588 e-Letters

published between 2016 and 2019

  • Response to Lidegaard et al.'s comment to our paper "Routine induction in late-term pregnancies: follow-up of a Danish induction of labour paradigm

    We appreciate the interest in our recently published paper on induction of labour and the very quick response by Lidegaard et al., giving us the opportunity to elaborate on the assumptions and questions raised.

    Our comments are listed below:
    Lidegaard et al. state that our study in BMJ Open is “yet an attempt to question a more offensive post-term induction practice” perhaps with a reference to a peer reviewed systematic review published earlier this year. First, we would like to point towards a professional way of communicating. Everyone, both the women and the professionals will benefit if we agree on being professional in our way of discussing research and clinical practice. Having said so, it is correct, that two of the authors of our BMJ Open publication have published a systematic review comparing routine induction of labour at 41+0/6 gestational weeks to 42+0/6 gestational weeks [1]. The systematic review revealed adverse maternal outcomes associated with routine induction of labour at 41+0/6 gestational weeks as well as both benefits and harms for the newborns by each regime. In the current paper, we did not study any offensive post-term labour induction practice as suggested by Lidegaard et al., but the practice of treating otherwise healthy pregnant women at 41+3/5 gestational weeks, where they are within the normal range of pregnancy and not yet post-term.
    We do not agree on the simple causal argumentation suggested by Lidegaard et al. based...

    Show More
  • Degenerative cervical myelopathy should build on the promise of post-operative physiotherapy for cervical radiculopathy

    We read with interest the excellent manuscript by Peolsson et al.[1] (Peolsson A, Peterson G, Hermansen A, et al. Physiotherapy after anterior cervical spine surgery for cervical disc disease: study protocol of a prospective randomised study to compare internet-based neck-specific exercise with prescribed physical activity. BMJ Open 2019;9. doi:10.1136/bmjopen-2018-027387).

    The authors present a protocol for a randomised study comparing internet-based neck exercises to prescribed physical activity for people who have undergone anterior cervical decompression and fusion (ACDF) surgery for cervical spondylotic radiculopathy.

    Whilst the authors outline this and a number of related, on-going knowledge gaps, we would like to highlight the interesting and totally unexplored parallels for cervical spondylotic myelopathy (CSM), a closely related condition.

    CSM, also referred to as degenerative cervical myelopathy [DCM], arises due to cervical spinal cord (as opposed to nerve root) compression from spondylosis. CSM is treated by surgery including ACDF[2] and most people with DCM experience pain, including neck pain, which is the recovery priority of people with DCM[3]. Despite this, surgery has been the focus of DCM research[4] and there has been no research into the role of post-operative rehabilitation in DCM[5]. Research to advance post-operative recovery in DCM is important given that surgery has been shown to be effective at halting disease progression...

    Show More
  • Sample Size Revision - Protocol for Compass: a randomised controlled trial of primary HPV testing versus cytology screening for cervical cancer in HPV-unvaccinated and vaccinated women aged 25–69 years living in Australia

    The primary purpose of this response letter is to update the protocol to revise the sample size of the Compass Trial.


    Compass is a randomised controlled trial, operating alongside the Australian National Cervical Screening Program (NCSP). Under the auspices of the Independent Data Safety Monitoring Committee (IDSMC) and Scientific Advisory Committee (SAC) we have performed a re-analysis of our original estimate of the total trial sample size. This was prompted by two factors: (1) impact of the NCSP transition to primary HPV screening and (2) emergence of new evidence relevant to the sample size calculation. With consideration to the resource implications of the renewed program on trial recruitment and acknowledging that the original sample size of 121,000 women for the main trial was calculated in 2014 (prior to the emergence of new relevant evidence) the trial sample size was re-estimated.

    The sample size recalculation has resulted in a reduced recruitment target for the cohort of women in Compass Trial who were age-eligible for publicly funded HPV vaccination in Australia (the younger cohort) from 84,700 to 40,000 women; consequently the total recruitment target has been revised from 121,000 to 76,300. The updated sample size estimate has been approved by the Human Research Ethics Committee and is reflected in the trial registration (ClinicalTrials.gov Identifier: NCT02328872).

    (1) Impact of the NCSP transition to primary HPV scree...

