eLetters

679 e-Letters

  • Don't throw the baby out with the bath water

    In their recently published meta-analyses Brignardello-Petersen et al. (1) concluded that knee arthroscopy including partial meniscectomy for degenerative knee disease provides very small benefits in pain and function over conservative therapy in the short term, but that the evidence fails to support any long term effect. They also claimed that there was no evidence of any subgroup of patients more likely to benefit from the procedure. However, this statement is not substantiated by the results of their systematic review and meta-analysis. Besides, the design of their study is not suited for evaluating subgroups. By making such an unsubstantiated claim, and subsequently adopting it in a clinical practice guideline (2), the risk is that we “throw the baby out with the bath water”.

    Despite the accumulated evidence that questions the effectiveness of knee arthroscopy for degenerative meniscus tears, clinical practice does not seem to change.(3-7) Hence, the key question is what information is required in order to effectively change the practice of knee arthroscopy in degenerative knee disease.
    Orthopedic surgeons have expressed concerns about the generalisability of the individual trial results, and point out that the study populations may not be representative to the subjects they select for surgery in their day-to-day clinical practice.(8-18) These concerns point to the common perception that some subgroups of patients may still benefit from the procedure. Hen...

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  • Findings in line with studies of whole populations

    We read with interest the letter from Steele et al regarding the Northwick Park study of screening pregnant women for GBS carriage.

    While the study was not large enough to meet most of the statistical probability tests referred to by Steele et al, the results were entirely in line with studies of whole populations such as that in the United States of America, where the incidence of early onset GBS disease in neonates has fallen by more than 80% since screening was recommended. Thus, from a Bayesian perspective, the study increased the already high probability that the introduction of screening into the UK would produce a similar beneficial effect, and moreover showed that it was feasible within existing resources.

    We fully support the calls from Steele et al for more and better research on the long term effects of intrapartum antibiotic prophylaxis, and have been greatly encouraged by a letter to us on the 10th April 2017 from Philip Dunne MP (until the dissolution of Parliament, the Minister of State for Health) which states that “I have asked the National Institute of Health Research to commission a clinical trial to compare universal screening for GBS against usual risk-based care”. Such a trial would be of major importance not just in the UK but also to the international community.

    Until the results of such a trial are available, we will continue to advocate that women should be given the facts and allowed to choose for themselves the balance be...

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  • High cholesterol is an advantage for the elderly

    There is no reason to lower the intake of palm oil or other types of foods rich in saturated fat because elderly people with high levels of LDL-cholesterol (the "bad" one) live the longest. This is what we have documented in a meta-analysis of 19 cohort studies including more than 68,000 individuals.(1). Those with high LDL-cholesterol lived even longer than those on statin treatment.
    Our study has been heavily criticized by several groups of supporters of the cholesterol hypothesis, but hitherto nobody has been able to find a study showing the opposite.

    Reference:
    (1) Ravnskov U, Diamond DM, Hama R et al. Lack of an association or an inverse association between low-density-lipoprotein cholesterol and mortality in the elderly: a systematic review. BMJ Open 2016;6:e010401. doi: 10.1136/bmjopen-2015-010401

  • Health economic burden that wounds impose on the National Health Service in the UK: request for further methodological information.

    Guest et al use routinely collected primary care data to estimate an annual prevalence of wounds in the UK of 4.5%.(1) They then report annual prevalence estimates for different wound sub-types, including venous leg ulcers. We have become aware of differences in the venous ulcer prevalence estimates of Guest et al (1) and our own estimates from THIN (2) and from surveys in Leeds (3) and Greater Manchester (data on file). We have calculated an annual UK prevalence of venous leg ulcers of 1.3 per 1000 (or 0.13%) compared with Guest’s estimate of 5.6 per 1000 (or 0.56%).

    Briefly our annual estimate was calculated by combining our 2011 point prevalence values (row B and C from Table 1: rounded to 0.3 per 1000. Please note since response format does not allow tables we have converted to text) with the 2006 UK annual incidence rate of venous leg ulcers estimate (row D Table 1), assuming that the annual incidence has not changed since 2006. Our value is very similar to the crude estimate of annual UK venous leg ulcer prevalence of 1.4 per 1000 people directly calculated by Petherick et al (2) using THIN and G(C)PRD (Row E: Table 1).

    We note that the annual prevalence estimate for venous leg ulcers of Guest et al (row A: Table 1) is four times higher than the others presented here. We also note that this is the most conservative estimate of the UK annual prevalence from Guest’s data given the large number of unspecified leg ulcers reported in this paper– a large...

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  • Revisiting criteria for safe term breech delivery

    We read with great interest the population-based study of Bjellmo et al1, who evaluated from the Norwegian Medical Birth Registry from years 1999-2009 the risk for stillbirth, neonatal mortality (NNM) and cerebral palsy in children born vaginally at term in breech position, as compared with the children born vaginally in cephalic position. Indeed, thanks to this way to address the crucial question of the over risk associated with breech presentation, these authors demonstrated that children in breech had a nearly threefold increased Odds Ratio (OR) for NNM compared with children born vaginally in cephalic, regardless of whether they were born vaginally or by caesarean delivery.
    Moreover, Bjellmo et al1 also found a higher proportion of infants born small-for-gestational-age (SGA) among children born in breech than in cephalic position, and suggested that SGA foetuses (with their risk factors for adverse outcomes) are more likely to present in breech than in cephalic posi¬tion at birth.
    In line with these findings, in a recent Finnish population-based case-control study, Macharey et al2 , who revisited the risk factors associated with adverse perinatal outcome in planned vaginal breech labours at term, found that the stillbirth rate was significantly higher compared to cephalic presentation (0.2 vs 0.1%) in association with SGA, oligohydramnios, and gestational diabetes. Furthermore this same group, in another recent survey from the same cohort of mother-neonate...

