Immortal time bias in survival analysis

By: Simon Knight | Posted on 17th December 2018

Whilst reviewing an article submitted to a transplant journal recently, my attention was brought to an issue that is often overlooked in survival analysis, called ‘immortal time bias’. The issue arises when the groups to be compared in the analysis are defined by a time-dependent event that can occur any time during follow-up. As standard […]

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The explosion of systematic reviews – have we gone too far?

By: Simon Knight | Posted on 14th September 2016

A fascinating recent paper from Professor John Ioannidis from Stanford University, published in the Milbank Quarterly, has examined the explosion in the publication of systematic reviews and meta-analyses over recent years. Publications between 1991 and 2014 increased by 2,728% for systematic reviews, and 2,635% for meta-analyses – far in excess of the rate of publication […]

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HIV Positive to HIV positive kidney transplantation- results at 3-5 years

By: Peter Morris | Posted on 12th June 2015

Although the outcome of kidney transplantation in HIV positive patients who receive organs from HIV negative donors has been reported as being similar to the outcome in HIV negative recipients, this report from South Africa is the first long term follow up of HIV positive patients who receive kidneys from HIV positive deceased donors. Over […]

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Deviation from intention-to-treat analysis alters treatment effect

By: John O'Callaghan | Posted on 12th June 2015

A recent article in the BMJ by Abraha et al, using large amounts of data from RCTs, has shown that deviation from intention-to-treat analysis (ITT) can lead to apparently larger treatment effects. When compared to standard intention-to-treat analysis there was a significant difference in the apparent treatment effect. When a deviation from ITT was compared […]

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Donor specific HLA alloantibodies (DSA) in liver transplantation

By: Peter Morris | Posted on 8th April 2014

A conference was held with an invited faculty (predominantly from the USA) and sponsored by industry to discuss the impact of DSA in liver transplantation and this article reports their opinions. It was agreed that the presence of DSA are recognised now to have a deleterious effect on outcome, particularly if HLA Class II antibodies, […]

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Origins of Evidence Based Medicine

By: Peter Morris | Posted on 21st February 2014

There was an interesting editorial by Richard Smith and Drummond Rennie in the BMJ recently. The editorial is based on two interviews of pioneers in this field by Richard Smith, the former editor of the BMJ. In the first oral history he interviews Iain Chalmers, Muir Gray and David Sackett. They said that authors from a […]

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Compliance with the Consort Statement in Surgery

By: Peter Morris | Posted on 4th February 2014

Recently, the Centre for Evidence in Transplantation published an analysis of compliance with the CONSORT statement in reports of randomised controlled trials (RCTs) in transplantation, and found that the compliance left much to desire. A recent article in the Annals of Surgery analysed Consort compliance in 150 recently published RCTs in surgery, most of these being in […]

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Trial methodology – is it small-print?

By: Simon Knight | Posted on 23rd August 2013

As any regular reader of peer-reviewed journals will know, the most important section of any paper is the description of methods.  Without the information in the methods section it is almost impossible to interpret the results of a paper and determine whether the author’s conclusions are justified.  Indeed, it is often justifiable to bin a […]

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Surgical Ethics

By: Peter Morris | Posted on 1st March 2013

This editorial by Professor Daniel Sokol on Surgical Ethics is well worth noting. Professor Sokol is a Barrister and also a Senior Lecturer in Medical Ethics at Imperial College. He has written a very perceptive editorial on this subject which is entirely relevant to transplant surgeons. But he also makes the point that the pamphlet […]

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