49 research outputs found

    Exposure to low-dose radiation and the risk of breast cancer among women with a familial or genetic predisposition:a meta-analysis

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    Women with familial or genetic aggregation of breast cancer are offered screening outside the population screening programme. However, the possible benefit of mammography screening could be reduced due to the risk of radiation-induced tumours. A systematic search was conducted addressing the question of how low-dose radiation exposure affects breast cancer risk among high-risk women. A systematic search was conducted for articles addressing breast cancer, mammography screening, radiation and high-risk women. Effects of low-dose radiation on breast cancer risk were presented in terms of pooled odds ratios (OR). Of 127 articles found, 7 were selected for the meta-analysis. Pooled OR revealed an increased risk of breast cancer among high-risk women due to low-dose radiation exposure (OR = 1.3, 95% CI: 0.9- 1.8). Exposure before age 20 (OR = 2.0, 95% CI: 1.3-3.1) or a mean of a parts per thousand yen5 exposures (OR = 1.8, 95% CI: 1.1-3.0) was significantly associated with a higher radiation-induced breast cancer risk. Low-dose radiation increases breast cancer risk among high-risk women. When using low-dose radiation among high-risk women, a careful approach is needed, by means of reducing repeated exposure, avoidance of exposure at a younger age and using non-ionising screening techniques

    Comparison of nuisance parameters in pediatric versus adult randomized trials: a meta-epidemiologic empirical evaluation

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    BACKGROUND We wished to compare the nuisance parameters of pediatric vs. adult randomized-trials (RCTs) and determine if the latter can be used in sample size computations of the former. METHODS In this meta-epidemiologic empirical evaluation we examined meta-analyses from the Cochrane Database of Systematic-Reviews, with at least one pediatric-RCT and at least one adult-RCT. Within each meta-analysis of binary efficacy-outcomes, we calculated the pooled-control-group event-rate (CER) across separately all pediatric and adult-trials, using random-effect models and subsequently calculated the control-group event-rate risk-ratio (CER-RR) of the pooled-pediatric-CERs vs. adult-CERs. Within each meta-analysis with continuous outcomes we calculated the pooled-control-group effect standard deviation (CE-SD) across separately all pediatric and adult-trials and subsequently calculated the CE-SD-ratio of the pooled-pediatric-CE-SDs vs. adult-CE-SDs. We then calculated across all meta-analyses the pooled-CER-RRs and pooled-CE-SD-ratios (primary endpoints) and the pooled-magnitude of effect-sizes of CER-RRs and CE-SD-ratios using REMs. A ratio < 1 indicates that pediatric trials have smaller nuisance parameters than adult trials. RESULTS We analyzed 208 meta-analyses (135 for binary-outcomes, 73 for continuous-outcomes). For binary outcomes, pediatric-RCTs had on average 10% smaller CERs than adult-RCTs (summary-CE-RR: 0.90; 95% CI: 0.83, 0.98). For mortality outcomes the summary-CE-RR was 0.48 (95% CIs: 0.31, 0.74). For continuous outcomes, pediatric-RCTs had on average 26% smaller CE-SDs than adult-RCTs (summary-CE-SD-ratio: 0.74). CONCLUSIONS Clinically relevant differences in nuisance parameters between pediatric and adult trials were detected. These differences have implications for design of future studies. Extrapolation of nuisance parameters for sample-sizes calculations from adult-trials to pediatric-trials should be cautiously done

    A randomized clinical trial indicates that levamisole increases the time to relapse in children with steroid-sensitive idiopathic nephrotic syndrome

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    Levamisole has been considered the least toxic and least expensive steroid-sparing drug for preventing relapses of steroid-sensitive idiopathic nephrotic syndrome (SSINS). However, evidence for this is limited as previous randomized clinical trials were found to have methodological limitations. Therefore, we conducted an international multicenter, placebo-controlled, double-blind, randomized clinical trial to reassess its usefulness in prevention of relapses in children with SSINS. The efficacy and safety of one year of levamisole treatment in children with SSINS and frequent relapses were evaluated. The primary analysis cohort consisted of 99 patients from 6 countries. Between 100 days and 12 months after the start of study medication, the time to relapse (primary endpoint) was significantly increased in the levamisole compared to the placebo group (hazard ratio 0.22 [95% confidence interval 0.11-0.43]). Significantly, after 12 months of treatment, six percent of placebo patients versus 26 percent of levamisole patients were still in remission. During this period, the most frequent serious adverse event (four of 50 patients) possibly related to levamisole was asymptomatic moderate neutropenia, which was reversible spontaneously or after treatment discontinuation. Thus, in children with SSINS and frequent relapses, levamisole prolonged the time to relapse and also prevented recurrence during one year of treatment compared to prednisone alone. However, regular blood controls are necessary for safety issues

    Systemic Hydrocortisone To Prevent Bronchopulmonary Dysplasia in preterm infants (the SToP-BPD study): Statistical analysis plan

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    Background: Bronchopulmonary dysplasia (BPD) is the most common complication of preterm birth with short-term and long-term adverse consequences. Although the glucocorticoid dexamethasone has been proven to be beneficial for the prevention of BPD, there are concerns about an increased risk of adverse neurodevelopmental outcome. Hydrocortisone has been suggested as an alternative therapy. The aim of the Systemic Hydrocortisone To Prevent Bronchopulmonary Dysplasia in preterm infants (SToP-BPD) trial is to assess the efficacy and safety of postnatal hydrocortisone administration for the reduction of death or BPD in ventilator-dependent preterm infants. Methods/design: The SToP-BPD study is a multicentre, double-blind, placebo-controlled hydrocortisone trial in preterm infants at risk for BPD. After parental informed consent is obtained, ventilator-dependent infants are randomly allocated to hydrocortisone or placebo treatment during a 22-day period. The primary outcome measure is the composite outcome of death or BPD at 36 weeks postmenstrual age. Secondary outcomes are short-term effects on pulmonary condition and long-term neurodevelopmental sequelae assessed at 2 years corrected age. Complications of treatment, other serious adverse events and suspected unexpected serious adverse reactions are reported as safety outcomes. This pre-specified statistical analysis plan was written and submitted without knowledge of the unblinded data

