An investigation of the impact of using different methods for network meta-analysis: a protocol for an empirical evaluation.

BACKGROUND: Network meta-analysis, a method to synthesise evidence from multiple treatments, has increased in popularity in the past decade. Two broad approaches are available to synthesise data across networks, namely, arm- and contrast-synthesis models, with a range of models that can be fitted within each. There has been recent debate about the validity of the arm-synthesis models, but to date, there has been limited empirical evaluation comparing results using the methods applied to a large number of networks. We aim to address this gap through the re-analysis of a large cohort of published networks of interventions using a range of network meta-analysis methods. METHODS: We will include a subset of networks from a database of network meta-analyses of randomised trials that have been identified and curated from the published literature. The subset of networks will include those where the primary outcome is binary, the number of events and participants are reported for each direct comparison, and there is no evidence of inconsistency in the network. We will re-analyse the networks using three contrast-synthesis methods and two arm-synthesis methods. We will compare the estimated treatment effects, their standard errors, treatment hierarchy based on the surface under the cumulative ranking (SUCRA) curve, the SUCRA value, and the between-trial heterogeneity variance across the network meta-analysis methods. We will investigate whether differences in the results are affected by network characteristics and baseline risk. DISCUSSION: The results of this study will inform whether, in practice, the choice of network meta-analysis method matters, and if it does, in what situations differences in the results between methods might arise. The results from this research might also inform future simulation studies

Obstacles to researching the researchers: A case study of the ethical challenges of undertaking methodological research investigating the reporting of randomised controlled trials

<p>Abstract</p> <p>Background</p> <p>Recent cohort studies of randomised controlled trials have provided evidence of within-study selective reporting bias; where statistically significant outcomes are more likely to be more completely reported compared to non-significant outcomes. Bias resulting from selective reporting can impact on meta-analyses, influencing the conclusions of systematic reviews, and in turn, evidence based clinical practice guidelines.</p> <p>In 2006 we received funding to investigate if there was evidence of within-study selective reporting in a cohort of RCTs submitted to New Zealand Regional Ethics Committees in 1998/99. This research involved accessing ethics applications, their amendments and annual reports, and comparing these with corresponding publications. We did not plan to obtain informed consent from trialists to view their ethics applications for practical and scientific reasons.</p> <p>In November 2006 we sought ethical approval to undertake the research from our institutional ethics committee. The Committee declined our application on the grounds that we were not obtaining informed consent from the trialists to view their ethics application. This initiated a seventeen month process to obtain ethical approval. This publication outlines what we planned to do, the issues we encountered, discusses the legal and ethical issues, and presents some potential solutions.</p> <p>Discussion and conclusion</p> <p>Methodological research such as this has the potential for public benefit and there is little or no harm for the participants (trialists) in undertaking it. Further, in New Zealand, there is freedom of information legislation, which in this circumstance, unambiguously provided rights of access and use of the information in the ethics applications. The decision of our institutional ethics committee defeated this right and did not recognise the nature of this observational research.</p> <p>Methodological research, such as this, can be used to develop processes to improve quality in research reporting. Recognition of the potential benefit of this research in the broader research community, and those who sit on ethics committees, is perhaps needed. In addition, changes to the ethical review process which involve separation between those who review proposals to undertake methodological research using ethics applications, and those with responsibility for reviewing ethics applications for trials, should be considered. Finally, we contend that the research community could benefit from quality improvement approaches used in allied sectors.</p

Lumbar segmental mobility disorders: comparison of two methods of defining abnormal displacement kinematics in a cohort of patients with non-specific mechanical low back pain

BACKGROUND: Lumbar segmental rigidity (LSR) and lumbar segmental instability (LSI) are believed to be associated with low back pain (LBP), and identification of these disorders is believed to be useful for directing intervention choices. Previous studies have focussed on lumbar segmental rotation and translation, but have used widely varying methodologies. Cut-off points for the diagnosis of LSR & LSI are largely arbitrary. Prevalence of these lumbar segmental mobility disorders (LSMDs) in a non-surgical, primary care LBP population has not been established. METHODS: A cohort of 138 consecutive patients with recurrent or chronic low back pain (RCLBP) were recruited in this prospective, pragmatic, multi-centre study. Consenting patients completed pain and disability rating instruments, and were referred for flexion-extension radiographs. Sagittal angular rotation and sagittal translation of each lumbar spinal motion segment was measured from the radiographs, and compared to a reference range derived from a study of 30 asymptomatic volunteers. In order to define reference intervals for normal motion, and define LSR and LSI, we approached the kinematic data using two different models. The first model used a conventional Gaussian definition, with motion beyond two standard deviations (2sd) from the reference mean at each segment considered diagnostic of rotational LSMD and translational LSMD. The second model used a novel normalised within-subjects approach, based on mean normalised contribution-to-total-lumbar-motion. An LSMD was then defined as present in any segment that contributed motion beyond 2sd from the reference mean contribution-to-normalised-total-lumbar-motion. We described reference intervals for normal segmental mobility, prevalence of LSMDs under each model, and the association of LSMDs with pain and disability. RESULTS: With the exception of the conventional Gaussian definition of rotational LSI, LSMDs were found in statistically significant prevalences in patients with RCLBP. Prevalences at both the segmental and patient level were generally higher using the normalised within-subjects model (2.8 to 16.8% of segments; 23.3 to 35.5% of individuals) compared to the conventional Gaussian model (0 to 15.8%; 4.7 to 19.6%). LSMDs are associated with presence of LBP, however LSMDs do not appear to be strongly associated with higher levels of pain or disability compared to other forms of non-specific LBP. CONCLUSION: LSMDs are a valid means of defining sub-groups within non-specific LBP, in a conservative care population of patients with RCLBP. Prevalence was higher using the normalised within-subjects contribution-to-total-lumbar-motion approach

