christopher eccleston
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Christopher Eccleston
Centre for Pain Research
The University of Bath
c.eccleston@bath.ac.uk
Order of service
• Cochrane Collaboration• Methods• Communication• Methods Development• Other
Cochrane Collaboration
• Founded in 1993 Iain Chalmers• Following Archie Cochrane• Principles of Evidence for all• 52 CRGs• Centres & Fields• Volunteer• Consumerist• Quality• Control over Bias• Living Library
Cochrane Collaboration Review GroupPain, Palliative & Supportive Care
PaPaS
• http://papas.cochrane.org
• Established in 1998• Based in Oxford• Updates 2 years• Cochrane Database
Systematic Reviews• The Cochrane Library• Field Editors
Current Status• Editorial Board
– Mike Bennett– Andrew Moore– Tim Steiner– Amanda Williams– Acute Pain Vacancy
• Title to Protocol to review
• 120 reviews• 70 protocols and titles• 2 overviews• IASP SIG Systematic Reviews• ACTINPAIN Writing Group
Quality improvement (Actinpain)
Methods• Guidance?• Common Methods• RevMan (free)• Supported (Title Reg)• Professional Searching• Published Protocols• International (not English)• Meta-analysis• Bias Control• Communication
www.cochrane-handbook.org/
Features
• Standard description of condition/intervention
• Full description of studies (Tables)
• Assessment of heterogeneity– Clinical pooling like with unlike– Statistical (small n)
• Sub-group analyses– (dose)
Meta-analysis +
• Effect sizes• Forest plots• Assumptions
– Fixed effects• Assume variation is
sampling error
• Violations– Heterogeneity– Small n
• Junk in Junk out– Quality of primary
Communication
• Abstracting
• Plain Language Summary
• Risk of Bias Tool
• Summary of Findings
• Podcast
• Journal Club
• PICO
Risk of Bias
Summary of Findings
Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, Schünemann HJ; GRADE Working Group. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008 Apr 26;336(7650):924-6.
The GRADE system classifies the quality of evidence in one of four grades:
GRADE DEFINITION
High
⊕⊕⊕⊕Further research is very unlikely to change our confidence in the estimate of effect.
Moderate
⊕⊕⊕
Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low
⊕⊕
Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very Low
⊕
Any estimate of effect is very uncertain.
Journal Club
Methods 1: Outcomes
• Use outcomes (IMMPACT) chronic• Pain reduction: 30% moderate, 50% Good• Other
– Time to re-medication– non-pain outcomes
• Not recommended– Odds ratios– Analgesic consumption
• No use of group means– Pain relief has a U shaped distribution– Response analysis on dichotomous data
• Adverse events
Core outcomes
Methods 2: ROB
• Use of quality rating scales?
• Jadad scale• Non-pharmacological
interventions?
PaPaS RAG
Methods 3: GRADE
Alternative?
Methods 4: NNT
• Inverse of the absolute risk• Benefits
– Easier to understand– Compare between treatments easily
• Costs– More is worse– Can hide effect (EMEA Report)
• Never an NNT alone• RR, NNT, NNH, percentage improvement
Stabilizing a review
• Publication bias• Stabilizing (not updating)
Not discussed• Overclaiming
– No effective or no evidence of effect• Quality control in non-pharmacological trials• Language of confidence• Simplify vs simplistic (95% read abstract)• 30 or 50 or 70• Responder analysis vs response analysis• Does pain relief drive QoL outcomes?• Comparing treatments
– Overview reviews– Stopping rules, Switch rules– Indirect comparisons
• Judgement biases– Behavioural economics (choices)– Myth of rational man
Communication
• What is the risk doctor?
• Tell it to me straight.
• What are my chances doctor?
• Tell it to me straight.
Thank you
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