eLetters

473 e-Letters

published between 2014 and 2017

  • Unwarranted conclusion may be supported by additional analyses

    I have read the authors’ report on the investigation of data collection mode effects during administration of a three-item patient-reported patient-centered communication measure with interest. While I greatly appreciate the work the authors invested in the study, I think one of their major conclusions is not supported by the reported analyses. It is repeatedly stated throughout the manuscript that the relative clinician performance rankings were stable across the different data collection modes. However, the analytic strategy described in the Methods section, the perfectly identical distances between physicians (on the logit-scale) across modes in Figure 1, and the detailed results made available in the Supplementary Appendices suggest that they included the clinician identifiers as main effects in the analyses without specifying an interaction term between data collection mode and physician identifiers. This means that the ranking of (and even equal metric distance in logit units between) clinicians was restricted to be identical across all levels of the covariates, including administration mode, by the statistical model. In other words, the stable clinician ranking was rather a non-falsifiable assumption than a finding of the analyses.
    This does not mean that the authors’ conclusion is necessarily wrong, only that the performed analyses did not check the hypothesis of constant clinician ranking across modes as intended. Additional analyses may show that this hypot...

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  • Re: Lack of evidence for interventions offered in UK fertility centres

    To The Editor, BMJ

    Dear Dr Godlee

    Balen et al have responded to our papers. [1,2] In our BMJ open paper we systematically identified 276 claims of benefit relating to 41 different fertility interventions and 16 published references were cited 21 times on 13 of the 74 websites we searched.[1] In our BMJ analysis paper, we systematically examined the evidence for ‘38 additional fertility interventions’ and found evidence of improvements in live birth rates for only five interventions. We used standard critical appraisal techniques (as detailed in our paper) to explore the quality of these studies. We identified that for all five of these interventions the studies had methodological problems, raising uncertainty about the significance of the results. This is a serious issue for patients, public health, public trust, and regulators.

    Balen et al suggest that our evidence review included - and found evidence lacking for - things which are not “add-ons”. We classified ‘add-ons’ in the BMJ analysis article in response to peer review where the issue was discussed (see online peer review comments).

    Peer review comment: ‘The methodology has led them to five interventions for which there may be some evidence of improvement in live birth rates. One of these is intrauterine insemination in a natural cycle. This is an alternative treatment, rather than an “add-on”, and usually not one applied to the population who require IVF, and certainly not one intended to...

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  • The analysis makes no comparison with a baseline position and is selective in reporting only some costs

    The need to compare with a Baseline
    The analysis describes how cases were chosen "where the NHS Pathways software indicated that a patient should be instructed to go to an A&E department" (so dispositions to an emergency department with codes such as Dx02 or Dx03) and how "the call handler told the patient that they would be called back by a GP".
    However, as part of the normal process in NHS 111 a further conversation takes place with the patient after the Dx code has been generated during which the specific location of the service that the patient should attend is agreed. As this is done a number of callers are directed to WIC, MIU etc. and to other services. The exact level will depend on various factors, most noticeably the number and location of these alternative services, but analysis from elsewhere of the referrals by call-handlers to Emergency Departments with a time frame of 1 and 4 hours (Dx02 and Dx03) concluded that 15% of those cases go to WIC + MIU 3% to other services, whilst perhaps 7 or 8% were referred to the ambulance service (so may well have been transported to the Emergency Department).
    Since, in the study, this conversation with the call-handler was effectively delayedto the later conversation with the GP the comparison should have been with a baseline case, not simply with the nominal NHS Pathways disposition. It seems likely that the impact if the authors had compared with a baseline period using informa...

