Carl Heneghan

University of Oxford, Oxford, England, United Kingdom

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Publications (148)1095.84 Total impact

  • Igho J. Onakpoya, Jack O’Sullivan, Carl J. Heneghan
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    ABSTRACT: Hundreds of dietary supplements are currently marketed as weight loss supplements. However, the advertised health claims of effectiveness for most of these are unproven. The purpose of this review was to critically appraise and evaluate the evidence for effectiveness of cactus pear, Opuntia ficus-indica (OFI), using data from published randomized clinical trials (RCTs).
    Nutrition. 12/2014;
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    ABSTRACT: Interventions to prevent influenza-related complications are recommended for individuals at the greatest risk of serious clinical deterioration. However, guidelines are based on consensus opinion rather than evidence, and do not specify risk factors in children. We aimed to provide an evidence-based definition of children who are most at risk of such complications. In this systematic review, we searched the Medline and Medline In Process, Embase, Science Citation Index, and CINAHL databases for studies published between inception and April 3, 2013. We included studies that reported data for underlying disorders and complications in children presenting in primary or ambulatory care with influenza or influenza-like illness. We requested unpublished data from investigators of studies that had obtained, but not published, relevant data. We analysed data with univariable meta-analysis and individual patient data multivariable meta-analysis methods. The primary outcome was admission to hospital as a proxy for complications of influenza or influenza-like illness. We included 28 articles that reported data from 27 studies (14 086 children). Strong risk factors for hospital admission were neurological disorders (univariable odds ratio [OR] 4· 62, 95% CI 2·82-7·55), prematurity (4·33, 2·47-7·58), sickle cell disease (3·46, 1·63-7·37), immunosuppression (2·39, 1·24-4·61), diabetes (2·34, 1·20-4·58), and age younger than 2 years (2·51, 1·71-3·69). However, reactive airways disease including asthma (1·36, 0·82-2·26) and obesity (0·99, 0·61-1·62) were not found to be risk factors. On the basis of individual patient data multivariable analysis (1612 children, four studies), the risk of hospital admission was higher in children with more than one risk factor than in children with just one risk factor, when age younger than 2 years was included as a risk factor (92 [74%] of 124 vs 428 [52%] of 817; difference 22%, 95% CI 13-30%, p<0·0001). We identified prematurity as a new strong risk factor for influenza-related complications in children. Our findings also support the inclusion of neurological disorders, sickle cell disease, immunosuppression, diabetes, and age younger than 2 years as risk factors in existing guidelines. Interventions to prevent influenza-related complications should be prioritised in these groups, but should also be considered for other children, especially those with more than one risk factor or severe underlying comorbidities. UK National Institute for Health Research. Copyright © 2014 Elsevier Ltd. All rights reserved.
    The Lancet. Respiratory medicine. 12/2014;
  • Cochrane database of systematic reviews (Online) 12/2014; · 5.70 Impact Factor
  • Igho J Onakpoya, Carl J Heneghan
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    ABSTRACT: Many different dietary supplements are currently marketed for the management of hypertension and diabetes, but the evidence for effectiveness is mixed. The objective of this systematic review was to critically appraise and evaluate the evidence for effectiveness of steviol glycosides (stevioside and rebaudioside A) on cardiovascular risk factors, using data from randomised clinical trials (RCTs). Electronic searches were conducted in Medline, Embase, Amed, Cinahl and The Cochrane Library. We also searched Google Scholar, and hand searched the bibliography of retrieved full texts. The reporting quality of included studies was assessed using the Cochrane criteria. Two reviewers independently determined the eligibility, assessed the reporting quality, and extracted the data. Nine studies with a total of 756 participants were included. There was a variation in the reporting quality of included studies. Meta-analysis revealed a non-significant difference in systolic blood pressure between steviol glycoside and placebo, mean difference (MD): -2.98 mm Hg (-6.23 to 0.27). Significant reductions in diastolic blood pressure and fasting blood glucose were observed. There was no significant effect on blood lipid profile. Heterogeneity was significant. Adverse events included abdominal fullness, epigastric pain, and dizziness. The evidence from published RCTs suggests that stevioside may generate reductions in blood pressure and fasting blood glucose. The sizes of the effects are small, and the substantial heterogeneity limits the robustness of any conclusions. Rebaudioside A does not appear to have any significant effects on blood pressure or cardiovascular risk factors. Available clinical trials vary in design and reporting quality, and some are characterised by inadequate sample sizes. In addition, the participants in most of the trials have high cardiovascular risk. Further clinical trials and regulatory assessments are warranted. © The European Society of Cardiology 2014 Reprints and permissions:
    European Journal of Preventive Cardiology 11/2014; · 3.90 Impact Factor
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    ABSTRACT: Identifying articles relevant to primary care is challenging for busy clinicians. Setting specific search strategies can be used to help clinicians find pertinent studies in a timely fashion.
