eLetters

1562 e-Letters

  • Response to: Hand acceleration time (HAT) as a diagnostic tool in the assessment of haemodialysis access-induced distal ischaemia (HAIDI): study protocol for a prospective cohort study in the Barcelona south metropolitan area, by Gonzalez et al.

    Response to: Hand acceleration time (HAT) as a diagnostic tool in the assessment of haemodialysis access-induced distal ischaemia (HAIDI): study protocol for a prospective cohort study in the Barcelona south metropolitan area, by Gonzalez et al.

    Reshabh Yadav MD PhD 1, Marc R.M. Scheltinga MD PhD

    Department of Surgery, Máxima Medical Center, Veldhoven, The Netherlands

    To the Editor,

    We congratulate Gonzalez et al. with their research protocol on HAT (hand acceleration time) in end stage renal disease (ESRD) patients requiring a haemodialysis access (1). They propose to conduct a study based on the assumption that HAT assessed by duplex ultrasound (DUS) reflects the vascular status of an arm. Aim is to quantify HAT before and after haemodialysis access construction and to determine whether pre- and postoperative HAT values can predict haemodialysis access-induced distal ischemia (HAIDI).

    Based on our experience with HAIDI, some aspects of the protocol are worthwhile commenting on:

    HAIDI in relation to ‘steal’.
    Earlier studies suggested that HAIDI is caused by reversal of blood flow (‘steal’) that is shunted away from the hand (‘stolen from the hand’) due to the presence of an arteriovenous connection as in a vascular access for haemodialysis. On the contrary, steal is a phenomenon that has no pathophysiological significance related to HAIDI (2). The authors justifiably conclude that ESRD patients who often have diabetes melli...

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  • Correction to analysis timelines

    Following the publication of the original article, it has come to the authors’ attention that the timing of the analysis was still based on the wording of the original funding application, and had not been updated prior to publication of the trial protocol paper.

    The original funding application where both the short- and long-term outcomes were deemed as co-primary outcomes and as such would have been analysed at study end. At point of funding by the NIHR, we were requested to consider only the short-term outcome to be the primary outcome, and as such the timing of the analysis should have been changed so that short term outcomes were analysed first and longer-term outcomes after 2 years post-partum. The analysis plan was adjusted at that time, according to the NIHRs request.

    The article currently states (under the Main analysis section) that: “All analyses will be undertaken after database lock following data collection at 2 years.”

    However, the wording in this section should read: “Analysis of the short-term outcomes will be carried out after database lock following data collection at birth. The longer-term outcomes will be analysed after database lock following data collection at 2 years post-partum.”

    To ensure that knowledge of the short-term outcomes will not impact the scientific integrity of the longer-term outcomes, we will continue to adhere to strict retention protocols to follow up the mothers at 2 years for the longer-term health...

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  • Response regarding the PAK-SEHAT Longitudinal Study on Premature Coronary Atherosclerosis

    The study protocol by Zaman et al describes PAK-SEHAT as the research initiative for investigating premature atherosclerotic cardiovascular disease (ASCVD) in Pakistan. The research targets an important knowledge gap in cardiovascular healthcare research for South Asia because its CVD prevalence continues to increase in populations with low-to-middle income status.

    Several comments arise from our reading of the research. The research identifies “young adults” as very mature males who are younger than 60 and very mature females who are younger than 65 years but this definition goes beyond the typical age range of 18–44 years [1]. The expanded population inclusion might dim the line separating early and conventional ASCVD manifestation.

    CCTA along with CIMT serves as an effective method to detect subclinical plaques in patients [2]. These expensive diagnostic tests represent a major barrier that affects the system-wide implementation of public health screening and intervention programs in Pakistan.

    Excluding participants with BMI higher than 40 kg/m² or eGFR lower than 60 ml/min/1.73m² may unintentionally exclude persons at high risk from the study. People with South Asian origins who have metabolic syndrome or renal impairment tend to develop ASCVD at an earlier stage according to research [3] and their removal from the study might diminish the application of study findings to wider populations.

    The protocol states it will recruit nationally in P...

