Time filter

Source Type

Robertson, United Kingdom

De Wet C.,National Health Service Education for Scotland | Spence W.,University of Glasgow | Mash R.,Stellenbosch University | Johnson P.,Robertson Center for Biostatistics | Bowie P.,National Health Service Education for Scotland
Quality and Safety in Health Care | Year: 2010

Introduction: Building a safety culture is an important part of improving patient care. Measuring perceptions of safety climate among healthcare teams and organisations is a key element of this process. Existing measurement instruments are largely developed for secondary care settings in North America and many lack adequate psychometric testing. Our aim was to develop and test an instrument to measure perceptions of safety climate among primary care teams in National Health Service for Scotland. Method: Questionnaire development was facilitated through a steering group, literature review, semistructured interviews with primary care team members, a modified Delphi and completion of a content validity index by experts. A cross-sectional postal survey utilising the questionnaire was undertaken in a random sample of west of Scotland general practices to facilitate psychometric evaluation. Statistical methods, including exploratory and confirmatory factor analysis, and Cronbach and Raykov reliability coefficients were conducted. Results: Of the 667 primary care team members based in 49 general practices surveyed, 563 returned completed questionnaires (84.4%). Psychometric evaluation resulted in the development of a 30-item questionnaire with five safety climate factors: Leadership, teamwork, communication, workload and safety systems. Retained items have strong factor loadings to only one factor. Reliability coefficients was satisfactory (α=0.94 and π=0.93). Discussion This study is the first stage in the development of an appropriately valid and reliable safety climate measure for primary care. Measuring safety climate perceptions has the potential to help primary care organisations and teams focus attention on safetyrelated issues and target improvement through educational interventions. Further research is required to explore acceptability and feasibility issues for primary care teams and the potential for organisational benchmarking.

Hennerici M.G.,University of Heidelberg | Bots M.L.,University Utrecht | Ford I.,Robertson Center for Biostatistics | Laurent S.,French Institute of Health and Medical Research | Touboul P.J.,Stroke Center
Cardiovascular Drugs and Therapy | Year: 2010

Purpose: PERFORM is exploring the efficacy of terutroban versus aspirin for secondary prevention in patients with a history of ischemic stroke or transient ischemic attacks (TIAs). The PERFORM Vascular Project will evaluate the effect of terutroban on progression of atherosclerosis, as assessed by change in carotid intima-media thickness (CIMT) in a subgroup of patients. Methods and results: The Vascular Project includes structural (CIMT, carotid plaques) and functional (carotid stiffness) vascular studies in all patients showing at least one carotid plaque at entry. Expected mean follow-up is 36 months. Primary endpoint is rate of change of CIMT. Secondary endpoints include emergent plaques and assessment of carotid stiffness. 1,100 patients are required for 90% statistical power to detect treatment-related CIMT difference of 0.025 mm. The first patient was randomized in April 2006. Conclusions: The PERFORM Vascular Project will investigate terutroban's effect on vascular structure and function in patients with a history of ischemic stroke or TIAs. © The Author(s) 2010.

Bocchi E.A.,University of Sao Paulo | Bohm M.,Saarland University | Borer J.S.,New York University | Ford I.,Robertson Center for Biostatistics | And 3 more authors.
Cardiology (Switzerland) | Year: 2015

Objectives: We explored the prescription of β-blockers with ivabradine in patients with systolic heart failure, focusing on the most frequently coprescribed β-blocker, carvedilol. Methods: We analyzed outcomes in SHIFT patients with systolic heart failure who were prescribed β-blockers (carvedilol, bisoprolol, metoprolol, or nebivolol) with ivabradine or placebo. Analysis was by intention to treat in patients prescribed a β-blocker at the time of the event. Results: Data were available for 2,596 patients receiving carvedilol, 1,483 bisoprolol, 1,424 metoprolol, and 197 nebivolol. Mean treatment duration was 19 months. There was no difference in the effect of ivabradine on the primary composite endpoint of cardiovascular death or heart failure hospitalization between the various β-blockers [hazard ratios (HR) for risk reduction, 0.75-0.89; p for interaction = 0.86]. Patients prescribed carvedilol with ivabradine had lower rates of primary composite endpoint (HR 0.80, 95% CI: 0.68-0.94), heart failure hospitalization (HR 0.73, 95% CI: 0.61-0.88), and cardiovascular hospitalization (HR 0.80, 95% CI: 0.69-0.92) versus carvedilol with placebo. The dosage of carvedilol had no detectable effect and there were no unexpected safety issues. Conclusions: Whatever β-blocker was coprescribed with ivabradine, there were improvements in cardiovascular outcomes in patients with systolic heart failure, especially with the most prescribed β-blocker - carvedilol. © 2015 S. Karger AG, Basel.

