Transcript Teaching NNT Through the Use of Practice, Role Play and Story

Innovative EBP: Teaching
NNT Through the Use of
Practice, Role Play, and Story
-Darcy Vavrek ND MS
University of Western States
Portland, OR
Today’s main points:
• Lecture introduces story (7 slides)
– Clinical application motivates learning
– Color card voting lets students see that EBP fosters
intelligent discussion but not agreement
• Practice problems (1 slide, 1 handout)
– With time management strategy
• Role play (4 slides, uses practice problems)
– Open ended exercise breaks up lecture
– Group discussion at the end motivates learning
Randomized Controlled Trials
• Experimental & Control Event Rates
• Risk Difference (RD)
• Numbers needed to Treat (NNT)
Surgery vs Prolonged Conservative
Treatment for Sciatica
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Randomized Clinical Trial
Severe sciatica of 6 to 12 weeks duration
U.S. – multi-center
283 participants
– Early surgery – 125/141 had microdiskectomy
– Conservative treatment – 55/142 underwent surgery
• Outcomes:
– Roland disability questionnaire, VAS for leg pain,
patient report of perceived recovery
Control & Experimental Event
Rates
Event
Yes
No
Treatment
a
b
Control
c
d
• Experimental event rate
a/(a+b) = rate of event in treatment group
• Control event rate
c/(c+d) = rate of event in control group
Unadjusted Conservative Care & Early
Surgery Event Rates at 2 weeks
Patient Reported Recovery
Yes
No
Early Surgery
87
54
Conservative Care
45
97
• Early surgery event rate
87/(87+54) = 87/141 = 61.70%
• Conservative care event rate
45/(45+97) = 45/142 = 31.69%
Early Surgery (n=141)
• Early surgery, microdiskectomy, scheduled
within 2 weeks after assignment and cancelled
only if spontaneous recovery occurred before
surgery.
• Rehabilitation of patients at home was
supervised by physiotherapists using a
standardized exercise protocol.
• 16 recovered before surgery could be
performed.
• Median time to surgery for the 125 remaining
was 1.9 weeks.
Conservative Care (n=142)
• General practitioners informed patients about favorable
prognosis, natural course of illness, and expectation of
successful recovery.
• Treatment aimed at restoring ADLs.
• Prescription pain meds as needed.
• Patients fearful of moving were referred to
physiotherapist.
• Surgery was recommended if:
– Sciatica present 6 months after randomization
– Increasing leg pain not responsive to medication
– Progressive neurological deficits
• Median time to surgery, for 55 who had surgery, was
14.6 weeks.
Early Surgery vs Conservative Care
• Those with recommended early surgery had a higher
rate of recovery, at 2 weeks, compared to those
receiving conservative treatment.
– Early surgery – 87/141 achieved “complete” or “nearly complete”
disappearance of symptoms, at 2 weeks, as measured on a 7point Likert scale.
• Early surgery event rate: 87/141 recovered (61.7% unadj.)
– Conservative treatment – 45/142 achieved recovery at 2 weeks
• Conservative care event rate: 45/142 recovered (31.7% unadj.)
•
Peul WC, Houwelingen HC, van den Hout WB, Brand R, Eekhof JAH, Tans JTJ,
Thomeer RTWM, Koes BW. Surgery versus prolonged conservative treatment for
sciatica. N Engl J Med 2007;356:2245-56.
Risk Difference (RD)
• Used in RCTs
• Is the difference in the probability of an event between
the treatment and control groups
• Thus, the formula for calculating RD is similar to
calculating harm in previous lecture:
a
c
a+b
c+d
• For early surgery vs conservative care this is:
– 62%-32%=30% improvement
– In the outcome, patient perceived recovery
Number needed to treat (NNT)
• NNT: The number of patients who would need to be
treated in order to achieve one additional good outcome
1
(a/(a+b))-(c/(c+d))
=
1
Risk Difference
• Unadjusted calculation from lecture:
– 1/0.30 = 3.3 NNT
• Adjusted calculation reported in paper:
– 1/.36 = 2.8 NNT
• 2.8 patients need to be treated, on average
– for one more patient to get appreciable benefit from
recommendation of early surgery compared to conservative care
– when assessed by “complete” or “nearly complete” resolution of
symptoms
NNT handout practice problems
• Columns
– 2, 8, 26, and 52 weeks
• Third row
– Adjusted risk difference
• Fourth row
– 95% CI for the adjusted RD
• Calculate
– The adjusted NNT
– 95% CIs
• In-class exercise
– Participants will use these numbers in role play
Breakout groups – 4 per group
• Role play
– Physician
– Intern
– Patient
– Family member
Patient History: LBP c Sciatica
• 55yo male presents for follow-up of LBP with
radiculopathy (sciatica).
• Pain began 5 months ago after a work injury.
• Unresponsive to treatment after 3 months.
• No pain with sitting.
• Imaging confirms a midline herniated disc.
• Patient is anxious and depressed.
• Surgery consult recommends surgery.
Operating Bias of Role Players
• Physician – does not want to talk patient into surgery
• Intern – wants to talk patient into surgery
• Patient – does not want surgery
• Family member – wants patient to get surgery
Reference article: Peul WC, Houwelingen HC, van den Hout WB, Brand R, Eekhof JAH,
Tans JTJ, Thomeer RTWM, Koes BW. Surgery versus prolonged conservative treatment for
sciatica. N Engl J Med 2007;356:2245-56.
Pros/Cons
• Cons discussed:
• Pros discussed:
• Decisions made:
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–
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–
–
–
Patient does not want surgery
Surgery might not work
Surgery is scary/risky
Recurrence risk
Pain pathways may recur
Family member wants to kick out family member
Lack of mobility forever
Pros/Cons
• Pros discussed:
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–
–
–
–
–
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Cusp of market improvement
If insurance benefit
Return to work faster
Less whining – may lead to less anxiety depression
May have stronger placebo effect
Chores around house
Replacement discs
• Decisions made:
–
–
–
–
–
Conservative care for 4 more weeks, wait 1 to 3 more months
Having surgery (golf), another, surgery
No surgery
Palmer – one of the groups had the pt die
Updated MRI after some more waiting