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Dive into the research topics where Philippa Davies is active.

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Featured researches published by Philippa Davies.


Journal of Clinical Epidemiology | 2016

ROBIS: A new tool to assess risk of bias in systematic reviews was developed

Penny F Whiting; Jelena Savovic; Julian P. T. Higgins; Deborah M Caldwell; Barnaby C Reeves; Beverley Shea; Philippa Davies; Jos Kleijnen; Rachel Churchill

Objective To develop ROBIS, a new tool for assessing the risk of bias in systematic reviews (rather than in primary studies). Study Design and Setting We used four-stage approach to develop ROBIS: define the scope, review the evidence base, hold a face-to-face meeting, and refine the tool through piloting. Results ROBIS is currently aimed at four broad categories of reviews mainly within health care settings: interventions, diagnosis, prognosis, and etiology. The target audience of ROBIS is primarily guideline developers, authors of overviews of systematic reviews (“reviews of reviews”), and review authors who might want to assess or avoid risk of bias in their reviews. The tool is completed in three phases: (1) assess relevance (optional), (2) identify concerns with the review process, and (3) judge risk of bias. Phase 2 covers four domains through which bias may be introduced into a systematic review: study eligibility criteria; identification and selection of studies; data collection and study appraisal; and synthesis and findings. Phase 3 assesses the overall risk of bias in the interpretation of review findings and whether this considered limitations identified in any of the phase 2 domains. Signaling questions are included to help judge concerns with the review process (phase 2) and the overall risk of bias in the review (phase 3); these questions flag aspects of review design related to the potential for bias and aim to help assessors judge risk of bias in the review process, results, and conclusions. Conclusions ROBIS is the first rigorously developed tool designed specifically to assess the risk of bias in systematic reviews.


BJA: British Journal of Anaesthesia | 2014

Systematic review and meta-analysis of the effect of intraoperative α2-adrenergic agonists on postoperative behaviour in children

Amelia Pickard; Philippa Davies; Kate Birnie; Richard M Beringer

Undergoing general anaesthesia is distressing for children, with up to two-thirds demonstrating abnormal behaviours after their procedure, such as emergence delirium (ED) and post-hospitalization behaviour change. The aim of this systematic review was to determine the effect of intraoperative i.v. α₂-adrenergic agonists on postoperative behaviour in children. We included published full-text reports of randomized controlled trials involving children who received i.v. clonidine or dexmedetomidine after induction of general anaesthesia, who were assessed for postoperative behavioural disturbance. After screening of references identified by the search strategy, a data collection form was developed and piloted. Data extraction was performed by one reviewer and checked by a second. Twelve randomized trials met the inclusion criteria. Ten studies (n=669) reported dichotomous data that were included in the pooled analysis of α₂-adrenergic agonists vs placebo. There was strong evidence that i.v. α₂-adrenergic agonists reduced postoperative ED (overall summary odds ratio 0.28, 95% confidence interval 0.19-0.40, P<0.001). No studies examined post-hospitalization negative behaviour changes. There was evidence that α₂-adrenergic agonists prolonged time in the recovery room. No adverse haemodynamic events were reported in any arm of any study. This meta-analysis provides evidence that intraoperative i.v. α₂-adrenergic agonists reduce the incidence of emergency delirium in children. The prolongation of time in recovery is unlikely to be clinically relevant. The absence of data regarding the effect on post-hospitalization behavioural changes provides an opportunity for future research.


Health Technology Assessment | 2017

Oral anticoagulants for primary prevention, treatment and secondary prevention of venous thromboembolic disease, and for prevention of stroke in atrial fibrillation: systematic review, network meta-analysis and cost-effectiveness analysis

Jonathan A C Sterne; Pritesh N Bodalia; Peter Bryden; Philippa Davies; José Antonio López-López; George Okoli; Howard Thom; Deborah M Caldwell; Sofia Dias; D Eaton; Julian P. T. Higgins; William Hollingworth; Chris Salisbury; Jelena Savovic; Reecha Sofat; A Stephens-Boal; Nicky J Welton; Aroon D. Hingorani

