Analysing randomised controlled trials with missing data : Choice of approach affects conclusions

Copyright © 2012 Elsevier Inc. All rights reserved. PMID: 22265924 [PubMed - indexed for MEDLINE]Peer reviewedPostprin

Using 'dead or dependent' as an outcome measure in clinical trials in Parkinson's disease

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.Peer reviewedPublisher PD

Primary and repeat surgical treatment for female pelvic organ prolapse and incontinence in parous women in the UK : a register linkage study

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Normative data for the Hospital Anxiety and Depression Scale

Acknowledgments The authors would like to thank all those involved in the EpiFunD study for their role in collecting the data used in this study, particularly the principal investigators Gary Macfarlane (University of Aberdeen) and John McBeth (Keele University, and the University of Manchester) who allowed use of the EpiFunD dataset. The EpiFunD study was funded by Arthritis Research UK (formerly the Arthritis Research Campaign), Grant Number: 17552.Peer reviewedPostprin

Outcomes of Childhood Asthma and Wheezy Bronchitis. A 50-Year Cohort Study

Rationale: Cohort studies suggest that airflow obstruction is established early in life, manifests as childhood asthma and wheezy bronchitis, and continues into early adulthood. Although an association between childhood asthma and chronic obstructive pulmonary disease (COPD) in later life has been demonstrated, it is unclear if childhood wheezy bronchitis is associated with COPD. Objectives: To investigate whether childhood wheezy bronchitis increases the risk of COPD in the seventh decade. Methods: A cohort of children recruited in 1964 at age 10 to 15 years, which was followed up in 1989, 1995, and 2001, was followed up again in 2014 when at age 60 to 65 years. Discrete time-to-event and linear mixed effects models were used. Measurements and Main Results: FEV1 and FVC were measured. COPD was defined as post-bronchodilator FEV1/FVC <0.7. Childhood wheezing phenotype was related to 1989, 1995, 2001, and 2014 spirometry data. Three hundred thirty subjects, mean age 61 years, were followed up: 38 with childhood asthma; 53 with childhood wheezy bronchitis; and 239 control subjects (of whom 57 developed adulthood-onset wheeze between ages 16 and 46 yr). In adjusted multivariate analyses, childhood asthma was associated with an increased risk of COPD (odds ratio, 6.37; 95% confidence interval, 3.73–10.94), as was childhood wheezy bronchitis (odd ratio 1.81; 95% confidence interval, 1.12–2.91). The COPD risk increased with childhood asthma, and wheezy bronchitis was associated with reduced FEV1 that was evident by the fifth decade and not an accelerated rate of FEV1 decline. In contrast, adulthood-onset wheeze was associated with accelerated FEV1 decline. Conclusions: Childhood wheezy bronchitis and asthma are associated with an increased risk of COPD and reduced ventilatory function

Predicting missing quality of life data that were later recovered : an empirical comparison of approaches

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Prevalence and causes of prescribing errors: the prescribing outcomes for trainee doctors engaged in clinical training (PROTECT) study

Objectives Study objectives were to investigate the prevalence and causes of prescribing errors amongst foundation doctors (i.e. junior doctors in their first (F1) or second (F2) year of post-graduate training), describe their knowledge and experience of prescribing errors, and explore their self-efficacy (i.e. confidence) in prescribing. Method A three-part mixed-methods design was used, comprising: prospective observational study; semi-structured interviews and cross-sectional survey. All doctors prescribing in eight purposively selected hospitals in Scotland participated. All foundation doctors throughout Scotland participated in the survey. The number of prescribing errors per patient, doctor, ward and hospital, perceived causes of errors and a measure of doctors' self-efficacy were established. Results 4710 patient charts and 44,726 prescribed medicines were reviewed. There were 3364 errors, affecting 1700 (36.1%) charts (overall error rate: 7.5%; F1:7.4%; F2:8.6%; consultants:6.3%). Higher error rates were associated with : teaching hospitals (p&#60;0.001), surgical (p = &#60;0.001) or mixed wards (0.008) rather thanmedical ward, higher patient turnover wards (p&#60;0.001), a greater number of prescribed medicines (p&#60;0.001) and the months December and June (p&#60;0.001). One hundred errors were discussed in 40 interviews. Error causation was multi-factorial; work environment and team factors were particularly noted. Of 548 completed questionnaires (national response rate of 35.4%), 508 (92.7% of respondents) reported errors, most of which (328 (64.6%) did not reach the patient. Pressure from other staff, workload and interruptions were cited as the main causes of errors. Foundation year 2 doctors reported greater confidence than year 1 doctors in deciding the most appropriate medication regimen. Conclusions Prescribing errors are frequent and of complex causation. Foundation doctors made more errors than other doctors, but undertook the majority of prescribing, making them a key target for intervention. Contributing causes included work environment, team, task, individual and patient factors. Further work is needed to develop and assess interventions that address these.</p

Methodology and reporting characteristics of studies using interrupted time series design in healthcare

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors for the design of the study and collection, analysis, and interpretation of data and in writing the manuscript. The Health Services Research Unit, University of Aberdeen, is core funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates.Peer reviewedPublisher PD

Investigating the missing data mechanism in quality of life outcomes: a comparison of approaches

Background: Missing data is classified as missing completely at random (MCAR), missing at random (MAR) or missing not at random (MNAR). Knowing the mechanism is useful in identifying the most appropriate analysis. The first aim was to compare different methods for identifying this missing data mechanism to determine if they gave consistent conclusions. Secondly, to investigate whether the reminder-response data can be utilised to help identify the missing data mechanism. Methods: Five clinical trial datasets that employed a reminder system at follow-up were used. Some quality of life questionnaires were initially missing, but later recovered through reminders. Four methods of determining the missing data mechanism were applied. Two response data scenarios were considered. Firstly, immediate data only; secondly, all observed responses (including reminder-response). Results: In three of five trials the hypothesis tests found evidence against the MCAR assumption. Logistic regression suggested MAR, but was able to use the reminder-collected data to highlight potential MNAR data in two trials. Conclusion: The four methods were consistent in determining the missingness mechanism. One hypothesis test was preferred as it is applicable with intermittent missingness. Some inconsistencies between the two data scenarios were found. Ignoring the reminder data could potentially give a distorted view of the missingness mechanism. Utilising reminder data allowed the possibility of MNAR to be considered.The Chief Scientist Office of the Scottish Government Health Directorate. Research Training Fellowship (CZF/1/31

Contemporary hormonal contraception and cervical cancer in women of reproductive age

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