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Graphical method to aid design and reporting of complex intervention trials Pat Yudkin Dept of Primary Health Care University of Oxford York 16 September.

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Presentation on theme: "Graphical method to aid design and reporting of complex intervention trials Pat Yudkin Dept of Primary Health Care University of Oxford York 16 September."— Presentation transcript:

1 Graphical method to aid design and reporting of complex intervention trials Pat Yudkin Dept of Primary Health Care University of Oxford York 16 September 2009

2 Examples of complex interventions All target behaviour change 50 hours of group sessions to reduce incidence of HIV in rural South Africa (Jewkes 2008) 12-weeks of group sessions for parents, to reduce problem behaviour in children and depression and stress in parents (Hutchings 2007) Home visits over 2 years by nurses to prevent recurrence of physical abuse and neglect of children (MacMillan 2005)

3 These interventions are complex Complex construction Complex mechanism of action

4 Complex construction Many different parts (components) Includes personal actions and interactions, which may be repeated or difficult Involves flexibility in delivery, depending on characteristics of recipient and setting

5 Two levels of description needed Simple, clear description at design stage and for readers of paper Detailed and comprehensive description needed for those delivering the intervention to ensure reproducibility

6 Review of non-drug intervention trials in UK primary care Systematic search of randomised trials, UK primary care Identified 169 non-drug trials Many aimed to improve lifestyle (diet, exercise, smoking) Perera et al, BMJ 2007;334:127-9

7 Problems identified in review 1.Descriptions of interventions long and wordy 2.Components of the intervention and its comparator not easy to identify 3.Missed crucial points like timing of delivery of some components 4.Difference between trial groups not clear 5.Timing of outcome not obvious

8 Describing the intervention Many ways to describe intervention - we see the delivery of a complex intervention as a set of different activities Some activities involve giving objects to the recipients of the intervention

9 Simple description of an activity 1.What form does it take? 2.What does it consist of? 3.Who delivers it? 4.Where and when does it happen? 5.How long does it take?

10 Can a diagram be clarifying?

11 TimelineInterventionControl Pre-randomisation Randomisation 1, 2, 3 months 6 months Outcome, 1 year b a ActivityObject

12 The DIGEM trial in Type 2 diabetes Does blood glucose self-monitoring, alone, or with training in interpretation to guide behaviour, improve glycaemic control? 1.No monitor, HbA1c measured 3-monthly by doctor 2.Int 1: Blood glucose monitor given with advice to contact doctor if readings persistently high 3.Int 2: Blood glucose monitor given with training in interpretation of results to guide behaviour

13 The DIGEM trial (2) All patients given information, education and support by trained nurses over one year. Content of nurse contacts different in each trial arm Main outcome: blood glucose level at 12 months

14 a bc a d a a a b b b c d e f g h i j ContInt 1Int 2Timeline Baseline, 2 wks after randomisation 2 wks before each visit 1, 3, 6, 9 months visits 2 wks after baseline Before randomisation b RANDOMISATION OUTCOME, 1 YEAR

15 b a a b c d Description Symbol Nurse training: 6 days, based on manual. Behaviour change techniques, theory etc 45 mins with nurse: review diet, exercise and drugs; set goals for behaviour change 45 mins with nurse: roles of diet, exercise and drugs discussed, glucose control emphasised e 45 mins with nurse: instruct in using blood glucose meter; review and set goals 45 mins with nurse: instruct in using meter and interpreting results; review and set goals Diary to record goals, strategies for achieving them, and whether achieved Blood glucose meter

16 Description Symbol Diary to record blood glucose results Phone call from nurse to reinforce use of meter and check for problems Diary to record blood glucose results and relate them to activities and diet Patient attends blood test at surgery to measure HbA1c 20 mins with nurse: HbA1c results reviewed 20 mins with nurse: blood glucose results reviewed to show specific relation between self-care and glycaemic control 20 mins with nurse: blood glucose results reviewed c d f g h i j

17 a bc a d a a a b b b c d e f g h i j ContInt 1Int 2Timeline Baseline, 2 wks after randomisation 2 wks before visits 1, 3, 6, 9 months visits 2 wks after baseline Before randomisation b RANDOMISATION OUTCOME, 1 YEAR

18 Advantages of diagram Structure of intervention easy to grasp Structure of comparator also made clear Timing of components clarified Difference between interventions obvious Timing of outcome measures clear

19 A diagram can’t do everything May not be helpful for all interventions Still need full material to describe interventions well enough for them to be reproduced

20 Acknowledgements Rafael Perera Andrew Farmer Ray Fitzpatrick Paul Glasziou Carl Heneghan David Mant Sasha Shepperd Alison WardSue Ziebland

21 Full screen F11 Select page Ctrl A


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