    Show More
  • Record low stillbirth rates in Denmark

    Thanks to Rydahl et al. for yet an attempt to question a more offensive post-term induction practice to have a main responsibility for the impressing reduction in stillbirths in Denmark (1). The more offensive induction practice was gradually implemented in Denmark through this century but accelerated by the National recommendation in 2010-2011 to induce post-term women so to ensure delivery before 42 gestational weeks (GW).
    The following comments assume that the data presented by Rydahl et al. are correct, we are currently looking at the same issue and the same data.
    First what we agree on:
    • There has from 2000 to 2012 been a substantial decrease in stillbirths in Denmark among women pregnant beyond 41+3 GW. The reduction was from 2.6 to <0.5 stillbirths per 1000 delivered, a reduction of at least 80%. Shouldn’t we start by congratulating each other for this impressing National achievement.
    • During the same period has the proportion of induced deliveries increased for women going beyond 41+3 GW from 25% to around 65%.
    • Despite this dramatic change in induction practice, both Caesarean section rates, low Apgar scores, and birth augmentation have been almost stable.
    • The proportion of instrumental births has decreased during the same period.

    It is of course an important issue what caused the dramatic decrease in stillbirths over the last two decades in Denmark. We have previously published evidence arguing that the more offe...

    Show More
  • Clarifications on misreported aspects of the COMPACT-2 trial

    We read with interest this paper reporting the results of the ROMPA trial on the efficacy of Coupled Plasma Filtration and Adsorption (CPFA) in reducing mortality in patients with septic shock. The trial was prematurely closed, after we informed the investigators of ROMPA that we had stopped our COMPACT-2 trial, designed on the same topic, for reasons of futility. COMPACT-2 (NCT01639664), whose protocol inspired ROMPA, was prompted by a pre-planned subgroup analysis coming from the overall negative COMPACT trial, suggesting that CPFA might have been effective, had a high volume of plasma been treated.
    The first planned interim analysis of COMPACT-2, aimed at assessing the feasibility of the technique, revealed a number of early deaths during CPFA. This induced the External Data and Safety Monitoring Committee (EDSMC) to request an unplanned interim analysis of safety. Such analysis, performed on the 113 recruited patients, showed significantly higher mortality in the CPFA group compared to controls, both at 3 days from randomization and at the 90-day survival analysis. We have now completed the clinical review of each recruited patient, performed through site visits by a team of independent experts, and plan to submit the manuscript to a scientific journal.
    In the meantime, we would like to clarify a couple of aspects related to our trial that were misreported in the present article and to comment on some sections of the paper. First, COMPACT-2 was not stopped...

    Show More
  • What constitutes informed consent in the treatment of childhood gender dysphoria?: some comments on the Trans20 study

    We wish to express concerns about the Trans20 longitudinal cohort study of transgender and gender diverse (TGD) youth from Melbourne’s Royal Children’s Hospital Gender Service (RCHGS) presented in the BMJ (Tollit et al BMJ Open 2019:9).

    While we agree with the authors that in regard to the management of TGD youth there is ‘’urgent need for more evidence to ensure optimal medical and psychosocial interventionsi”, we have grave reservations about the ethical underpinnings and methodology of the study as described.

    The Trans20 study aims to “document the natural history of gender diversity presenting in children”. It is not clear to us how the methodological design could allow observation of the ‘natural’ history of TGD youth when it intervenes in the developmental trajectories of all 600 expected participants. Given that a vast majority of young people who commence puberty blockers proceed to cross-sex hormonesii, it may well be the case that early intervention ‘locks’ a child into a persistent gender incongruence, closing them off to future choices in identity. We already do possess good data on the ‘natural history’ of gender confusion which shows that a majority of children desist at puberty and return to a gender identity congruent with their natal sexiii. Is this fact presented to concerned families?

    The RCHGS adopts an exclusively gender-affirming model of care, offering psychosocial and biological interventions to children as young as 3. Although...

    Show More
  • The Summary Care Record: A Forgotten, Underutilized, But Indispensable Tool in the Era of Electronic Records

    Dear Editor,
    We read the excellent article by Warren and colleagues [1] with interest and agree wholeheartedly with the need for consolidated access to health records for clinicians across the healthcare ecosystem in the UK.
    As junior doctors, we are often left with the laborious task of sourcing and amalgamating these disparate records for individual patients, with patients often surprised that we do not have access to all their information.
    We note the authors recommend the common adoption of the same EHR software for trusts in the same region and the transfer of records between systems by open APIs. These aims are laudable, however, remain problematic:
    1) Utilising the same EHR between NHS trusts does not necessarily guarantee any further ease of transfer than alternate EHRs; many trusts customise their EHR to their local preferences and hence implementations and data structures may vary significantly between trusts despite adopting the same EHR [2]. Further, even with the same systems, each trust will likely operate on differing domains, often requiring lengthy governance processes to facilitate transfer of records.
    2) Open APIs such as Fast Healthcare Interoperability Resources (FHIR) [3] are available and implemented by the 3 major EHR vendors in the UK [4–6]. Despite this, exchange of records between different NHS trust systems remains limited.
    The Summary Care Record (SCR) was initially intended as a repository of essential medic...

