eLetters

1110 e-Letters

  • RE: Blood pressure and cognitive function across the eighth decade: a prospective study of the Lothian Birth Cohort of 1936

    Altschul et al. conducted a prospective study to investigate the association between blood pressure (BP) and cognitive functions across the eighth decade (1). Women with higher early-life cognitive function had lower BP during the eighth decade. In addition, prescribed antihypertensive medication was closely associated with lower BP, but antihypertensive medication had no effect on better cognitive function. Regarding no relationship between BP and cognitive decline, I have some concerns.

    First, Ou et al. conducted a meta-analysis regarding the association between BP and cognitive impairment/dementia in prospective studies (2). The significant relationship of BP with cognitive impairment/dementia was observed in different BP variables, which were classified into midlife and late-life periods. In addition, prescribed antihypertensive medications exhibited a 21% reduction in dementia risk, which was different from data by Altschul et al. I suspect that long-term follow-up might change the relationship between BP and cognitive functions. Long survivors’ effect on BP and cognitive functions should be specified by further study.

    Second, visit-to-visit variability in blood pressure was a significant predictor of subsequent cognitive decline in old subjects (3,4). But the association between BP variability and cognitive impairment was not mediated by BP lowering medication (5). As BP variables such as high systolic BP, low diastolic BP, excessive BP variability, and...

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  • Correction to meta-analysis of pulsed electromagnetic field in osteoarthritis (OA)

    Dear Dr Aldcroft,

    We read with interest the paper entitled “Efficacy and safety of the pulsed electromagnetic field in osteoarthritis: a meta-analysis”.1 This paper concluded that “PEMF could alleviate pain and improve physical function for patients with knee and hand [osteoarthritis] OA, but not for patients with cervical [osteoarthritis] OA.” We have a few concerns with their conclusion.

    The first concern is that the review reports very large effect sizes for some trials,2-5 but does not alert the reader to how atypical these results are. For example, Figure 3 of the manuscript1 contains three examples of effect sizes of ~3 and 4 standardised mean difference (SMD). Effect sizes this large are usually a red flag that something is amiss, either with the results of the review or the original trial. Unfortunately, both problems are present.

    The review reported a SMD for the Nelson trial5 of -3.72; but this a mistake. The authors have confused the standard deviation (SD) with the standard error (SE) and when their error is corrected the true effect size is -0.74 [95% confidence interval (CI) -1.44 to -0.04] compared with -3.72 [95% CI -4.88 to -2.56] reported in the review. The correction also changes the pooled effect to -0.33 [-0.70 to 0.04] and would support the conclusion that the treatment is not effective for knee OA.

    The other two large effect sizes are driven by outcomes in the treatment group and no change in the control group.2,3 For...

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  • Future prospectives

    We would like to thank RJ Aitken for presenting his basic scientist view on our clinical trial.

    His first comment addresses the fact that we include “idiopathic infertility patients irrespective of their redox status “. He suggests that we should only include patients with proven oxidative stress. We would like to respond that, of course, we would prefer to follow his advice, on the condition that validated test are available to differentiate between men that do suffer (constantly) from oxidative stress and those that do not, or that are even at risk for reductive stress. If we could all agree on the reliability of such tests, then it would certainly be worthwhile to try and get additional funding for pre- and post-therapy testing in (a subset of) our patients, then analyze them separately according to their redox status. Such an addition might provide a more solid basis for the antioxidant therapy. However, sperm DNA fragmentation tests are very costly and there is as yet no international consensus on which sperm DNA fragmentation test should be used as becomes obviously clear when reading the extensive review of the literature composed by Agarwal et al and the extensive discussion it awakened with more than 50 commentary letters published.(1,2) As to the danger of causing reductive stress, we think this is limited, as Impryl does not contain direct and strong scavenging antioxidants such as vitamin C and E, but rather focuses on the homocysteine pathway and the 1...

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  • Application To Covid-19

    Cloth masks, while comforting to some, should not be implied to provide anything but marginal (at best) protection to this "epidemic". When referring to virus particles that can spread via droplets it is fairly apparent that cloth masks do little to nothing for protection (except piece of mine)...and sorry, but 3ish% is not even a nominal value, its a toss value when referring to health.

    Take a covid 19 positive patient, have them where a cloth mask and exhale sharply, sneeze, or cough in front of a mirror....watch what happens. I understand this is an overly simplified example, but it gets the point across.

    As a last ditch effort with nothing else? Sure, but as a primary line of active defense for at risk individuals? Not even close. These individuals should be protected, away from the "herd" community.

  • MS.

    These look wonderful!
    I wonder, though, if the filter placements could be moved or they could be reshaped to allow the wearer's mouth to show better for the hearing impaired.

