Values and Preferences in Clinical Practice Guidelines

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Values and Preferences in Clinical Practice
Guidelines
Gordon Guyatt Clarity Research Group McMaster
University
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Plan

• what is the problem?
• whose values and preferences?
• how can we find out about values and preferences?
• applying best estimates of V and P

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What is the problem?

• almost all decisions/recommendations involve
  tradeoffs
• benefits versus harms, burden, costs
• antithrombotic therapy
• thrombosis reduction vs bleeding, burden, costs
• tradeoffs require V and P judgments
• value reducing MI, stroke, DVT vs bleed and
  burden

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What are values and preferences?

• judgments of disutility
• burden or negative outcomes associated with a
  particular health state
• a broad term that includes patient perspectives,
  beliefs, expectations, and goals for their health
  and life, including the process that patients go
  through in weighing the potential benefits,
  harms, costs, and burdens associated with
  different treatments or disease management
  options

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What have guideline panels done in the past ?

• ignored
• unaware that making V and P judgments
• implicit, unconscious V and P of panelists
• remains least understood, most poorly practiced
  area of guideline development

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Whose values and preferences?

• guideline panel members
• health care providers
• policy makers
• subjects of the guideline
• patients
• general public

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How to determine patient values and preferences?

• systematic review of patient V and P
• use guideline panel members
• act as proxies for their patients V and P
• patients on panel
• collect own values and preferences data

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Systematic review

• comprehensive search
• 48 studies
• 16 a fib, 10 stroke or MI, 5 VTE, 17 burden
• higher disutility on stroke than gastrointestinal
  bleed and much greater disutility on stroke than
  on treatment burden
• example of the relative value of health states
• a reasonable trade-off between nonfatal stroke
  and bleeds is a ratio of disutility of 2.1 to 3.1

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Systematic review, continued

• little consistency in health state preferences
• contributing factors?
• measurement methods (understanding)
• prior experience with the treatment
• description of event
• prior experience with adverse event, example
  stroke
• cause of the adverse event treatment-related
  versus natural higher value avoiding
  treatment-induced events than avoiding events
  treatment prevents
• age, sex

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Using systematic review results

• systematic review results require interpretation
• how should guideline panel proceed?
• systematic V and P rating exercise
• ACCP
• consider systematic review
• make ratings for typical patients
• rate scenarios, time frame of one year

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Venous limb gangrene scenario
Physical You suddenly develop severe pain in the leg where you have your blood clot and your toes start to turn black.
Treatment You have to stay in hospital. You stop taking warfarin. The swelling in your leg gets worse and the pain is severe. You receive a new blood thinner through your intra-venous line
Recovery After a few weeks, your toes return to normal.
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? Maximum
Feeling thermometer Venous limb gangrene
? Mean
? Minimum
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Disutility with stroke in a child
Physical Symptoms   Your child suddenly becomes unresponsive Your child is unable to move one arm and one leg Your child cannot speak to you
Mental Symptoms   Your child is irritable and upset You find it difficult to console your child Family and friends find the diagnosis difficult to accept
Pain Your child has a headache for a number of days
Recovery Your childs stay in hospital is prolonged Your child recovers some function, including speech and movement slowly over weeks to months Your child complains of tiredness for months Your child needs help to attend normal school Your child has multiple hospital visits for physiotherapy and rehabilitation You must alter your hopes and dreams for your childs future
Further Risk   You are told your child is not at risk of further strokes, You find your childs ongoing limitations very hard to accept
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? Maximum
Feeling thermometer Major stroke in a child
? Mean
? Minimum
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Disutility with a gastrointestinal bleed
Symptoms You feel nauseated and unwell for two days, and then suddenly you vomit blood and feel faint.
Diagnostic tests and treatment You are taken by ambulance to a busy emergency department. An intravenous catheter is placed and a catheter is placed through your nose into your stomach to help drain the blood You receive blood transfusions to replace the blood you lost You are admitted to hospital A doctor puts a tube down your throat into your stomach to see where you are bleeding from and to provide treatment You receive sedation by intravenous to ease the discomfort of the test You do not require an operation to stop the bleeding You must stop taking your blood thinner stopping the blood thinner puts you at risk of developing a new blood clot.
Recovery You stay in the hospital for a few days You feel much better at the end of your hospital stay You need to take pills for the next six month to prevent further bleeding After that, you are back to normal About 2 weeks after your bleeding you restart your blood thinning therapy you worry every day about more bleeding for the first month after restarting After that, your worry gradually decreases
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? Maximum
Feeling thermometer Gastrointestinal bleed
? Mean
? Minimum
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Key decisions

• myocardial infarction pulmonary embolus
  venous thrombosis gastrointestinal bleed
• stroke 3 bleeds (and thus three of any other
  major event)

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What lowers strength of recommendation?

• strong recommendation
• confident more good than harm
• almost all informed patient make same choice
• tight balance
• uncertainty about typical V and P
• uncertainty about variability in V and P
• V and P highly variable

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• Strong recommendation for warfarin

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Alternatives experience of clinicians in shared
decision making
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Patients on panel

• often advocated
• may be useful in issues overlooked
• no guarantee reflects typical V and P

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V and P can help if disagreement

• establish that everyone agrees with evidence
  summary
• clarify values and preferences
• Review evidence about patient V and P

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Conclusions

• value and preference judgments ubiquitous
• panels MUST make judgments explicit
• quantitation desirable
• values those who bear consequences
• weak recommendation more likely
• close trade-off
• uncertainty in typical V and P
• highly variable V and P

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Conclusions

• systematic review of V and P routine
• still need panel input
• study results require interpretation
• results likely incomplete
• structured elicitation of panel V and P
• patients on panel questionable
• expert panel shared decision-making