This week's journal reviews on Doctors.net.uk
Journal Watch is a service provided to summarise some of the most popular medical journals.
Doctors.net.uk has a panel of specialist advisers responsible for reviewing a range of journals of general medical interest and some more specialised publications.
General Journal Watch is written by Dr Druin Burch, Consultant in Internal Medicine
This week's journals include....
Failing to treat type 1 diabetes
A masterpiece of marketing and spin in which real science drowns. This is another trial looking at whether it's possible to preserve lingering beta-cell function in newly diagnosed type 1 diabetics. Here they use a variant of anti-CD3 antibodies and the primary outcome is the dubious composite of insulin use and HbA1c at one year. Surely, for a new drug operating in a new way, a harder endpoint is required? Not that this primary outcome is even positive, although you won't know that unless you read the trial in reasonable detail. The discussion notes the composite outcome "has not been used or validated previously" yet uses this to imply it probably would have been positive if better chosen - a really breathtaking piece of spin. The statistical section is even more revealing: "The second primary analysis, secondary analyses, and post-hoc analyses were regarded as exploratory and hypothesis generating because they were originally planned only to be assessed if the primary outcome was significant. " Prespecified primary and secondary outcomes were all negative, yet The Lancet allows the final paragraphs of the paper's abstract and conclusion to talk as though the trial was positive. It even publishes an accompanying editorial on page 459 stating we should put these antibodies into immediate and widespread practice - absolutely shameful!. I've read this paper repeatedly in disbelief and it gets worse each time. If I was Richard Horton I'd sack someone or resign.
Bad science and breast cancer screening
The bad science here doesn't refer to this study, which is good, but to the catastrophic failure to properly answer a question which has left us flailing around ever since. Breast cancer screening picks up cancers and raises queries about them when they aren't there - it causes definite harms and possible benefits. It was introduced without hard evidence of it doing more good than harm over the long term and we've been left desperately uncertain whether we've made a terrible mistake in starting it up. Political pressure (aided by scientific stupidity) is too strong for it to be withdrawn, but the chance that it's a bad thing is very real. This study looks at European regions where it was introduced at different times. Breast cancer mortality dropped over the years screening was introduced, but showed no association with the local timing of its introduction. We'll never overturn screening with circumstantial evidence and we're unlikely, now that it's become established based on its own circumstantial evidence, to ever have a trial capable of telling us its overall impact.
Should we save the lives of smokers?
A remarkable study and a remarkably well written one. A 20% drop in lung cancer mortality was seen in persons undergoing three annual consecutive CTs compared with three consecutive annual chest X-rays, in a 5-year follow-up study. Should we plunge into a widespread screening programme, saving lives here, there and everywhere? Over 95% of positive findings on screening were false positives, yet the number of adverse events was remarkably low. The authors, though, question the cost-effectiveness of their findings, question what would happen if screening were performed outside of the centres of excellence involved in their study and question what would happen with today's more sensitive CT scanners. That's a lot of questions and very few answers. We're left in the odd position of reading that screening for lung cancer appears to work but being told we shouldn't introduce it.
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