with nonuse. The risk estimates were greater among lean women (body mass index [BMI] <25 kg/m Use of HRT and subtypes, particularly previous, but not current, use and use for more than 2 years, is associated with an increased risk of severe asthma exacerbation in perimenopausal ostmenopausal women with established asthma. Lean women and smokers are at greater risk than heavier women and nonsmokers, respectively.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Oxford University Press (OUP)
Date: 09-07-2015
Publisher: Elsevier BV
Date: 2021
DOI: 10.2139/SSRN.3789264
Publisher: Elsevier BV
Date: 05-2021
Publisher: Public Library of Science (PLoS)
Date: 22-02-2022
DOI: 10.1371/JOURNAL.PMED.1003927
Abstract: Several countries restricted the administration of ChAdOx1 to older age groups in 2021 over safety concerns following case reports and observed versus expected analyses suggesting a possible association with cerebral venous sinus thrombosis (CVST). Large datasets are required to precisely estimate the association between Coronavirus Disease 2019 (COVID-19) vaccination and CVST due to the extreme rarity of this event. We aimed to accomplish this by combining national data from England, Scotland, and Wales. We created data platforms consisting of linked primary care, secondary care, mortality, and virological testing data in each of England, Scotland, and Wales, with a combined cohort of 11,637,157 people and 6,808,293 person years of follow-up. The cohort start date was December 8, 2020, and the end date was June 30, 2021. The outcome measure we examined was incident CVST events recorded in either primary or secondary care records. We carried out a self-controlled case series (SCCS) analysis of this outcome following first dose vaccination with ChAdOx1 and BNT162b2. The observation period consisted of an initial 90-day reference period, followed by a 2-week prerisk period directly prior to vaccination, and a 4-week risk period following vaccination. Counts of CVST cases from each country were tallied, then expanded into a full dataset with 1 row for each in idual and observation time period. There was a combined total of 201 incident CVST events in the cohorts (29.5 per million person years). There were 81 CVST events in the observation period among those who a received first dose of ChAdOx1 (approximately 16.34 per million doses) and 40 for those who received a first dose of BNT162b2 (approximately 12.60 per million doses). We fitted conditional Poisson models to estimate incidence rate ratios (IRRs). Vaccination with ChAdOx1 was associated with an elevated risk of incident CVST events in the 28 days following vaccination, IRR = 1.93 (95% confidence interval (CI) 1.20 to 3.11). We did not find an association between BNT162b2 and CVST in the 28 days following vaccination, IRR = 0.78 (95% CI 0.34 to 1.77). Our study had some limitations. The SCCS study design implicitly controls for variables that are constant over the observation period, but also assumes that outcome events are independent of exposure. This assumption may not be satisfied in the case of CVST, firstly because it is a serious adverse event, and secondly because the vaccination programme in the United Kingdom prioritised the clinically extremely vulnerable and those with underlying health conditions, which may have caused a selection effect for in iduals more prone to CVST. Although we pooled data from several large datasets, there was still a low number of events, which may have caused imprecision in our estimates. In this study, we observed a small elevated risk of CVST events following vaccination with ChAdOx1, but not BNT162b2. Our analysis pooled information from large datasets from England, Scotland, and Wales. This evidence may be useful in risk–benefit analyses of vaccine policies and in providing quantification of risks associated with vaccination to the general public.
Publisher: Elsevier BV
Date: 12-2021
Location: United Kingdom of Great Britain and Northern Ireland
Location: Pakistan
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Syed Ahmar Shah.