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  • Authors' reply to Steele et al.

    We thank Steele et al for their interest in the article. 1,2
    We agree that over ascertainment and treatment is a limitation of the currently available screening methods as they do not accurately identify which of the carriers will pass on the infection to the baby. But screening will, at least, ensure that IAP is given to most women who may pass on the infection to the baby. This is in contrast to risk based IAP where IAP is given to women who do not carry GBS and consequently cannot pass the infection to the baby. Furthermore, the potential to be effective is limited by the fact that an estimated 65% of the mothers of babies with EOGBS infection do not have risk factors. 3
    We wish to point out that we never set out to undertake a comparative trial. We implemented screening based IAP as a service improvement in response to rates of EOGBS reaching to 1.65/1000 live births in 2013, considerably higher than average for the UK. 3
    An analysis adjusting for confounding variables was not originally undertaken for three reasons. Firstly, the number of EOGBS cases was small, and thus may not be sufficient for a fully adjusted analysis. Additionally, the full patient level data was unavailable for all cases in the pre-screening period, meaning we were unable to perform an analysis with adjustments for more than one variable. Finally, whilst statistically significant due to the large sample size, differences in age and mode of birth are fairly negligible practical...

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  • Correction to cohort numbers

    On further analysis of the cohort data, two participants from one cohort from Kenya (EMEP) were found with implausible birth weights. It was not possible to discover the true birth weights, and so these women have been censored from ongoing analyses, decreasing the cohort from 14635 to 14633 deliveries. This does not affect the conclusions of the paper.

  • Gaps in the evidence base

    We are grateful to the authors of “Outcome of a screening programme for the prevention of neonatal invasive early-onset group B Streptococcus infection in a UK maternity unit:
    an observational study” for publishing the results of the screening programme for GBS carriage at Northwick Park Hospital.1 The impetus behind the programme was clearly driven by concern for the health of newborn babies and enthusiasm to reduce the rate of EOGBS in the hospital’s population.

    However, the national policy on culture based screening at 35-37 weeks gestation is that this should not be offered. In large part this is informed by concern about the screening test’s inability to reliably distinguish between women whose babies would be affected by EOGBS and those whose babies would not. The consequence of this is a high rate of overdiagnosis and subsequent overtreatment. The Northwick Park experience provides an insight into this which was not brought out in the paper.

    The paper reports an EOGBS rate of 0.99 / 1000 deliveries prior to screening and a GBS carriage rate of 29% in the population. With 9098 live births in the study period 9 cases of EOGBS in approximately 2600 carriers would be expected. Screening at 35 – 37 weeks aims to identify these carriers and offer IAP to reduce the risk of EOGBS. From what is presented in the paper regarding transmission rates, and elsewhere regarding test accuracy,2,3 between 60% and 80% of these carriers would be eligible for IAP wh...

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  • We're not as popular as we look! Explaining the high view numbers for this paper...

    Dear all readers,

    It's the authors here. We just wanted to add a note about the enthusiastic article metrics this paper has been generating. No doubt, of course, a number of these are genuine. However, the runaway popularity of the paper earlier this year was, we now know, driven by a badly behaved function on our university website: this function is supposed to collect related links for blog posts we carry, but was in fact looping incorrectly and triggering hits on the journal's website page for the paper. This fault - entirely non-malicious, we should stress - has now been corrected. Hopefully reading figures will go down to the levels of interest we might expect for those interested in inequalities in care for minority ethnic groups, and vignette methods. Apologies to the journal, and to readers, for this occurrence.

    Best wishes,

    Jenni Burt
    [on behalf of the authors]

  • Little evidence to support OPAT versus oral antibiotics

    Mitchell and colleagues make the point that OPAT has not realized its full potential in the UK because there is a paucity of evidence of effectiveness, associated risks and patient preferences for this form of treatment. However, there is another reason why OPAT is not used more and that is there is no evidence to support intravenous antibiotics versus oral antibiotics for a large proportion of the patients using OPAT services. OPAT is often used to treat skin infections such as cellulitis (1) for which the evidence supports short courses of oral antibiotics (2,3).
    Very few of the other indications for OPAT are supported by evidence of superiority over oral continuation therapy, as there are few clinical trials, and where evidence exists of comparison it is often from retrospective studies (4). MacGregor summarized the evidence, and the obstacles, 10 years ago (5).
    There are perverse incentives for the use of OPAT; payments to hospitals to provide OPAT as an alternative to inpatient IV therapy and thus an incentive to recommend IV therapy instead of oral. During a recently completed clinical trial we faced problems recruiting from hospitals that had OPAT services, as they would receive a lower payment if they prescribed oral flucloxacillin instead of IV ceftriaxone delivered via OPAT.
    The infectious diseases community need to provide us with good evidence that the IV antibiotic therapies being recommended have a sound evidence base. The present support fo...

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