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  • Regulated vs. Non-Regulated AI in UK Medicine: Commentary on Warrington and Holm (2024) and the Role of LLM Risk Assessment

    Comments related to the findings reported by Warrington and Holm regarding the use of Artificial Intelligence (AI) by UK General Medical Council (GMC) registered doctors (Warrington DJ, Holm S. BMJ Open 2024;14:e089090. doi:10.1136/bmjopen-2024-089090).
    A key observation regarding the study is its apparent lack of distinction between participants' use of regulated AI products (classified as medical devices) and non-regulated AI tools (such as general-purpose LLMs). The wide range of respondent specialties reported further highlights this potential issue; for instance, clinicians in radiology or pathology are more likely to encounter regulated, task-specific AI, whereas those in public health or psychiatry might be more likely to experiment with non-regulated, general-purpose models.
    During the review process, I used Gemini Advanced (specifically, the model designated by the user as 2.5 Pro Experimental) to assist with processing screenshots of table1, table 2 and fig 1 into spreadsheet processable data. The same Large Language Model (LLM) was also prompted to categorize the clinical risks associated with the AI uses listed in Figure 1 of the original paper. The author is of the opinion that the LLM’s risk categorisation (column 2 in table A below) adopted a patient-centric perspective.
    However, the author is of the opinion that a "composite" clinical risk assessment, which considers both the nature of the specific usage instance and the pot...

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  • Overdiagnosis: Misuse in Breast Cancer Screening

    In breast cancer screening, the term "overdiagnosis" is a misnomer. It would be more accurate to state that the natural history of screen-detected cancer has not been adequately verified.
    Overdiagnosis is typically defined as the diagnosis of a lesion as cancer that will not cause symptoms or result in death. This definition assumes that cancer detection is appropriate and occurs in individuals for whom the diagnosis would be clinically relevant. For instance, in elderly patients, cancer may not lead to symptoms or death within their life expectancy. However, the issue in breast cancer screening is not related to the duration of observation but rather to the diagnosis itself.
    Cancer is generally diagnosed when a mass is detected through imaging or endoscopy and its malignant nature is confirmed histopathologically. However, early-stage breast cancer is an unusual case. These lesions may not form a detectable mass and are diagnosed as cancer based solely on histopathological findings. There is no scientific or clinical verification that cancers identified in this manner are biologically cancerous. Consequently, most clinical studies on breast cancer screening are essentially uncontrolled case series, lacking rigorous controls and, as such, are not scientifically interpretable or statistically reliable.
    A systematic review by the U.S. Preventive Services Task Force (USPSTF) did not provide clear evidence that breast cancer screening reduces cancer...

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  • Spa Therapy Is Not a Pill: Reconsidering Methods in the Evaluation of Complex Interventions

    RJ Forestier, FB Erol Forestier, I Santos, A Muela Garcia, A Françon.
    Centre de Recherches Rhumatologiques et Thermales d’Aix-les-Bains, Aix Les Bains, France.

    This meta-analysis approaches spa therapy as if it were a pharmaceutical intervention, which we believe does not fully reflect the complex and multifaceted nature of such treatments.
    We have been conducting clinical trials and systematic reviews in this field for over 30 years. In our experience, spa therapy is a complex intervention traditionally based on the use of thermal mineral water, often combined with massages, baths, showers, mud applications, and supervised pool-based exercises -each of which may have therapeutic effects of its own.
    We were surprised by the conclusions of this meta-analysis regarding both the therapeutic effect and the risk of bias, as they differ markedly from our own findings and appear to stem from several questionable methodological choices.
    Bibliographic Incompleteness
    The limited scope of the literature search is particularly problematic. In 2020, we identified 122 comparative trials on balneotherapy, whereas this meta-analysis included only 42 randomized controlled trials. Our complementary search updated to 2025 identified 42 trials focused solely on knee osteoarthritis, and a total of 141 trials after removing duplicates related to multiple conditions. The highly selective inclusion criteria adopted in this meta-analysis substantially reduced t...