    Family practice. 10/2014;
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    10/2014; 384(9950):1260–1261.
  • The British journal of general practice : the journal of the Royal College of General Practitioners. 10/2014; 64(627):e681-3.
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    ABSTRACT: Informed decision-making is increasingly being adopted by global healthcare policy to improve evidence based treatment decisions yet its uptake into clinical practice has been slow. Whilst current clinical practice guidelines and synthesised products (e.g. systematic reviews, evidence summaries) increase access to evidence of treatment effects, they often fail to provide additional information needed to make a fully informed choice. Moreover, a lack of brevity and the use of research jargon are barriers to their implementation in practice. As well as access to information about the benefits and harms of healthcare interventions, consumers also need additional information such as treatment costs, dosage, and the quality of evidence underpinning treatment effects in order to make informed choices. Currently, there are few examples of clinical practice guidelines or synthesised products that present this additional information in one-place and in a concise manner. Here we present such a method and describe how we developed the Evidence of Effects Page. The Evidence of Effects Page is a unique one-page summary of evidence that presents information not only on treatment effects and harms, but also precision of estimates, the quality of evidence and treatment costs. Our methodology can be applied to create additional Evidence of Effects Pages for treatments and interventions for other medical conditions as required. Compared with current products, the Evidence of Effects Page provides additional information for making decisions about healthcare treatments and has potential to facilitate greater adoption of informed decision-making and patient centered care in clinical practice.
    British Journal of Health Informatics and Monitoring. 09/2014; 1(2):25-44.
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    ABSTRACT: Most guidelines recommend the use of capillary refill time (CRT) as part of the routine assessment of unwell children, but there is little consensus on the optimum method of measurement and cut-off time.
    Archives of disease in childhood. 09/2014;
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    ABSTRACT: Management of acute sore throat poses a significant burden on UK general practices, with almost 10% of registered patients attending their GP with sore throat every year. Nearly half of all patients presenting with acute sore throat are treated with antibiotics, despite their limited effect. In a recent systematic review we demonstrated that a single dose of steroids reduced the severity and time to resolution of sore throat. However, all of the trials included looked at the use of steroids alongside antibiotics and only one was in a primary care setting. This trial aims to assess the efficacy and cost-effectiveness of a single oral dose of corticosteroids on symptoms of sore throat in patients receiving either a delayed antibiotic prescription or no antibiotics at all in UK primary care.
    Trials. 09/2014; 15(1):365.
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    British Journal of Haematology 08/2014; · 4.94 Impact Factor
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    Cochrane database of systematic reviews (Online) 07/2014; · 5.70 Impact Factor
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    ABSTRACT: Many healthcare professionals use smartphones and tablets to inform patient care. Contemporary research suggests that handheld computers may support aspects of clinical diagnosis and management. This systematic review was designed to synthesise high quality evidence to answer the question; Does healthcare professionals' use of handheld computers improve their access to information and support clinical decision making at the point of care?
    BMC Medical Informatics and Decision Making 07/2014; 14(1):56. · 1.60 Impact Factor
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    ABSTRACT: Several dietary supplements are currently marketed for management of hypertension, but the evidence for effectiveness is conflicting. Our objective was to critically appraise and evaluate the evidence for the effectiveness of chlorogenic acids (CGAs) on blood pressure, using data from published randomized clinical trials (RCTs). Electronic searches were conducted in Medline, Embase, Amed, Cinahl and The Cochrane Library. We also hand-searched the bibliographies of all retrieved articles. Two reviewers independently determined the eligibility of studies and extracted the data. The reporting quality of all included studies was assessed by the use of a quality assessment checklist adapted from the Consolidated Standard of Reporting Trials Statement. Disagreements were resolved through discussion. Seven eligible studies were identified, and five including 364 participants were included. There were variations in the reporting quality of the included RCTs. Meta-analysis revealed a statistically significant reduction in systolic blood pressure in favour of CGA (mean difference (MD): -4.31 mm Hg; 95% confidence interval (CI): -5.60 to -3.01; I(2)=65%; P<0.00001). Meta-analysis also showed a significant reduction in diastolic blood pressure favouring CGA (MD: -3.68 mm Hg; 95% CI: -3.91 to -3.45; I(2)=97%; P<0.00001). All studies reported no adverse events. In conclusion, the evidence from published RCTs suggests that CGA intake causes statistically significant reductions in systolic and diastolic blood pressures. The size of the effect is moderate. Few clinical trials have been conducted; they vary in design and methodology and are confined to Asian populations and funded by CGA manufacturers. Large independent trials evaluating the effects of CGA on blood pressure are warranted.Journal of Human Hypertension advance online publication, 19 June 2014; doi:10.1038/jhh.2014.46.