  • Hospitalizations of children and young people with Down syndrome

    Hughes-McCormack et al. investigated live birth, death rates and childhood hospitalisations in people with Down syndrome (1). Regarding childhood hospitalisations, adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) of people with Down syndrome for hospital admission, readmission, and emergency admission were 1.84 (1.68, 2.01), 2.56 (2.08, 3.14), and 2.87 (2.61, 3.15), respectively. In addition, people with Down syndrome presented longer lengths of stays than controls. I have a query about their study.

    Fitzgerald et al. described patterns of hospitalisations for children and young people with Down syndrome (2). Children with Down syndrome were at increased risk of morbidity for varied causes. Rate ratio (RR) (95% CI) of children with Down syndrome for overall hospitalisations was 5.2 (4.3, 6.2) by setting Silva data (3) as a control. I think that HR or RR would be changed according to control data, and hospitalisation rate would be changed with time. In addition, socioeconomic status would also be closely related to hospitalisation rate. Regarding the improved prognosis of people with Down syndrome, comprehensive analysis is needed by compiling information on medication and other social supporting systems.

    References
    1. Hughes-McCormack LA, McGowan R, Pell JP, et al. Birth incidence, deaths and hospitalisations of children and young people with Down syndrome, 1990-2015: birth cohort study. BMJ Open. 2020;10(4):e033770. Published 2020 Apr 1. d...

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  • Inflation adjustment

    We do not see how the cost data has been adjusted for Taiwanese inflation, considering that the data collected covers a long period. If this has not been done, we may have underestimated cost data. We understand that this needs to be reviewed when considering the data.

  • This article DOES NOT apply to COVID-19/SARS-CoV2

    When 85% of the viruses found in laboratory tests were rhinoviruses, which are about four times smaller than SARS-CoV2, no conclusion from this article can be applied to COVID-19/SARS-CoV2. No coronaviruses of any kind were found even though the tests were performed. Finally, their claim that "Penetration of cloth masks by particles was almost 97%" is of no value when the particles sizes are not stated. Furthermore, since many viruses, such as influenza, herpes simplex, and coronaviruses are surrounded by a fatty layer, called a "lipid envelope," one wonders about the choice of sodium chloride particles instead of oil particles, taking in consideration that the instrument used (TSI 8110 Filter tester) can use either.

  • The need for high quality evidence remains

    We read the response to our systematic review by Henk Giele with great interest. The respondent stated:

    “An uncritical reading of this and other reviews on the subject suggest that intra-articular steroid injections should not be used as no beneficial effect is demonstrated”

    No such suggestion is made in our article and our conclusion is very clear in stating that the current evidence is equivocal regarding the use of injection therapy in base of thumb osteoarthritis. An absence of evidence is not an evidence of absence. The respondent also touches on some interesting aspects of the complexity of injection therapy as an intervention, such as the type of steroid and dosage, while there are many other elements which merit consideration such as the education given concomitantly, the period of rest, splint use, the type of injection guidance, the use of local anaesthetic, and patient factors such as stage of osteoarthritis and degree of synovitis. One of the key flaws in the current evidence base as highlighted by our review was the minimal regard paid to the overall package of care, and even something as simple as the advice and education given with a steroid injection may have a significant influence on outcome.

    Without a large adequately powered methodologically robust RCT, we simply cannot be confident of what to tell our patients, both in terms of the degree of potential short term benefits, but also in terms of the potential longer term harms....

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  • Comment to ‚Cost-effectiveness of total knee replacement in addition to non-surgical treatment: a 2-year outcome from a randomised trial in secondary care in Denmark‘ (Skou et al. BMJ Open. 2020 Jan 15;10(1):e033495)

    Recently, Skou and collegues published a trial-based cost-utility analysis that evaluated the cost per quality-adjusted life year (QALY) gained for total knee replacement (TKR) in addition to non-surgical treatment compared to non-surgical treatment alone (Skou 2020). Fortunately, this study now adds economic data on TKR based on a high-level evidence. However, with regard to the intrepretation of the results, the reader is left with some open questions.
    Clinical and economic data was based on a randomised-controlled trial which provided data on TKR at the same time (Skou 2015). According to the study design, regression analyses were used to estimate incremental costs and quality-adjusted life years (QALYs) and, data was analysed in accordance with the intention-to-treat principle. In the base-case-scenario, the regression analyses were adjusted for covariates (i.e., age, sex and baseline costs/QALY), while two additional scenarios did not take covariates into account (Scenario 1), and did not consider either covariates or missing values/imputations (Scenario 2). While the base-case-scenario resulted in additional costs of 6070€ with a QALY-gain of 0.186 (incremental cost-effectiveness ratio of 32,611 €/QALY), the additional scenarios showed cost-utility-ratios below 20,000€/QALY (and thus below the NICE-threshold of 22,665 €/QALY). However, the results provided and the claimed cost-effective potential of TKR raises two concerns:
    First, for the base-case costs...

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