Research highlights – 16 December 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.

Scores for predicting type 2 diabetes in adults
“Application of prognostic models requires unambiguous definitions of predictors and reproducible measurements using methods available in clinical practice” concluded Karel Moons and colleagues in the last part of their BMJ series on prognostic research (BMJ 2009;338:b606). Douglas Noble and colleagues have now reinforced and extended that argument with their systematic and realist review of published prognostic scores for type 2 diabetes and related follow-up studies assessing usability and impact.

There’s no shortage of such scores: the authors’ extensive search found 145 examples and they studied 94 in detail. Many scores had been well developed and validated and were technically sound. But few, concluded the authors, are usable in real life. Indeed, just seven of the scores met their criteria for having high potential for use in practice and improving patients’outcomes.
One of the reviewers for this paper said “perhaps the greatest value of this review is to document an approach for mapping and evaluating the growing number of tools. The authors demur from selecting a single best instrument—as they rightly argue, usefulness depends on context.” She also thought that readers might be reassured to see this validation of their “feelings of perplexity at the growing number of clinical scales and scores that they may be expected to use.”

Effects of delayed cord clamping in Western settings
Delaying clamping of the umbilical cord after a baby is born allows placental blood to flow to the infant, and this placental transfusion increases the total blood volume of a term infant by about 30%. In developing countries with a high prevalence of iron deficiency anaemia, such delayed cord clamping has been shown to improve iron status in infants within the first months of life, but in Western countries with a low prevalence of iron deficiency anaemia it has been suggested that delayed clamping might lead to over-transfusion and result in polycythaemia, hyperviscosity syndrome, or hyperbilirubinaemia.

To clarify the situation, Ola Andersson and colleagues undertook this randomised clinical trial to compare the effects of delayed and early cord clamping in 400 healthy, term Swedish infants.  They found that delayed clamping (≥180 seconds after delivery) improved iron status and decreased the risk for iron deficiency at 4 months of age compared with early clamping (≤10 seconds after delivery) and was not associated with neonatal jaundice or other adverse effects.  The authors conclude that further study is warranted to establish the long term effects of delayed cord clamping, particularly on neurodevelopment, which can be impaired by iron deficiency.

In his linked editorial Patrick van Rheenen looks at the reasoning and assumptions behind the widespread adoption of early cord clamping in Western medicine and concludes that this study by Andersson and colleagues “is convincing enough to encourage a change of practice.” Indeed, judging from the online responses to the full paper on—almost universally positive and mainly from obstetricians asking about practical details of the procedure—the article has sparked considerable interest.

How fast does the Grim Reaper walk?
Fiona Stanaway and colleagues estimate how fast older men might have to walk in order to avoid death (doi:10.1136/bmj.d7679).

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