eLetters

1088 e-Letters

  • RE: Influence of combined exposure to perceived risk at work and unstable employment on self-rated health

    Cho et al. investigated the combined effect of exposure to perceived risk at work and unstable employment on self-rated health (1). Among Korean employees, odds ratios (ORs) (95% confidence intervals [CIs]) of perceived risk at work and unstable employment for poor self-rated health were 2.00 (1.80 to 2.22) and 1.18 (1.09 to 1.28), respectively. In addition, OR (95% CI) of both perceived risk at work and unstable employment for poor self-rated health was 3.22 (2.72 to 3.81), and relative excess risk due to interaction (RERI) (95% CI) was 1.03 (0.48 to 1.58). Among European employees, ORs (95% CIs) of perceived risk at work and unstable employment for poor self-rated health were 3.20 (2.93 to 3.49) and 1.04 (0.97 to 1.13), respectively. In addition, OR (95% CI) of both perceived risk at work and unstable employment for poor self-rated health was 3.41 (2.93 to 3.98), and RERI (95% CI) was 0.18 (-0.36 to 0.71).There was a supra-additive interaction between perceived risk at work and unstable employment on poor self-rated health among Korean employees, and I have a query about data among Korean employees.

    Kim et al. reported that odds ratio of precarious employment for poor health was marginally significant, by adjusting socio-demographic covariates, job satisfaction, job insecurity, and monthly wage (2). Kwon et al. also evaluated the association between employment status and self-rated health (3). The percentage of non-permanent workers was 20.8 %, and OR of non-perma...

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  • RE: Protective effects of oral anticoagulants on cerebrovascular diseases and cognitive impairment in patients with atrial fibrillation

    Saji et al. intended a prospective study to know the effects of warfarin therapy and direct oral anticoagulants (DOACs) on cerebrovascular diseases and cognitive impairment (CI) in patients with non-valvular atrial fibrillation (NVAF) over an estimated duration of 36 months (1). I want to present some information.

    First, Mongkhon et al. investigated the risk of dementia/CI among newly diagnosed atrial fibrillation (AF) patients with and without oral anticoagulation (OAC) treatment over a mean follow-up of 5.9 years (2). Hazard ratios (HRs) (95% confidence intervals [CIs) of OAC treatment and antiplatelets for dementia/CI were 0.90 (0.85-0.95) and 0.84 (0.79-0.90), respectively. In contrast, HR (95% CI) of DOACs treatment against warfarin for dementia/CI was 0.89 (0.70-1.14). Furthermore, HR (95% CI) of dual therapy (OAC plus antiplatelets) for dementia/CI was 1.17 (1.05-1.31). Saji et al. set two clinical outcomes, and study period was shorter. In addition, safety evaluation on bleeding might also be required.

    Second, Diener et al. recommended randomized trials to evaluate whether OAC, including warfarin and DOACs, reduces dementia/CI in AF patients (3). Dementia/CI, including vascular dementia and Alzheimer's disease, might be related to ischemic stroke, cerebral micro-infarcts, cerebral hemorrhage, and reduced cerebral blood flow. Taken together, risk assessment of medications for dementia/CI in AF patients would be closely associated with types of cer...

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  • Response to the comments

    We thank Dr. Elizabeth A Pritts, Dr. David L Olive, and Dr. William H. Parker for their great interest in our study and for the very qualified comments. To investigate the influence of uterine fibroids on obstetrical outcomes is complex and can be viewed from different angles. - We aimed to investigate symptomatic uterine fibroids. Well conducted cohort studies are the best available substitutes when experiments are not possible. Methodological limitations need to be taken into consideration, and associations can be explored. We are fully aware that limitations must be relevantly discussed. David A Grimes 1 pointed out some important issues regarding cohort studies:
    1) The exposure should be clear: we argue to have a clearly defined exposure.
    2) The importance of potential confounders: we have been able to include important confounders using the directed acyclic graph, DAG.
    3) Awareness that the risk of a weak association (HR 0.5-2) is likely to be due to bias and not causation: We have clearly stated that we have found associations and further that the association could be interesting for further research, but we do not recommend changes in clinical recommendations.
    The risks of misclassification of exposure were related to the uterine fibroid diagnoses codes. The daily clinical coding may be incorrect or lacking due to various work-related distractions or variable individual interpretation of clinical cases. The low prevalence of uterine fibroids...