    Journal of human hypertension. 06/2014;
  • BMJ Clinical Research 06/2014; 348:g3768. · 14.09 Impact Factor
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    ABSTRACT: Effective use of warfarin involves keeping the international normalised ratio (INR) within a relatively narrow therapeutic range. However, patients respond widely to their dose of warfarin. Overcoagulation can lead to an increased risk of excessive bleeding, while undercoagulation can lead to increased clot formation. There is some evidence that patients with a variable response to warfarin may benefit from a concomitant low dose of vitamin K. To assess the effects of concomitant supplementation of low-dose oral vitamin K for anticoagulation control in patients being initiated on or taking a maintenance dose of warfarin. To identify previous reviews, we searched the Database of Abstracts of Reviews of Effects (DARE via The Cochrane Library, Wiley) (Issue 2, 2011). To identify primary studies, we searched the Cochrane Central Register of Controlled Trials (CENTRAL via The Cochrane Library, Wiley) (Issue 2, 2014), Ovid MEDLINE (R) In-Process & Other Non-Indexed Citations database and Ovid MEDLINE (R) (OvidSP) (1946 to 25 February 2014), Embase (OvidSP) (1974 to week 8 of 2014), Science Citation Index Expanded™ & Conference Proceedings Citation Index - Science (Web of Science™) (1945 to 27 February 2014), and the NHS Economics Evaluations Database (NHS EED) (via The Cochrane Library, Wiley) (Issue 2, 2014). We did not apply any language or date restrictions. We used additional methods to identify grey literature and ongoing studies. Randomised controlled trials comparing the addition of vitamin K versus placebo in patients initiating warfarin or already taking warfarin. Two review authors independently selected and extracted data from included studies. When disagreement arose, a third author helped reached a consensus. We also assessed risk of bias. We identified two studies with a total of 100 participants for inclusion in the review. We found the overall risk of bias to be unclear in a number of domains. Neither study reported the time taken to the first INR in range. Only one study (70 participants) reported the mean time in therapeutic range as a percentage. This study found that in the group of participants deemed to have poor INR control, the addition of 150 micrograms (mcg) oral vitamin K significantly improved anticoagulation control in those with unexplained instability of response to warfarin. The second study (30 participants) reported the effect of 175 mcg oral vitamin K versus placebo on participants with high variability in their INR levels. The study concluded that vitamin K supplementation did not significantly improve the stability of anticoagulation for participants on chronic anticoagulation therapy. However, the study was only available in abstract form, and communication with the lead author confirmed that there were no further publications. Therefore, we interpreted this conclusion with caution. Neither study reported any thromboembolic events, haemorrhage, or death from the addition of vitamin K supplementation. Two included studies in this review compared whether the addition of a low dose (150 to 175 mcg) of vitamin K given to participants with a high-variability response to warfarin improved their INR control. One study demonstrated a significant improvement, while another smaller study (published in abstract only) suggested no overall benefit. Currently, there are insufficient data to suggest an overall benefit. Larger, higher quality trials are needed to examine if low-dose vitamin K improves INR control in those starting or already taking warfarin.
    Cochrane database of systematic reviews (Online) 05/2014; 5:CD009917. · 5.70 Impact Factor
  • Journal of alternative and complementary medicine (New York, N.Y.) 05/2014; 20(5):A20. · 1.69 Impact Factor
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    ABSTRACT: Surveys show GPs use placebos in clinical practice and reported prevalence rates vary widely.Aim.To explore GPs' perspectives on clinical uses of placebos.Design and setting.A web-based survey of 783 UK GPs' use of placebos in clinical practice. Qualitative descriptive analysis of written responses ('comments') to three open-ended questions. Comments were classified into three categories: (i) defining placebos and their effects in general practice; (ii) ethical, societal and regulatory issues faced by doctors and (iii) reasons why a doctor might use placebos and placebo effects in clinical practice. GPs typically defined placebos as lacking something, be that adverse or beneficial effects, known mechanism of action and/or scientific evidence. Some GPs defined placebos positively as having potential to benefit patients, primarily through psychological mechanisms. GPs described a broad array of possible harms and benefits of placebo prescribing, reflecting fundamental bioethical principles, at the level of the individual, the doctor-patient relationship, the National Health Service and society. While some GPs were adamant that there was no place for placebos in clinical practice, others focused on the clinically beneficial effects of placebos in primary care. This study has elucidated specific costs, benefits and ethical barriers to placebo use as perceived by a large sample of UK GPs. Stand-alone qualitative work would provide a more in-depth understanding of GPs' views. Continuing education and professional guidance could help GPs update and contextualize their understanding of placebos and their clinical effects.
