836 e-Letters

  • Diagnosing IDNA

    Iron Deficiency is the most common mineral deficiency worldwide and this review highlights important aspects for clinical care. Firstly and foremost is the astonishing lack of research (and recognition) for a condition that affects 10-15% of all people at any one point in time and a top 10 global cause for years living with disability. Second and pertinant to this specific review is how clinicains should diagnose iron deficiency. The 18 clinical trials listed used the definition of Iron Deficiency used was as a low serum ferritin, which varied from less than 50 to less than 15ug/L. The WHO defines Iron Deficiency as a serum Ferritin < 15ug/L. In athletes the repeated stress of exercise creates inflamation that in turn activates the iron regulation protein, Hepcidin that reduces iron bioavailibility causing a functional iron deficiency. In this setting, Transferrin Saturations (%) may be a more accurate indicator of Iron Deficiency. In the the four studies using Ferritin < 16, Transferrin Saturations averaged over 20% in three, i.e. the majority of individuals may have had potential normal iron. Finally, and along the same theme, in the presence of exercise induced / functional iron defiency oral the effect of oral iron is limited so it is not suprising that iron tablets failed to have an effect. Moving forwards, there is a need to better identify and define Iron Deficiency in the 'healthy' female and further studies with appropriate interventions are need...

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  • Adjusting Hospital Scores to Account for Differences in Patient Characteristics

    We read with interest the recent article by Rubens et al. “Impact of Patient Characteristics on the Canadian Patient Experiences Survey–Inpatient Care: Survey Analysis from an Academic Tertiary Care Centre.” This work adds to the literature by examining patient characteristics associated with response patterns on the Canadian Patient Experience Inpatient Care Survey. The authors conclude that caution is needed when comparing performance between different entities assessed by this survey, as observed differences could be explained by variation in patient mix rather than variation in performance. While we agree that patient characteristics are likely to explain some of the variation in observed patient experience scores, as has been found in similar settings in the US and UK (Elliott et al. 2009, Paddison et al. 2012), we do not believe that this is problematic for the validity of patient experience scores. Following the common practice of adjusting entity scores for patient characteristics such as self-reported health, education, and age allows for valid comparisons as if all hospitals had treated the same patient population. In practice, one typically adjusts for the average within-hospital difference associated with patient characteristics not under the control of the hospital via a linear regression mode with hospital intercepts.

    In the US inpatient setting, for example, Elliott et al. 2009 showed that self-reported health status had the greatest explanatory pow...

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  • Re: Child discipline was not measured

    Dr diPierro,

    Thank you for your feedback. Our conclusions do not refer to discipline practices at home, in schools and elsewhere. This is an ecological analysis of the link between bans and youth fighting based on country differences. There are of course limitations in this sort of design and these are discussed in the article.

    We conclude that societies that have less physical violence are safer places to grow up in because they are less violent.

  • I can't make a network diagram in the article by using the raw data.

    Dear author:

    I am just a beginner network meta-analysis. Your article has been a great help to my study, but I have a question to ask you. I hope you can answer my doubts. In this article, the “Network of eligible comparisons for treatment efficacy network meta-analysis for Kashin-Beck disease” showed that “Se-Se+VC-Placebo”and ”Se-Se+VC-VC” were two closed loops, but there was no direct comparison between Se and Se+VC in the original studies. So I could not use the raw data to create a network similar to this article. Could you tell me why? Am I mistaken?

    Thank you and best regards.

  • A qualitative research method should be used in the survey which study the impact of workplace violence and compassionate behaviour in hospitals on stress, sleep quality and subjective health status among Chinese nurses

    Meijuan Jin, School of Nursing, Nantong University, Nantong, Jiangsu, PR China
    Cheng Ji, Nantong higher vocational and technical school, Jiangsu, PR China
    Cheng Ji, Nantong higher vocational and technical school, Jiangsu, PR China
    E-mail: nantongjinzi@163.com

    To the Editor:
    I have read the article written by Shu-E Zhang and her coworkers on Impact of workplace violence and compassionate behaviour in hospitals on stress, sleep quality and subjective health status among Chinese nurses: a cross-sectional survey1 with great interest and respect. The authors used a cross-sectional online survey study to describe the current state of workplace violence and compassionate behaviour towards nurses and to explain how they affect nurses’ stress, sleep quality and subjective health status. Approximately 75.4% participants had experienced some form of violence. They found that WPV can damage nurses’ health outcomes,while compassionate behaviours were beneficial to their health outcomes. A harmonious nursing environment should be provided to minimise threats to nurses’ health status.Although we are agree with this view, there are some opinions against this article.
    Firstly, the authors used the cross-sectional online survey study and there were about 75.4% effective response which we think is a quite low level. That would make the results unrepresentative and give rise to...