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  • Clinical Trial Results: Time To Revisit ICH-GCP Guidelines

    Interestingly, Raza et. al., address an important issue related to the clinical trial enterprise. Despite the high intention to disseminate results to trial participants by trial investigators, there is a systemic lack in the feedback methods and regulatory framework. It is worthwhile to revisit the ICH-GCP guidelines and mandate trial result dissemination. Clinical trial participant data box (PDB) should be made mandatory for timely disclosure of trial results to participants and should be spread throughout the clinical trial process, tracking the trial’s performance on matters major and minuscule. There are reasons for this requirement: Firstly, the participants have the right to know the trial outcome. Secondly, the local community should know about the trials being conducted, to enhance public trust, Thirdly, the disclosure helps international participants and research community to calibrate their decisions. Similar to an airline's black box, the participant data box may reveal everything about the trial, or point the way and, rarely will they offer no clue at all. Additionally, the participant data box may also help trial investigators, sponsors, and participants to assess and learn from mistakes.

  • RE: Protective effects of oral anticoagulants on cerebrovascular diseases and cognitive impairment in patients with atrial fibrillation

    Saji et al. intended a prospective study to know the effects of warfarin therapy and direct oral anticoagulants (DOACs) on cerebrovascular diseases and cognitive impairment (CI) in patients with non-valvular atrial fibrillation (NVAF) over an estimated duration of 36 months (1). I want to present some information.

    First, Mongkhon et al. investigated the risk of dementia/CI among newly diagnosed atrial fibrillation (AF) patients with and without oral anticoagulation (OAC) treatment over a mean follow-up of 5.9 years (2). Hazard ratios (HRs) (95% confidence intervals [CIs) of OAC treatment and antiplatelets for dementia/CI were 0.90 (0.85-0.95) and 0.84 (0.79-0.90), respectively. In contrast, HR (95% CI) of DOACs treatment against warfarin for dementia/CI was 0.89 (0.70-1.14). Furthermore, HR (95% CI) of dual therapy (OAC plus antiplatelets) for dementia/CI was 1.17 (1.05-1.31). Saji et al. set two clinical outcomes, and study period was shorter. In addition, safety evaluation on bleeding might also be required.

    Second, Diener et al. recommended randomized trials to evaluate whether OAC, including warfarin and DOACs, reduces dementia/CI in AF patients (3). Dementia/CI, including vascular dementia and Alzheimer's disease, might be related to ischemic stroke, cerebral micro-infarcts, cerebral hemorrhage, and reduced cerebral blood flow. Taken together, risk assessment of medications for dementia/CI in AF patients would be closely associated with types of cer...

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  • RE: Sleep-cognition hypothesis in maritime pilots, what is the effect of long-term work-related poor sleep on cognition and amyloid accumulation in healthy middle-aged maritime pilots. To be continued

    I previously made a comment on a protocol paper by Thomas et al (1), and I want to add some information on the sleep monitoring method. The authors used actigraphy, named Actiwatch-2® (Philips Respironics), an accelerometer-based device, to obtain objective sleep parameters. The Actiwatch-2® was worn around the non-dominant wrist and they measured total sleep time and number of awakenings during sleep. Actiwatch was used for consecutive 10 days in combination with sleep diary and one-day measurement of sleep polysomnography. I reported a validation study of Actiwatch® (2), and also reported a comment on validity (3-7). In these papers, I described that caution should be paid to the data, especially in subjects with poor sleep.

    Thomas et al. handled healthy middle-aged subjects with long-term work-related poor sleep, and the level of cognition and amyloid accumulation were evaluated in relation to sleep. Actigraphy does not detect brain activity during sleep, and disagreement between actigraphy and sleep polysomnography might be observed especially awakenings during sleep without movement. I discussed sleep by actigraphy in patients with Alzheimer disease (8), and appropriate adjustment of sleep parameters by actigraphy is needed for the analysis.

    If the authors plan to publish their original paper, validation data in combination with Actiwatch-2® and sleep polysomnography should be included.

    References
    1. Thomas J, Ooms S, Verbeek M, et al. Sleep...

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  • RE: Working hours, common mental disorder and suicidal ideation among junior doctors in Australia: a cross-sectional survey

    Petrie et al. examined the relationship between average weekly working hours and junior doctors' mental health (1). Common mental disorder (CMD) was assessed using a cut-off of 4 as a threshold on General Health Questionnaire 28-item scale score. Suicidal ideation (SI) was assessed with a single item. Adjusted OR (95% confidence interval [CI]) of working over 55 h/week against working 40-44 h/week for CMD and for SI were 2.05 (1.62 to 2.59) and 2.00 (1.42 to 2.81), respectively. I have some concerns about their study.

