Nick Steen

Sample Size Calculations for Cluster Randomised Trials

Objectives: Cluster randomised trials, in which groups of individuals are randomised, are increasingly being used in the health field. Adopting a clustered approach has implications for the design of such trials, and sample size calculations need to be inflated to accommodate for the clustering effect. Reliable estimates of intracluster correlation coefficients (ICCs) are required for robust sample size calculations to be made; however, little empirical evidence is available on their likely size, and on factors which influence their magnitude. The aim of this study was to generate empirical estimates of ICCs and to explore factors which may affect their magnitude. Methods: Empirical estimates of ICCs were calculated for both process variables and patient outcomes from a number of datasets of primary and secondary care implementation studies. Results: Estimates of ICCs varied according to setting and type of outcome. Estimates of ICCs for process variables were higher than those for patient outcomes, and estimates derived from secondary care were higher than those from primary care. ICCs for process variables in primary care were of the order of 0.05–0.15, whilst those in secondary care were of the order of 0.3. Estimates for patient outcomes in primary care were generally lower than 0.05. Conclusions: Adopting cluster randomisation has implications for the design, size and analysis of clinical trials. This study gives an insight into the potential size of ICCs in primary and secondary care, and provides a practical guide to researchers to aid the planning of future studies in this area.

The Diabetes Health Profile (DHP): a new instrument for assessing the psychosocial profile of insulin requiring patients--development and psychometric evaluation.

The aim of the studies was to evaluate the psychometric properties and construct validity of the Diabetes Health Profile (DHP-1). Content for the DHP-1 was derived following in-depth interviews with 25 insulin dependent and insulin requiring patients, a review of the literature and discussions with health care professionals. Initial analysis of the factor structure of the DHP-1 was carried out on the responses of 239 insulin dependent and insulin requiring patients, with a mean age of 40.85 years (SD=13.0), resulting in a 43 item three factor solution. The 43 item version of the DHP-1 was completed by 2,239 insulin dependent/requiring patients (mean age = 39.8, SD=10) years. Fifty-one per cent were men. A forced three factor Principal Factoring Analysis with varimax rotation was carried out. Eleven items were excluded with item factor cross loadings >0.30 or item factor loadings <0.30. PAF analysis of the 32 items resulted in a three factor solution accounting for 33% of the total explained variance. The three factors were interpreted as Psychological Distress, Barriers to Activity and Disnhibited Eating. Factor congruence between subsamples were: Psychological distress (0.93), Barriers to Activity (0.93) and Disinhibited Eating (0.99). Coefficients of congruence between men and women were 0.94, 0.92 and 0.99 for Psychological Distress, Barriers to Activity and Disinhibited Eating respectively. Internal consistency of the three factors (Cronbachs α) were: Psychological Distress (0.86), Barriers to Activity (0.82), and Disinhibited Eating (0.77). Construct-convergent validity was investigated on a sample of 233 insulin dependent and insulin requiring patients (mean age = 51.46 years). Psychological Distress and Barriers to Activity subscales correlated with the Hospital Depression and Anxiety Scale = 0.50 to 0.62, p<0.01 and subscales of the SF-36 (range: r=−0.17 to -0.62, p<0.01). These findings lend support to the construct validity and reliability of the DHP-1 and that it is suitable for further development.

A new self-completion outcome measure for diabetes: is it responsive to change?

Self-completion instruments assessing subjective health are increasingly being used to measure patient outcome. However, there is very little evidence as yet of existing instruments responsiveness to change. This paper describes a study to evaluate the responsiveness to change of a self-completion instrument for the measurement of clinical outcome in patients with diabetes. A prospective follow-up study of 48 patients with non-insulin-dependent diabetes commencing insulin therapy was carried out, with assessments at baseline (i.e. pre-intervention), 6 weeks and 3 months post-intervention. The outcome measures used were the changes in scores on the self-completion instrument for symptom level, physical function, energy, depression, psychological distress and barriers to activity, HbA1c, non-fasting serum cholesterol and the body mass index (BMI). There were significant improvements in HbA1c and non-fasting serum cholesterol and worsening of the BMI, as expected. The self-completion instrument detected significant improvements in patient-reported symptoms within 6 weeks of the intervention (p<0.01) and in energy levels (p<0.05). There is evidence from this study of the self-completion instruments ability to respond to change and it has potential for use in evaluative studies.