    Family Practice 04/2014; · 1.83 Impact Factor
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    ABSTRACT: To describe the potential benefits and harms of zanamivir. Systematic review of clinical study reports of randomised placebo controlled trials and regulatory information Clinical study reports, trial registries, electronic databases, regulatory archives, and correspondence with manufacturers. Randomised placebo controlled trials in adults and children who had confirmed or suspected exposure to natural influenza. Time to first alleviation of symptoms, influenza outcomes and complications, admissions to hospital, and adverse events in the intention to treat (ITT) population. We included 28 trials in stage 1 (judgment of appropriate study design) and 26 in stage 2 (formal analysis). For treatment of adults, zanamivir reduced the time to first alleviation of symptoms of influenza-like illness by 0.60 days (95% confidence interval 0.39 to 0.81, P<0.001, I(2)=9%), which equates to an average 14.4 hours' reduction, or a 10% reduction in mean duration of symptoms from 6.6 days to 6.0 days. Time to first alleviation of symptoms was shorter in all participants when any relief drugs were allowed compared with no use. Zanamivir did not reduce the risk of self reported investigator mediated pneumonia (risk difference 0.17%, -0.73% to 0.70%) or radiologically confirmed pneumonia (-0.06%, -6.56% to 2.11%) in adults. The effect on pneumonia in children was also not significant (0.56%, -1.64% to 1.04%). There was no significant effect on otitis media or sinusitis in both adults and children, with only a small effect noted for bronchitis in adults (1.80%, 0.65% to 2.80%), but not in children. There were no data to assess effects on admissions in adults and children. Zanamivir tended to be well tolerated. In zanamivir prophylaxis studies, symptomatic influenza in individuals was significantly reduced (1.98%, (0.98% to 2.54%); reducing event rates from 3.26% to 1.27%, which means 51 people need to be treated to prevent one influenza case (95% confidence interval, 40 to 103). In contrast, the prophylaxis effect on asymptomatic influenza cases was not significant in individuals (risk difference 0.14%, -1.10% to 1.10%) or in households (1.32%, -2.20% to 3.84%). In households treated prophylactically there was an effect on symptomatic influenza (14.84%, 12.18% to 16.55%), but this was based on only two small studies including 824 participants. Prophylaxis in adults reduced unverified pneumonia (0.32%, 0.09% to 0.41%; NNTB (number needed to treat to benefit) 311, 244 to 1086) but had no effect on pneumonia in children or on bronchitis or sinusitis in adults or children (risk difference 0.32%, 0.09% to 0.41%; NNTB 311, 244 to 1086). Based on a full assessment of all trials conducted, zanamivir reduces the time to symptomatic improvement in adults (but not in children) with influenza-like illness by just over half a day, although this effect might be attenuated by symptom relief medication. Zanamivir also reduces the proportion of patients with laboratory confirmed symptomatic influenza. We found no evidence that zanamivir reduces the risk of complications of influenza, particularly pneumonia, or the risk of hospital admission or death. Its harmful effects were minor (except for bronchospasm), perhaps because of low bioavailability.
    BMJ (online) 04/2014; 348:g2547. · 17.22 Impact Factor
  • BMJ (online) 02/2014; 348:g1604. · 17.22 Impact Factor

Publication Stats

1k Citations
1,095.84 Total Impact Points


  • 2006–2014
    • University of Oxford
      • • Oxford Centre for Evidence Based Medicine
      • • Department of Primary Care Health Sciences
      Oxford, England, United Kingdom
    • University of Auckland
      • School of Population Health
      Auckland, Auckland, New Zealand
  • 2013
    • University of Exeter
      Exeter, England, United Kingdom
  • 2012
    • Oregon Health and Science University
      • Department of Family Medicine
      Portland, OR, United States
  • 2010–2012
    • University of Tasmania
      • School of Medicine
      Newnham, Tasmania, Australia
  • 2011
    • The Cochrane Collaboration
      Oxford, England, United Kingdom
    • Royal College of Physicians
      Londinium, England, United Kingdom
  • 2009
    • Bond University
      Gold Coast, Queensland, Australia