BACKGROUND Warfarin is effective for stroke prevention in atrial fibrillation (AF), but anticoagulation is underused in clinical care. The risk of venous thromboembolic disease during hospitalisation can be reduced by low-molecular-weight heparin (LMWH): warfarin is the most frequently prescribed anticoagulant for treatment and secondary prevention of venous thromboembolism (VTE). Warfarin-related bleeding is a major reason for hospitalisation for adverse drug effects. Warfarin is cheap but therapeutic monitoring increases treatment costs. Novel oral anticoagulants (NOACs) have more rapid onset and offset of action than warfarin, and more predictable dosing requirements. OBJECTIVE To determine the best oral anticoagulant/s for prevention of stroke in AF and for primary prevention, treatment and secondary prevention of VTE. DESIGN Four systematic reviews, network meta-analyses (NMAs) and cost-effectiveness analyses (CEAs) of randomised controlled trials. SETTING Hospital (VTE primary prevention and acute treatment) and primary care/anticoagulation clinics (AF and VTE secondary prevention). PARTICIPANTS Patients eligible for anticoagulation with warfarin (stroke prevention in AF, acute treatment or secondary prevention of VTE) or LMWH (primary prevention of VTE). INTERVENTIONS NOACs, warfarin and LMWH, together with other interventions (antiplatelet therapy, placebo) evaluated in the evidence network. MAIN OUTCOME MEASURES Efficacy Stroke, symptomatic VTE, symptomatic deep-vein thrombosis and symptomatic pulmonary embolism. Safety Major bleeding, clinically relevant bleeding and intracranial haemorrhage. We also considered myocardial infarction and all-cause mortality and evaluated cost-effectiveness. DATA SOURCES MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library, reference lists of published NMAs and trial registries. We searched MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library. The stroke prevention in AF review search was run on the 12 March 2014 and updated on 15 September 2014, and covered the period 2010 to September 2014. The search for the three reviews in VTE was run on the 19 March 2014, updated on 15 September 2014, and covered the period 2008 to September 2014. REVIEW METHODS Two reviewers screened search results, extracted and checked data, and assessed risk of bias. For each outcome we conducted standard meta-analysis and NMA. We evaluated cost-effectiveness using discrete-time Markov models. RESULTS Apixaban (Eliquis®, Bristol-Myers Squibb, USA; Pfizer, USA) [5 mg bd (twice daily)] was ranked as among the best interventions for stroke prevention in AF, and had the highest expected net benefit. Edoxaban (Lixiana®, Daiichi Sankyo, Japan) [60 mg od (once daily)] was ranked second for major bleeding and all-cause mortality. Neither the clinical effectiveness analysis nor the CEA provided strong evidence that NOACs should replace postoperative LMWH in primary prevention of VTE. For acute treatment and secondary prevention of VTE, we found little evidence that NOACs offer an efficacy advantage over warfarin, but the risk of bleeding complications was lower for some NOACs than for warfarin. For a willingness-to-pay threshold of > £5000, apixaban (5 mg bd) had the highest expected net benefit for acute treatment of VTE. Aspirin or no pharmacotherapy were likely to be the most cost-effective interventions for secondary prevention of VTE: our results suggest that it is not cost-effective to prescribe NOACs or warfarin for this indication. CONCLUSIONS NOACs have advantages over warfarin in patients with AF, but we found no strong evidence that they should replace warfarin or LMWH in primary prevention, treatment or secondary prevention of VTE. LIMITATIONS These relate mainly to shortfalls in the primary data: in particular, there were no head-to-head comparisons between different NOAC drugs. FUTURE WORK Calculating the expected value of sample information to clarify whether or not it would be justifiable to fund one or more head-to-head trials. STUDY REGISTRATION This study is registered as PROSPERO CRD42013005324, CRD42013005331 and CRD42013005330. FUNDING The National Institute for Health Research Health Technology Assessment programme.


