Browsing by Author "Walker, David"

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    Higher persistence in newly diagnosed nonvalvular atrial fibrillation patients treated with dabigatran versus warfarin.
    (Circulation. Cardiovascular quality and outcomes, 2013-09) Zalesak, Martin; Siu, Kimberly; Francis, Kevin; Yu, Chen; Alvrtsyan, Hasmik; Rao, Yajing; Walker, David; Sander, Stephen; Miyasato, Gavin; Matchar, David; Sanchez, Herman

    Background

    Oral anticoagulation therapy is the primary tool in reducing stroke risk in patients with nonvalvular atrial fibrillation but is underused. Patients nonpersistent with therapy contribute to this underuse. The objective of this study was to compare persistence rates in newly diagnosed nonvalvular atrial fibrillation patients treated with warfarin versus dabigatran as their oral anticoagulation.

    Methods and results

    US Department of Defense administrative claims were used to identify patients receiving warfarin or dabigatran between October 28, 2010, and June 30, 2012. Patient records were examined for a minimum of 12 months before index date to restrict the analyses to those newly diagnosed with nonvalvular atrial fibrillation and naive-to-treatment, identifying 1775 on warfarin and 3370 on dabigatran. Propensity score matching was used to identify 1745 matched pairs. Persistence was defined as time on therapy to discontinuation. Kaplan-Meier curves were used to depict persistence over time. Cox proportional hazards model was used to determine the factors significantly associated with persistence. Using a 60-day permissible medication gap, the persistence rates were higher for dabigatran than for warfarin at both 6 months (72% versus 53%) and 1 year (63% versus 39%). Patients on dabigatran with a low-to-moderate risk of stroke (CHADS2<2) or with a higher bleed risk (HEMORR2HAGES>3) had a higher likelihood of nonpersistence (hazard ratios, 1.37; 95% confidence interval, 1.17-1.60; P<0.001; and hazard ratios, 1.24; 95% confidence interval, 1.04-1.47; P=0.016).

    Conclusions

    Patients who initiated dabigatran treatment were more persistent than patients who began warfarin treatment. Within each cohort, patients with lower stroke risk were more likely to discontinue therapy.
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    Mixed-methods evaluation of the Perioperative Medicine Service for High-Risk Patients Implementation Pilot (POMSHIP): a study protocol
    (BMJ Open, 2018-10) Walker, David; Wagstaff, Duncan; McGuckin, Dermot; Vindrola-Padros, Cecilia; Swart, Nicholas; Morris, Stephen; Crowe, Sonya; Fulop, Naomi J; Moonesinghe, S Ramani
    IntroductionPerioperative complications have a lasting effect on health-related quality of life and long-term survival. The Royal College of Anaesthetists has proposed the development of perioperative medicine (POM) services as an intervention aimed at improving postoperative outcome, by providing better coordinated care for high-risk patients. The Perioperative Medicine Service for High-risk Patients Implementation Pilot was developed to determine if a specialist POM service is able to reduce postoperative morbidity, failure to rescue, mortality and cost associated with hospital admission. The service involves individualised objective risk assessment, admission to a postoperative critical care unit and follow-up on the surgical ward by the POM team. This paper introduces the service and how it will be evaluated.Methods and analysis of the evaluationA mixed-methods evaluation is exploring the impact of the service. Clinical effectiveness of the service is being analysed using a ‘before and after’ comparison of the primary outcome (the PostOperative Morbidity Score). Secondary outcomes will include length of stay, validated surveys to explore quality of life (EQ-5D) and quality of recovery (Quality of Recovery-15 Score). The impact on costs is being analysed using ‘before and after’ data from the Patient-Level Information and Costing System and the National Schedule of Reference Costs. The perceptions and experiences of staff and patients with the service, and how it is being implemented, are being explored by a qualitative process evaluation.Ethics and disseminationThe study was classified as a service evaluation. Participant information sheets and consent forms have been developed for the interviews and approvals required for the use of the validated surveys were obtained. The findings of the evaluation are being used formatively, to make changes in the service throughout implementation. The findings will also be used to inform the potential roll-out of the service to other sites.
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    Prospective Investigation of Markers of Elevated Delirium Risk (PRIMED Risk) study protocol: a prospective, observational cohort study investigating blood and cerebrospinal fluid biomarkers for delirium and cognitive dysfunction in older patients
    (Wellcome Open Research) Whitby, Jonathan; Bampoe, Sohail; Fullerton, James N; Smaje, Ashley; Hornby, Joanna; Hajdu, Bence; Schofield, Nick; Stafford, Ronnie; Zetterberg, Henrik; McAuley, Daniel F; Passmore, Peter; Cunningham, Emma; Whittle, John; Walker, David; Davis, Daniel
    Background: Delirium is a common post-operative complication, particularly in older adults undergoing major or emergency procedures. It is associated with increased length of intensive care and hospital stay, post-operative mortality and subsequent dementia risk. Current methods of predicting delirium incidence, duration and severity have limitations. Investigation of blood and cerebrospinal fluid (CSF) biomarkers linked to delirium may improve understanding of the underlying pathophysiology, particularly with regard to the extent this is shared or distinct with underlying dementia. Together, these have the potential for development of better risk stratification tools and perioperative interventions. Methods: 200 patients over the age of 70 scheduled for surgery with routine spinal anaesthetic will be recruited from UK hospitals. Their cognitive and functional baseline status will be assessed pre-operatively by telephone. Time-matched CSF and blood samples will be taken at the time of surgery and analysed for known biomarkers of neurodegeneration and neuroinflammation. Patients will be assessed daily for delirium until hospital discharge and will have regular cognitive follow-up for two years. Primary outcomes will be change in modified Telephone Interview for Cognitive Status (TICS-m) score at 12 months and rate of change of TICS-m score. Delirium severity, duration and biomarker levels will be treated as exposures in a random effects linear regression models. PRIMED Risk has received regulatory approvals from Health Research Authority and London – South East Research Ethics Committee. Discussion: The main anticipated output from this study will be the quantification of biomarkers of acute and chronic contributors to cognitive impairment after surgery. In addition, we aim to develop better risk prediction models for adverse cognitive outcomes.