“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.
- Is treatment of periodontal disease during pregnancy associated with a reduced rate of preterm births?
- Are longlasting nets treated with insecticide effective in reducing incidence of visceral leishmaniasis in India and Nepal?
- How well does a new QRISK model estimate lifetime risk of cardiovascular disease?
- Can simple ultrasound rules be used as a triage test to predict benignity or malignancy in an adnexal mass?
Periodontal disease, pregnancy, and preemies
Can a woman’s oral hygiene affect her unborn baby? All sorts of research on the effect of periodontal disease on preterm birth has been published in the past 16 years. Observational studies suggest that pregnant patients with periodontal disease have an increased risk of preterm birth, but the largest randomised study to date said that treating periodontal disease had no effect on the rate of preterm birth and low birthweight infants.
Now Nikolaos Polyzos and colleagues have published a meta-analysis of studies on treatment of periodontal disease during pregnancy, which they hope will put the issue to rest. Only five of the 11 trials they identified were of sufficiently high methodological quality, and these trials provided clear evidence that treatment of periodontal disease has no effect on the rate of preterm births, low birthweight infants, spontaneous abortions and stillbirths, or overall adverse pregnancy outcomes. The six low quality trials, however, indicated that treatment did have a beneficial effect.
In a linked editorial George Macones says: “Disappointingly, despite years of basic, clinical, and translational research, no robust data support the treatment of any infection to reduce preterm birth or improve pregnancy outcomes . . . It may be time to re-examine some basic assumptions about the cause of adverse pregnancy outcomes and explore new mechanisms and treatments.” However, both Professor Macones and the study authors emphasise that maintenance of oral health should be encouraged as part of routine preventive care, irrespective of its effect on pregnancy outcomes.
Evaluating adnexal masses
Whether an adnexal mass is malignant or not affects the choice of treatment, but making this decision requires an experienced ultrasound examiner. Dirk Timmerman and colleagues have tested a decision making tool that should make this process a bit easier for less experienced ultrasound examiners.
The rules they devised comprised five ultrasonic features (including shape, size, solidity, and results of colour Doppler examination) to predict a malignant tumour (M features) and five to predict a benign tumour (B features). If one or more M features were present in the absence of a B feature, the mass was classified as malignant, whereas if one or more B features were present in the absence of an M feature, it was classified as benign. Findings using these rules were then compared with whether the excised adnexal mass was classified as benign or malignant on histological assessment.
The rules correctly discriminated between benign and malignant masses in 77% of cases. When conclusive, the rules performed as well as subjective assessment by an experienced examiner. The authors suggest that their ultrasound rules should be used as a triage test and subjective assessment by an experienced ultrasound examiner should be used as a second stage test in those masses for which the simple rules yield an inconclusive result.
New algorithm for lifetime cardiovascular risk
Julia Hippisley-Cox and colleagues have developed an algorithm for lifetime cardiovascular risk. Patients with high lifetime risk were more likely to be younger, male, from non-white ethnic groups, and have a positive family history of premature coronary heart disease than those identified as being at high risk with the 10 year QRISK2 score. But in younger patients, the risk-benefit ratio of medical interventions might be narrow, and the authors admit that we need more data on their cost effectiveness and acceptability.
Editorialists Rod Jackson and colleagues aren’t convinced that lifetime risk estimation adds much, but they like the graphs produced by the calculator at www.qrisk.org/lifetime. These predict patients’ cumulative cardiovascular risk throughout their lifetime on the basis of both current risk profiles and what will happen if their risk profiles improve.
Research online: For this and other new research articles see www.bmj.com/research
Efficacy of scorpion antivenom
Being stung by the Indian red scorpion (Mesobuthus tamulus), the most lethal species of the Buthidae family in India, is bad news enough. But to make things worse, the efficacy of scorpion antivenom is unknown.
Himmatrao Saluba Bawaskar and Pramodini Himmatrao Bawaskar have conducted an open label randomised controlled trial in India to determine for sure the effects of the monospecific F(ab)2 scorpion antivenom on the cardiac pathophysiological effects of scorpion sting. They found that addition of scorpion antivenom to the a1 blocker prazosin, which is widely used for the management of M tamulus sting, within six hours hastened recovery and shortened hospital stay compared with prazosin alone.
However, they point out that the total cost of treatment with antivenom approaches a month’s salary for a labourer in rural India, whereas the cost of 10 tablets of 1 mg prazosin is very much cheaper.