Determining the sample size for a cluster-randomised trial: Bayesian hierarchical modelling of the ICC estimate

In common with many cluster-randomised trials, it was difficult to determine the appropriate sample size for the planned trial of the effectiveness of a systematic voiding programme for post-stroke incontinence due to the lack of a robust estimate of the intra-cluster correlation coefficient (ICC). One approach to overcome this problem is a method of combining ICC values in the Bayesian framework (Turner et al. 2005). We adopted this approach and used Bayesian hierarchical modelling to estimate the ICC

Changing stroke mortality trends in middle-aged people: an age-period-cohort analysis of routine mortality data in persons aged 40 to 69 in England

Background: In the UK, overall stroke mortality has declined. A similar trend has been seen in coronary heart disease, although recent reports suggest this decline might be levelling off in middle-aged adults. Aim: To investigate recent trends in stroke mortality among those aged 40–69 years in England. Methods: The authors used routine annual aggregated stroke death and population data for England for the years 1979–2005 to investigate time trends in gender-specific mortalities for adults aged 40 to 69 years. The authors applied log-linear modelling to isolate effects attributable to age, linear ‘drift’ over time, time period and birth cohort. Results; Between 1979 and 2005, age-standardised stroke mortality aged 40 to 69 years dropped from 93 to 30 per 100 000 in men and from 62 to 18 per 100 000 in women. Mortality was higher in older age groups, but the difference between the older and younger age groups appears to have decreased over time for both sexes. Modelling of the data suggests an average annual reduction in stroke deaths of 4.0% in men and 4.3% in women, although this decrease has been particularly marked in the last few years. However, we also observed a relative rate increase in mortality among those born since the mid-1940s compared with earlier cohorts; this appears to have been sustained in men, which explains the levelling off in the rate of mortality decline observed in recent years in the younger middle-aged. Conclusions: If observed trends in middle-aged adults continue, overall stroke mortalities may start to increase again

Does repetitive task training improve functional activity after stroke? A Cochrane systematic review and meta-analysis.

Repetitive task training resulted in modest improvement across a range of lower limb outcome measures, but not upper limb outcome measures. Training may be sufficient to have a small impact on activities of daily living. Interventions involving elements of repetition and task training are diverse and difficult to classify: the results presented are specific to trials where both elements are clearly present in the intervention, without major confounding by other potential mechanisms of action

Factors affecting thrombolysis in acute stroke: longer door-to-needle (DTN) time in younger people? [Abstract No. 53]

Introduction: Shortening the time to delivery of IV thrombolysis improves patient outcomes and reduces adverse events. This research aimed to explore patient and service delivery factors that increase or decrease DTN time for thrombolysis. Method: We conducted a Service Evaluation from July 2011 to March 2013, using stroke data from SINAP and DASH databases. Data was provided by 6 acute trusts in Lancashire and Cumbria which used telemedicine, and 11 stroke services within the North East of England which instead used face-to-face. Our investigation concentrates on admissions to hospital occurring out of routine working hours, when resources are particularly constrained. Descriptive and inferential analyses, focusing on multivariate Cox regressions models selected using a forward stepwise approach, were then carried out to determine which factors impacted on DTN time, our main outcome variable. Results: After testing alternative specifications, our final model included these potential risk factors: mode of thrombolysis decision-making (either face-to-face or telemedicine); hospital; age; sex. Our results show that DTN time was strongly influenced by patient’s age (p<0.01), with older people receiving thrombolysis more quickly. Among the statistically significant variables, type of hospital (p<0.001) appeared to affect DTN times, together with patient’s sex (p¼0.01), suggesting that males had shorter DTN times. Conclusion: Older age was associated with shorter DTN times, with this effect being independent of other factors. Therefore, our research suggests that age played a predominant role in the delivery of thrombolysis, rather than solely through the choice of assessing acute strokethrough face-to-face or telemedicine

A systematic review of repetitive task training with modelling of resource use, costs and effectiveness

OBJECTIVES: To determine whether repetitive functional task practice (RFTP) after stroke improves limb-specific or global function or activities of daily living and whether treatment effects are dependent on the amount of practice, or the type or timing of the intervention. Also to provide estimates of the cost-effectiveness of RFTP. DATA SOURCES: The main electronic databases were searched from inception to week 4, September 2006. Searches were also carried out on non-English-language databases and for unpublished trials up to May 2006. REVIEW METHODS: Standard quantitative methods were used to conduct the systematic review. The measures of efficacy of RFTP from the data synthesis were used to inform an economic model. The model used a pre-existing data set and tested the potential impact of RFTP on cost. An incremental cost per quality-adjusted life-year (QALY) gained for RFTP was estimated from the model. Sensitivity analyses around the assumptions made for the model were used to test the robustness of the estimates. RESULTS: Thirty-one trials with 34 intervention-control pairs and 1078 participants were included. Overall, it was found that some forms of RFTP resulted in improvement in global function, and in both arm and lower limb function. Overall standardised mean difference in data suitable for pooling was 0.38 [95% confidence interval (CI) 0.09 to 0.68] for global motor function, 0.24 (95% CI 0.06 to 0.42) for arm function and 0.28 (95% CI 0.05 to 0.51) for functional ambulation. Results suggest that training may be sufficient to have an impact on activities of daily living. Retention effects of training persist for up to 6 months, but whether they persist beyond this is unclear. There was little or no evidence that treatment effects overall were modified by time since stroke or dosage of task practice, but results for upper limb function were modified by type of intervention. The economic modelling suggested that RFTP was cost-effective. Given a threshold for cost-effectiveness of 20,000 pounds per QALY gained, RFTP is cost-effective so long as the net cost per patient is less than 1963 pounds. This result showed some sensitivity to the assumptions made for the model. The cost-effectiveness of RFTP tends to stem from the relatively modest cost associated with this intervention. CONCLUSIONS: The evidence suggests that some form of RFTP can be effective in improving lower limb function at any time after stroke, but that the duration of intervention effect is unclear. There is as yet insufficient good-quality evidence to make any firm recommendations for upper limb interventions. If task-specific training is used, adverse effects should be monitored. While the effectiveness of RFTP is relatively modest, this sort of intervention appears to be cost-effective. Owing to the large number of ongoing trials, this review should be updated within 2 years and any future review should include a comparison against alternative treatments. Further research should evaluate RFTP upper limb interventions and in particular constraint-induced movement therapy, address practical ways of delivering RFTP interventions, be directed towards the evaluation of suitable methods to maintain functional gain, and be powered to detect whether RFTP interventions are cost-effective

