Transcript Karl Claxton

Prioritising HTA funding:
The benefits and challenges of using value
of information in anger
K Claxton, L Ginnelly, MJ Sculpher, Z Philips.
Centre for Health Economics,
University of York, UK
CENTRE FOR HEALTH ECONOMICS
Overview
• Overview of methods
• Screening for age-related macular degeneration
– Considered by NCCHTA diagnostic and screening panel
• Manual chest physiotherapy techniques for asthma and chronic
obstructive pulmonary disease
– Considered by NCCHTA therapeutic procedures panel
• long-term antibiotic treatment for preventing recurrent urinary
tract infections (UTI) in children
– Considered by Prioritisation Strategy Group (PSG)
An overview of methods
Background
• Other methods
– Research as a means changing clinical practice
• Statistical decision theory
– Reduction in the costs of decision uncertainty
– Value consistent with objective and constraints of service provision
Methods
• Constructions of decision analytic model
• Probabilistic analysis to characterise decision uncertainty
• Value of information analysis
Identifying research priorities
• EVPI
– Maximum return to research (decision problem)
– Comparing the EVPI to the costs of research
– Comparing EVPI across technologies
• Partial EVPI
– Maximum return to research (endpoint)
– Comparing partial EVPIs
– Considering the costs of research
Screening for age-related macular degeneration (AMD)
Options
• Weekly self screening with Amsler grid
• No screen but self referral on decline in visual acuity
• No PDT treatment and no screening
Indications
•
•
•
•
1st eye neovascular AMD
20/40 and 20/80 visual acuity
Male and female (age 55-64)
Eligibility of PDT consistent with NICE guidance
Time horizon of 10 years
NHS Perspective
Model structure for AMD screening
No AMD
(starting Visual
accuity)
p(T+|no AMD)
Eye
examination
1-p(Sub|classic)
p(AMD)
p(Classic|NV AMD)
AMD
Visual Accuity
(0)
p(T+|AMD)
Eye
examination
p(NV AMD|AMD)=1
p(Sub|classic)
Angiography
1- p(Classic|NV AMD)
p(VA loss)
1-p(Sub|classic)
p(refer|VA-1)
)
AMD
Visual Accuity
(-1)
Net Benefit of
PDT| VA (0)
p(T+|AMD)
p(Classic|NV AMD)
Eye
examination
p(Sub|classic)
p(NV AMD|AMD)=1
Angiography
Net Benefit of
PDT| VA (-1)
1- p(Classic|NV AMD)
1-p(Sub|classic)
p(VA loss)
p(refer|VA-2)
p(Classic|NV AMD)
AMD
Visual Accuity
(-2)
p(T+|AMD)
Eye
examination
p(Sub|classic)
p(NV AMD|AMD)=1
Angiography
Net Benefit of
PDT| VA (-2)
1- p(Classic|NV AMD)
1-p(Sub|classic)
p(VA loss)
p(refer|VA-3)
p(Classic|NV AMD)
AMD
Visual Accuity
(-3)
p(T+|AMD)
Eye
examination
p(Sub|classic)
p(NV AMD|AMD)=1
Angiography
1- p(Classic|NV AMD)
Net Benefit of
PDT| VA (-3)
Manual chest physiotherapy techniques for asthma
Patient groups
•
•
•
Children treated in the community
Adults treated in the community
Children treated in hospital
Options
•
•
•
•
Massage therapy
Chiropractic spinal manipulation (CSM)
Physical therapy
No manual therapy
Time horizon of 30-days
NHS perspective
Manual Chest Physiotherapy Techniques for adults with
Chronic Obstructive Pulmonary Disease (COPD)
Patient groups
•
Adults with stable COPD
Options
•
•
•
•
•
Autogenic drainage
Active breathing,
Heat lamp
Chest percussion with drainage
No manual therapy
Time horizon of 30-days
NHS perspective
Structure of the asthma and COPD model
Predicted
Quality of Life
Predicted
hospital cost*
Baseline FEV
Predicted drug
cost
proportional change
from trials
Predicted
Quality of Life
Predicted
hospital cost*
Intervention
FEV
Predicted drug
cost
* physical therapy in children with severe asthma only
Intervention
cost
long-term antibiotic treatment for preventing recurrent
urinary tract infections (UTI) in children
Patient groups
•
•
•
•
Infants of 1 year and children age 3
Girls and boys
Recurrent UTI (no abnormalities)
Mild VUR (grade I and II)
Options
•
Long-term low dose antibiotics (Cochrane review)
(Trimethoprim, Nitrofurantoin, Cotrimoxazole)
•
Intermittent treatment of UTIs
Time horizon
•
3 years of long-term antibiotics and follow-up to end stage renal disease
NHS perspective