    Show More
  • Response to comment regarding “Early childhood vaccination and subsequent mortality or morbidity: are observational studies hampered by residual confounding? A Danish register-based cohort study”

    In our previous response we listed a number of differences between the study by Jensen et al.[1] and the studies by Sørup et al.[2, 3]. We thank Jensen et al. for providing the estimates for a restricted cohort of children who received 2 doses of DTP before 11 months of age (Table 1: https://bmjopen.bmj.com/pages/wp-content/uploads/sites/7/2019/11/table-1...). However,
    restriction of the cohort to children with 2 DTP vaccines before 11 months of age only removes a limited part of the differences we mentioned; hence, the results in Table 1 are still incomparable to the previous studies by Sørup et al.
    Jensen et al. included the 2DTP+MMR group in the modelling of effects (which Sørup et al. did not), and they did not analyse the data by type of infection, by sequence of vaccinations, and by the many confounders we had used. Since we specifically limited our studies to the period before PCV was part of the routine immunization programme, it should be noted that Jensen et al include many years where PCV was used (2007-2016). The introduction of PCV, a vaccine against respiratory infections, may have eliminated the need for some of the beneficial non-specific effects of MMR.
    Rather than testing something else, finding something else, and concluding that previous studies testing and finding different things were flawed, the fruitful way forward would be to investigate the...

    Show More
  • Points to be considered when using cardio ankle vascular index (CAVI) as a marker of arterial stiffness

    Letter to editor:
    We read with interest the article by Zhang et al. [1], in which they concluded that total hip bone mineral density was correlated with cardio ankle vascular index (CAVI). However, some common mistakes can happen in the studies using CAVI as a marker of arterial stiffness. First, Pearson’s correlation between this marker and other continuous variables should be considered after testing both variables for normality. Normality of the variables had been proposed as an assumption for the Pearson’s correlation analysis [2], if this assumption is not met, Spearman’s correlation should be performed after categorization of the continuous variables.
    Second point that is essential in evaluation of CAVI is the effects of age on CAVI. Age has been proved to be largely correlated to CAVI and many studies tried to make reference values for CAVI in different age groups. Namekata et al. [3] provided reference values which can be used to categorize CAVI in the study individuals. Although Zhang et al. [1] controlled for age in the multiple linear regression, using reference values of CAVI in every individual could completely change the results and conclusions of their study. Although in the study of Zhange et al. [1] we can see the biggest correlation (r=0.631, P<0.001) between age and CAVI, correlation of age with other variables cannot be seen and there is a possibility that age and bone mineral density is also high. So, conclusions about the independent as...

    Show More
  • In reply to the authors' response to "Concerns regarding the inference that EDS is not rare"

    We thank Demmler and colleagues for their reply to our concerns (dated 29th November 2019). In particular we appreciate the analysis required to demonstrate that the Joint Hypermobility Syndrome (JHS) and Ehlers-Danlos syndromes (EDS) cohorts in their study shared similar characteristics across the 35 Read chapter categories. This is a valuable observation of itself.

    Demmler and colleagues say in their reply that we ‘asserted that diagnosed JHS is known to be common’. We assume they have misconstrued our opening comments about combining common with rare conditions. We used the words ‘common’ and ‘diagnosed JHS’ to describe their findings, and based on the prevalence of ‘diagnosed JHS’ in the population they studied. We recognise that this study is the first to directly report a healthcare record-based population prevalence for JHS and a healthcare record-based population prevalence for EDS.

    We read that the authors agree with our comments that it is not possible to know what proportion of people who met the Brighton criteria for JHS also meet the 2017 hEDS criteria, and, that the authors agree that further studies are required to determine how common hypermobility spectrum disorder (HSD), hypermobile EDS (hEDS), and other forms of EDS are.

    We appreciate that the authors did not “seek to remove the protected ‘rare’ status from all subtypes of EDS”, and that they “regret if their work has been misquoted on social media”. Demmler et al. also reply that...

    Show More