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Dive into the research topics where Rafael Perera is active.

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Featured researches published by Rafael Perera.


BMJ | 2014

Better reporting of interventions: template for intervention description and replication (TIDieR) checklist and guide

Tammy Hoffmann; Paul Glasziou; Isabelle Boutron; Ruairidh Milne; Rafael Perera; David Moher; Douglas G. Altman; Virginia Barbour; Helen Macdonald; Marie Johnston; Sarah E Lamb; Mary Dixon-Woods; Peter McCulloch; Jeremy C. Wyatt; An-Wen Chan; Susan Michie

Without a complete published description of interventions, clinicians and patients cannot reliably implement interventions that are shown to be useful, and other researchers cannot replicate or build on research findings. The quality of description of interventions in publications, however, is remarkably poor. To improve the completeness of reporting, and ultimately the replicability, of interventions, an international group of experts and stakeholders developed the Template for Intervention Description and Replication (TIDieR) checklist and guide. The process involved a literature review for relevant checklists and research, a Delphi survey of an international panel of experts to guide item selection, and a face to face panel meeting. The resultant 12 item TIDieR checklist (brief name, why, what (materials), what (procedure), who provided, how, where, when and how much, tailoring, modifications, how well (planned), how well (actual)) is an extension of the CONSORT 2010 statement (item 5) and the SPIRIT 2013 statement (item 11). While the emphasis of the checklist is on trials, the guidance is intended to apply across all evaluative study designs. This paper presents the TIDieR checklist and guide, with an explanation and elaboration for each item, and examples of good reporting. The TIDieR checklist and guide should improve the reporting of interventions and make it easier for authors to structure accounts of their interventions, reviewers and editors to assess the descriptions, and readers to use the information.


The Lancet | 2006

Self-monitoring of oral anticoagulation: A systematic review and meta-analysis

Carl Heneghan; Pablo Alonso-Coello; J M Garcia-Alamino; Rafael Perera; Emma Meats; Paul Glasziou

BACKGROUND Near-patient testing has made self-monitoring of anticoagulation with warfarin feasible, and several trials have suggested that such monitoring might be equal to or better than standard monitoring. We did a systematic review and meta-analysis of all randomised controlled trials that assessed the effects of self-monitoring or self-management (self-testing and self-dosage) of anticoagulation compared with standard monitoring. METHODS We searched the Cochrane Register of Controlled Trials, MEDLINE, EMBASE to April 2005, and contacted manufacturers and authors of relevant studies. Outcomes analysed were: major haemorrhage, thromboembolic events, death, tests in range, minor haemorrhage, frequency of testing, and feasibility of self-monitoring. FINDINGS We identified 14 randomised trials of self-monitoring: pooled estimates showed significant reductions in thromboembolic events (odds ratio 0.45, 95% CI 0.30-0.68), all-cause mortality (0.61, 0.38-0.98), and major haemorrhage (0.65, 0.42-0.99). Trials of combined self-monitoring and self-adjusted therapy showed significant reductions in thromboembolic events (0.27, 0.12-0.59) and death (0.37, 0.16-0.85), but not major haemorrhage (0.93, 0.42-2.05). No difference was noted in minor haemorrhage. 11 trials reported improvements in the mean proportion of international normalisation ratios in range. INTERPRETATION Self-management improves the quality of oral anticoagulation. Patients capable of self-monitoring and self-adjusting therapy have fewer thromboembolic events and lower mortality than those who self-monitor alone. However, self-monitoring is not feasible for all patients, and requires identification and education of suitable candidates.


Circulation-cardiovascular Quality and Outcomes | 2008

Anticoagulation Control and Prediction of Adverse Events in Patients With Atrial Fibrillation A Systematic Review

Yi Wan; Carl Heneghan; Rafael Perera; Nia Roberts; Jennifer Hollowell; Paul Glasziou; Clare Bankhead; Yongyong Xu