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  • Jason Conviser, Ph.D., FACSM

    I have read the protocol for The LIFTMOR-M (Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation for Men) trial: protocol for a semi-randomised controlled trial of supervised targeted exercise to reduce risk of osteoporotic fracture in older men with low bone mass and have questions and concerns that I wish your consideration and response:
    1. Your protocol calls for 8 months of exposure to the bio Density system. Manufacturers recommendations supported by peer reviewed studies have shown that BMD changes require a minimum of 9 months and many individuals begin to show changes with DEXA at the 11 and 12 month period.
    2. Those studies which have shown changes in DEXA as a result of bio Density exposure have done so with subjects who are in osteopenia and not osteoporosis. Your inclusion of males in osteopenia could complicate analysis and conclusions. The best that we have seen is a baseline of those with osteopenia (not getting worse). Also the greater the negative DEXA (ie -3.0, or greater we have seen the greatest change with bio Density exposure). Regression to the mean can be expected.
    3. The protocol allows for 2 x per week exposure. The manufacturers recommendations call for once a week.
    4. I question if it is appropriate to ask 50 year old men to not perform any form of exercise for 8 or more months while participating in this study. Will the health risk of not exercising be acceptable to the IRB? Other st...

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  • Note from the Editor in reference to the response from Dr Adam Balen

    The response below should have been posted in January 2017. It responds both to this BMJ Open article and to a related article in The BMJ (http://www.bmj.com/content/355/bmj.i6295). It was posted on bmj.com on January 18 2017 but failed to be replicated within BMJ Open. We apologise for this. The authors have been asked to respond.

  • Lack of evidence for interventions offered in UK fertility centres

    To The Editor, BMJ

    Dear Dr Godlee

    Re: Lack of evidence for interventions offered in UK fertility centres.

    We are writing to express our concern regarding the papers by Heneghan et al, (2016) and Spencer et al (2016) owing to their lack of scientific robustness.

    We would like to state at the outset that we oppose the provision of procedures or treatments that do not have a scientific basis and we welcome the initiative by the Human Fertilisation and Embryology Authority (HFEA), which has been endorsed by the British Fertility Society (BFS), to introduce a grading scheme for “add-ons”.

    Spencer, Heneghan and colleagues have unfortunately obscured their important message by mixing various categories of treatment, not all of which come under the category of “add-ons”. Indeed, a number are accepted components of routine treatment. The papers have grouped together three categories of care: (i) necessary investigations (e.g. assessment of ovarian reserve, which is vital in determining correct dosage of ovarian stimulation drugs to optimise outcome and ensure patient safety), (ii) essential treatments (e.g. surgical sperm retrieval) and (iii) interventions that can be termed “add-ons” - namely an addition to a pathway of care, whether as an additional drug or therapeutic procedure. Many of the items identified have a clearly defined role in specific situations; e.g. for a man with a physical blockage sperm has to be extracted surgically, frozen an...

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  • Newly developed spirometry prediction models for Indian adults

    I read the article written by Rajkumar et al. [1] with great interest and appreciate the efforts taken by the investigators to screen the prevalence of COPD in different age groups in India. However, there are two aspects on which I would like to make some comments. The authors have stated “Globally COPD was the fourth leading cause of death (5.1%) in 2004 and is projected to occupy the third position (8.6%) in 2030”, I assume that the statistics are quite overestimated. Mathers and Loncar (2006) [2], provided a more comprehensive picture about the projected scenario of COPD globally and they concluded that COPD is at present the 5th leading cause of mortality and morbidity globally and is likely to step up to 4th position by 2030 with an increment of 160%. I think that the authors need to consider the fact. Secondly, the authors might have missed that recently, Desai and colleagues (2016) have published spirometry prediction equations for Indian adults residing in the western parts of India [3]. The equations have successfully overcome a long-awaited aspiration for standard prediction models in Indian perspective and could be used as Indian standard. Most of the existing prediction models such as the global lung function equations developed by Quanjer et al. (2012) [4] which were developed for Europeans either under-diagnose or over-diagnose the disease, hence I think the newly published models would serve the purpose.

    References:
    1. Rajkumar P, Pattabi K, Va...

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  • Response to Uffe Ravnskov

    As the two comments posted on PubMed for the cited article by Dr Ravnskov et al clearly state, there are several major shortcomings in the design and analysis of their meta-analysis. In addition, benefits of statins in reducing risk of myocardial infarction in older age patients without cardiovascular disease have been shown in several randomized trials.
    Our analysis adds to the literature by providing an insight on how use of palm oil for cooking (as opposed to sunflower oil) may worsen lipid profiles in a population from a low-income country with implications for cardiovascular disease. As we have discussed, a large case-control study has already shown an association between palm oil use and non-fatal myocardial infarction.

  • 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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