On The Pulse - 8th June 2012
Which risk score for cardiovascular disease?
At least seven models are commonly used to evaluate cardiovascular risk (Framingham, ASSIGN, SCORE, PROCAM, QRISK1, QRISK2 and Reynolds risk score) and a systematic review of comparative studies in the BMJ investigates which has the best prognostic performance. Unfortunately, there’s no clear answer, despite more than 50 head-to-head comparisons. The investigators say that the results were inconsistent, not fully reported, biased or difficult to interpret, and call for studies in independent samples by people who weren’t involved in the development of these models.
The NEJM has a review on the topic of drowning, which attracts little research attention but is a frequent cause of death, especially among boys aged 5–14. Briefly, resuscitation attempts should begin on land unless you have special training, and the airway-breathing-circulation sequence should begin with airways, as the chief problem is lack of oxygen. Active attempts to expel water from the airway will delay ventilation and increase the risk of vomiting, and should be avoided. You’ll have to read the article for the latest on prehospital care, ICU treatment, the likely outcomes and unusual complications.
Screening for lung cancer
Lung cancer is the leading cause of cancer death worldwide, and most patients have advanced disease by the time they are diagnosed, which means that the outlook is grim. Screening with low-dose computed tomography might offer a way forward, but the potential harms from radiation and invasive investigation of lung nodules that eventually turn out to be benign are substantial. A systematic review in JAMA scrutinises the findings of eight RCTs of screening and concludes that benefits might outweigh harms – but only for people aged 55–75 with a history of > 30 pack-years of cigarette smoking.
Rhythm vs rate control in atrial fibrillation
Randomised trials have shown little difference between rhythm and rate control strategies in the management of atrial fibrillation. However, an observational study in Archives of Internal Medicine following 26,000 patients finds that despite little difference in mortality between the strategies at 4 years, rhythm control was superior after 5 and 8 years, with hazard ratios of 0.89 and 0.77, respectively. An accompanying Commentary commends the sophistication of the analysis, needed to counter the obvious problem of confounding by indication, and thinks we must at least consider the possibility that trials to date have been too short.
Malignant pleural effusions
Malignant pleural effusions cause disabling dyspnoea and make the last few months of life miserable for people with terminal cancer. Pleurodesis with talc is successful about 70% of the time but requires hospitalisation. Another approach is to insert an indwelling pleural catheter and teach patients or the people looking after them how to drain the effusion every few days. An RCT in JAMA finds nothing to choose between these two options, judged by patient-reported dyspnoea over the next 6 weeks. Hospital stay was shorter for those allocated to the indwelling catheter, but adverse events – mainly infections – were commoner.
PD-1 immunotherapy in advanced cancer
Two phase I trials in the NEJM use antibodies to target the programmed death 1 (PD-1) receptor in advanced cancer, which in theory could produce fewer side effects and greater antitumour activity than existing immunotherapy approaches. The first uses an antibody vs PD-1 itself, the second an antibody to its ligand PD-L1, both in about 200 patients. Both produced durable responses: the direct antibody at a rate of 20–25%, with tumour expression of PD-L1 a predictor of response. An accompanying Editorial thinks this approach is likely to provide a new benchmark for antitumour activity in immunotherapy.
Why people develop pain at the calcaneal origin of the plantar fascia is a mystery. If it occurs in someone who runs, it’s usually put down to overuse, but whether this is the real explanation is another matter; most cases occur in older people who haven’t gone faster than a walking pace for years. A randomised trial of treatment in the BMJ finds that ultrasound-guided steroid injection reduces pain better than saline injection, but as the average improvement is fairly small (10 points on a 100 point pain scale) and only lasts for 4 weeks, it’s hard to see it being cost effective. There’s a video of the injection technique here.
Renal outcomes in diabetes
The microvascular benefits of tight glycaemic control in diabetes are well established, the macrovascular benefits less so. A meta-analysis in Archives of Internal Medicine analyses seven trials following ~28,000 patients for 2–15 years, and finds no evidence that keeping HbA1c < 7.0% improves major renal outcomes. Two accompanying Commentaries take contrasting views of this result. One reminds us that the risks of intensive control may well outweigh the benefits, and thinks efforts may be better focused elsewhere. The other worries that many of the studies included had limited follow-up, and thinks that the evidence still favours tight control.