Background—To date, there has been no systematic examination of the relationship between international normalized ratio (INR) control measurements and the prediction of adverse events in patients with atrial fibrillation on oral anticoagulation. Methods and Results—We searched MEDLINE, EMBASE, and Cochrane through January 2008 for studies of atrial fibrillation patients receiving vitamin-K antagonists that reported INR control measures (percentage of time in therapeutic range [TTR] and percentage of INRs in range) and major hemorrhage and thromboembolic events. In total, 47 studies were included from 38 published articles. TTR ranged from 29% to 75%; percentage of INRs ranged from 34% to 84%. From studies reporting both measures, TTR significantly correlated with percentage of INRs in range (P<0.001). Randomized controlled trials had better INR control than retrospective studies (64.9% versus 56.4%; P=0.01). TTR negatively correlated with major hemorrhage (r=−0.59; P=0.002) and thromboembolic rates (r=−0.59; P=0.01). This effect was significant in retrospective studies (major hemorrhage, r=−0.78; P=0.006 and thromboembolic rate, r=−0.88; P=0.03) but not in randomized controlled trials (major hemorrhage, r=0.18; P=0.33 and thromboembolic rate, r=−0.61; P=0.07). For retrospective studies, a 6.9% improvement in the TTR significantly reduced major hemorrhage by 1 event per 100 patient-years of treatment (95% CI, 0.29 to 1.71 events). Conclusions—In atrial fibrillation patients receiving orally administered anticoagulation treatment, TTR and percentage of INRs in range effectively predict INR control. Data from retrospective studies support the use of TTR to accurately predict reductions in adverse events.


The Lancet | 2006

Clinical recognition of meningococcal disease in children and adolescents

Matthew Thompson; Nelly Ninis; Rafael Perera; Richard Mayon-White; Claire Phillips; Linda Bailey; Anthony Harnden; David Mant; Michael Levin

BACKGROUND Meningococcal disease is a rapidly progressive childhood infection of global importance. To our knowledge, no systematic quantitative research exists into the occurrence of symptoms before admission to hospital. METHODS Data were obtained from questionnaires answered by parents and from primary-care records for the course of illness before admission to hospital in 448 children (103 fatal, 345 non-fatal), aged 16 years or younger, with meningococcal disease. In 373 cases, diagnosis was confirmed with microbiological techniques. The rest of the children were included because they had a purpuric rash, and either meningitis or evidence of septicaemic shock. Results were standardised to UK case-fatality rates. FINDINGS The time-window for clinical diagnosis was narrow. Most children had only non-specific symptoms in the first 4-6 h, but were close to death by 24 h. Only 165 (51%) children were sent to hospital after the first consultation. The classic features of haemorrhagic rash, meningism, and impaired consciousness developed late (median onset 13-22 h). By contrast, 72% of children had early symptoms of sepsis (leg pains, cold hands and feet, abnormal skin colour) that first developed at a median time of 8 h, much earlier than the median time to hospital admission of 19 h. INTERPRETATION Classic clinical features of meningococcal disease appear late in the illness. Recognising early symptoms of sepsis could increase the proportion of children identified by primary-care clinicians and shorten the time to hospital admission. The framework within which meningococcal disease is diagnosed should be changed to emphasise identification of these early symptoms by parents and clinicians.


BMC Family Practice | 2010

Adaptation and validation of the Charlson Index for Read/OXMIS coded databases

Nada F. Khan; Rafael Perera; Stephen Harper; Peter W. Rose

BackgroundThe Charlson comorbidity index is widely used in ICD-9 administrative data, however, there is no translation for Read/OXMIS coded data despite increasing use of the General Practice Research Database (GPRD). Our main objective was to translate the Charlson index for use with Read/OXMIS coded data such as the GPRD and test its association with mortality. We also aimed to provide a version of the comorbidity index for other researchers using similar datasets.MethodsTwo clinicians translated the Charlson index into Read/OXMIS codes. We tested the association between comorbidity score and increased mortality in 146 441 patients from the GPRD using proportional hazards models.ResultsThis Read/OXMIS translation of the Charlson index contains 3156 codes. Our validation showed a strong positive association between Charlson score and age. Cox proportional models show a positive increasing association with mortality and Charlson score. The discrimination of the logistic regression model for mortality was good (AUC = 0.853).ConclusionWe have translated a commonly used comorbidity index into Read/OXMIS for use in UK primary care databases. The translated index showed a good discrimination in our study population. This is the first study to develop a co-morbidity index for use with the Read/OXMIS coding system and the GPRD. A copy of the co-morbidity index is provided for other researchers using similar databases.


