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Evidence Watch: BMJ EBM       

Each week our editors select from over 100 journals reliable and useful evidence summarised in BMJ Evidence-Based Medicine.

Carl Heneghan, Editor in Chief

There’s a lot of research at the moment on blood pressure and what’s the right target to treat too.  A JAMA systematic review looked at mortality and cardiovascular disease across blood pressure levels. [1] In 74 trials (and a lot of patient-years) they found that above a baseline BP of 160 mm Hg treatment reduced risk for death, but below 140 mm Hg, treatment was not associated with mortality reductions.

A  Hong Kong study of Proton pump inhibitors (PPIs) link with gastric cancer among H Pylori infected people reported that  PPIs use was associated with an increased risk of cancer. [2] Note though there’s a lot of associations for PPI use but little in terms to say on causation. The good news, though, is the risk remain small: out of 63 397 subjects, 153 (0.24%) developed cancer during a median follow-up of 7.6 years.

An RCT of 955 patients assigned to subcutaneous Erenumab (a monoclonal antibody that inhibits the calcitonin gene-related peptide receptor)  or placebo for the prevention of an episodic migraine reported reductions in migraine frequency and the use of the migraine medications over six months. [3]  Data on long-term are lacking, its lacking independent replication and this treatment will break the bank: some estimates have the cost at between $8,000 and $20,000 annually.

A Cochrane review including 7 RCTs of oral anticoagulants showed they had no effect in people with cancer through but did increase the risk of bleeding. [4[  Lots of problems with underpowered research, commercial influences and moderate quality evidence.  This is a  living systematic review (not sure though if this is the right term as it suggests some reviews are dead) meaning it will be continually updated –  good news given how long some Cochrane reviews take to be updated.

Evidence Watch provides the articles likely to impact practice: access the summaries at BMJ Evidence-Based Medicine:


[1] Association of blood pressure lowering with mortality and cardiovascular disease across blood pressure levels a systematic review and meta-analysis. Brunstrom M. & Carlberg B. 2018. JAMA Internal Medicine, 178(1), 28-36. (PubMed)

[2] Long-term proton pump inhibitors and risk of gastric cancer development after treatment for Helicobacter pylori: a population-based study. Cheung K.S. et al. 2018. Gut, 67(1), 28-35. (PubMed)

[3] A controlled trial of erenumab for episodic migraine. Goadsby P.J. et al. 2017. The New England Journal of Medicine, 377(22), 2123-2132. (PubMed)

[4] Oral anticoagulation in people with cancer who have no therapeutic or prophylactic indication for anticoagulation. Kahale L.A. et al. 2017. Cochrane Database of Systematic Reviews,2017(12), CD006466. (PubMed)

BMJ Evidence-Based Medicine – original evidence-based research, insights and opinions on what matters for health care.

BMJ EBM accepts submissions of a wide range of article types, including original research, debate, analysis & opinion, and clinical spotlight.

Read more about BMJ EBM content in the Welcome to BMJ Evidence-Based Medicine Editorial.





Carl Heneghan is Professor of EBM at the University of Oxford, Director of CEBM and Editor in Chief of BMJ EBM

Follow on twitter @carlheneghan

Competing interests

Carl has received expenses and fees for his media work including BBC Inside Health. He holds grant funding from the NIHR, the NIHR School of Primary Care Research, The Wellcome Trust and the WHO. He has also received income from the publication of a series of toolkit books published by Blackwells. CEBM jointly runs the EvidenceLive Conference with the BMJ and the Overdiagnosis Conference with some international partners which are based on a  non-profit model. 

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