On The Pulse - 11th May 2012
Warfarin in heart failure
Heart failure is a risk factor for atrial fibrillation, in turn increasing the risk of stroke, so a study in the NEJM tries randomising 2300 such patients to warfarin (target INR 2.0–3.5) or aspirin (325 mg/day). At 3.5 years, ischaemic stroke was modestly lower in the warfarin group, but major bleeds were more frequent and there was no significant improvement in mortality or the primary composite endpoint of stroke (ischaemic or haemorrhagic) or death. An accompanying Editorial agrees that while anticoagulant therapy appears to prevent stroke in heart failure patients with severe systolic dysfunction, the effect is too small to justify its routine use.
Depression in primary care
An article in JAMA warns that 1 in 10 primary care patients has a major depressive disorder, the Beating the Blues website claims that 1 in every 5 people is affected by depression or anxiety, and the Tavistock and Portman Foundation Trust says that mental health problems affect 1 in 4 people. A column in the BMJ , which discusses where these figures come from and what they might actually mean, reckons that inflated and poorly explained prevalence estimates don’t help anyone. Still, depression is undoubtedly a common problem, and the JAMA article provides an helpful account of current approaches to management.
Screening for congenital heart defects in newborns
Early identification of congenital heart defects is likely to improve prognosis. A meta-analysis in the Lancet assesses pulse oximetry as a screening strategy, based on detecting degrees of hypoxaemia that are not clinically evident. From 13 studies of 229,421 newborns, they conclude that while the sensitivity of this technique is only ~75%, its specificity is close to 100%. However, an accompanying Comment points out that, while pulse oximetry is cheap and safe, effective follow-up after a positive screen is also required for the strategy to be worthwhile.
Synthetic arteriovenous grafts provide good vascular access for haemodialysis, but they have high rates of thrombosis, usually at the venous end, where intimal hyperplasia causes stenosis. Ten years ago, a small trial (n=24) reported that dietary supplementation with ω-3 fatty acids greatly prolonged graft survival, but as so often with small trials, the benefits turned out to be illusory. JAMA now has a large trial showing that patency rate of these grafts over the first year was no better in those taking daily fish oil supplements than it was in a control group taking corn oil.
Radioiodine in thyroid cancer
Radioiodine reduces recurrence after total thyroidectomy for thyroid cancer, but the dose obviously needs to be minimised. Two studies in the NEJM, one in the UK and one in France , show that a low dose of 1.1 GBq is as effective in low-risk patients as a higher dose of 3.7 GBq, with fewer adverse events in the UK low-dose group. An accompanying Editorial agrees that the results should change practice, but wonders whether some low-risk patients need radioiodine at all, and is sceptical that the convenience of preparation with thyrotropin alfa justifies its cost.
ARBs and cancer
Angiotensin II receptors regulate angiogenesis, cell proliferation and tumour progression which, at least theoretically, gives cause for concern about cancer in people taking angiotensin receptor blockers for long periods. A study in the BMJ uses data from the UK general practice research database to check. Overall, rates of cancer were no higher in people taking ARBs than they were in those taking ACE inhibitors. And although there was a hint that breast and prostate cancers might be slightly commoner in people taking ARBs, the lack of any association with duration of treatment makes a cause-and-effect relation doubtful.
Following a report by an expert advisory group in 1995, provision of cancer treatment in the UK gradually moved to multidisciplinary teams in specialist centres. Although this shift is generally thought to be a good thing, there hasn’t been much hard evidence of better outcomes. The BMJ has an observational study comparing outcomes of treatment of breast cancer in two regions of Scotland in which multidisciplinary working was introduced at different times. The introduction of multidisciplinary care was associated with substantial improvements in patient survival, a reduction in variation in outcome between treatment centres and reorganisation of care away from poorly-performing hospitals.
Antipsychotics for preventing relapse in schizophrenia
Schizophrenia is often a lifelong problem, and relapse is common. A meta-analysis in the Lancet assesses whether antipsychotics can prevents relapse over the next year in patients who have had a single psychotic episode, assessing 65 trials in 6493 patients. While the relapse rate was significantly lower compared to placebo (27% vs 64%), there were more adverse effects, including weight gain, movement disorders and sedation, and fewer than a third of relapses actually required readmission. An accompanying Comment thinks we need to both investigate the risks and benefits more thoroughly and ask deeper questions.