21 research outputs found

    Impact of cause of death adjudication on the results of the European prostate cancer screening trial

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    Background:The European Randomised Study of Prostate Cancer Screening has shown a 21% relative reduction in prostate cancer mortality at 13 years. The causes of death can be misattributed, particularly in elderly men with multiple comorbidities, and therefore accurate assessment of the underlying cause of death is crucial for valid results. To address potential unreliability of end-point assessment, and its possible impact on mortality results, we analysed the study outcome adjudication data in six countries.Methods:Latent class statistical models were formulated to compare the accuracy of individual adjudicators, and to assess whether accuracy differed between the trial arms. We used the model to assess whether correcting for adjudication inaccuracies might modify the study results.Results:There was some heterogeneity in adjudication accuracy of causes of death, but no consistent differential accuracy by trial arm. Correcting the estimated screening effect for misclassification did not alter the estimated mortality effect of screening.Conclusions:Our findings were consistent with earlier reports on the European screening trial. Observer variation, while demonstrably present, is unlikely to have materially biased the main study results. A bias in assigning causes of death that might have explained the mortality reduction by screening can be effectively ruled out

    Angiotensin-converting enzyme I/D polymorphism and preeclampsia risk: evidence of small-study bias

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    BACKGROUND: Inappropriate activation of the renin-angiotensin system may play a part in the development of preeclampsia. An insertion/deletion polymorphism within the angiotensin-I converting enzyme gene (ACE-I/D) has shown to be reliably associated with differences in angiotensin-converting enzyme (ACE) activity. However, previous studies of the ACE-I/D variant and preeclampsia have been individually underpowered to detect plausible genotypic risks. METHODS AND FINDINGS: A prospective case-control study was conducted in 1,711 unrelated young pregnant women (665 preeclamptic and 1,046 healthy pregnant controls) recruited from five Colombian cities. Maternal blood was obtained to genotype for the ACE-I/D polymorphism. Crude and adjusted odds ratio (OR) and 95% confidence interval (CI) using logistic regression models were obtained to evaluate the strength of the association between ACE-I/D variant and preeclampsia risk. A meta-analysis was then undertaken of all published studies to February 2006 evaluating the ACE-I/D variant in preeclampsia. An additive model (per-D-allele) revealed a null association between the ACE-I/D variant and preeclampsia risk (crude OR = 0.95 [95% CI, 0.81-1.10]) in the new case-control study. Similar results were obtained after adjusting for confounders (adjusted per-allele OR = 0.90 [95% CI, 0.77-1.06]) and using other genetic models of inheritance. A meta-analysis (2,596 cases and 3,828 controls from 22 studies) showed a per-allele OR of 1.26 (95% CI, 1.07-1.49). An analysis stratified by study size showed an attenuated OR toward the null as study size increased. CONCLUSIONS: It is highly likely that the observed small nominal increase in risk of preeclampsia associated with the ACE D-allele is due to small-study bias, similar to that observed in cardiovascular disease. Reliable assessment of the origins of preeclampsia using a genetic approach may require the establishment of a collaborating consortium to generate a dataset of adequate size

    Change of tumour characteristics and treatment over time in both arms of the European Randomized study of Screening for Prostate Cancer

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    Objective: To evaluate a change in tumour characteristics and applied treatments over time in the control arm of all centres of the European Randomized study of Screening for Prostate Cancer (ERSPC) and to compare this with similar data of the screening arm. Methods: Between 1993 and 2003, 182,160 men, aged 50-74 years, were randomised to the screening arm (N = 82,816) and the control arm (N = 99,184). Men in the screening arm were offered Prostate Specific Antigen (PSA) testing every 4 years whilst men in the control arm received usual care. Tumour characteristics and treatment were evaluated in all men diagnosed with prostate cancer up to December 2006 or the third screening round. Data on the control arm were divided into 3 periods: 1994-1998, 1999-2002 and 2003-2006. Results: Tumour characteristics were more favourable over time in both the control and the screening arm, with especially increasing proportions of T1C tumours with 29% in 1994-1998 versus 50% in 2003-2006 and 48% at the initial screening round versus 75% at the third screening round, respectively. Tumour characteristics observed in the last period of the control arm were comparable to tumour characteristics in the initial screening round. In the control arm, treatment changed over time with surgery as the most common treatment in the entire observed period, but almost doubling of expectant management and the combination of hormone therapy and radiotherapy over time. In the initial screening round, surgery was the most common treatment (42%), changing over time to expectant management as the most frequently applied treatment in the third screening round (33%). Conclusion: Tumour characteristics in the control arm became more favourable over time and show similarity with prostate cancer cases detected at the initial screening round. The most prominent change in treatment over time was an increase of application of expectan

    Endothelial NO synthase genotype and risk of preeclampsia: a multicenter case-control study.

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    Polymorphisms in the endothelial NO synthase (eNOS) gene have been evaluated as risk factors for preeclampsia. However, data from small studies are conflicting. We assessed whether eNOS genotypes alter the risk of preeclampsia in a population in which the incidence of this disorder is high. A total of 844 young pregnant women (322 preeclamptic and 522 controls) were recruited from 5 cities. Genotyping for the Glu298Asp, intron-4 and -786T-->C polymorphisms in the eNOS gene was conducted. Multivariate odds ratios (ORs) were obtained to estimate the association of individual polymorphisms and haplotypes with preeclampsia risk. No increase in the risk of preeclampsia for the intron-4 or -786T-->C polymorphisms was observed under any model of inheritance. In contrast, in women homozygous for the Asp298 allele, the adjusted OR for preeclampsia was 4.60 (95% confidence interval [CI], 1.73 to 12.22) compared with carriers of the Glu298 allele. After a multivariate analysis, carriage of the "Asp298-786C-4b" haplotype was also associated with increased risk of preeclampsia (OR, 2.11 [95% CI, 1.33 to 3.34]) compared with carriers of the "Glu298-786T-4b" haplotype. The eNOS Glu298Asp polymorphism and the Asp298-786C-4b haplotype are risk factors for preeclampsia

    Estimating the harms and benefits of prostate cancer screening as used in common practice versus recommended good practice: A microsimulation screening analysis

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    BACKGROUND: Prostate-specific antigen (PSA) screening and concomitant treatment can be implemented in several ways. The authors investigated how the net benefit of PSA screening varies between common practice versus “good practice.”. METHODS: Microsimulation screening analysis (MISCAN) was used to evaluate the effect on quality-adjusted life-years (QALYs) if 4 recommendations were followed: limited screening in older men, selective biopsy in men with elevated PSA, active surveillance for low-risk tumors, and treatment preferentially delivered at high-volume centers. Outcomes were compared with a base model in which annual screening started at ages 55 to 6
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