BMC Gastroenterology | 2009

A systematic review and meta-analysis: Probiotics in the treatment of irritable bowel syndrome

Nourieh Hoveyda; Carl Heneghan; Kamal R Mahtani; Rafael Perera; Nia Roberts; Paul Glasziou

BackgroundIrritable Bowel Syndrome (IBS) is a common chronic gastrointestinal disorder and the evidence for efficacy of most drug therapies in the treatment of IBS is weak. A popular alternative is probiotics, which have been used in several conditions. including IBS. Probiotics are live microbial food supplements.The aim of this systematic review and meta-analysis of randomized trials study was to evaluate the efficacy of probiotics in alleviating symptoms in patients with irritable bowel syndrome. We searched Ovid versions of MEDLINE (1950–2007), EMBASE (1980–2007), CINAHL (1982–2007), AMED (1985–2007), the Cochrane library and hand searched retrieved papers.ResultsWe identified 14 randomized placebo controlled trials. Combined data suggested a modest improvement in overall symptoms after several weeks of treatment: for dichotomous data from seven trials the overall Odds Ratio (OR) was 1.6 (95% CI, 1.2 to 2.2); for continuous data from six trials the standardised mean difference (SMD) was 0.23 (95% CI, 0.07 to 0.38).For individual symptoms the results differed between the pooled dichotomous and pooled continuous data. Trials varied in relation to the length of treatment (4–26 weeks), dose, organisms and strengths of probiotics used.ConclusionProbiotics may have a role in alleviating some of the symptoms of IBS, a condition for which currently evidence of efficacy of drug therapies is weak. However, as IBS is a condition that is chronic and usually intermittent longer term trials are recommended. Such research should focus on the type, optimal dose of probiotics and the subgroups of patients who are likely to benefit the most.


BMJ | 2012

Cardiovascular disease risk in healthy children and its association with body mass index: systematic review and meta-analysis.

Claire Friedemann; Carl Heneghan; Kamal R Mahtani; Matthew Thompson; Rafael Perera; Alison Ward

Objectives To describe the association and its magnitude between body mass index category, sex, and cardiovascular disease risk parameters in school aged children in highly developed countries. Design Systematic review and meta-analysis. Quality of included studies assessed by an adapted version of the Cochrane Collaboration’s risk of bias assessment tool. Results of included studies in meta-analysis were pooled and analysed by Review Manager version 5.1. Data sources Embase, PubMed, EBSCOHost’s cumulative index to nursing and allied health literature, and the Web of Science databases for papers published between January 2000 and December 2011. Review methods Healthy children aged 5 to 15 in highly developed countries enrolled in studies done after 1990 and using prospective or retrospective cohort, cross sectional, case-control, or randomised clinical trial designs in school, outpatient, or community settings. Included studies had to report an objective measure of weight and at least one prespecified risk parameter for cardiovascular disease. Results We included 63 studies of 49 220 children. Studies reported a worsening of risk parameters for cardiovascular disease in overweight and obese participants. Compared with normal weight children, systolic blood pressure was higher by 4.54 mm Hg (99% confidence interval 2.44 to 6.64; n=12 169, eight studies) in overweight children, and by 7.49 mm Hg (3.36 to 11.62; n=8074, 15 studies) in obese children. We found similar associations between groups in diastolic and 24 h ambulatory systolic blood pressure. Obesity adversely affected concentrations of all blood lipids; total cholesterol and triglycerides were 0.15 mmol/L (0.04 to 0.25, n=5072) and 0.26 mmol/L (0.13 to 0.39, n=5138) higher in obese children, respectively. Fasting insulin and insulin resistance were significantly higher in obese participants but not in overweight participants. Obese children had a significant increase in left ventricular mass of 19.12 g (12.66 to 25.59, n=223), compared with normal weight children. Conclusion Having a body mass index outside the normal range significantly worsens risk parameters for cardiovascular disease in school aged children. This effect, already substantial in overweight children, increases in obesity and could be larger than previously thought. There is a need to establish whether acceptable parameter cut-off levels not considering weight are a valid measure of risk in modern children and whether methods used in their study and reporting should be standardised.


The Lancet | 2012

Self-monitoring of oral anticoagulation: systematic review and meta-analysis of individual patient data

Carl Heneghan; Alison Ward; Rafael Perera; Clare Bankhead; A Fuller; Richard L. Stevens; Kairen Bradford; Sally Tyndel; Pablo Alonso-Coello; Jack Ansell; Rebecca J. Beyth; Artur Bernardo; Thomas Decker Christensen; Manon E. Cromheecke; Robert Edson; David Fitzmaurice; Alain P A Gadisseur; Josep M. García-Alamino; Chris Gardiner; Michael Hasenkam; Alan K. Jacobson; Scott Kaatz; Farhad Kamali; Tayyaba Khan; Eve Knight; Heinrich Körtke; Marcel Levi; David B. Matchar; Bárbara Menéndez-Jándula; Ivo Rakovac

