A TimeTradeOff Method to Assess Health States Associated with Infected Hip Arthroplasty

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A Time-Trade-Off Method to Assess Health States
Associated with Infected Hip Arthroplasty
1Christopher F Wolf, MD 2Ning Y Gu, BS
2Jason N Doctor, PhD 1Paul A Manner, MD 1Seth
S Leopold, MD 1University of Washington,
Seattle, WA 2 University of Southern
California, Los Angeles, CA
IRB Approved
2
Disclosure

• None of the parties involved in this project
  have any financial
• interests to disclose.

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INTRODUCTION

•  
• Infected total hip arthroplasty (THA) is a
  tremendous burden on a population of patients
  that is often afflicted with other medical
  comorbidities. Gold standard treatment in the
  U.S. typically involves a two-stage procedure,
  which entails a prolonged period of recumbence
  and a significant surgical risk. An alternative
  approach, more popular in Europe, is a
  single-stage, direct-exchange revision
  arthroplasty.
•  
• Little is known about how patients value the
  health states associated with treating an
  infected hip arthroplasty. This study sought to
  derive utility values for health states
  associated with the treatment of an infected THA,
  by means of a time trade-off method.

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METHODS

• Two similar surveys were constructed, one for
  adult patients naïve to the health states in
  question and without hip pathology
  (a standard approach in decision analysis) as
  well as another for orthopaedic surgeons who have
  high volume THA practices. The survey defined 10
  health states, 6 chronic and 4 temporary,
  commonly seen after THA. (Table 1) The
  administrator gave the adult patients an
  introduction to hip arthroplasty as well as to
  the a paper based format of the survey. The
  surgeon survey was given electronically or in
  paper format to THA subspecialists across the
  country.

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• Health States
• Chronic States
• 1. Successful Revision Hip Arthroplasty
• 2. Reinfection Treated with Long Term
  Antibiotics
• 3. Infected THA Treated with Resection
• 4. Infected THA Treated with Staged Revision
• 5. Long-term Medical Complication
• 6. Constant Severe Pain
• Temporary States
• 7. Interval between Staged Surgeries
• 8. Mechanical Complication Treated Non
  Operatively
• 9. Mechanical Complication Treated
  Operatively
• 10. Short-term Major Medical Complication
•  

TABLE 1
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METHODS

• The survey asked participants to make
  time-trade offs between impaired health and full
  health with shortened life, as well as between
  differing states of temporary health impairment.
  (Figure1)
• For example, in addressing chronic health
  conditions, a respondent could remain in a given
  health state for 15 years (t15) or choose some
  number of years (x) that they are willing to
  relinquish in exchange for a shortened life span
  in full health (t x).
•  
• With temporary health state, respondents were
  asked to choose between 4 months with a
  particular health impairment verses a shorter
  length of time in constant severe pain followed
  by a state of negligible impairment.

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Sample Question Imagine your friend/patient is
expected to live for 15 years with the quality of
life that described below  Constant
Severe Pain - No ability to avoid
severe pain regardless of position/activity
- 7.5 - 10 Hip Pain on a 0 -10 scale,
indefinitely Suppose a treatment could restore
this person to full health, but would shorten
their life. At most, how much time would you
advise giving up out of 15 years? I would advise
giving up at most ____ years to avoid the above
health state and return to full health. YEARS
0 1 2 3 4 5 6 7 8 9 10 11
12 13 14
FIGURE 1
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RESULTS

• Of 70 volunteer patients that were approached,
  50 fit the inclusion criteria and agreed to do
  the survey, giving a response rate of 71.4. Of
  the 20 experienced THA subspecialists approached,
  16 completed the survey as requested for a
  response rate of 80.
• Surgeon-derived utility values were
  significantly lower than patient-derived utility
  values for five of the ten health states surveyed
  and lower for 9 of the 10 health states surveyed.
  (Figure 3) The largest difference was noted
  for health state 6, constant severe pain.

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RESULTS

• This indicates that patients consistently
  tended to choose to live a longer life in a less
  desirable health state rather by contrast,
  surgeons tended to value health states that
  reduced pain and disability at the cost of years
  of life.

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FIGURE 3
Statistical Significance p lt 0.5
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DISCUSSION

• Surgeon derived utility values were lower than
  patient-derived utility values for nine of the
  ten health states considered, which define the
  convalescent experience associated with the
  treatment of the infected THA. This suggests
  that, compared to patients, surgeons tend to
  endorse interventions that overestimate how much
  quantity of life a patient is willing to
  relinquish in order to improve quality.
• This implies that surgeons may tend to advise
  patients to take a greater risk to improve
  quality of life than patients might themselves
  choose.

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CONCLUSION

• 1. Surgeons tend to favor trade-offs in health
  states that produce improved quality of life, at
  the expense of decreased length of life.
• 2. Patients tend to make decisions that favor
  length of life over quality of life.
• 3. The difference between patients and surgeons
  in this regard was consistent and statistically
  significant across a wide variety of
• THA-related health states.

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