A randomised controlled trial of a patient based Diabetes Recall and Management System: the DREAM trial: a study protocol [ISRCTN32042030].

BackgroundWhilst there is broad agreement on what constitutes high quality health care for people with diabetes, there is little consensus on the most efficient way of delivering it. Structured recall systems can improve the quality of care but the systems evaluated to date have been of limited sophistication and the evaluations have been carried out in small numbers of relatively unrepresentative settings. Hartlepool, Easington and Stockton currently operate a computerised diabetes register which has to date produced improvements in the quality of care but performance has now plateaued leaving substantial scope for further improvement. This study will evaluate the effectiveness and efficiency of an area wide extended system incorporating a full structured recall and management system, actively involving patients and including clinical management prompts to primary care clinicians based on locally-adapted evidence based guidelines.MethodsThe study design is a two-armed cluster randomised controlled trial of 61 practices incorporating evaluations of the effectiveness of the system, its economic impact and its impact on patient wellbeing and functioning.

Chained time trade-off and standard gamble methods

It may be difficult to value palliative health states using health state valuation methods such as the time trade-off (TTO) and standard gamble (SG) where health states are traditionally valued relative to perfect/good health and death. Chained methods have been developed to help in this context. However, few studies have compared the values produced by chained TTO and SG methods. To address this issue, a study was conducted to measure the health state values associated with oesophageal cancer using chained TTO and SG techniques. The methods were found to be acceptable amongst the sample respondents, who had previously been treated for oesophageal cancer. There were no significant differences between the health state values produced by the TTO and the SG methods. Within each method, however, there were significant differences between the health states valued. It is concluded that the use of health state valuation techniques such as the TTO and SG is feasible amongst people with a history of oesophageal cancer.

Is organizational justice associated with clinical performance in the care for patients with diabetes in primary care? Evidence from the improving Quality of care in Diabetes study

BACKGROUNDnType 2 diabetes is an increasingly prevalent illness, and there is considerable variation in the quality of care provided to patients with diabetes in primary care.nnnOBJECTIVESnThe aim of this study was to explore whether organizational justice and organizational citizenship behaviour are associated with the behaviours of clinical staff when providing care for patients with diabetes.nnnMETHODSnThe data were from an ongoing prospective multicenter study, the improving Quality of care in Diabetes (iQuaD) study. Participants (N = 467) were clinical staff in 99 primary care practices in the UK. The outcome measures were six self-reported clinical behaviours: prescribing for glycaemic control, prescribing for blood pressure control, foot examination, giving advice about weight management, providing general education about diabetes and giving advice about self-management. Organizational justice perceptions were collected using a self-administered questionnaire. The associations between organizational justice and behavioural outcomes were tested using linear multilevel regression modelling.nnnRESULTSnHigher scores on the procedural component of organizational justice were associated with more frequent weight management advice, self-management advice and provision of general education for patients with diabetes. The associations between justice and clinical behaviours were not explained by individual or practice characteristics, but evidence was found for the partial mediating role of organizational citizenship behaviour.nnnCONCLUSIONSnQuality improvement efforts aimed at increasing advice and education provision in diabetes management in primary care could target also perceptions of procedural justice.

