On the Pulse

On the Pulse - 24th July 2009

Case fatality in H1N1 influenza
A vital question about the new strain of influenza is the severity of illness that it causes. So far, data suggest that it’s fairly mild, with a case fatality around 0.5%, which isn’t very different from that seen for seasonal influenza. But there seems to be substantial variation between countries, and deaths have occurred in much younger people than is the case for seasonal influenza. An article in the BMJ warns that simple interpretations of crude figures at the beginning of a pandemic can be misleading, because of the difficulty in fully ascertaining cases and delay between disease onset and knowing the final outcome.

Independent sector treatment centres
The Independent Sector Treatment Centre programme employs private healthcare organisations to provide elective surgery and other services to the NHS. The Department of Health hopes it will reduce waiting times, promote innovation and build relations between the NHS and the private sector. An article in the Journal of the Royal Society of Medicine points out that the programme is costing a fortune – the projected total cost is over £5 billion – and no data are being collected on whether it’s providing value for money. An audit of a similar scheme in Scotland raised the strong possibility that money was paid out for patients who never actually received treatment.

Hormone therapy and ovarian cancer
It’s become clear in recent years that use of HRT in women is associated with increased risk of ovarian cancer, but studies have disagreed over whether such details as regimen, duration and timing are important. A study in JAMA that follows over 900,000 Danish women for an average of 8 years shows that the details probably don’t matter. The increase in risk is small (about 1 extra case of ovarian cancer per 8000 women taking HRT) but was present regardless of duration, route, oestrogen dose or progestin type. This essentially backs up the results of the earlier Million Women Study, so should lay the matter to rest.

Walk to work
Not very many people walk or bike to work, according to a cross sectional survey of middle-aged men and women in the US reported in Archives of Internal Medicine. But those that do have lower levels of BMI, triglycerides, blood pressure and insulin, and they’re also fitter as judged by a treadmill exercise test. These findings aren’t in any way surprising and, because people who commute under their own steam are self-selecting and probably have lifestyles that are healthier in other ways too, they’re a long way from showing cause and effect. Even so, the authors think the positive health benefits of active commuting are worth pursuing.

Statin-induced myopathy
If a patient taking statins reports muscle symptoms, a serum creatine phosphokinase level is often useful in deciding whether to advise discontinuation – or is it? A study in the Canadian Medical Association Journal suggests not. Of 44 patients with statin-associated myopathy, biopsy of the vastus lateralis revealed muscle damage in 25, many of whom had no elevation of creatine phosphokinase. However, while discontinuation of statins generally resolves symptoms almost immediately, muscle damage was found in 9 of the 15 who had discontinued at least 3 weeks ago, suggesting that the connection between symptoms and biopsy findings is not simple.

An elderly man with abdominal pain
A 73-year-old paraplegic man presents with abdominal pain. His abdomen is distended and tympanic, but soft and non-tender to palpation. His medical history includes hypertension, type II diabetes mellitus and, more than 10 years earlier, a neurosurgical resection of a medullary ependymoma of the spinal cord – the cause of his paraplegia. An article in PLoS Medicine takes this case as a starting point for a review of the diagnosis and management of bowel obstruction. The differential diagnosis is between malignant obstructing diseases, such as colon cancer, or benign conditions, such as sigmoid volvulus or diverticulitis, which despite not being cancerous can be life-threatening because of the risk of colonic ischaemia and perforation. Of course, in a patient with chronic immobility and paraplegia, there’s always the possibility of faecal impaction too.

Circumcision and HIV
Earlier observational studies suggested a reduced risk of HIV transmission to the partners of circumcised men. However, after 2 years an interventional RCT in the Lancet finds no effect from circumcising HIV-infected men, and was stopped as futile. Part of the problem may be that couples often resumed sex before post-surgery healing was complete, making things worse rather than better. An accompanying Comment points out that circumcision campaigns will continue anyway because they have benefits for the transmission of other STDs, and may still help prevent men from acquiring HIV. But condoms remain the only reliable way to prevent transmission.

DVT in pregnancy
Pregnancy is a risk factor for deep-vein thrombosis, but pregnant women are seldom included in clinical trials of its diagnosis and treatment. A paper in Annals of Internal Medicine assesses whether clinical assessment can predict the presence of clots in pregnant symptomatic women. Only 17 of the 194 subjects actually had a thromboembolism, making conclusions difficult, but any one of these three criteria should raise suspicion: pain in the left leg only, presentation in the first trimester, or calf circumference swollen by > 2 cm. Why the left leg, you may wonder? Because the left common iliac vein is compressed by the gravid uterus, with consequent reduced venous flow.