June 16th, 2014

Selections from Richard Lehman’s Literature Review: June 16th

CardioExchange is pleased to reprint this selection from Dr. Richard Lehman’s weekly journal review blog at BMJ.com. Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.

NEJM 12 June 2014 Vol 370

CPAP, Weight Loss, or Both for Obstructive Sleep Apnea (pg. 2265): Obstructive sleep apnoea is often a result of weight gain, and unfortunately, once it is established, losing weight does not reduce it. But losing weight has benefits of its own (he sighs wistfully), as this trial of weight reduction, continuous positive airways pressure, or both for OSA demonstrates. I carry my flabby, insulin resistant, borderline hypertensive, tired all the time body around until the happy moment when I can put on my mask and feel the cool whoosh of air that signals sleep time. Would I do better to lose weight? Oh yes. It would not reduce my C-reactive protein (assuming it needs reducing), but it would certainly help reduce my triglycerides and insulin resistance (not that I have much idea about them either).

CPAP vs. Oxygen in Obstructive Sleep Apnea (pg. 2276): In OSA, CPAP reduces BP. Nice to be able to use these abbreviations, because I have spelt them out above; well actually I haven’t spelt out BP. It stands for blood pressure. In a cohort of people with OSA and high BP, supplemental nocturnal oxygen was tried instead of CPAP for 12 weeks. Result: O2 a no-no for lowering BP in OSA.

JAMA 11 Jun 2014  Vol 311

Association Between Intensification of Metformin Treatment With Insulin vs Sulfonylureas and CV Events and All-Cause Mortality Among Patients With Diabetes (pg. 2288): This issue of JAMA is all about diabetes. Why does that make me want to run away and hide? Nobody in the field had ever heard of me until I entered the fray in 2009 with an editorial in The BMJ, shared with Harlan Krumholz, about the new QOF target for HbA1c. It drew 25 rapid responses, and ever since then I have been dragged back into commenting on diabetes, although I had said pretty much all I have to say in that short piece. Which is simply that the management of diabetes is a mess, and won’t be sorted out until we give patient-important outcomes a higher rank than surrogate outcomes. Alas, this implies that we need new long term trials of considerable complexity.

In the meantime, we have to go by what evidence we have, which is almost entirely observational. We would like to know if adding insulin to metformin is a better strategy than adding a sulfonylurea. Enter the Veterans’ Administration database and some cutting edge statistical wizardry. Not just propensity scores, but also marginal structural Cox proportional hazards models, inverse probability weights, and estimates of the magnitude of imbalance in unmeasured confounders, which might skew the results. What could possibly go wrong? Well, just about anything, as a very good editorial by Monika Safford explains. The conclusion of the study is that, among patients with diabetes who were receiving metformin, the addition of insulin rather than a sulfonylurea was associated with an increased risk of a composite of nonfatal cardiovascular outcomes and all cause mortality. But short of a randomised trial, we just can’t know for sure.

JAMA Internal Med Jun 2014

Statins and Physical Activity in Older Men (OL): “When you are old and grey and full of sleep, A dosset box of statins you shall keep.” This comes from the poetic language summary of the latest NICE guidance on statins. The prose version says “Offer a statin to all individuals aged 85 or over,” which sounds entirely bonkers to me, though I am generally in favour of offering statins to everyone. But by the time I get to 85, I think I might want to die of something, to save further trouble. The benefits of statins are certain and accrue over many years; the harms are less certain, and generally stop as soon as you stop the statin. The trouble is that the main adverse effect of statins is to make muscles ache, and this is so common in old age that people may not put it down to their tablets. This could be the reason that a new analysis of data, collected for the Osteoporotic Fractures in Men study, finds that men who take statins have slightly lower rates of physical activity. Or maybe not. There may be a hidden confounder to account for these minor differences. If you are looking for a stick to beat statins with, this is more like a twig.

Ann Intern Med 3 Jun 2014

Transitional Care Interventions to Prevent Readmissions for Persons With Heart Failure (pg. 774): “Heart failure (HF) is a leading cause of hospitalization and health care costs in the United States. Up to 25% of patients hospitalized with HF are readmitted within 30 days. Readmissions after an index hospitalization for HF are related to various conditions. An analysis of Medicare claims data from 2007 to 2009 found that 35% of readmissions within 30 days were for HF; the remainder were for diverse indications (for example, renal disorders, pneumonia, and arrhythmias).” There are a lot of people who are working on this, trying out new models of care, such as the so-called “transitional care interventions” that form the basis of this review. In the context of the USA, anything that promoted primary care and team working reduced admissions and mortality. What about the UK? I have been thinking about this for 20 years, and I don’t know, for the simple reason that I have not properly asked people with HF and their carers what would be of greatest help to them. I’d suggest that somebody does this, rather than working from a cost reduction perspective and asking cardiologists, just because that is the easiest way to get a grant. I suspect that if I get heart failure, I will just want a place of safety when I am weak and breathless and feel like I’m about to die: which may happen a lot before I actually do.

Lancet 14 Jun 2014 Vol 383

Differential Clinical Outcomes After 1 Year vs. 5 Years in a Randomised Comparison of Zotarolimus-Eluting and Sirolimus-Eluting Coronary Stents (pg. 2047): Well Dave, you can hear the anticipation in the capacity crowd here at Rio as these two great teams line up in the tunnel. The last time these titans met at a World Cup, it was Sirolimus that came away one-nil, but four years later can Zotarolimus even the honours? We know this pitch is not in perfect shape—it looks like an open label job to me—and we’re hoping there won’t be any of those questionable decisions by the ref and the linesmen that marred previous clashes. Oh, and they’re off. (Five years seem to elapse). Well that was 90 minutes of pure magic, ending in a goalless draw! Still, both managers will have something to take away from this. Alfonso Medtronico of Zotarolimus has brought the side into major surplus, and his old rival Johnson Johnson on the Sirolimus side won’t be too unhappy either. It’s the fans I feel sorry for. In the old bare metal days, a stent match used to be a family affair, when you could bring your small lads along and ten bob would cover the game and a pie afterwards. Some of these fans have paid over a thousand pounds to watch this match. It sometimes makes me want to elute.

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