Reflective and automatic processes in healthcare professional behaviour: an application of a dual process model

Background: Theorised pathways in an ‘extended’ common-sense model of illness representations (CSM) in those affected by Irritable Bowel Syndrome (IBS) were examined. Analysis contrasted between those using complementary medicines (CAM-users) and those not using CAM (non-users). n nMethods: A web-based cross-sectional survey. Participants (n=653) were recruited from an IBS self-help network and other online illness discussion forums and assessed on the IPQ-R, the BMQ-General, the Brief-COPE and IBS-QOL. n nFindings: CAM-users reported poorer quality of life compared to non-users. Stronger perceptions of illness consequences and emotional representations were strongly correlated with reduced quality of life and poorer emotional outcomes in both groups. Self-blame and behavioural disengagement partially mediated the pathway from perception to outcome. n nDiscussion: Findings suggest consistency with CSM theory. The detected influence of representations on quality of life (via coping strategies) suggests health psychologists could address components of illness perceptions to improve quality of life in those affected by IBS.Background: Psychological preparation has been demonstrated to improve post-operative outcomes including pain and health care resource use. This systematic review (registered with the Cochrane Anaesthesia Review Group) will investigate which methods of preparation are effective and for which outcomes. Economic data will be reviewed where available. Methods: Randomised controlled trials (RCTs) of adults undergoing elective surgery under general anaesthesia are included. Papers are identified using electronic searches, reference lists and contact with authors of studies to identify unpublished research. Expected results: In a meta-analysis including 38 RCTs, Johnston and Vogele (1993) found psychological preparation to be effective in improving various postoperative outcomes. It is expected that this up-dated review will provide further evidence about which techniques are effective because more studies are now available. Current stage of work: Papers are being screened for inclusion. Discussion: Identifying effective pre-surgical interventions may result in improved patient outcomes and healthcare resource use.[Extract] Background: Qualities of resilience have been strongly identified within farming populations. This resilience is being challenged, with high suicide rates raising concerns about the mental health of the farming population. This research explored those factors which impacted the resilience of farming families of Australia. Methods: Interviews were conducted (N=53 participants) and analysed using Grounded Theory and Content Analysis. Based on qualitative findings, a subsequent sample (N=278) of farming families from across Australia completed the survey. Measures of stressors, work-life balance, coping, buffering characteristics and well-being were distributed. Findings: Outcomes suggested themes of commitment and identification with farming helped build resilience. Path analysis indicated that buffering characteristics mediated and moderated the impact of stressors and role interference on indicators of well-being, χ² (18)=23.98, p=0.156. Discussion: Recommendations were made for raising awareness to the farming community of the risk factors for poor health and suggestions for increasing the resilience of groups at-risk of poor well-being.Background: Identity has been argued to be a pre-requisite for mental health. The aim of this study was to explore factors affecting mental health and cultural identity of urban Australian Aboriginal and Torres Strait Islander people in North Queensland, Australia. n nMethods: A qualitative research design was conducted with a sample of 19 Australian Aboriginal and Torres Strait Islander participants. Data was collected via individual semi-structured interviews and focus groups. Qualitative analysis was conducted using a grounded theory method. n nFindings: Four themes emerged as reflecting health and wellbeing – coping skills, knowledge social support, and connectedness. The overarching theme of connectedness – to country, family and kinship, knowledge and social networks, emerged as reflecting a unique contribution to both mental health and cultural identity. n nDiscussion: This information has implications for cross-cultural clinical practice, through developing culturally safe health and wellbeing programs that sustain and nurture the cultural identity and mental health of Indigenous people.Resiliance and Health - 26th Conference of the European Health Psychology Society, Prague, Czech Republic, 21st - 25th August 2012Background: To date, skin cancer prevention initiatives have focused on attitudes and cognitions surrounding deliberate sun exposure such as tanning. In North Queensland (NQ)however, comparatively few people deliberately tan. This indicates that much of the damage caused by excessive sun exposure happens incidentally, whilst performing normal daily activities. Incidental exposure is not planned or deliberate, thus theoretical modelling used in research should reflect this. Methods: Twenty-nine semi-structured interviews were conducted in NQ. Sun-related attitudes and behaviours were explored using content analysis. Findings: While participants reported negative perceptions of deliberate tanners, those who acquire a tan incidentally are perceived in a positive light. Similarly, participants considered their own incidental exposure to be non-risky. Discussion: The focus on deliberate sun exposure has meant that attitudes surrounding incidental exposure have not been adequately explored. Future research should target attitudes and behaviour surrounding incidental sun exposure, especially in high-risk regions such as NQ.Using two behavioral risk tasks (Balloon Analogue Risk Task BART; Lejueznet al. 2002 and Columbia Card Task, CCT; Figner et al. 2009) that mimic important featuresnof real-world risk taking behaviors, we investigated the effects of different types of negativenaffect on risk taking. Methods: Participants (N¼50) were first administered the HospitalnAnxiety and Depression Scale (HADS; Zigmond et al. 1983). One month later, they completednthe BART and the cold CCT, in counterbalanced order. State mood was assessed beforenparticipants played the CCT and BART. Findings: Higher levels of anxiety were associatednwith less risk taking in both tasks; depression was unrelated to risk taking. Hierarchicalnregression analysis showed that these findings were robust to mood effects. Discussion:nFindings from the current study indicated that healthy subjects’ risk taking tendencies varynbetween anxiety and depression. Implications for prevention of health risks are discussed.n194 EHPS 2012 abstractsnDownloaded byBackground: Physical exercise contributes to healthy ageing, and strength training has beenshown to improve independence in older people.Method: Six hundred older people wererandomly selected from ...Background: Conceptual clarification of salutogenesis (Antonovsky 1987) and resilience – what is common and different? Methods: A systematic research synthesis 1992–2010 based on about 1300 papers ...Resiliance and Health - 26th Conference of the European Health Psychology Society, Prague, Czech Republic, 21st - 25th August 2012This conference abstract looks provides an analysis of the behaviour change techniques used in Scottish Government supported behaviour change interventionsBackground: The aim of this research was to examine variables that influence attention to health information in order to develop a predictive model. Methods: Community participants(N=330) were randomly assigned to one of two conditions presenting information about coronary heart disease (CHD) or road accidents. Information was either risk or neutral in valency. Attention to information was measured using a surprise recall task. Other variables measured included perceived risk, optimism, control and coping strategies. Findings: Overall, participants in the CHD condition remembered significantly more risk information than participants in the road condition. Participants in the road condition endorsed significantly lower beliefs in personal control perceptions while also endorsing greater beliefs in other’s control over their own road outcomes. Discussion: While perceived control is usually emphasised as integral in adopting protective behaviours these findings suggest that they are also central in communicating health information.

