Monday 15 November 2010

JOURNAL SNIPPETS November 2

JAMA 11 Nov 2010 Vol 304
2028 It's not often that you see a paper in JAMA written by a real working British GP - so congratulations to Louis Levene from Leicester for an excellent study that seeks to inform US practice by showing what happens to coronary heart disease mortality in relation to the recorded characteristics of individual primary care trusts. This was quite a statistical feat in itself, but would have been even more useful had it been done on an individual practice basis - after all, the data are out there, literally for all to see. Anyway, rejoice: CHD in the UK has fallen by nearly a half in the last decade, and although there are regional variations, these are not due to variations in the quality of general practice, except in the detection of high blood pressure, which could easily be remedied.
http://jama.ama-assn.org/cgi/content/abstract/304/18/2028

2059 A neat Commentary piece discusses the dilemmas of interventional cardiology in the light of the COURAGE and SYNTAX studies which show that medical treatment is as effective as percutaneous coronary intervention for stable coronary artery disease. When the first study appeared in 2007, interventional cardiologists were asked if they would now have the conviction of their COURAGE and stop putting stents into every stenosis they happened to see at angiography - what has been described as the "oculo-stenotic reflex". All immediate stenting is lumped together as "ad hoc PCI" and accounts for more than 80% of PCI in the USA; done for acute syndromes, it is generally appropriate, but in other situations, often not. This is a thoughtful, balanced discussion which however tactfully bypasses one factor which may keep ad hoc PCI going in the USA - money. There may be a double incentive - patients and HMOs may want to save the cost of a second angiography; and cardiologists and their institutions may just want the extra dollars they get for putting in a stent there and then. This piece argues that there where there is clinical doubt there should always be informed patient decision-making, even if this means taking a two-week pause between the diagnostic angiogram and the procedure.
http://jama.ama-assn.org/cgi/content/extract/304/18/2059

Lancet 13 Nov 2010 Vol 376

1658 A huge trial called SEARCH was set up in Oxford in 1998 in the hope of demonstrating that 80mg of simvastatin would be better than 20mg at preventing further coronary events in survivors of MI, and that additional benefit would result from lowering homocysteine. In fact it has shown neither. The high dose simvastatin group showed a 26-fold increase in significant myopathy, an expected fall in lipid cholesterol (LDL-C), but no significant difference in vascular events at a mean of 6.7 years. Yet in the summary this is taken to mean that high dose simvastatin is preferable, since that fits into a general meta-analysis of statin trials on p.1670. Although medicine has been taught alongside logic in Oxford for 850 years there is still room for improvement. Consider the following three statements:
- there is a continuous association between the observed level of LDL-C and coronary heart disease (CHD)
- all statin drugs lower LDL-C
- all statin drugs lower CHD in the same proportion that they lower LDL-C.

Does it therefore follow that:
(1)statin drugs lower CHD entirely by means of lowering LDL-C
(2) all drugs that lower LDL-C will lower CHD to the same degree as statins?
It would be good to think that any canny medieval Oxford schoolman would immediately answer no to both deductions, or rather "quod non erat demonstrandum".

In the case of (1), the best we can say is that this is a reasonable hypothesis, but a hard one to test. In the case of (2) we can say that this is a weak hypothesis, since every drug class has a mixture of actions, and so far no LDL-C lowering drugs other than statins have been shown to lower CHD. Nor should we prescribe them until they have. But the writing committees of these two studies, sharing a number of Oxford notables, behave more like theologians than logicians. LDL-cholesterol to them is an infallible surrogate, and anything that lowers it must be good, even though they have only studied statins. It's enough to make you want to burn your gown. As for The Lancet: this is the second time in two weeks that they've let triallists write a summary which misrepresents the result of trial which was negative for its primary end-point (SEARCH this week, VITAL last) - not good enough.

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)60310-8/abstracthttp://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)61350-5/abstract


BMJ 13 Nov 2010 Vol 341
1034 Do you like PROMs? When I was 16, I didn't mind queuing for tickets outside the Albert Hall and standing in the top gallery, but now being older, if you buy tickets on-line you can sit down and actually hear the players. This abbreviation also applies to patient-reported outcome measures, of the kind looked at in the context of heart failure. Suddenly these kinds of PROMs have become fashionable politically and get repeated mention in the White Paper "Liberating the NHS" - although they were never designed for service development but as end-points for clinical trials. Their quality and relevance varies widely, as you learn rapidly. This ground-breaking study devised an instrument with a high degree of inter-observer agreement to allow the assessment of PROMs in cardiovascular trials. Suffice to say that in many of the trials where they appear, they are used badly or irrelevantly, while in 70% of trials where they should appear, they don't.
http://www.bmj.com/content/341/bmj.c5707.full

Arch Intern Med 8 Nov 2010 Vol 170
1834 Delay From Symptom Onset to Hospital Presentation for Patients With Non–ST-Segment Elevation Myocardial Infarction. If you're a veteran scanner of titles in the US cardiovascular outcomes literature, the next thing you'll look for is the name of Harlan Krumholz in the authors list - ah yes, there it is, and so too is the name of Brahmajee Nallamothu, co-author of the thoughtful commentary piece on PCI in this week's JAMA. As a result of their work, and that of Henry Ting and John Spertus, who also appear in the credits, we know a huge amount in great detail about the workings of acute cardiology in the USA, despite the great variety of institutional arrangements. As a result of this exercise, for example, we know the exact time delay and clinical characteristics of 104 622 patients admitted to 568 US hospitals with NSTEMI - and realise that there has been no reduction in the delay time between 2001 and 2006. http://archinte.ama-assn.org/cgi/content/abstract/170/20/1834

1842 Now the interventional trials for ST-Elevation MI tell us that time means myocardium, so great efforts have been made in the US as in the UK to ensure that door-to-balloon time should be as short as possible. But what have we here? A study of 8771 patients admitted to a Michigan hospitals group between 2003 and 2008 which shows that although door-to-balloon time improved dramatically, outcomes remained the same. More data from UK studies quickly please: and since we do not have 568 acute hospitals and they all belong to one organisation, this should be a piece of cake compared with Harlan's work.
http://archinte.ama-assn.org/cgi/content/abstract/170/20/1842

1858 From time to time, serious medical journals like to publish pieces about chocolate, which are sure to get them a mention in the global news media. This research letter also involves women, thus allowing journalists to trot out their very funny jokes about the dear ladies and their chocolate. A group from Perth, Australia followed up a female cohort for 10 years to examine the effect of calcium supplements, and happened to ask about chocolate intake in their questionnaire. Here they report that chocolate consumption seems to have a dose-related protective effect against vascular disease in women. Ooh, come on girls, have another. http://archinte.ama-assn.org/cgi/content/extract/170/20/1857

1 comment:

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