Model Structure for UTI
Frequency of
recurrent UTIs
Number of
pyelonephritic attacks
Progressive
renal scaring
End-stage renal disease
No UTI
1 UTI
Pyelonephritic
attack
2 UTIs
Pyelonephritic
attack
3 UTIs
Pyelonephritic
attack
4 UTIs
Pyelonephritic
attack
Transplant
Number of
attacks
Progressive
renal
scaring
Development
of ESRD
Age at
ESRD onset
Dialysis
The evidence
Effectiveness
• Existing reviews (variable quality)
• Meta analysis, Multiple parameter synthesis
• Probabilistic trial based model
Natural history
• Epidemiological studies
• Pooled trial baselines
• Registry studies
• Clinical judgement
Quality of life
• Published studies
• Survey
Costs
• Published studies
• Published unit costs and dosage (BNF, PSSRU, CIPFA)
Results: cost-effectiveness acceptability curve
1
Intermittent
0.9
Cotrimoxazole
Nitrofurantoin
0.8
Trimethoprim
Probability cost-effective
0.7
Frontier
0.6
0.5
0.4
0.3
0.2
0.1
0
£0
£10,000
£20,000
£30,000
£40,000
Threshold for cost-effectiveness
£50,000
£60,000
Results: population EVPI
(girls
Population
EVPI age 3 with no VUR)
£4,000,000
£3,500,000
Populaion EVPI
£3,000,000
£2,500,000
£2,000,000
£1,500,000
£1,000,000
£500,000
£0
£0
£10,000
£20,000
£30,000
£40,000
Cost-effectiveness threshold
£50,000
£60,000
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Expected Value of Perfect Information
Partial EVPI (girls age 3 with no VUR)
£2,500,000
£2,000,000
£1,500,000
£1,000,000
£500,000
£0
Results: EVPI
Topic
Patient Group
AMD Screening
20/40
20/80
£6,950,000 Quality of life with and
£18,220,000 without PDT
Asthma Physiotherapy
Children in Community
Adults in Community
Children in Hospital
Adults in Community
£14,500,000
0
£1,200,000
0
COPD Physiotherapy
UTI prophylaxis
Girls 3, no VUR
Girls 3, VUR
Girls 1, no VUR
Girls 1, VUR
Boys 3, no VUR
Boys 3, VUR
Boys 1, no VUR
Boys 1, VUR
Population EVPI
Partial EVPI
Effect of massage
Effect on LOS and FEV
-
£2,240,000 Effect of prophylaxis on UTI
£613,000 Effect < 6 months
£690,000 Effect of:
£544,000
Trimethoprim
£41,000
Cotrimoxazole
£23,000
Nitrofurantoin
£267,000
£176,000
Conclusions
Asthma
•
•
•
Children treated in the community
– Massage therapy may be cost-effective
– Further research is potentially cost-effective
– Effect of massage therapy on FEV1 (no value in effect of CSM)
Manual physiotherapy for adults treated in the community
– Manual therapy not cost effective
– Further research not cost-effective
Children treated in hospital
– Physical therapy may be cost-effective
– Further research is potentially cost-effective
– Effect of physical therapy on hospital length of stay and FEV1
COPD
– Manual chest physiotherapy for stable COPD is not cost-effective.
– Further research not cost-effective
– Inpatient manual chest physiotherapy?
Conclusions
AMD
– Screening may be cost-effective
– Further research appears to be potentially cost-effective
– Evidence about the quality of life with and without PDT
UTI Prophylaxis
– Long-term antibiotics are cost-effective for all patient groups
• Which of the antibiotics should be used is uncertain
– Primary research maybe required for selected patient groups
• girls age 3 with no VUR
– Trials should include head to head comparisons
• Cotrimoxazole and trimethoprim or all three antibiotics
– Longer follow-up would be worthwhile
• trials with 6 month follow-up are unlikely to be worthwhile
Feasibility and policy impact
• Feasibility
– Completed despite not meeting selection criteria
– Analysis conducted and presented within NCCHTA time
lines
• Policy impact
– Mixed responses from panel members
– Potential (selective) role at PSG
– Impact on commissioning decisions
Methods and implementation
• Methods
–
–
–
–
–
More complex and resource intensive than anticipated
Comprehensive searching for model parameters
Methods of evidence synthesis
Quality of evidence (bias and exchangeability)
Sensitivity analysis (evidence, model structure)
• Implementation
– Communicating complex material
– Requires an iterative process
– Identifying topics where VoI should be conducted