Descriptive epidemiology of somatising tendency: findings from the CUPID study.

Somatising tendency, defined as a predisposition to worry about common somatic symptoms, is importantly associated with various aspects of health and health-related behaviour, including musculoskeletal pain and associated disability. To explore its epidemiological characteristics, and how it can be specified most efficiently, we analysed data from an international longitudinal study. A baseline questionnaire, which included questions from the Brief Symptom Inventory about seven common symptoms, was completed by 12,072 participants aged 20-59 from 46 occupational groups in 18 countries (response rate 70%). The seven symptoms were all mutually associated (odds ratios for pairwise associations 3.4 to 9.3), and each contributed to a measure of somatising tendency that exhibited an exposure-response relationship both with multi-site pain (prevalence rate ratios up to six), and also with sickness absence for non-musculoskeletal reasons. In most participants, the level of somatising tendency was little changed when reassessed after a mean interval of 14 months (75% having a change of 0 or 1 in their symptom count), although the specific symptoms reported at follow-up often differed from those at baseline. Somatising tendency was more common in women than men, especially at older ages, and varied markedly across the 46 occupational groups studied, with higher rates in South and Central America. It was weakly associated with smoking, but not with level of education. Our study supports the use of questions from the Brief Symptom Inventory as a method for measuring somatising tendency, and suggests that in adults of working age, it is a fairly stable trait

Low Back and Neck Pain in Locomotive Engineers Exposed to Whole-Body Vibration

The objective of this study was to determine the prevalence and excess risk of low back pain and neck pain in locomotive engineers, and to investigate the relationship of bothwith whole-body vibration exposure. A cross-sectional survey comparing locomotive engineers with other rail worker referents was conducted. Current vibration levels were measured, cumulative exposures calculated for engineers and referents, and low back and neck pain assessed by a self-completed questionnaire. Median vibration exposure in the z- (vertical) axis was 0.62 m/s2. Engineers experienced more frequent low back and neck pain, odds ratios (ORs) of 1.77 (95% confidence interval [CI]: 1.19-2.64) and 1.92 (95% CI: 1.22-3.02), respectively. The authors conclude that vibration close to the "action levels" of published standards contribute to low back and neck pain. Vibration levels need to be assessed conservatively and control measures introduced

Retroalimentación (feedback) o biorretroalimentación (biofeedback) para aumentar el entrenamiento muscular del piso pelviano en la incontinencia urinaria de la mujer

