On The Pulse - 27th April 2012

Appendicitis
A meta-analysis in the BMJ combines data from six trials of treatment of acute appendicitis and finds that intravenous antibiotics are at least as good as surgery. Compared with appendicectomy, antibiotic treatment resulted in fewer complications without increasing the length of time spent in hospital. Surgeons of course will find this difficult to believe, as several sceptical Rapid Responses already show. But it isn’t really such a surprise because, at the other end of the colon, antibiotics are invariably the first-line treatment for acute diverticulitis, with surgery reserved for non-responders.

PCI vs CABG
The ASCERT study, published in the NEJM, compares coronary artery bypass grafting and percutaneous coronary intervention in ~180,000 patients aged ≥65 years who had coronary artery disease without acute myocardial infarction, linking a national cardiovascular registry and an adult cardiac surgery database to claims data for 2004–2008. No difference in outcomes was evident at 1 year, but adjusted all-cause mortality at 4 years was lower with CABG (16.4%) than with PCI (20.8%). However, an accompanying Editorial thinks that, while the data are valuable, residual confounding is likely to be an issue, and the need for randomised trials still remains.

A pregnant woman in contact with a child with a rash
A 21-year-old woman, 38 weeks into her second pregnancy, mentions that her first child has been ill. He had been diagnosed with chickenpox a week ago after developing an itchy rash and high temperature. The patient can’t remember if she has ever had chickenpox or shingles herself, or if she has been vaccinated against varicella, and she seems unaware of any risk to her unborn child. What should you do? If you’re not sure, the BMJ has a Practice article which discusses what action needs to be taken.

Insulin degludec
Two trials in the Lancet – one in type 1 diabetes , one in type 2 – investigate insulin degludec, which after injection forms multihexamer chains in subcutaneously, yielding a slower, steadier release. Both studies compared it with insulin glargine, and were open-label. Outcomes were very similar for the two insulins in both trials, but degludec was associated with slightly lower rates of confirmed hypoglycaemia in type 2 patients (111 vs 136 episodes per patient-year). An accompanying Comment notes that hypoglycaemia is often the greatest barrier to effective insulin therapy, and that > 80% of patients still had symptoms of hypoglycaemia in both studies.

Helicopter ambulances
Transporting ill patients to hospital by helicopter is dramatic but expensive. Does it really get them to specialist care more quickly and, even if it does, are outcomes improved? An observational study from the US in JAMA compares outcomes in 60,000 trauma patients flown to specialist centres by helicopter versus more than double that number transported by ground services. Overall, 7813 patients (12.6%) taken by helicopter died, compared with 17,775 patients (11%) carried by ground services. This small benefit (odd ratio for survival = 1.16) was still apparent after adjusting for likely confounders.

Correcting spinal deformity in children
Spinal deformities in children are common, but repeated surgical interventions are both difficult for patients and expensive. A case series in the Lancet tries a growing rod system that is magnetically controlled, eliminating the need for repeated procedures to adjust its length. Of five patients implanted, two have now reached 24 months’ follow-up with no subsequent surgery, continued correction of scoliosis and a high level of patient satisfaction. An accompanying Commentary notes that the incidence of problems such as device migration and breakage needs further investigation, but reckons regulatory barriers to developing such technologies in the US are too high.

Treating alopecia
Often dismissed as only a ‘cosmetic’ problem, alopecia areata can be devastating for quality of life and self-esteem. If you’re not familiar with the current treatment options, the NEJM has a useful review of its presentation, pathology and management. Evidence is growing for a T-cell-mediated autoimmune aetiology, and treatment options are split between immunosuppressants such as triamcinolone or glucocorticoids, or immunomodulation therapies such as the antipsoriatic dithranol or diphenylcyclopropenone. Topical minoxidil may also be useful. Unfortunately, even when these treatments are effective, the condition is liable to recur.

Estimating effect and modelling risk
Something that is true of a whole isn’t necessarily true of its parts and people who argue otherwise commit the fallacy of division. A Viewpoint in JAMA reckons this fallacy is a fundamental problem in evidence-based medicine, where evidence derived from groups is applied to individuals. When the effect of an intervention is measured in a randomised trial, the summary result doesn’t apply to everyone: some may benefit more, some less and some will be harmed. The same is true of risk scores, which as far as individual patients are concerned, are no more than half-informed guesses. Clinicians who rely on evidence-based medicine to decide patient care may find this uncomfortable reading.