BJUI | 2016

Symptomatic and quality‐of‐life outcomes after treatment for clinically localised prostate cancer: a systematic review

Penny F Whiting; Theresa Hm Moore; Catherine M Jameson; Philippa Davies; Mari-Anne Rowlands; Margaret Burke; R Beynon; Jelena Savovic; Jenny Donovan

To conduct a systematic review of the risks of short‐term outcomes after major treatments for clinically localised prostate cancer. MEDLINE, EMBASE and the Cochrane Library were searched from 2004 to January 2013. Study arms that included ≥100 men with localised prostate cancer in receipt of surgery, radiotherapy or active surveillance and reported symptomatic and quality‐of‐life (QoL) data from 6 to 60 months after treatment were eligible. Data were extracted by one reviewer and checked by another. In all, 64 studies (80 treatment cohorts) were included. Most were single treatment cohorts from the USA or Europe. Radiotherapy was the most common treatment (40 cohorts, including 31 brachytherapy cohorts) followed by prostatectomy (39 cohorts), with only one active surveillance cohort. Most frequently measured symptoms were urinary, followed by sexual, and bowel; QoL was assessed in only 17 cohorts. Most studies used validated measures, although poor data reporting and differences between studies meant that it was not possible to pool data. Data on the precise impact of short‐term symptomatic and QoL outcomes after treatment for localised prostate cancer are of insufficient quality for clear guidance to men about the risks to these aspects of their lives. It is important that future studies focus on collecting core outcomes through validated measures and comply with reporting guidelines, so that clear and accurate information can be derived for men considering screening or treatment for prostate cancer.


BMJ | 2017

Oral anticoagulants for prevention of stroke in atrial fibrillation: systematic review, network meta-analysis, and cost effectiveness analysis

José Antonio López-López; Jonathan A C Sterne; Howard Thom; Julian P. T. Higgins; Aroon D. Hingorani; George Okoli; Philippa Davies; Pritesh N Bodalia; Peter Bryden; Nicky J Welton; William Hollingworth; Deborah M Caldwell; Jelena Savovic; Sofia Dias; Chris Salisbury; D Eaton; A Stephens-Boal; Reecha Sofat

Abstract Objective To compare the efficacy, safety, and cost effectiveness of direct acting oral anticoagulants (DOACs) for patients with atrial fibrillation. Design Systematic review, network meta-analysis, and cost effectiveness analysis. Data sources Medline, PreMedline, Embase, and The Cochrane Library. Eligibility criteria for selecting studies Published randomised trials evaluating the use of a DOAC, vitamin K antagonist, or antiplatelet drug for prevention of stroke in patients with atrial fibrillation. Results 23 randomised trials involving 94 656 patients were analysed: 13 compared a DOAC with warfarin dosed to achieve a target INR of 2.0-3.0. Apixaban 5 mg twice daily (odds ratio 0.79, 95% confidence interval 0.66 to 0.94), dabigatran 150 mg twice daily (0.65, 0.52 to 0.81), edoxaban 60 mg once daily (0.86, 0.74 to 1.01), and rivaroxaban 20 mg once daily (0.88, 0.74 to 1.03) reduced the risk of stroke or systemic embolism compared with warfarin. The risk of stroke or systemic embolism was higher with edoxaban 60 mg once daily (1.33, 1.02 to 1.75) and rivaroxaban 20 mg once daily (1.35, 1.03 to 1.78) than with dabigatran 150 mg twice daily. The risk of all-cause mortality was lower with all DOACs than with warfarin. Apixaban 5 mg twice daily (0.71, 0.61 to 0.81), dabigatran 110 mg twice daily (0.80, 0.69 to 0.93), edoxaban 30 mg once daily (0.46, 0.40 to 0.54), and edoxaban 60 mg once daily (0.78, 0.69 to 0.90) reduced the risk of major bleeding compared with warfarin. The risk of major bleeding was higher with dabigatran 150 mg twice daily than apixaban 5 mg twice daily (1.33, 1.09 to 1.62), rivaroxaban 20 mg twice daily than apixaban 5 mg twice daily (1.45, 1.19 to 1.78), and rivaroxaban 20 mg twice daily than edoxaban 60 mg once daily (1.31, 1.07 to 1.59). The risk of intracranial bleeding was substantially lower for most DOACs compared with warfarin, whereas the risk of gastrointestinal bleeding was higher with some DOACs than warfarin. Apixaban 5 mg twice daily was ranked the highest for most outcomes, and was cost effective compared with warfarin. Conclusions The network meta-analysis informs the choice of DOACs for prevention of stroke in patients with atrial fibrillation. Several DOACs are of net benefit compared with warfarin. A trial directly comparing DOACs would overcome the need for indirect comparisons to be made through network meta-analysis. Systematic review registration PROSPERO CRD 42013005324.