Antecedentes: El entrenamiento muscular del piso pelviano (EMPP) es un tratamiento efectivo para la incontinencia urinaria de esfuerzo en la mujer. Aunque en su mayoría los ensayos de EMPP se han realizado en mujeres con incontinencia urinaria de esfuerzo, también hay algunas pruebas de ensayos de que el EMPP es efectivo en la incontinencia urinaria de urgencia y la incontinencia urinaria mixta. La retroalimentación o biorretroalimentación son complementos habituales utilizados juntos con el EMPP para ayudar a enseñar a contraer el músculo del piso pelviano de forma voluntaria o mejorar la realización del entrenamiento. Objetivos: Determinar si la retroalimentación o biorretroalimentación añade un beneficio adicional al EMPP en las mujeres con incontinencia urinaria. Comparar la efectividad de diferentes formas de retroalimentación o biorretroalimentación. Estrategia de búsqueda: Se realizaron búsquedas en el Registro Especializado de Ensayos del Grupo Cochrane de Incontinencia (Cochrane Incontinence Group) (búsqueda 13 de mayo de 2010) y en las listas de referencias de los artículos pertinentes. Criterios de selección: Ensayos aleatorios o cuasialeatorios en mujeres con incontinencia urinaria de esfuerzo, de urgencia o mixta (según los síntomas, los signos o la urodinamia). Al menos dos brazos de los ensayos incluyeron EMPP. Además, al menos un brazo incluyó retroalimentación verbal o biorretroalimentación mediada por un dispositivo. Obtención y análisis de los datos: La elegibilidad y el riesgo de sesgo de los ensayos se evaluaron de forma independiente. Dos revisores extrajeron los datos y los verificaron de forma cruzada. Los desacuerdos se resolvieron mediante discusión o la opinión de un tercer revisor. El análisis de los datos se realizó según el Manual Cochrane para Revisiones Sistemáticas de Intervención (Cochrane Handbook for Systematic Reviews of Interventions) (versión 5.1.0). El análisis dentro de los subgrupos se basó en la existencia de una diferencia en el EMPP entre los dos brazos que se habían comparado. Resultados principales: Veinticuatro ensayos que incluían a 1583 mujeres cumplían los criterios de inclusión; 17 ensayos contribuyeron con datos para el análisis de uno de los resultados primarios. Todos los ensayos contribuyeron con datos para uno o más de los resultados secundarios. Las mujeres que recibieron biorretroalimentación tuvieron significativamente más probabilidades de informar que su incontinencia urinaria se había resuelto o había mejorado en comparación con las que recibieron EMPP solo (cociente de riesgos 0,75; intervalo de confianza del 95%: 0,66 a 0,86). Sin embargo, fue frecuente que las mujeres de los brazos de biorretroalimentación tuvieran más contacto con el profesional sanitario que las de los brazos de ninguna biorretroalimentación. Muchos ensayos presentaron un riesgo de sesgo de moderado a alto, según los informes de los ensayos. Hubo mucha variedad en los regímenes propuestos para agregar retroalimentación o biorretroalimentación al EMPP solo, y a menudo no estuvo claro lo que incluyó la intervención real o cuál fue el objetivo de la intervención. Conclusiones de los autores: La retroalimentación o biorretroalimentación puede proporcionar efectos beneficiosos además del entrenamiento muscular del piso pelviano a las mujeres con incontinencia urinaria. Sin embargo, se necesitan estudios de investigación adicionales para diferenciar si es la retroalimentación o biorretroalimentación la que causa el efecto beneficioso o alguna otra diferencia entre los brazos del ensayo (como el mayor contacto con los profesionales sanitarios)

Feedback or biofeedback to augment pelvic floor muscle training for urinary incontinence in women

Pelvic floor muscle training (PFMT) is an effective treatment for stress urinary incontinence in women. Whilst most of the PFMT trials have been done in women with stress urinary incontinence, there is also some trial evidence that PFMT is effective for urgency urinary incontinence and mixed urinary incontinence. Feedback or biofeedback are common adjuncts used along with PFMT to help teach a voluntary pelvic floor muscle contraction or to improve training performance. To determine whether feedback or biofeedback adds further benefit to PFMT for women with urinary incontinence.To compare the effectiveness of different forms of feedback or biofeedback. We searched the Cochrane Incontinence Group Specialised Trials Register (searched 13 May 2010) and the reference lists of relevant articles. Randomised or quasi-randomised trials in women with stress, urgency or mixed urinary incontinence (based on symptoms, signs or urodynamics). At least two arms of the trials included PFMT. In addition, at least one arm included verbal feedback or device-mediated biofeedback. Trials were independently assessed for eligibility and risk of bias. Data were extracted by two reviewers and cross-checked. Disagreements were resolved by discussion or the opinion of a third reviewer. Data analysis was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Intervention (version 5.1.0). Analysis within subgroups was based on whether there was a difference in PFMT between the two arms that had been compared. Twenty four trials involving 1583 women met the inclusion criteria; 17 trials contributed data to analysis for one of the primary outcomes. All trials contributed data to one or more of the secondary outcomes. Women who received biofeedback were significantly more likely to report that their urinary incontinence was cured or improved compared to those who received PFMT alone (risk ratio 0.75 , 95% confidence interval 0.66 to 0.86). However, it was common for women in the biofeedback arms to have more contact with the health professional than those in the non-biofeedback arms. Many trials were at moderate to high risk of bias, based on trial reports. There was much variety in the regimens proposed for adding feedback or biofeedback to PFMT alone, and it was often not clear what the actual intervention comprised or what the purpose of the intervention was. Feedback or biofeedback may provide benefit in addition to pelvic floor muscle training in women with urinary incontinence. However, further research is needed to differentiate whether it is the feedback or biofeedback that causes the beneficial effect or some other difference between the trial arms (such as more contact with health professionals