February 17th, 2014
Selections from Richard Lehman’s Literature Review: February 17th
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.
JAMA Internal Medicine
Rates of Complications and Mortality in Older Patients With Diabetes Mellitus (pg. 251): Goodness, it’s taken a long time for the diabetes community to come to terms with the obvious. A study of people over 60 with diabetes finds that the main ill effects of their condition in old age are coronary artery disease and hypoglycaemia. In people who develop diabetes after the age of 60, microvascular disease is so uncommon it is hardly a consideration: whereas the commonest treatments given to lower sugar frequently cause hypoglycaemia and have little or no effect on coronary disease. Step back, guys: treating type 2 diabetes is a whole different ball game in a 65 year old as compared with a 35 year old. One size does not fit all ages. In fact, each patient of any age needs to be treated in accordance with his or her own goals and informed preferences. People with diabetes have for so long been misinformed about the benefits and harms of treatment that I suspect we often keep them on drugs out of sheer embarrassment at admitting we didn’t know what we were doing. And it’s still going on: we “put people on” drugs like incretin mimetics when we haven’t a clue what they do to long-term outcomes, and then congratulate ourselves just because their HbA1c has gone down.
Hospital Variation in the Use of Noninvasive Cardiac Imaging and Its Association With Downstream Testing, Interventions, and Outcomes (online): Another week, another great paper from a Yale medical student. If this is beginning to sound like advertising, I don’t care: I wish every medical school had a Harlan Krumholz and Joe Ross who would encourage attached students to produce work of such quality. This time the student’s name is Kyan Safavi, and he did a massive survey of data about variation in non-invasive cardiac imaging for suspected ischaemia across US hospitals. “Hospitals with higher imaging rates did not have substantially different rates of therapeutic interventions or lower readmission rates for AMI but were more likely to admit patients and perform angiography.” So non-invasive imaging leads to invasive imaging without showing any clear benefit in patient outcomes. Those Americans, eh? But I bet you would find exactly the same variation in the UK, especially between district general and teaching hospitals.
Percutaneous Renal Denervation in Patients with Treatment-Resistant Hypertension (pg. 622) In this paper, the abstract conclusion (called Interpretation) can afford to be laconic: “Changes in blood pressure after renal denervation persist long term in patients with treatment-resistant hypertension, with good safety.” This is indeed true of the 88 out of 153 patients who had full follow-up data at 36 months in this Medtronic-funded Symplicity HTN-1 trial. These were people whose blood pressure remained high despite treatment with an average of five different agents. And the drop in BP following percutaneous radiofrequency ablation of the renal nerve supply was little short of spectacular: a mean fall of 32 mm Hg in systolic and 14.4 mm diastolic. So something really big is happening here, and you could say that this is the kind of intervention which did not get a randomized trial because it didn’t need one. What it did need, however, was tighter follow-up. I know this is something Medtronic are keen to carry out in the future, and to be fair they didn’t design this trial themselves: it was instigated by a company they bought up half way through. But it was a missed opportunity to do better from the outset in the evaluation of a treatment which looks to have immense potential.