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Diana Elbourne

Publications and source records attributed to Diana Elbourne.

28 records · Page 2Linked to original sources
PubMed2002

Meta-analysis combining parallel and cross-over clinical trials. I: Continuous outcomes.

Among clinical trials assessing a given treatment, often parallel and cross-over designs are used together. In the first paper of a series of three, we explore two methods to pool continuous outcomes in a meta-analysis combining parallel and cross-over trial designs: the weighted mean difference (WMD) and the standardized weighted mean difference (SWMD). The combined design meta-analytic formulae are based on a weighted average of the two design treatment estimates. A random effects model can be implemented. Both WMD and SWMD can be used, the choice of the method is determined by the type of outcomes obtained in the trials. Compared to the number of included subjects, the relative weight of the cross-over design is large in combined-design meta-analysis. Differences in the weight estimation between WMD and SWMD can also accentuate the relative weight of cross-over trials, which must be considered a case of design-specific bias.

Blood Pressure↗
PubMed2002

Meta-analysis combining parallel and cross-over clinical trials. II: Binary outcomes.

We examine different methods to pool binary outcomes used both in parallel and cross-over trials. Odds ratio (OR) estimators obtained from joint conditional probabilities in cross-over trials, such as the Mantel-Haenszel and Peto methods, are compared to an OR estimator using marginal results of cross-over trials. When there is correlation between the outcomes in the two cross-over periods, joint conditional ORs differ from marginal ORs and cannot be combined with OR estimates from parallel trials. The marginal OR estimate is independent of the between-period correlation and it includes a correction for cross-over correlation in the variance estimate. As its computation is similar in cross-over and parallel trials, it is the method of choice to pool results from parallel and cross-over trials in a combined design meta-analysis.

Albuminuria↗
PubMed2002

Meta-analysis combining parallel and cross-over clinical trials. III: The issue of carry-over.

In meta-analysis combining results from parallel and cross-over trials, there is a risk of bias originating from the carry-over effect in cross-over trials. When pooling treatment effects estimated from parallel trials and two-period two-treatment cross-over trials, meta-analytic estimators of treatment effect can be obtained from the combination of parallel trial results either with cross-over trial results based on data of the first period only or with cross-over trial results analysed with data from both periods. Taking data from the first cross-over period protects against carry-over but gives less efficient treatment estimators and may lead to selection bias. This study evaluates in terms of variance reduction and mean square error the cost of calculating meta-analysis estimates with data from the first period instead of data from the two cross-over periods. If the information on cross-over sequence is available, we recommend performing two combined design meta-analyses, one using the first cross-over period data and one based on data from both cross-over periods. To investigate simultaneously the statistical significance of these two estimators as well as the carry-over at meta-analysis level, a method based on a multivariate analysis of the meta-analytic treatment effect and carry-over estimates is proposed.

Blood Pressure↗
PubMedDate not supplied

Ultrasonography in the diagnosis and management of developmental hip dysplasia (UK Hip Trial): clinical and economic results of a multicentre randomised controlled trial.

BACKGROUND: Clinical screening aims to identify and treat neonatal hip instability associated with increased risk of hip displacement, but risks failures of diagnosis and treatment (abduction splinting), iatrogenic effects, and costs to parents and health services. Our objectives were to assess clinical effectiveness and net cost of ultrasonography compared with clinical assessment alone, to provide guidance for management of infants with clinical hip instability. METHODS: Infants with clinical hip instability were recruited from 33 centres in UK and Ireland and randomised to either ultrasonographic hip examination (n=314) or clinical assessment alone (n=315). The primary outcome was appearance on hip radiographs by 2 years. Secondary outcomes included surgical treatment, abduction splinting, level of mobility, resource use, and costs. Analysis was by intention to treat. FINDINGS: Protocol compliance was high, and radiographic information was available for 91% of children by 12-14 months and 85% by 2 years. By age 2 years, subluxation, dislocation, or acetabular dysplasia were identified by radiography on one or both hips of 21 children in each of the groups (relative risk 1.00; 95% CI 0.56-1.80). Fewer children in the ultrasonography group had abduction splinting in the first 2 years than did those in the no-ultrasonography group (0.78; 0.65-0.94; p=0.01). Surgical treatment was required by 21 infants in the ultrasonography group (6.7%) and 25 (7.9%) in the no-ultrasonography group (0.84; 0.48-1.47). One child from the ultrasonography group and four from the no-ultrasonography group were not walking by 2 years (0.25; 0.03-2.53; p=0.37). Infants in the ultrasonography group incurred significantly higher ultrasound costs over the first 2 years (pound 42 vs pound 23, mean difference pound 19, 95% CI 11-27); total hospital costs were lower for those infants, but the difference was not significant. INTERPRETATION: The use of ultrasonography in infants with screen-detected clinical hip instability allows abduction splinting rates to be reduced, and is not associated with an increase in abnormal hip development, higher rates of surgical treatment by 2 years of age, or significantly higher health-service costs.

Costs and Cost Analysis↗
PubMedDate not supplied

Assessment of the clinical effectiveness of pulmonary artery catheters in management of patients in intensive care (PAC-Man): a randomised controlled trial.

BACKGROUND: Over the past 30 years the pulmonary artery catheter (PAC) has become a widely used haemodynamic monitoring device in the management of critically ill patients, though doubts exist about its safety. Our aim was, therefore, to ascertain whether hospital mortality is reduced in critically ill patients when they are managed with a PAC. METHODS: We did a randomised controlled trial to which we enrolled 1041 patients from 65 UK intensive care units. We assigned individuals to management with (n=519) or without (n=522) a PAC. The timing of insertion and subsequent clinical management were at the discretion of the treating clinician. Intensive care units decided a priori to have the option of using an alternative cardiac output-monitoring device in control patients. FINDINGS: 1014 patients were eligible for analysis. We noted no difference in hospital mortality between patients managed with or without a PAC (68% [346 of 506] vs 66% [333 of 507], p=0.39; adjusted hazard ratio 1.09, 95% CI 0.94-1.27). We noted complications associated with insertion of a PAC in 46 of 486 individuals in whom the device was placed, none of which was fatal. INTERPRETATION: Our findings indicate no clear evidence of benefit or harm by managing critically ill patients with a PAC. Efficacy studies are needed to ascertain whether management protocols involving PAC use can result in improved outcomes in specific groups if these devices are not to become a redundant technology.

Adolescent↗