    Computer-aided detection in breast MRI: a systematic review and meta-analysis

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    To evaluate the additional value of computer-aided detection (CAD) in breast MRI by assessing radiologists' accuracy in discriminating benign from malignant breast lesions. A literature search was performed with inclusion of relevant studies using a commercially available CAD system with automatic colour mapping. Two independent researchers assessed the quality of the studies. The accuracy of the radiologists' performance with and without CAD was presented as pooled sensitivity and specificity. Of 587 articles, 10 met the inclusion criteria, all of good methodological quality. Experienced radiologists reached comparable pooled sensitivity and specificity before and after using CAD (sensitivity: without CAD: 89%; 95% CI: 78-94%, with CAD: 89%; 95%CI: 81-94%) (specificity: without CAD: 86%; 95% CI: 79-91%, with CAD: 82%; 95% CI: 76-87%). For residents the pooled sensitivity increased from 72% (95% CI: 62-81%) without CAD to 89% (95% CI: 80-94%) with CAD, however, not significantly. Concerning specificity, the results were similar (without CAD: 79%; 95% CI: 69-86%, with CAD: 78%; 95% CI: 69-84%). CAD in breast MRI has little influence on the sensitivity and specificity of experienced radiologists and therefore their interpretation remains essential. However, residents or inexperienced radiologists seem to benefit from CAD concerning breast MRI evaluation

    Evaluating safety and effectiveness of the early-onset sepsis calculator to reduce antibiotic exposure in Dutch at-risk newborns: a protocol for a cluster randomised controlled trial

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    Introduction Newborns are at risk for early-onset sepsis (EOS). In the Netherlands, EOS affects less than 0.2% of newborns, but approximately 5% are treated with empirical antibiotics. These numbers form an example of overtreatment in countries using risk-factor based guidelines for administrating antibiotics. An alternative to these guidelines is the EOS calculator, a tool that calculates an individual EOS risk and provides management recommendation. However, validation outside the North-American setting is limited, especially for safety outcomes. We aim to investigate whether EOS calculator use can safely reduce antibiotic exposure in newborns with suspected EOS compared with the Dutch guideline. Methods and analysis This protocol describes a cluster randomised controlled trial assessing whether EOS calculator use is non-inferior regarding safety, and superior regarding limiting overtreatment, compared with the Dutch guideline. We will include newborns born at ≥34 weeks' gestation, with at least one risk factor consistent with EOS within 24 hours after birth. After 1:1 randomisation, the 10 participating Dutch hospitals will use either the Dutch guideline or the EOS calculator as standard of care for all newborns at risk for EOS. In total, 1830 newborns will be recruited. The coprimary non-inferiority outcome will be the presence of at least one of four predefined safety criteria. The coprimary superiority outcome will be the proportion of participants starting antibiotic therapy for suspected and, or proven EOS within 24 hours after birth. Secondary outcomes will be the total duration of antibiotic therapy, the percentage of antibiotic therapy started between 24 and 72 hours after birth, and parent-reported quality of life. Analyses will be performed both as intention to treat and per protocol. Ethics and dissemination This trial has been approved by the Medical Ethics Committee of the Amsterdam UMC (NL78203.018.21). Results will be presented in peer-reviewed journals and at international conferences. Trial registration number NCT05274776

    A systematic review to investigate the measurement properties of goal attainment scaling, towards use in drug trials

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    One of the main challenges for drug evaluation in rare diseases is the often heterogeneous course of these diseases. Traditional outcome measures may not be applicable for all patients, when they are in different stages of their disease. For instance, in Duchenne Muscular Dystrophy, the Six Minute Walk Test is often used to evaluate potential new treatments, whereas this outcome is irrelevant for patients who are already in a wheelchair. A measurement instrument such as Goal Attainment Scaling (GAS) can evaluate the effect of an intervention on an individual basis, and may be able to include patients even when they are in different stages of their disease. It allows patients to set individual goals, together with their treating professional. However, the validity of GAS as a measurement instrument in drug studies has never been systematically reviewed. Therefore, we have performed a systematic review to answer two questions: 1. Has GAS been used as a measurement instrument in drug studies? 2: What is known of the validity, responsiveness and inter- and intra-rater reliability of GAS, particularly in drug trials? We set up a sensitive search that yielded 3818 abstracts. After careful screening, data-extraction was executed for 58 selected articles. Of the 58 selected articles, 38 articles described drug studies where GAS was used as an outcome measure, and 20 articles described measurement properties of GAS in other settings. The results show that validity, responsiveness and reliability of GAS in drug studies have hardly been investigated. The quality of the reporting of validity in studies in which GAS was used to evaluate a non-drug intervention also leaves much room for improvement. We conclude that there is insufficient information to assess the validity of GAS, due to the poor quality of the validity studies. Therefore, we think that GAS needs further validation in drug studies, especially since GAS can be a potential solution when a small heterogeneous patient group is all there is to test a promising new drug. The protocol has been registered in the PROSPERO international prospective register for systematic reviews, with registration number CRD42014010619. http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD4201401061
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