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  • No reason to be concerned about dyslipidaemia in women

    In their paper Bakesiima et al. are concerned about their finding that women using hormonal contraceptives become dyslipidaemic.1 However, very few studies, if any at all, have shown that dyslipidaemia in women is a risk factor for cardiovascular disease, and no cholesterol-lowering trial has succeeded with prolonging their life. Furthermore, if a woman on hormonal contraceptives wants to become pregnant or forgets to take the hormone drug and continue with statin treatment, there is a great risk that she may give birth to a child with serious malformations.2 Dyslipidaemia may even be advantageous, because in a recent analysis of 19 follow-up study of more than 68,000 elderly people we found that those with the highest LDL-cholesterol lived the longest; even longer than those on statin treatment.3

    1. Bakesiima R, Byakika-Kibwika P, Tumwine JK et al. Dyslipidaemias in women using hormonal contraceptives: a cross sectional study in Mulago Hospital Family Planning Clinic, Kampala, Uganda. BMJ Open. 2018;8:e022338. doi: 10.1136/bmjopen-2018-022338.
    2. Edison RJ, Muenke M. Central nervous system and limb anomalies in case reports of first trimester statin exposure. N Engl J Med 2004;350:1579-82.
    3. 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

  • Child discipline was not measured

    Dr. Elgar,

    I don’t have an issue with your hypothesis but your conclusion is not completely correct.

    You state:

    "Conclusions Country prohibition of corporal punishment is associated with less youth violence. Whether bans precipitated changes in child discipline or reflected a social milieu that inhibits youth violence remains unclear due to the study design and data limitations. However, these results support the hypothesis that societies that prohibit the use of corporal punishment are less violent for youth to grow up in than societies that have not.”

    I don’t see that you measured or hypothesized any changes in child discipline. You measured changes in child violence. This is a very important distinction.


    Charles G. diPierro, MD, MS, PhD, MPH

  • Correspondence on: Impact of hepatitis C virus infection on long-term mortality after acute myocardial infarction

    Dear Editor,

    We have read with great interest the study entitled “Impact of hepatitis C virus infection on long-term mortality after acute myocardial infarction: a nationwide population-based, propensity-matched cohort study in Taiwan ” by Kuo and colleagues in the BMJ Open. We would like to congratulate the authors for this analysis, and make some comments.

    First, we would like to mention that prior studies have reported increased incidence of atherosclerosis and cardiovascular disease as well as cardiovascular mortality in patients with chronic hepatitis C infection. In your study, the authors reported in the narrative that Hepatitis C Virus infection increased the 12-year mortality of patients after an acute myocardial infarction. However, figure 2 showed that Hepatitis C negative patients had more deaths compared to Hepatitis C positive patients. It is unclear if the columns in the figure were mislabeled or the numbers were reversed.

    Second, we believe that the use of propensity score matching in the statistical analysis was not appropriate. Propensity score matching is the probability to receive an experimental treatment based on pre-treatment covariates, and it is used when patients could be theoretically randomized to a treatment arm or a control arm. Chronic Hepatitis C infection is a patient characteristic, and thus patients cannot be randomized to that condition.  The appropriate analysis would be multivariable Cox regression comparing Hep...

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  • Commentary on the recruitment of clinic patients

    Quattrocchi et al’s recent publication explored the association between tuberculosis (TB) stigma and delays in care among Italians.1 As the authors note, this investigation distinguishes itself from other research on the topic of tuberculosis stigma and its impact on delays in care by assessing this association in a European population in contrast to prior work, which has primarily focused on Asian and African populations. Thus, while the results add to a growing body of literature, several limitations and biases, many of which the authors acknowledge, narrow the generalizability of the results. Specifically, selection bias may have underestimated the findings with regard to patient delay (PD).

    In this investigation, healthcare providers at participating clinics collected data during an in-person visit in which tuberculosis patients were diagnosed or initiating treatment. If the underlying question of interest is Does increased TB stigma lead to longer delays in care? and the answer is Yes, then the current study is not constructed to accurately capture that association since those with the highest levels of perceived TB stigma may never present at the clinic and would therefore be excluded from the study. This is of particular concern given the estimated 10.4 million cases of TB worldwide, 4 million of which are presumed missing.2

    For illustrative purposes, we can use data provided in the paper to roughly construct a contingency table that would yield the r...

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  • Understanding the pathways linking socioeconomic factors to the risk of childhood unintentional injuries

    Dear Editor,

    Sato et al's research shows no social gradient in unintentional injury (UI) risk in preschool children in Japan. However, many previous studies have shown clear evidence of increased risk of UI in children living in more disadvantaged circumstances. [1,2] Our analysis of data from the UK Millennium Cohort study shows that the relationship between SECs and risk of UIs is not static relationship, and that the association changes with age. (Figure 1) Further research is needed to understand the complex pathways linking social conditions to risk of childhood unintentional injuries, and how these vary across different settings.

    Figure 1 illustrates the relative risk ratios for an unintentional injury at different ages comparing the highest and lowest household income quintiles measured at birth.


    1 Engström K, Laflamme L, Diderichsen F. Equalisation of socioeconomic differences in injury risks at school age? A study of three age cohorts of Swedish children and adolescents. Soc Sci Med 2003;57:1891–9. doi:10.1016/S0277-9536(03)00054-6

    2 Laflamme L, Hasselberg M, Burrows S. 20 years of research on socioeconomic inequality and children’s unintentional injuries understanding the cause-specific evidence at hand. Int J Pediatr 2010;2010:23 pages. doi:...

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