Training emergency services’ dispatchers to recognise stroke: an interrupted time-series analysis

Background: Stroke is a time-dependent medical emergency in which early presentation to specialist care reduces death and dependency. Up to 70% of all stroke patients obtain first medical contact from the Emergency Medical Services (EMS). Identifying ‘true stroke’ from an EMS call is challenging, with over 50% of strokes being misclassified. The aim of this study was to evaluate the impact of the training package on the recognition of stroke by Emergency Medical Dispatchers (EMDs). Methods: This study took place in an ambulance service and a hospital in England using an interrupted time-series design. Suspected stroke patients were identified in one week blocks, every three weeks over an 18 month period, during which time the training was implemented. Patients were included if they had a diagnosis of stroke (EMS or hospital). The effect of the intervention on the accuracy of dispatch diagnosis was investigated using binomial (grouped) logistic regression. Results: In the Pre-implementation period EMDs correctly identified 63% of stroke patients; this increased to 80% Post-implementation. This change was significant (p=0.003), reflecting an improvement in identifying stroke patients relative to the Pre-implementation period both the During-implementation (OR=4.10 [95% CI 1.58 to 10.66]) and Post-implementation (OR=2.30 [95% CI 1.07 to 4.92]) periods. For patients with a final diagnosis of stroke who had been dispatched as stroke there was a marginally non-significant 2.8 minutes (95% CI −0.2 to 5.9 minutes, p=0.068)reduction between Pre- and Post-implementation periods from call to arrival of the ambulance at scene. Conclusions: This is the first study to develop, implement and evaluate the impact of a training package for EMDs with the aim of improving the recognition of stroke. Training led to a significant increase in the proportion of stroke patients dispatched as such by EMDs; a small reduction in time from call to arrival at scene by the ambulance also appeared likely. The training package has been endorsed by the UK Stroke Forum Education and Training, and is free to access on-line

Motivational Interviewing Post-Stroke: An Analysis of Stroke Survivors' Concerns and Adjustment

Our earlier research demonstrated that participation in four sessions of motivational interviewing (MI) early post-stroke has a positive impact on stroke survivors' mood. However, the theoretical underpinnings of MI in supporting adjustment (rather than its traditional use in supporting behavior change) require clarification. This article describes a content analysis of MI transcripts for 10 participants in our previous study, to identify the focus of discussions (patient "concerns") and potential effective components of our MI approach. Patients' post-stroke concerns were shown in 16 categories, including frustration, family impact, and getting well. There was a pattern of change discourse across sessions: "Sustain talk" (reasons for not changing) reduced from Session 1 onward, "change talk" (intent to change) increased then reduced, and "change expressed" (changes achieved) increased from Sessions 1 to 4. MI facilitates healthy adjustment post-stroke in some patients, in turn affecting mood, but clarification of how this effect is achieved requires further exploration

Assessing fidelity to complex interventions: the icons experience

Background Assessing fidelity to complex healthcare interventions in clinical trials is a challenging area. ‘ICONS' is a cluster randomised controlled feasibility trial of a systematic voiding programme (SVP), incorporating bladder training and prompted voiding, to promote post-stroke continence. Here we describe feasibility of one aspect of fidelity assessment: the day-to-day implementation of the SVP through analysis of clinical logs. Methods Nurses completed clinical logs daily, which included documenting: the toileting interval, proposed toileting times and times toileted. Clinical logs were sampled across trial sites. The original intention was to assess fidelity by exploring the degree of concordance between proposed times and times toileted. Initial analysis revealed the unfeasibility of this method due to documentation errors in toileting intervals and proposed times. Consequently, the planned method was changed to identification of key ‘quality indicators' (QIs) for documentation of practice. Results The need to revise the method of measurement demonstrates the difficulty in assessing fidelity. Assessment of clinical logs revealed low levels of adherence to key quality indicators. However, it is unclear whether this indicates poor fidelity or an imprecise method of fidelity assessment. Conclusion This study highlights challenges of assessing fidelity to complex interventions. Lessons learned will inform the measurement of fidelity in a future trial. Researchers should be aware that the practical implementation of complex healthcare interventions may not be exactly as intended. For ICONS, clinical logs constituted a proxy measure of day-to-day fidelity to the intervention: identification of alternative methods could be considered