The effects of inadequate preparation quality for colonoscopy Eric Sherer and Michael Catlin August 20 th, 2010 HSR&D Work-in-Progress 1

Outline Background – Lengthy – Adenoma detection rates – Appendix… or stand alone??? Outcomes Methods – Random questions Compliance Costs Mortality Preliminary results ORANGE TEXT => INPUT FROM AUDIENCE 2

Background 3

Detection rates - Literature Harewood et al – 93,004 colonoscopies – Adequate vs. Inadequate – POLYPS – <10 MM Froechlich et al – 5,832 colonoscopies – Low vs. Intermediate quality – Low vs. High quality – POLYPS – <10 MM 4

Unanswered questions What about adenomas? Diminutive (<=5mm) vs. small (<10mm) adenomas? – “cannot exclude adenomas <=5mm” Adjust for individual colonoscopist Want sensitivity NOT detection rates 5

Adenoma detection rates P adequate vs. fair = 0.17 P adequate vs. poor <

Adenoma detection rates P adequate vs. fair = 0.62 P adequate vs. poor = 0.80 P adequate vs. fair = 0.28 P adequate vs. poor <

Adenoma detection rates P adequate vs. fair = 0.25 P adequate vs. poor <

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 P adequate vs. fair = 0.16 P adequate vs. poor =

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 10

Surveillance colonoscopy findings 11

Outcomes Effects of inadequate preparation quality – Missed adenomas => Δ cancer 12

Recommendations after 1 st colonoscopy colonoscopy prep qualities – 1,675 (64.1%) adequate – 750 (28.7%) fair – 187 (7.1%) poor ADEQUATE PREP QUALITY FAIR PREP QUALITY POOR PREP QUALITY ADEQUATE v. FAIR FAIR v. POOR Colonoscopy finding Mean recommended follow-up (s.d.) Δ Follow-up [95% CI] Δ Follow-up [95% CI] No adenomas (10yrs) 8.01yrs (2.69) n = yrs (2.65) n = yrs (2.07) n = yrs [2.72, 3.08] 3.48yrs [3.23, 3.73] 1-2 non-advanced adenomas only (5-10yrs) 4.66yrs (1.00) n = yrs (1.48) n = yrs (1.50) n = yrs [1.10, 1.36] 1.62yrs [1.34, 1.90] 3+ non-advanced adenomas only (3yrs) 3.24yrs (1.03) n = yrs (1.21) n = yrs (0.53) n = yrs [0.77, 1.07] 1.13yrs [0.91, 1.35] any advanced adenoma2.05yrs (1.36) n = yrs (1.32) n = yrs (1.49) n = yrs [0.38, 0.76] 0.29yrs [-0.17, 0.75] 13

Effect of inadequate preparation Rex et al – 400 patients 200 public hospital 200 private hospital – Authors assumed… Perfect inadequacy Perfect compliance Procedure invariance Number of projected colonoscopies Year Ideal Preparation Private Hospital Public Hospital 0 – – – – – – – Total Increase12.9%24.1% Projected total costs Cost$213,841$239,068 Cost$220,260$267,566 Increase11.8%21.5% 14

Outcomes Effects of inadequate preparation quality – Missed adenomas => Δ cancer – Earlier recalls => Δ number of tests 15

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 16

Methods 17

Calculations Monte Carlo trials 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? Implementation All adequate prep scenario “Normal” prep scenario Range of compliances – Independent & greedy assumptions To-do: Sensitivity analysis – Costs 18

Functions 19

Measuring patient outcomes Quality-Adjusted Life Years (QALYs) 40 years Perfect health (utility 1.0) 40 QALYs 20

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 21

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 non-cancerous0.91 local CRC0.74 regional CRC0.50 metastatic CRC0.25 Utility of model states (Ness et al. 2000) 22

Measuring clinic costs CRC treatment Initial costs Continuing costs (Ness et al. 2000) Colonoscopies Colonoscopy Polypectomy Pathology Complications Perforation LocalRegionalMetastatic Initial$16,051 / yr$18,457 / yr$21,093 / yr Continuing$425 / yr$1,944 / yr$21,209 / yr 23

Measuring clinic costs CRC treatment Initial costs Continuing costs (Ness et al. 2000) Terminal care costs not included Colonoscopies Colonoscopy Polypectomy Pathology Complications Perforation LocalRegionalMetastatic Initial$16,051 / yr$18,457 / yr$21,093 / yr Continuing$425 / yr$1,944 / yr$21,209 / yr 24

Measuring clinic 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 25

Measuring clinic costs CRC treatment Initial costs Continuing costs Colonoscopies Colonoscopy Polypectomy Pathology Complications Perforation (0.2% incidence, 0.01% mortality) (Tafazzoli et al. 2009) 26

Measuring mortality Discount each event by the probability of prior mortality. 27

Measuring mortality Discount each event by the probability of prior mortality. Patient viability with age Patient age Probability of surviving from age 50 A i = age at first colonoscopy A f = current age 28

Preliminary Results 29

Clinic outcomes E[colonoscopies / patient / life-year] 30

E[N] of surveillance colonoscopies: Independent event assumption w/ ghosts 26.8% of surveillance colonoscopies due to inadequate prep 31

Patient outcomes E[QALY / patient] E[colon costs / patient] E[CRC / patient] 32

E[QALY / patient] 33

E[colon costs / patient] 34

E[CRC / patient] 35

Secondary Outcome Effect of prep quality intervention 36

E[N] surveillance colonoscopies 100% compliance InterventionLifetime E[N] surveillance colonoscopies % due to prep quality No intervention % 10% bumped 1 level % bumped 1 level % bumped 1 level

Big Picture Overall project Objective: – “Best” time for a patient to receive colon tests Tools needed – Longitudinal predictions Test parameters – Cost-utility – Decision analysis 38 Adequate First-time (Roudebush data)2.07% Following (model) First-time colonoscopy0.68% Second-time colonoscopy0.16% Third-time colonoscopy0.02%

Thank you 39

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Limitations Discussed in Rex et al Correlation in prep qualities Additional surveillance colonoscopies Additional Likelihood of CRC Intermediate preps, detection & recs Longitudinal adenoma prevalence Study interval bias 43