Cochrane Database of Systematic Reviews | 2010

Mindfulness-based 'third wave' cognitive and behavioural therapies versus other psychological therapies for depression

Vivien Hunot; Theresa Hm Moore; Deborah M Caldwell; Philippa Davies; Hannah Jones; Glyn Lewis; Rachel Churchill

This is the protocol for a review and there is no abstract. The objectives are as follows: To examine the effectiveness and acceptability of all third wave CBT approaches compared with all other psychological therapy approaches for acute depression.To examine the effectiveness and acceptability of different third wave CBT approaches (ACT,compassionate mind training, functional analytic psychotherapy, extended behavioural activation and meta-cognitive therapy) compared with all other psychological therapy approaches for acute depression.To examine the effectiveness and acceptability of all third wave CBT approaches compared with different psychological therapy approaches (psychodynamic, behavioural, humanistic, integrative, cognitive-behavioural) for acute depression.


Systematic Reviews | 2017

An overview of systematic reviews of complementary and alternative therapies for fibromyalgia using both AMSTAR and ROBIS as quality assessment tools

Rachel E Perry; Verity Leach; Philippa Davies; Christopher Penfold; Andy R Ness; Rachel Churchill

BackgroundFibromyalgia (FM) is a chronic, debilitating pain disorder. Dissatisfaction with conventional medicine can lead people with FM to turn to complementary and alternative medicine (CAM). Two previous overviews of systematic reviews of CAM for FM have been published, but they did not assessed for risk of bias in the review process.MethodsFive databases Medline, Embase, AMED (via OVID), Web of Science and Central were searched from their inception to December 2015. Reference lists were hand-searched. We had two aims: the first was to provide an up-to-date and rigorously conducted synthesis of systematic reviews of CAM literature on FM; the second was to evaluate the quality of the available systematic review evidence using two different tools: AMSTAR (Shea et al. BMC Med Res Methodol 15; 7:10, 2007) and a more recently developed tool ROBIS (Whiting et al. J Clin Epidemiol 69:225-34, 2016) specifically designed to assess risk of bias in systematic reviews. Any review that assessed one of eight CAM therapies for participants diagnosed with FM was considered. The individual studies had to be randomised controlled trials where the intervention was compared to placebo, treatment as usual or waitlist controls to be included. The primary outcome measure was pain, and the secondary outcome measure was adverse events.ResultsWe identified 15 reviews that met inclusion criteria. There was low-quality evidence that acupuncture improves pain compared to no treatment or standard treatment, but good evidence that it is no better than sham acupuncture. The evidence for homoeopathy, spinal manipulation and herbal medicine was limited.ConclusionsOverall, five reviews scored 6 or above using the AMSTAR scale and the inter-rater agreement was good (83.6%), whereas seven reviews achieved a low risk of bias rating using ROBIS and the inter-rater agreement was fair (60.0%). No firm conclusions were drawn for efficacy of either spinal manipulation or homoeopathy for FM. There is limited evidence for topical Capsicum, but further research is required. There is some evidence to support the effectiveness of acupuncture for FM, but further high-quality trials are needed to investigate its benefits, harms and mechanisms of action, compared with no or standard treatment.Systematic review registrationPROSPERO CRD42016035846.


Health Technology Assessment | 2017

Screening strategies for atrial fibrillation: a systematic review and cost-effectiveness analysis

Nicky J Welton; Alexandra McAleenan; Howard Thom; Philippa Davies; William Hollingworth; Julian P. T. Higgins; George Okoli; Jonathan A C Sterne; Gene Feder; D Eaton; Aroon Hingorani; Christopher G. Fawsitt; Trudie Lobban; Peter Bryden; Alison Richards; Reecha Sofat