Improving the delivery of care for patients with diabetes through understanding optimised team work and organisation in primary care: Study protocol

BackgroundType 2 diabetes is an increasingly prevalent chronic illness and is an important cause of avoidable mortality. Patients are managed by the integrated activities of clinical and non-clinical members of the primary care team. Studies of the quality of care for patients with diabetes suggest less than optimum care in a number of areas.AimThe aim of this study is to improve the quality of care for patients with diabetes cared for in primary care in the UK by identifying individual, team, and organisational factors that predict the implementation of best practice.DesignParticipants will be clinical and non-clinical staff within 100 general practices sampled from practices who are members of the MRC General Practice Research Framework. Self-completion questionnaires will be developed to measure the attributes of individual health care professionals, primary care teams (including both clinical and non-clinical staff), and their organisation in primary care. Questionnaires will be administered using postal survey methods. A range of validated theories will be used as a framework for the questionnaire instruments. Data relating to a range of dimensions of the organisational structure of primary care will be collected via a telephone interview at each practice using a structured interview schedule. We will also collect data relating to the processes of care, markers of biochemical control, and relevant indicator scores from the quality and outcomes framework (QOF). Process data (as a proxy indicator of clinical behaviours) will be collected from practice databases and via a postal questionnaire survey of a random selection of patients from each practice. Levels of biochemical control will be extracted from practice databases. A series of analyses will be conducted to relate the individual, team, and organisational data to the process, control, and QOF data to identify configurations associated with high quality care.Study registrationUKCRN ref:DRN120 (ICPD)