A Study on the Relative Efficiency Of Colorectal Endoscopists

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A Study on the Relative Efficiency Of Colorectal
Endoscopists

• Barbara Lum
• Nathan Hedges
• Ruwan Kiringoda
• Sarah Hong

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Colonoscopy

• Colonoscopy is the best technique for examination
  of the large intestine, and for the biopsy and
  treatment of mucosal lesions

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Data Source for the Project

• The Cleveland Clinic in Cleveland, Ohio

Conducted by a group member at the Cleveland
Clinic, this study examined the frequency and
impact of problems that interfere with smooth
colonoscopy
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Goals of the Study

• To create an objective, quantifiable method of
  measuring the efficiency with which a doctor
  operates
• To determine whether there are mathematically
  significant differences in efficiency levels
  between doctors
• Determine what independent factors may be
  responsible for varying efficiency levels and to
  what degree each factor is responsible.

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Background

• Colonoscopy is the visual examination of the
  large intestine (colon) using a lighted, flexible
  fiber-optic or video endoscope.

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Background (cont)

• The colon begins in the right-lower abdomen and
  looks like a big question mark as it moves
  through the abdomen, ending in the rectum. It is
  5 to 6 feet long.

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Equipment

• The flexible colonoscope can be directed and
  moved around the many bends of the colon

• The scope uses a small, optically-sensitive
  computer chip at the end.

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Equipment (cont)

• Electronic signals are transmitted to the
  computer.

• An open channel in the scope allows other
  instruments to be passed through in order to
  perform biopsies, remove polyps, etc.

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Colonoscopies are not fun!
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Benefits

• Identification and/or correction of a problem in
  the colon.
• Allows for diagnosis and specific treatment.

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The Study (some numbers to keep in mind)

• Five staff surgeons were observed as they
  performed colonoscopies.
• A total of 203 colonoscopies were observed.
• The study began in June 2002 and concluded the
  following September.
• 104 men, 99 women.
• Mean age of 61 standard deviation of 12 years.

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Efficiency Errors

• The study focused on the incidence of potential
  efficiency problems that occur during the
  implementation of the procedure.

• The phrase efficiency error was used to
  define any error in setup, procedure or scope
  function that results in the avoidable loss of
  time.

• The researcher quantified how much time was
  lost by using a stopwatch.

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Four Types of Errors

• Setup - valves, caps, hoses not fastened securely
• Scope function - scope clogged
• Procedural - Switching colonoscope midway through
  the exam, errors by trainees.
• Torque - Scope hose overly twisted, needs to be
  re-set.

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Efficiency error results
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Statistical Analysis, Chi- Squared Test 1
Graph 1 Ho p .376 Ha P? .376 ChiTest(28.9
7,12.04,3.39,21.07,10.53 ,41,32,9,56,28) "The
chi-squared value is", 134.2603333, "where there
are", 5, "classes, and a probability of about ",
0., "percent that the null hypothesis is true and
we see such chi squared value." "In particular
this test is highly significant and we may reject
the null hypothesis based on it"
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Chi- Squared Test, Graph 1
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Revised Efficiency Error Results
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Statistical Analysis, Chi- Squared Test 2
Graph 2 Ho p .280 Ha P? .280 ChiTest(8.96
,2.52,15.68,7.84 ,9,1,16,9) "The
chi-squared value is", 1.095167234, "where there
are", 4, "classes, and a probability of about ",
77.82408589, "percent that the null hypothesis is
true and we see such chi squared value. "In
particular this test is not significant and we
should not reject the null hypothesis based on it"
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Chi- Squared Test, Graph 2
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Part II

• What factors could potentially affect the
  colonoscopists incidence of error?
• Possible factors
• Years of Practice at the Cleveland Clinic
• Level of Specialty Education
• Ex Residencies, fellowships, graduate degrees
• Number of American Board Certifications

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The Doctors
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Years Practicing
Regression of Percentage Errors on
? 0.05 with 3 d.f T 2.77 Critical value
2.353
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Regression of Percentage Errors on
Years of Specialty Education

• 0.05 with 3 d.f
• T -2.24
• Critical value 2.353

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Regression of Percentage Errors on
Number of Board Certifications
? 0.05 with 3 d.f T -3.90 Critical value
2.353
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Multivariate Regression of Percentage Errors on
Years Practicing, Years of Specialty Education
and Number of Board Certifications
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Regression Analysis

• All three variables appear to be negatively
  related to percentage of efficiency errors
• Relation is not strong enough to be
  statistically conclusive
• Directions of correlations appear right, but
  more doctors need to be sampled to obtain medical
  significance.

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Conclusions

• By a medically-acceptable level of significance,
  one of the doctors was found to be operating at a
  far inferior efficiency level than the other
  endoscopists.
• Efficiency errors, however, refer only to small
  errors that result in a loss of time for the
  procedure. They do not, necessarily have an
  impact on patient safety or welfare.

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Implications

• If a doctor can be established in a court of law
  as being inferior, then potential litigation
  could be brought by unknowing patients who
  experience deleterious effects as a result of
  inferior treatment.
• Patients should know of a doctors track record
  before undergoing the procedure

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Limitations of this study

• Number of trials
• Only 202.
• Perforated colons, the most serious of
  operational errors, only occur in 1/1000
  operations.
• Number of doctors
• Only 5.
• What would a study of 500 doctors yield?

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Summary

• The overall scope of the study is limited
• Does not take into account other factors
• Patient experience in terms of suffering
• Risk
• As outlined by the abstract, we have met the
  goals set forth in this presentation.

Overall, this study provides a helpful and
informative framework for future studies.