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The effects of inadequate preparation quality for colonoscopy. Eric Sherer and Michael Catlin August 20 th , 2010 HSR&D Work-in-Progress. Outline. Background Lengthy Adenoma detection rates Appendix… or stand alone???. Outcomes Methods Random questions Compliance Costs Mortality

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The effects of inadequate preparation quality for colonoscopy

The effects of inadequate preparation quality for colonoscopy

Eric Sherer and Michael Catlin

August 20th, 2010

HSR&D Work-in-Progress


Outline
Outline

  • Background

    • Lengthy

    • Adenoma detection rates

    • Appendix… or stand alone???

  • Outcomes

  • Methods

    • Random questions

      • Compliance

      • Costs

      • Mortality

  • Preliminary results

ORANGE TEXT => INPUT FROM AUDIENCE



Detection rates literature
Detection rates - Literature

  • Harewood et al. 2003

    • 93,004 colonoscopies

    • Adequate vs. Inadequate

    • POLYPS

    • <10 MM

  • Froechlich et al. 2005

    • 5,832 colonoscopies

    • Low vs. Intermediate quality

    • Low vs. High quality

    • POLYPS

    • <10 MM


Unanswered questions
Unanswered questions

  • What about adenomas?

  • Diminutive (<=5mm) vs. small (<10mm) adenomas?

    • “cannot exclude adenomas <=5mm”

  • Adjust for individual colonoscopist

  • Want sensitivity NOT detection rates


Adenoma detection rates
Adenoma detection rates

Padequate vs. fair = 0.17

Padequate vs. poor < 0.01


Adenoma detection rates1
Adenoma detection rates

Padequate vs. fair = 0.28

Padequate vs. poor < 0.01

Padequate vs. fair = 0.62

Padequate vs. poor = 0.80


Adenoma detection rates2
Adenoma detection rates

Padequate vs. fair = 0.25

Padequate vs. poor < 0.01


Adenoma detection rates3
Adenoma detection rates

  • Medium adenomas (6-9mm)

    • Adequate vs. poor prep qualities

      • 22% relative difference; 3.2% absolute difference

    • Adequate vs. fair prep qualities

      • 13% relative difference; 1.9% absolute difference

Padequate vs. fair = 0.16

Padequate vs. poor = 0.21


Adenoma detection rates4
Adenoma detection rates

  • Medium adenomas (6-9mm)

    • Adequate vs. poor prep qualities

      • 22% relative difference; 3.2% absolute difference

    • Adequate vs. fair prep qualities

      • 13% relative difference; 1.9% absolute difference



Outcomes
Outcomes

  • Effects of inadequate preparation quality

    • Missed adenomas => Δcancer


Recommendations after 1 st colonoscopy
Recommendations after 1st colonoscopy

  • 2003-2010 colonoscopy prep qualities

    • 1,675 (64.1%) adequate

    • 750 (28.7%) fair

    • 187 (7.1%) poor


Effect of inadequate preparation
Effect of inadequate preparation

  • Rex et al. 2002

    • 400 patients

      • 200 public hospital

      • 200 private hospital

    • Authors assumed…

      • Perfect inadequacy

      • Perfect compliance

      • Procedure invariance


Outcomes1
Outcomes

  • Effects of inadequate preparation quality

    • Missed adenomas => Δcancer

    • Earlier recalls => Δnumber of tests


Outcomes2
Outcomes

  • Primary

    • Patient

      • Δ E[Quality adjusted life-year (QALY)]

      • Δ E[colon costs]

      • Δ lifetime CRC risk

    • Clinic

      • Δ E[colonoscopies / patient / life-year]

        • (How many more colonoscopies are done per patient each year)

  • Secondary

    • Prep quality intervention



Calculations
Calculations

Monte Carlo trials

Implementation

All adequate prep scenario

“Normal” prep scenario

Range of compliances

Independent & greedy assumptions

To-do: Sensitivity analysis

Costs

  • Select patient

    • Colon disease free & 50<=age<=80

  • r1 Select random prep quality

    • f (gender, BMI, prev prep quality)

  • r2 Random colonoscopy findings

    • History dependent

  • r3 Select compliance

    • 40% - 80% reported in literature

    • Independent events vs. All-or-nothing

  • r4 Determine follow-up interval

    • Expected vs. distributed behavior

  • r5 Age > 80? Age > 100?



Measuring patient outcomes
Measuring patient outcomes

Quality-Adjusted Life Years (QALYs)

40 years

Perfect health (utility 1.0)

40 QALYs


Measuring patient outcomes1
Measuring patient outcomes

Quality-Adjusted Life Years (QALYs)

40 years

Perfect health (utility 1.0)

40 QALYs

80 years

Poor health (utility 0.5)

40 QALYs


Measuring patient outcomes2
Measuring patient outcomes

Quality-Adjusted Life Years (QALYs)

40 years

Perfect health (utility 1.0)

40 QALYs

Utility of model states (Ness et al. 2000)

80 years

Poor health (utility 0.5)

40 QALYs


Measuring clinic costs
Measuringclinic costs

  • CRC treatment

    • Initial costs

    • Continuing costs

      (Ness et al. 2000)

  • Colonoscopies

    • Colonoscopy

    • Polypectomy

    • Pathology

  • Complications

    • Perforation


  • Measuring clinic costs1
    Measuringclinic costs

    • CRC treatment

      • Initial costs

      • Continuing costs

        (Ness et al. 2000)

      • Terminal care costs not included

  • Colonoscopies

    • Colonoscopy

    • Polypectomy

    • Pathology

  • Complications

    • Perforation


  • Measuring clinic costs2
    Measuringclinic costs

    • CRC treatment

      • Initial costs

      • Continuing costs

  • Colonoscopies

    • Colonoscopy ($614 per procedure)

    • Polypectomy ($131 for removal of polyps)

    • Pathology ($67 per polyp examined)

      (Tafazzoli et al. 2009)

  • Complications

    • Perforation


  • Measuring clinic costs3
    Measuringclinic costs

    • CRC treatment

      • Initial costs

      • Continuing costs

  • Colonoscopies

    • Colonoscopy

    • Polypectomy

    • Pathology

  • Complications

    • Perforation (0.2% incidence, 0.01% mortality)

      (Tafazzoli et al. 2009)


  • Measuring mortality
    Measuring mortality

    Discount each event by the probability of prior mortality.


    Measuring mortality1
    Measuring mortality

    Discount each event by the probability of prior mortality.

    Probability of surviving from age 50

    Patient viability with age

    Ai = age at first colonoscopy

    Af = current age

    Patient age



    Clinic outcomes

    Clinic outcomes

    E[colonoscopies / patient / life-year]


    E n of surveillance colonoscopies independent event assumption w ghosts
    E[N] of surveillance colonoscopies:Independent event assumption w/ ghosts

    26.8% of surveillance colonoscopies due to inadequate prep


    Patient outcomes

    Patient outcomes

    E[QALY / patient]

    E[colon costs / patient]E[CRC / patient]





    Secondary outcome

    Secondary Outcome

    Effect of prep quality intervention



    Big picture
    Big Picture

    • Overall project Objective:

      • “Best” time for a patient to receive colon tests

    • Tools needed

      • Longitudinal predictions

        • Test parameters

      • Cost-utility

      • Decision analysis



    Limitations
    Limitations

    Discussed in Rex et al. 2002

    Additional

    Likelihood of CRC

    Intermediate preps, detection & recs

    Longitudinal adenoma prevalence

    Study interval bias

    • Correlation in prep qualities

    • Additional surveillance colonoscopies


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