Transcript Estimating the cost impact of NICE policy guidance: a comparison of

Quantifying uncertainty in
long-term care costs following
introduction of new drug
therapy: the importance of
model choice
Paul McNamee, Alessandra Vanoli,
Debbie Hutchings, Ian McKeith, John
Bond
In the next 25 minutes...
• Aims, methods and results of the paper
• Conclusions and points for discussion
Aims of the paper
• To compare two approaches in modelling the net
NHS costs of drug treatment for Alzheimer’s
Disease
• Application of deterministic and probabilistic
modelling methods to estimate costs and explore
uncertainty about likely “budget impact” to the
NHS over 10 years
• Apply these methods to 3 different policies (ALL,
NG1, NG2)
Some background
• AD affects a large and growing number of older
people
• Drugs are effective at slowing disease progression
• Uncertainty over whether they are ‘cost-effective’
• NICE recommends assessment of “budget impact”
for NHS, but only partially done for AD drugs in
2001
• Recent guidance (March 05) - treatment should no
longer be prescribed for new patients
Methods -1
• Simulate cost impact for AD population
(England and Wales)
– ONS population data
– MRC ageing study for AD prevalence rates
– Systematic review of effects of treatment on
cognition
– Long term prognosis from observational studies
• OLS and GLM regression models estimate
cost effect of changes in disease progression
Methods – 2
Regression models
Ordinary least squares
(OLS)
• Identity link
• Normal (Gaussian)
distribution
Generalized Linear Model
(GLM)
• Log link
• Gamma or Negative
Binomial Distribution
N=371
dependent variable: weekly cost
Constant term allowed.
independent variables: sex, age, ADL, MMSE
Estimated incremental cost impact over
10 yrs 2002/03 prices £m
method Deterministic
based on OLS
pop.
estimates
ALL
550
NG1
NG2
drugs 851
115
drugs 233
298
drugs 449
With extra
clinic visits
NICE 2001
794
N/A
182
Drugs 42 pa
427
N/A
Estimated incremental 10 yr cost per
patient 2002/03 prices £
(% diff from OLS estimate)
method OLS det
OLS prob
GLM det GLM prob
pop.
All cohort
1792
1810
2107
(+18)
1608
(-11)
NG1
597
607
736
(+23)
334
(-45)
NG2
1550
1591
1785
(+15)
1389
(-13)
Conclusions
• Drug treatment for AD likely to lead to
additional costs to the NHS
• Choice of modelling method makes a
difference to magnitude of estimates
Discussion points
• A GLM framework for probabilistic
analysis more likely to produce outliers
• Lack of evidence on long term effects
• Estimates based on 10 year old observations
of costs of care
• Estimates assume full adoption for different
NICE policy decisions – but how realistic?
• How important is the “budget impact”
question to local and national decisionmakers?