BACKGROUND Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of thromboembolic events. Anticoagulation therapy to prevent AF-related stroke has been shown to be cost-effective. A national screening programme for AF may prevent AF-related events, but would involve a substantial investment of NHS resources. OBJECTIVES To conduct a systematic review of the diagnostic test accuracy (DTA) of screening tests for AF, update a systematic review of comparative studies evaluating screening strategies for AF, develop an economic model to compare the cost-effectiveness of different screening strategies and review observational studies of AF screening to provide inputs to the model. DESIGN Systematic review, meta-analysis and cost-effectiveness analysis. SETTING Primary care. PARTICIPANTS Adults. INTERVENTION Screening strategies, defined by screening test, age at initial and final screens, screening interval and format of screening {systematic opportunistic screening [individuals offered screening if they consult with their general practitioner (GP)] or systematic population screening (when all eligible individuals are invited to screening)}. MAIN OUTCOME MEASURES Sensitivity, specificity and diagnostic odds ratios; the odds ratio of detecting new AF cases compared with no screening; and the mean incremental net benefit compared with no screening. REVIEW METHODS Two reviewers screened the search results, extracted data and assessed the risk of bias. A DTA meta-analysis was perfomed, and a decision tree and Markov model was used to evaluate the cost-effectiveness of the screening strategies. RESULTS Diagnostic test accuracy depended on the screening test and how it was interpreted. In general, the screening tests identified in our review had high sensitivity (> 0.9). Systematic population and systematic opportunistic screening strategies were found to be similarly effective, with an estimated 170 individuals needed to be screened to detect one additional AF case compared with no screening. Systematic opportunistic screening was more likely to be cost-effective than systematic population screening, as long as the uptake of opportunistic screening observed in randomised controlled trials translates to practice. Modified blood pressure monitors, photoplethysmography or nurse pulse palpation were more likely to be cost-effective than other screening tests. A screening strategy with an initial screening age of 65 years and repeated screens every 5 years until age 80 years was likely to be cost-effective, provided that compliance with treatment does not decline with increasing age. CONCLUSIONS A national screening programme for AF is likely to represent a cost-effective use of resources. Systematic opportunistic screening is more likely to be cost-effective than systematic population screening. Nurse pulse palpation or modified blood pressure monitors would be appropriate screening tests, with confirmation by diagnostic 12-lead electrocardiography interpreted by a trained GP, with referral to a specialist in the case of an unclear diagnosis. Implementation strategies to operationalise uptake of systematic opportunistic screening in primary care should accompany any screening recommendations. LIMITATIONS Many inputs for the economic model relied on a single trial [the Screening for Atrial Fibrillation in the Elderly (SAFE) study] and DTA results were based on a few studies at high risk of bias/of low applicability. FUTURE WORK Comparative studies measuring long-term outcomes of screening strategies and DTA studies for new, emerging technologies and to replicate the results for photoplethysmography and GP interpretation of 12-lead electrocardiography in a screening population. STUDY REGISTRATION This study is registered as PROSPERO CRD42014013739. FUNDING The National Institute for Health Research Health Technology Assessment programme.


Cochrane Database of Systematic Reviews | 2010

Cognitive behavioural therapies versus treatment as usual for depression

Vivien Hunot; Theresa Hm Moore; Deborah M Caldwell; Philippa Davies; Hannah F Jones; Toshi A. Furukawa; Glyn Lewis; Rachel Churchill

This is the protocol for a review and there is no abstract. The objectives are as follows: To examine the effectiveness and acceptability of all cognitive behavioural therapies compared with treatment as usual/waiting list/attention placebo control conditions for acute depression.To examine the effectiveness and acceptability of different cognitive behavioural therapy models (cognitive therapy, rational emotive behaviour therapy, problem-solving therapy, self-control therapy and the Coping with Depression course) compared with treatment as usual/waiting list/attention placebo control conditions for acute depression.To examine the effectiveness and acceptability of all cognitive behavioural therapies compared with different types of comparator (standard care, no treatment, waiting list, attention placebo) for acute depression.


Cochrane Database of Systematic Reviews | 2010

Cognitive behavioural therapies versus other psychological therapies for depression

Rachel Churchill; Theresa Hm Moore; Deborah M Caldwell; Philippa Davies; Hannah F Jones; Toshi A. Furukawa; Glyn Lewis; Vivien Hunot

This is the protocol for a review and there is no abstract. The objectives are as follows: To examine the effectiveness and acceptability of all CBT approaches compared with all other psychological therapy approaches for acute depressionTo examine the effectiveness and acceptability of different CBT approaches (cognitive therapy, rational emotive behaviour therapy, problem-solving therapy, self-control therapy and Coping with Depression course) compared with all other psychological therapy approaches for acute depression.To examine the effectiveness and acceptability of all CBT approaches compared with different psychological therapy approaches (psychodynamic, behavioural, humanistic, integrative, third wave CBT) for acute depression.

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Glyn Lewis

University College London

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Hannah Jones

University of Nottingham

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