54 research outputs found
Accounting for centre-effects in multicentre trials with a binary outcome – when, why, and how?
No full textOpen Access Research article
Accounting for centre-effects in multicentre trials with a binary outcome – when, why, and how?
Brennan C Kahan
Correspondence: Brennan C Kahan [email protected]
Author Affiliations
Pragmatic Clinical Trials Unit, Queen Mary University of London, 58 Turner Street, London E1 2AB, UK
MRC Clinical Trials Unit at UCL, 125 Kingsway, London WC2B 6NH, UK
BMC Medical Research Methodology 2014, 14:20 doi:10.1186/1471-2288-14-20
The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2288/14/20
Received: 5 July 2013
Accepted: 3 February 2014
Published: 10 February 2014
© 2014 Kahan; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.
Formula display:
Abstract
Background
It is often desirable to account for centre-effects in the analysis of multicentre randomised trials, however it is unclear which analysis methods are best in trials with a binary outcome.
Methods
We compared the performance of four methods of analysis (fixed-effects models, random-effects models, generalised estimating equations (GEE), and Mantel-Haenszel) using a re-analysis of a previously reported randomised trial (MIST2) and a large simulation study.
Results
The re-analysis of MIST2 found that fixed-effects and Mantel-Haenszel led to many patients being dropped from the analysis due to over-stratification (up to 69% dropped for Mantel-Haenszel, and up to 33% dropped for fixed-effects). Conversely, random-effects and GEE included all patients in the analysis, however GEE did not reach convergence. Estimated treatment effects and p-values were highly variable across different analysis methods.
The simulation study found that most methods of analysis performed well with a small number of centres. With a large number of centres, fixed-effects led to biased estimates and inflated type I error rates in many situations, and Mantel-Haenszel lost power compared to other analysis methods in some situations. Conversely, both random-effects and GEE gave nominal type I error rates and good power across all scenarios, and were usually as good as or better than either fixed-effects or Mantel-Haenszel. However, this was only true for GEEs with non-robust standard errors (SEs); using a robust ‘sandwich’ estimator led to inflated type I error rates across most scenarios.
Conclusions
With a small number of centres, we recommend the use of fixed-effects, random-effects, or GEE with non-robust SEs. Random-effects and GEE with non-robust SEs should be used with a moderate or large number of centres
Service provision and barriers to care for homeless people with mental health problems across 14 European capital cities
No full textAbstract Background Mental health problems are disproportionately higher amongst homeless people. Many barriers exist for homeless people with mental health problems in accessing treatment yet little research has been done on service provision and quality of care for this group. The aim of this paper is to assess current service provision and identify barriers to care for homeless people with mental health problems in 14 European capital cities. Method Two methods of data collection were employed; (i) In two highly deprived areas in each of the 14 European capital cities, homeless-specific services providing mental health, social care or general health services were assessed. Data were obtained on service characteristics, staff and programmes provided. (ii) Semi-structured interviews were conducted in each area with experts in mental health care provision for homeless people in order to determine the barriers to care and ways to overcome them. Results Across the 14 capital cities, 111 homeless-specific services were assessed. Input from professionally qualified mental health staff was reported as low, as were levels of active outreach and case finding. Out-of-hours service provision appears inadequate and high levels of service exclusion criteria were evident. Prejudice in the services towards homeless people, a lack of co-ordination amongst services, and the difficulties homeless people face in obtaining health insurance were identified as major barriers to service provision. Conclusions While there is variability in service provision across European capital cities, the reported barriers to service accessibility are common. Homeless-specific services are more responsive to the initial needs of homeless people with mental health problems, while generic services tend to be more conducive to long term care. Further research is needed to determine the effectiveness of different service delivery models, including the most effective coordination of homeless specific and generic services.</p
Reply to Haydar, Bishr; Holman, Ashlee; Galante, Dario, regarding their comment “ESPA pain management ladder: Caudal clonidine and cost/benefit considerations”
No full textPrevalência de sintomas depressivos em pacientes hipertensos internados nas enfermarias de Clínica Médica do HU-UFSC
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Clinica Medica
Extended Postoperative Analgesia via Caudal Catheters for Major Surgery in Neonates—A 6-Year Retrospective Study
No full textBackground: Caudal anesthesia is an important regional anesthetic technique in neonates. The placement of a catheter can provide excellent analgesia for a prolonged period; the role of adjuvants, in particular morphine, however, remains unclear. We aimed to describe our experience with caudal catheters for major surgery in neonates. Methods: We included all neonates who had a caudal catheter placed for major abdominal and thoracic surgery and explored postoperative pain management and catheter complications. This retrospective case series included neonates with caudal catheter placement from October 2012 to April 2018 at a tertiary university hospital. Results: A total of 33 caudal catheter placements in 32 neonates were included in this study, of which 28 (85%) were a laparotomy and 5 (15%) a thoracotomy. The mean catheter duration was 135 h with a postoperative failure rate of 3%. Patients who did not receive intravenous opioids postoperatively had a significantly shorter stay in the intensive care unit than those who did (341 h vs. 674 h, p = 0.01). All patients received continuous local anesthetics over the catheter, and 79% received additional intermittent epidural morphine postoperatively for a median period of 42 h. No infectious complications were reported. Conclusions: Caudal catheters are a valuable option for perioperative analgesia for major surgery in neonates. We found no serious catheter-related complication. Further research is needed to define the optimal approach and combination of different analgesic techniques
Características epidemiológicas dos pacientes que foram a óbito por síndrome da imunodeficiência adquirida no Hospital Nereu Ramos, em Florianópolis no ano de 2003
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Clínica Médica
Rape as a tool of war: a critical study
No full textIncludes abstract.Includes bibliographical references.This study analyses current conceptualisations of rape as a "tool of war" in various academic disciplines and approaches including Anthropological Studies, Feminist Studies and Historical Studies. The analysis also includes Political Studies and its various sub-disciplines, case studies of African conflicts and more specifically studies of the Rwandan conflict, together with the civil war of 1990 and the genocide of 1994. The analysis will highlight the strengths and weaknesses in our current understanding of rape as a "tool of war", in order to develop a clarified framework for future analysis
Cluster Randomized Trial of a Patient-Centered Contraceptive Decision Support Tool, My Birth Control
No full text- …
