Guidelines With Global Implications

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Guidelines With Global Implications

• Robert West, PhD

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Outline

• Need for a global evidence base
• Aims and methods
• Examples of evidence statements
• Conclusions

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Need for Global Evidence Base

• Guideline development is an ongoing process
  worldwide
• Repeating evidence reviews in each case is
  potentially wasteful, error-prone, and a source
  of inconsistencies
• Guidelines themselves must take account of local
  circumstances, but the global evidence baseis
  generalisable

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Aim

• To present up-to-date, top-line conclusions on
  efficacy and effect size estimates of major
  clinical smoking-cessation interventions,
  together with caveats and qualifications, using a
  consistent format that can be used to calculate
  the cost-effectiveness of these interventions in
  preventing morbidity and mortality

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Methods

• Evidence base
• Cochrane Reviews supplemented by individual
  studies to provide caveats and qualifications or
  to utilize when Cochrane Reviews are not
  available
• Effect size estimate
• 6-month continuous abstinence rate
• Divide by 2 to get effect on permanent
  cessation
• Basis of effect size estimate
• Russell Standard where possible (West et al.
  2005)

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Clear Evidence

• When given to population category,
  intervention category has been found in type
  of study/analysis to increase 6-month
  abstinence rates by range of values/NT range
  compared with comparator

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Suggestive Evidence

• When given to population category, evidence
  from type of study/analysis suggests that
  intervention category increases 6-month
  abstinence rates by range of values compared
  with comparator

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Inconsistent Evidence

• Evidence from type of study/analysis is
  inconsistent on the effectiveness of
  intervention category compared with
  comparator

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Negative Evidence

• Adequately powered and designed studies have
  failed to find an effect of intervention
  category compared with comparator

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Insufficient Evidence

• Insufficient evidence is available from which to
  draw conclusions about/regarding statement
  concerning intervention category

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Caveats and Qualifications

• Factors that may limit generalisability
• Additional comparisons
• Observational evidence of effectiveness
  intoreal-world settings

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Brief Advice Evidence Statement

• Brief opportunistic advice involves a health
  professional raising the topic of smoking with a
  patient, advising the patient to stop, and
  offering support and follow-up
• When given to unselected smokers attending a
  consultation for some other condition, brief
  advice has been found in multiple randomised
  controlled trials to increase 6-month abstinence
  rates by an average of 1 to 3 over a baseline
  quit rate of 3 (NNT33-100) compared with doing
  nothing

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Brief Advice Caveats and Qualifications 1

• There is insufficient evidence to draw firm
  conclusions regarding the optimal manner in which
  the advice is given, and in any event this advice
  may vary according to the prevailing culture.
  Some guidelines have suggested an approach based
  on the 5 As Ask, Advise, Assess, Assist,
  Arrange. However, no evidence suggests that such
  an approach is more effective than one that, for
  example, asks about smoking and at the same time
  offers helpwith stopping
• There is insufficient information to draw
  conclusions about whether this type of advice
  given by health professionals who are not
  physicians is effective

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Brief Advice Caveats and Qualifications 2

• The studies to date have mostly been carried out
  in a context in which medication and specialist
  behavioural support to aid cessation were not
  available. Encouraging smokers to use these
  treatments may increase the net effect of
  opportunistic advice
• The studies were carried out in a context in
  which few other environmental factors promoting
  smoking cessation were present in the population
  (eg, indoor smoking restrictions). The effect in
  other contexts may vary
• Brief opportunistic advice appears to have its
  effect by triggering a quit attempt. Whether quit
  attempts triggered in this way are more likely to
  be successful than quit attempts triggered in
  other ways is not known

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Behavioural SupportEvidence Statements

• Behavioural support involves providing advice and
  encouragement and sometimes practical exercises
  designed to bolster and sustain motivation to
  remain abstinent and minimize motivation to smoke
  during a quit attempt
• When given to smokers seeking help with stopping,
  behavioural support has been found in multiple
  randomised controlled trials to increase 6-month
  continuous abstinence rates by 3 to 7
  (NNT14-33) compared with a control group quit
  rate of 5 for patients trying to quit but not
  receiving face-to-face support, only written
  materials, or brief advice

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Behavioural Support Caveats and Qualifications 1

• The studies conducted to date have usually
  involved multiple sessions provided by specially
  trained health professionals over a period of 1
  to more than 4 weeks after a clearly specified
  target quit date. Single sessions of support or
  support provided by individuals who have not been
  specially trained or who are mainly employed on
  other duties and have to fit the behavioural
  support into those duties do not have clear
  evidence of effectiveness
• The support can be provided to groups of smokers
  or individual smokers face to face or by
  telephone. Insufficient evidence is available
  from which to draw firm conclusions about whether
  any of these modes of delivery are likely to be
  more effective than others
• Adding scheduled sessions of telephone support to
  face-to-face support has been found in multiple
  randomized controlled trials to increase 6-month
  continuous abstinence rates by 2 to 3
  (NNT33-50)

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Behavioural Support Caveats and Qualifications 2

• Insufficient evidence is available from which to
  draw conclusions about whether different
  approaches to behavioural support are more
  effective than others. Specifically, whether
  cognitive behavioural therapy or motivational
  interviewing is more effective than support not
  based on any particular theoretical position is
  not known
• Insufficient evidence is available from which to
  draw conclusions about whether behavioural
  support is effective for long-term cessation,
  specifically in patients awaiting surgery
• When given to hospital inpatients, behavioural
  support only appearsto be effective in promoting
  long-term smoking cessation if it continues for
  at least 1 month after discharge
• Adequately powered and designed studies have
  failed to find an effect of relapse-prevention
  sessions after the initial acute withdrawal
  period (usually 4 weeks) compared with no
  additional intervention

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Conclusions

• A need exists for a global evidence base for use
  in treatment guidelines with findings expressed
  in a consistent format that can be used to
  determine cost-effectiveness
• The current review uses the most rigorous
  available reviews supplemented by additional
  studies to
• Provide quantitative effect size estimates
• List caveats and qualifications that are
  important in interpreting these estimates