Research highlights – 20 May 2011

Research questions“Research highlights” is a weekly round-up of research papers appearing in the print BMJ. We start off with this week’s research questions, before providing more detail on some individual research papers and accompanying articles.

Clinical officers and caesarean section

“Clinical officers” – non-medics who are trained to do tasks usually done by doctors – are an important part of healthcare in many countries, especially in those with lower resources and a shortage of medically trained doctors. Obstetric care is one setting that makes great use of clinical officers, but uncertainty remains about their ability to perform emergency operations, and their scope to do so varies between countries.

To address the safety concerns, Amie Wilson and colleagues did a systematic review and meta-analysis of studies looking at the effectiveness of clinical officers in caesarean section. Data came from Zaire, Mozambique, Malawi, Burkina Faso, and Tanzania. They found no significant differences between clinical officers and medical doctors for maternal or perinatal death, although a higher rate of wound infection and dehiscence for clinical officers might indicate a particular training need.

There is some uncertainty about the results, because no randomised trials were available for assessment. The authors also found statistical heterogeneity in the results, possibly because of the diversity of the studies’ settings. For example, in the full paper online the authors discuss how the way clinical officers are used can vary and introduce bias. In one study, clinical officers were only asked to do the procedure in emergencies, and as emergency caesarean section is associated with worse outcomes than elective ones, the results could have been biased in the favour of doctors. In another setting, though, the perceived severity of an emergency caesarean could result in doctors rather than clinical officers carrying out the operation, leading to bias in favour of clinical officers.

Despite this uncertainty, it’s important to assess the available evidence. Since caesarean section is the most common major surgical procedure in sub-Saharan Africa and can be lifesaving if delivered quickly, clinical officers could potentially play an important part in increasing accessibility and availability of emergency obstetric care – and, in turn, in meeting Millennium Development Goals 4 (reducing child mortality) and 5 (improving maternal health). Staffan Bergström discusses this further in an editorial.

Reporting of ethics review and consent in cluster randomised trials

It’s a prerequisite of any randomised controlled trial that participants give informed consent, isn’t it? Well, not always: in cluster randomised controlled trials the consent may be given by a proxy on behalf of a large group of people, something that surely ought to be fully described in any paper reporting such a trial. Yet Monica Taljaard and colleagues’ review of a random sample of 300 cluster randomised trials published between 2000 and 2008 found that the ethics aspects, including the details of ethics approval, were unreported in 77 of the papers and inadequately reported in many others. In the full version of their paper they illustrate why cluster randomised trials pose ethical challenges that need particularly clear reporting, and cite a paper where “responsible authorities at each hospital, as well as birth attendants, provided written consent to participate in the trial; no consent was sought from patients, as outcomes were part of routine data collected at each hospital with no personal identifying information transmitted” (N Engl J Med 2008;358:1929-40).

Research online: For these and other new research articles see
Dietary calcium intake and risk of fracture and osteoporosis

In a prospective longitudinal study of data from the Swedish Mammography Cohort, Eva Warensjö and colleagues found that the lowest levels of dietary calcium intakes (below approximately 700 mg per day) were associated with an increased risk of hip fracture, any fracture, and of osteoporosis in women. Above this level, they saw only minor differences in risk as dietary calcium increased, and the rate of hip fracture was even increased in women with the highest dietary calcium intakes.