Regaining power lost by non-compliance via full probability modelling

Benefits and challenges of using the cohort multiple randomised controlled trial design for testing an intervention for depression

BACKGROUND

Trials which test the effectiveness of interventions compared with the status quo frequently encounter challenges. The cohort multiple randomised controlled trial (cmRCT) design is an innovative approach to the design and conduct of pragmatic trials which seeks to address some of these challenges.

MAIN TEXT

In this article, we report our experiences with the first completed randomised controlled trial (RCT) using the cmRCT design. This trial-the Depression in South Yorkshire (DEPSY) trial-involved comparison of treatment as usual (TAU) with TAU plus the offer of an intervention for people with self-reported long-term moderate to severe depression. In the trial, we used an existing large population-based cohort: the Yorkshire Health Study. We discuss our experiences with recruitment, attrition, crossover, data analysis, generalisability of results, and cost. The main challenges in using the cmRCT design were the high crossover to the control group and the lower questionnaire response rate among patients who refused the offer of treatment. However, the design did help facilitate efficient and complete recruitment of the trial population as well as analysable data that were generalisable to the population of interest. Attrition rates were also smaller than those reported in other depression trials.

CONCLUSION

This first completed full trial using the cmRCT design testing an intervention for self-reported depression was associated with a number of important benefits. Further research is required to compare the acceptability and cost effectiveness of standard pragmatic RCT design with the cmRCT design.

TRIAL REGISTRATION

ISRCTN registry: ISRCTN02484593 . Registered on 7 Jan 2013.

Depressed patients treated by homeopaths: a randomised controlled trial using the "cohort multiple randomised controlled trial" (cmRCT) design

BACKGROUND

Despite controversy regarding homeopathy, some patients consult homeopaths for depression. Evidence is required to determine whether this is an effective, acceptable and safe intervention for these patients.

METHODS

A pragmatic trial using the "cohort multiple randomised controlled trial" design was used to test the effectiveness of adjunctive treatment by homeopaths compared to usual care alone, over a period of 12 months in patients with self-reported depression. One third of patients were randomly selected for an offer of treatment provided by a homeopath. The primary outcome measure was the Patient Health Questionnaire (PHQ-9) at 6 months. Secondary outcomes included depression scores at 12 months; and the Generalised Anxiety Disorder (GAD-7) outcome at 6 and 12 months.

RESULTS

The trial over-recruited by 17% with a total of 566 patients. Forty percent took up the offer and received treatment. An intention-to-treat analysis of the offer group at 6 months reported a 1.4-point lower mean depression score than the no offer group (95% CI 0.2, 2.5, p = 0.019), with a small standardized treatment effect size (d = 0.30). Using instrumental variables analysis, a moderate treatment effect size in favour of those treated was found (d = 0.57) with a between group difference of 2.6 points (95% CI 0.5, 4.7, p = 0.018). Results were maintained at 12 months. Secondary analyses showed similar results. Similar results were found for anxiety (GAD-7). No evidence suggested any important risk involved with the intervention.

CONCLUSION

This trial provides preliminary support for both the acceptability and the effectiveness of treatment by a homeopath for patients with self-reported depression. Our results provide support for further pragmatic research to provide more precise estimates of treatment effect.

TRIAL REGISTRATION

ISRCTN registry, ISRCTN02484593 . Registered on 7 January 2013.

HeLP-Diabetes: randomised controlled trial protocol

Background

Type 2 Diabetes Mellitus (T2DM) is common, affecting nearly 400 million people worldwide. Achieving good health for people with T2DM requires active self-management; however, uptake of self-management education is poor, and there is an urgent need to find better, more acceptable, cost-effective methods of providing self-management support. Web-based self-management support has many potential benefits for patients and health services. The aim of this trial is to determine the effectiveness and cost-effectiveness of a web-based self-management support programme for people with T2DM.

Methods

This will be a multi-centre individually randomised controlled trial in primary care, recruiting adults with T2DM who are registered with participating general practices in England. Participants will be randomised to receive either an evidence-based, theoretically informed, web-based self-management programme for people with T2DM which addresses medical, emotional, and role management, called Healthy Living for People with type 2 Diabetes (HeLP-Diabetes) or a simple information website. The joint primary outcomes are glycated haemoglobin (HbA1c) and diabetes-related distress, measured by the Problem Areas In Diabetes (PAID) questionnaire. Secondary outcomes include cardiovascular risk factors, depression and anxiety, and self-efficacy for self-management of diabetes. Health economic data include health service use, costs due to the intervention, and EQ-5D for calculation of Quality Adjusted Life Years (QALYS). Data will be collected at baseline, 3 months and 12 months, with the primary endpoint at 12 months. Practice nurses, blinded to patient allocation, collect clinical data; patients complete online questionnaires for patient reported measures. A sample size of 350 recruited participants allows for attrition of up to 15 % and will provide 90 % power of detecting at a 5 % significance level a true average difference in the PAID score of 4.0 and 0.25 % change in HbA1c (both small effect sizes). The analysis will follow a pre-specified analysis plan, based on comparing the groups as randomised (intention-to-treat).

Discussion

The findings of this trial are likely to be of interest to policy makers, clinicians, and commissioners, all of whom are actively seeking additional forms of self-management support for people with T2DM.

Trial registration

The Trial Registration number is ISRCTN 02123133; date of registration 14.2.13.

The impact of adherence on sports injury prevention effect estimates in randomised controlled trials: looking beyond the CONSORT statement

OBJECTIVE

To investigate estimated outcome effects of a sports injury prevention intervention when analysed by means of a per protocol (PP) analysis approach.

DESIGN

Randomised controlled trial (RCT) involving 522 athletes who sustained a lateral ankle sprain allocated to either an intervention (received a preventive programme in addition to usual care) or control group who were followed prospectively for one year.

METHODS

Secondary analysis of data relating to registered ankle sprain recurrences, exposure and adherence to the allocated intervention using a PP analysis approach.

RESULTS

Twenty-three percent of the RCT intervention group indicated to have fully adhered with the neuromuscular training programme. A per protocol analysis only considering fully adherent athletes and control athletes, showed a Hazard Ratio of 0.18 (95% CI: 0.07-0.43). Significantly fewer recurrent ankle sprains were found in the fully adherent group compared to the group that was not adherent (relative risk = 0.63; 95% CI: 0.43-0.99).

CONCLUSIONS

A PP analysis on fully adherent athletes versus control group athletes showed that the established intervention effect was over threefold higher compared to an earlier intention-to-treat based analysis approach. This shows that outcomes of intervention studies are heavily biased by adherence to the allocated intervention.