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  • Overdiagnosis: Misconceptions About Prostate and Breast Cancer Screening

    Overdiagnosis occurs when a lesion is identified as cancer despite the absence of symptoms or subsequent cancer-related death. (1) This is particularly common in elderly patients with shorter follow-up periods, assuming the cancer diagnosis is accurate. For prostate and breast cancers, the natural history of screen-detected cases remains unverified, and many of these cancers remain asymptomatic or non-lethal even with extended observation. Therefore, the issue lies with the diagnostic tests, not the duration of observation. While it is accurate to state that "colorectal cancer screening results in overdiagnosis in the elderly," describing prostate cancer as having an overdiagnosis issue is misleading. Instead, it should be clarified that "the natural history of screen-detected prostate cancer has not been verified" or that "there are limitations in the diagnostic tests."
    Cancer is typically diagnosed by detecting the formation of a mass through endoscopy or imaging, followed by histopathological confirmation that the cells are malignant. However, screen-detected prostate and breast cancers do not form masses and are diagnosed based solely on histopathology. Whether a lesion diagnosed in this way is biologically cancerous—that is, its natural history—has not been clinically or scientifically verified. (2-4)
    In cancer statistics, both prostate and breast cancers rank among the highest in terms of incidence. (5) However, most of these...

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  • Pre- and in-hospital pre-ROSC EEG during cardiopulmonary resucitation

    February 23, 2025, Eichinger et al. published a plan for pre-hospital bispectral index measurements (BIS) during CPR in out-of-hospital cardiac arrest patients and at hospitalization to
    a) determine feasibility of BIS during CPR,
    b) assess neurological outcomes -particularly return of consciousness before ROSC and
    c) grade cerebral performance category (CPC) at 1 month

    Highlighted strenghts were systematic data collection and focus on feasibility of BIS during and after CPR, whereas limitations included recruiting 45 patients, reliance on a particular EMS system and prioritization study feasibility over clinical outcomes (1).

    However, there are more weaknesses:
    Muscle signals (EMG) and artifacts in BIS due heart massage are expected to blur the EEG assessments – but easily eliminated by sedatives and paralytic agents. The major problem is 'noise' from EEG devices, electrical installations and human activities at the scene of arrest because the 'noise level' dictates whether electrocortical activities can be identified (2).
    Quality of Life (QoL) interviews of family members are suggested although one's own
    perception of life quality before CPR does not relate to qualities one month later.
    The reference list includes 18 articles of which 17 were published in 2017 or later and one neurosurgical from 1975.
    The number of patients is 45 whivch weakens the upper 95% confidence interval for th...

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  • Fair Informed Consent: is the tide turning?

    This article continues the evidence that the current Participant Information Sheet isn’t fit for its purpose. It no longer supports fair consent, rather, it has become a legal document focused on the needs of the research team, not the potential participant. Having spent much time as Research Ethics Advisor to the National Research Ethics Advisor and subsequently the Health Research Authority trying (unsuccessfully) to address this, I would support the authors' concluding sentence.
    But I believe the tide is turning (https://blogs.bmj.com/medical-ethics/posts-page/). The USA Food and Drug Administration draft guidance / requirements support and expect all patient-facing material to start with a comprehensible summary of information of importance to potential participants. Their requirements, if accepted, will carry great weight (https://www.fda.gov/media/176663/download) . On the Oxford A UK Research Ethics Committee, we were similarly concerned about this issue and together drew up and published proposals, which, perhaps unsurprisingly, overlap with the USA material (https://journals.sagepub.com/doi/10.1177/17470161231176932l ).
    These were shown to patient groups who responded very positively, but they now need to be tested in real practice, involving all with...

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  • A call for transparent reporting of methodological limitations when conducting RWD transportability analysis

    The recently published study investigates transportability of overall survival estimates from US to UK populations receiving first-line treatment for advanced non-small cell lung cancer. Transportability is indeed an important topic when local data is not available or sufficient, which is especially true for rare diseases or, in this context, rare biomarker alterations. However, upon careful examination of the present paper, several points emerge that demand attention and reflection.
    First, since only aggregated data from the UK were available, the authors chose to use unanchored matching-adjusted indirect comparison (MAIC). This method, however, requires the very strong assumption that all effect modifiers and prognostic factors are accounted for [1], which is very improbable given that only few patient characteristics were available from the used comparator study. Additionally, MAIC analyses are subject to assumptions about the distribution of covariates in the population for which only summary measures are available. We strongly recommend discussing these issues in connection with the choice of method.
    Moreover, the extrapolation of results from one country to another without considering country-specific factors is quite problematic. Especially, fundamental differences between the US and UK health care systems were only addressed in a half-sentence in the Box on “strengths and limitations of this study“ but were not mentioned in the discussion. Health care c...

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