January 12th, 2015
Selections from Richard Lehman’s Literature Review: January 12th
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.
Ann Intern Med 6 Jan 2015 Vol 162
D-dimer Testing to Select Patients With a First Unprovoked Venous Thromboembolism Who Can Stop Anticoagulant Therapy (pg. 27): Having an unprovoked deep vein thrombosis is a powerful risk factor for having a second DVT. The risk declines over time but never quite goes away. Researchers in Canada sought to establish whether it would be useful to measure D-dimer before stopping anticoagulation, and then, if the D-dimer was negative, stop the anticoagulants, measure it again after a month and restart the drugs if it had become positive. Or leave them off if both tests were negative. It didn’t quite work in men, who showed a 9.7% annual recurrence rate even after two negative tests. In women the rate was 5.4%, which might just be acceptable.
Effects of Blood Pressure Reduction in Mild Hypertension (OL): Are you the kind of clinician who actually treats blood pressure? If you’re a GP, that means you’re probably responsible for about 400 people taking drugs for let’s say an average of 15 years = 52 million drug-hours. So do click on the link and take half an hour of your own time to mull over this free systematic review of the effects of BP reduction in mild hypertension. Consider what you are trying to do. Reduce cardiovascular risk, right? If you have come across John Yudkin’s Ten Commandments, you will remember the one that says “Thou shalt treat according to level of risk and not to level of risk factor.” So for each “patient” on BP-lowering medication, you have calculated a risk score such as QRISK? And discussed each element of it with each individual and what non-drug and drug treatments might help to reduce it? Giving every person an individualized number-needed-to-treat and number needed-to-harm for each intervention? If you have answered yes to all of these questions, you must be lying, because the information to support this detail of shared decision making simply isn’t there. This review, which lumps together all sorts of individuals—with and without diabetes, some with previous treatment and some not—ends up concluding that treating people with “grade 1 hypertension” is probably going to reduce cardiovascular events but that the confidence intervals are huge. So which risk-reducing intervention is it going to be? More physical activity? A statin? A BP lowering agent? A more “Mediterranean” diet? Metformin? All of the above, or none of them? After all, it is the symptomless individual who has to decide on the basis of the information you give them. This is the mess we are in and the mess we need to get out of if shared decision making about risk reduction is going to become a reality. Because “mild hypertension” is not a thing in itself: it is just a single risk factor. And “all-cause mortality”—the thing that gets us all in the end—does not seem to be postponed by any of the mild BP treatments described in this paper.
JAMA Intern Med Jan 2015
Association Between Dietary Whole Grain Intake and Risk of Mortality: Perhaps the grim reaper can be held off a while by eating more whole grain products. This is one possible conclusion to be drawn from dietary information fed into those two familiar American cohort studies, 74 341 women from the Nurses’ Health Study (1984–2010) and 43 744 men from the Health Professionals Follow-Up Study (1986–2010). ” These data indicate that higher whole grain consumption is associated with lower total and CVD mortality in US men and women, independent of other dietary and lifestyle factors.” So the genes that make people like to eat grainy things may be associated with the genes that make people die less from cardiovascular disease. Or maybe the grainy things themselves have that effect. Either way, I shall eat what I like, avoiding buckwheat and couscous and similar vile things.
Lancet 10 Jan 2015 Vol 385
Efficacy and Safety of LDL-Lowering Therapy Among Men and Women (OL): The Cholesterol Treatment Trialists’ Collaboration offer a paper on “Efficacy and safety of LDL-lowering therapy among men and women: meta-analysis of individual data from 174 000 participants in 27 randomised trials.” But although there is now some weak evidence LDL-C lowering with ezetimibe may improve cardiovascular outcomes, all the evidence in this review is about statins. These drugs certainly lower LDL-C and “These results indicate that, for each 1 mmol/L reduction in LDL cholesterol, statin therapy reduced major vascular events by about a fifth, major coronary events by a quarter, coronary revascularisations by a quarter, and ischaemic stroke by just under a fifth, and that these proportional reductions were similar in men and women, even though on average women had somewhat lower absolute cardiovascular risk in these trials.” But it’s not just pedantic obstinacy that makes me chary about putting all this down to LDL-C lowering. I’m worried that people will therefore carry on treating cholesterol as some kind of target independent from total cardiovascular risk, whereas we need always to obey the commandment “Treat to level of risk and not to level of risk factor.” And scientifically I still can’t understand how statins can produce marked improvements in acute events before they have had time to reduce HDL-C.