BACKGROUND Uptake of self-testing and self-management of oral anticoagulation [corrected] has remained inconsistent, despite good evidence of their effectiveness. To clarify the value of self-monitoring of oral anticoagulation, we did a meta-analysis of individual patient data addressing several important gaps in the evidence, including an estimate of the effect on time to death, first major haemorrhage, and thromboembolism. METHODS We searched Ovid versions of Embase (1980-2009) and Medline (1966-2009), limiting searches to randomised trials with a maximally sensitive strategy. We approached all authors of included trials and requested individual patient data: primary outcomes were time to death, first major haemorrhage, and first thromboembolic event. We did prespecified subgroup analyses according to age, type of control-group care (anticoagulation-clinic care vs primary care), self-testing alone versus self-management, and sex. We analysed patients with mechanical heart valves or atrial fibrillation separately. We used a random-effect model method to calculate pooled hazard ratios and did tests for interaction and heterogeneity, and calculated a time-specific number needed to treat. FINDINGS Of 1357 abstracts, we included 11 trials with data for 6417 participants and 12,800 person-years of follow-up. We reported a significant reduction in thromboembolic events in the self-monitoring group (hazard ratio 0·51; 95% CI 0·31-0·85) but not for major haemorrhagic events (0·88, 0·74-1·06) or death (0·82, 0·62-1·09). Participants younger than 55 years showed a striking reduction in thrombotic events (hazard ratio 0·33, 95% CI 0·17-0·66), as did participants with mechanical heart valve (0·52, 0·35-0·77). Analysis of major outcomes in the very elderly (age ≥85 years, n=99) showed no significant adverse effects of the intervention for all outcomes. INTERPRETATION Our analysis showed that self-monitoring and self-management of oral coagulation is a safe option for suitable patients of all ages. Patients should also be offered the option to self-manage their disease with suitable health-care support as back-up. FUNDING UK National Institute for Health Research (NIHR) Technology Assessment Programme, UK NIHR National School for Primary Care Research.


Circulation-cardiovascular Quality and Outcomes | 2008

Anticoagulation Control and Prediction of Adverse Events in Patients With Atrial FibrillationCLINICAL PERSPECTIVE

Yi Wan; Carl Heneghan; Rafael Perera; Nia Roberts; Jennifer Hollowell; Paul Glasziou; Clare Bankhead; Yongyong Xu

Background—To date, there has been no systematic examination of the relationship between international normalized ratio (INR) control measurements and the prediction of adverse events in patients with atrial fibrillation on oral anticoagulation. Methods and Results—We searched MEDLINE, EMBASE, and Cochrane through January 2008 for studies of atrial fibrillation patients receiving vitamin-K antagonists that reported INR control measures (percentage of time in therapeutic range [TTR] and percentage of INRs in range) and major hemorrhage and thromboembolic events. In total, 47 studies were included from 38 published articles. TTR ranged from 29% to 75%; percentage of INRs ranged from 34% to 84%. From studies reporting both measures, TTR significantly correlated with percentage of INRs in range (P<0.001). Randomized controlled trials had better INR control than retrospective studies (64.9% versus 56.4%; P=0.01). TTR negatively correlated with major hemorrhage (r=−0.59; P=0.002) and thromboembolic rates (r=−0.59; P=0.01). This effect was significant in retrospective studies (major hemorrhage, r=−0.78; P=0.006 and thromboembolic rate, r=−0.88; P=0.03) but not in randomized controlled trials (major hemorrhage, r=0.18; P=0.33 and thromboembolic rate, r=−0.61; P=0.07). For retrospective studies, a 6.9% improvement in the TTR significantly reduced major hemorrhage by 1 event per 100 patient-years of treatment (95% CI, 0.29 to 1.71 events). Conclusions—In atrial fibrillation patients receiving orally administered anticoagulation treatment, TTR and percentage of INRs in range effectively predict INR control. Data from retrospective studies support the use of TTR to accurately predict reductions in adverse events.


Cochrane Database of Systematic Reviews | 2010

Cognitive behavioural therapy for tinnitus

Pablo Martinez-Devesa; Rafael Perera; Megan Theodoulou; Angus Waddell

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects and safety of CBT for tinnitus in adults.

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Brian Shine

John Radcliffe Hospital

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Tom Lung

University of Sydney

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