    First, Soares and Chan described stress levels and the psychological wellbeing of current junior medical officers (JMOs) (2). They used the Short Form-36 and Perceived Stress Scale-14 (PSS14), and JMOs were more likely to have a high PSS-14 score or to have a low mental health score if they reported higher career anxiety. Working hours are closely associated to sleeping time and other lifestyle behaviors, and these factors should be considered for the risk assessment of stress and psychological wellbeing of JMOs.

    Second, Rosta and Aasland conducted a survey to experienced doctors to examine the perception of working hours for postgraduate training doctors (3). The question is “How do you think that self-reported total weekly working 45 hours is too short, sufficient, or too long to meet the quality requirements of obligatory postgraduate training for junior doctors?” Although the majority perceived as sufficient for obligatory postgraduate...

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  • The Black Box Called Clinical Trial Results

    The authors Raza et. al., address an important set back inherent to the clinical trial enterprise. Despite the high intention to disseminate results to trial participants by trial investigators, there is a systemic lack in the feedback methods and regulatory will by the ethics committees. The research ethics committee oversees the fact that the majority of the end of study reports ignore the mention of the dissemination of trial results to participants. The ICH-GCP guidelines emphasize little or none about trial result dissemination. Among the many gaps, the foremost among them is the end of the study report, submitted to the ethics committee after six months of study completion, is in a prescribed form. The form lacks the data fields to insist on the investigators to disseminate trial results to the participants. Participant data box (PDB) to mandate disclosure of trial results should be spread throughout the clinical trial process like blood capillaries in the body, tracking the trial’s performance on matters major and minuscule. There are reasons for this requirement, irrespective of whether a trial was successful or not. Firstly, the participants have the right to know the trial outcome. Secondly, the local community should know about the trials being conducted, to enhance public trust, Thirdly, the disclosure helps international participants and research community to calibrate their decisions. Similar to an airline's black box, the participant data box may revea...

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  • Answer to Mette Juul and Per K Andersen

    Thanks to midwife Mette Juhl (MJ) and statistician Per K Andersen (PKA) for their interest in the still hot topic about the risk of stillbirth with increasing gestational age (GA).

    MJ and PKA suggest that our calculated cumulative rates of stillbirths by increasing GA are not a good approximation of the cumulative proportion of deaths by increasing GA. The argument for this statement is that there are “competing risks” because “the vast majority of ongoing pregnancies will end in a live birth and only very few in a fetal death”. MJ and PKA prefer to use the cumulative proportions per 1000 deliveries given in Table 1 in our paper.

    It is correct that the figures in Fig. 2 are cumulated rates, not per 1000 deliveries but per 1000 ongoing pregnancies. So, these curves demonstrate the risk of fetal death as a function of number of women at risk. We think this way of presenting the increasing risk of fetal death by increasing GA should be just the cumulated incidence rates as a function of the risk time (GA). These curves are thus cumulated rates and should probably have been called that in the publication (instead of cumulated proportion). We do not agree that these cumulated rates are misleading as a documentation of the dramatically increasing risk of fetal death when pregnancy goes weeks beyond term.

    The cumulative proportion of deaths per 1000 born is not suited to illustrate the increasing cumulative rate of stillbirth with increasing GA. According to...

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  • RE: High prevalence of hyperuricaemia and its impact on non-valvular atrial fibrillation: the cross-sectional Guangzhou (China) Heart Study

    Lin et al. conducted across-sectional study to evaluate the relationship between the prevalence of hyperuricaemia (HUA) and non-valvular atrial fibrillation (NVAF) (1). Age, living in urban areas, alcohol consumption, central obesity, elevated fasting plasma glucose level, elevated blood pressure, lower high-density lipoprotein cholesterol level and elevated triglycerides level were significantly associated with increased risk of HUA, and HUA were at higher risk for NVAF. Regarding sex difference, serum uric acid level had a modest predictive value for NVAF in women. I have some concerns about their study.

    First, Tu et al. conducted a prospective study to evaluate the risk of gout in patients with alcohol-related diseases and alcohol dependence syndrome (2). Alcohol-related diseases were significantly associated with gout risk, and severe alcohol-dependent patients were significantly associated with an increased risk of gout. The authors recommended that alcohol use assessment and measures to prevent alcohol dependence in patients with gout. I agree with their recommendation, which would partly lead to prevent NVAF.

    Second, Yu et al. presented strategies to improve gout/hyperuricemia management for preventing acute arthritis attacks, cardiovascular disease, kidney disease, and other urate-related disorders (3). Alcohol consumption is closely related to gout/hyperuricemia, and psycho-social factors should also be considered for the management.

    Third, Ku...

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