Freathy R.M.,University of Bristol | Freathy R.M.,University of Exeter | Kazeem G.R.,Glaxosmithkline | Morris R.W.,University College London | And 25 more authors.
International Journal of Epidemiology | Year: 2011

Background Cigarette smoking is associated with lower body mass index (BMI), and a commonly cited reason for unwillingness to quit smoking is a concern about weight gain. Common variation in the CHRNA5-CHRNA3-CHRNB4 gene region (chromosome 15q25) is robustly associated with smoking quantity in smokers, but its association with BMI is unknown. We hypothesized that genotype would accurately reflect smoking exposure and that, if smoking were causally related to weight, it would be associated with BMI in smokers, but not in never smokers. Methods We stratified nine European study samples by smoking status and, in each stratum, analysed the association between genotype of the 15q25 SNP, rs1051730, and BMI. We meta-analysed the results (n = 24 198) and then tested for a genotype × smoking status interaction.Results There was no evidence of association between BMI and genotype in the never smokers {difference per T-allele: 0.05 kg/m 2 [95% confidence interval (95% CI): -0.05 to 0.18]; P = 0.25}. However, in ever smokers, each additional smoking-related T-allele was associated with a 0.23 kg/m 2 (95% CI: 0.13-0.31) lower BMI (P = 8 × 10 -6). The effect size was larger in current [0.33 kg/m 2 lower BMI per T-allele (95% CI: 0.18-0.48); P = 6 × 10 -5], than in former smokers [0.16 kg/m 2 (95% CI: 0.03-0.29); P = 0.01]. There was strong evidence of genotype × smoking interaction (P = 0.0001).Conclusions Smoking status modifies the association between the 15q25 variant and BMI, which strengthens evidence that smoking exposure is causally associated with reduced BMI. Smoking cessation initiatives might be more successful if they include support to maintain a healthy BMI. Published by Oxford University Press on behalf of the International Epidemiological Association © The Author 2011; all rights reserved.

McArthur K.S.,University of Glasgow | Johnson P.C.D.,Robertson Center for Biostatistics | Quinn T.J.,University of Glasgow | Higgins P.,University of Glasgow | And 6 more authors.
Stroke | Year: 2013

BACKGROUND AND PURPOSE - Use of the modified Rankin scale (mRS) in multicenter trials may be limited by interobserver variability. We assessed the effect of this on trial power and developed a novel group adjudication approach. METHODS - We generated power and sample size estimates from simulated trials modeled with varying mRS reliability. We conducted a virtual acute stroke trial across 14 UK sites to develop a group adjudication approach. Traditional mRS interviews, performed at local sites, were digitally recorded and scored by adjudication committee. We assessed the effect of translation by comparing scores in translated mRS interviews, originally conducted in English and Mandarin. Agreement was measured using κ and weighted κ (κw) statistics and intraclass correlation coefficient. RESULTS - Statistical simulations suggest that improving mRS reliability from κ=0.25 to κ=0.5 or 0.7 may allow reductions in sample size of n=386 or 490 in a typical n=2000 study. Our virtual acute stroke trial included 370 participants and 563 mRS video assessments. We adjudicated mRS in 538 of 563 (96%) study visits. At 30 and 90 days, 161 of 280 (57.5%) and 131 of 258 (50.8%) clips showed interobserver disagreement. Agreement within the adjudication committee was good (30-day κw=0.85 [95% confidence interval, 0.81-0.86]; 90-day κw=0.86 [95% confidence interval, 0.82-0.88]) without significant or systematic bias in mRS scoring compared with the local mRS. Interobserver reliability of translated mRS assessments was similar to native language clips (native [n=69] κw=0.91 [95% confidence interval, 0.94-0.99]; translated [n=89] κw=0.90 [95% confidence interval, 0.83-0.96]). CONCLUSIONS - Achievable improvements in interobserver reliability may substantially reduce study sample size, with associated financial benefits. Central adjudication of mRS assessments is feasible (including across international centers), valid and reliable despite the challenges of mRS assessment in large clinical trials. © 2013 American Heart Association, Inc.

Discover hidden collaborations