Economic evaluation of MRCBHF Heart Protection Study

1
Economic evaluation of MRC/BHF Heart Protection
Study

• Heart Protection Study Collaborative
  GroupUniversity of Oxford
• UK

2
HPS Eligibility criteria

• Increased risk of CHD death due to prior disease
• Myocardial infarction or other CHD
• Occlusive disease of non-coronary arteries or
• Diabetes mellitus or treated hypertension
• Age 40-80 years
• Total cholesterol ? 3.5 mmol/l (? 135mg/dl)
• Statin or vitamins not considered clearly
  indicated or contraindicated by patients own
  doctors

3
Cost-effectiveness analysis of allocation to 40mg
daily simvastatin

• Based on within trial period only (mean 5 years)
• Costs for UK National Health Service (2001)
• Cost-effectiveness analyses undertaken
• per major vascular event avoided
• per vascular death avoided
• overall and in subgroups at differing absolute
  risk
• first or subsequent heart attack, stroke or
  revascularisation following randomisation

4
Major vascular events (MVE) and vascular deaths
per 1000 patients
5
HPS Methods of calculating costs

• Costs included
• Study simvastatin (40mg daily at 1/day) and any
  non-study statin
• Hospitalisations for all major and other
  vascular events
• Costs excluded
• Non-statin drugs
• Hospitalisations for non-vascular events (no
  significant differences between groups)
• Primary and social care costs (no data
  available in HPS)

6
Mean costs per patient for statin use and
hospitalisation for any vascular event
7
Overall cost-effectiveness within trial (95 CI)

• Cost per MVE avoided
• 11,000 (8-16,000)
• Cost per vascular death avoided
• 66,000 (42-135,000)

8
Assessing subgroup effects reliably

• Analyses in different subgroups indicate
• Similar relative reduction in vascular events
• Similar relative reduction in costs of vascular
  events
• Similar absolute difference in statin treatment
  cost
• Hence, cost-effectiveness for subgroups estimated
  by applying overall treatment effects to placebo
  event rates and costs observed in each subgroup

9
Cox model on baseline characteristics used to
create 5 multivariate risk groups
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(No Transcript)
11
Similar relative reduction in first MVE by LDL
HDL
SIMVASTATIN
PLACEBO
Rate ratio 95 CI
Baseline
(10269)
(10267)
feature
STATIN better
PLACEBO better
LDL Cholesterol (mmol/l)
lt3.0
17.6
22.2

3.0 lt3.5
19.0
25.7

3.5
22.0
27.2
HDL Cholesterol (mmol/l)
lt0.9
22.6
29.9

0.9 lt1.1
20.0
25.1

1.1
17.0
20.9
24 SE 3
ALL PATIENTS
19.8
25.2
reduction
(2Plt0.00001)
0.4
0.6
0.8
1.0
1.2
1.4
12
Similar relative reduction in first MVE by risk
group
SIMVASTATIN
PLACEBO
Rate ratio 95 CI
Risk
(10269)
(10267)
group
STATIN better
PLACEBO better
1 (low risk)
8.3
11.8
2
13.9
18.2
3
18.4
24.9
4
24.5
29.6
5 (high risk)
33.8
41.4
24 SE 3
ANY OF ABOVE
19.8
25.2
reduction
(2Plt0.00001)
0.4
0.6
0.8
1.0
1.2
1.4
13
Similar relative reduction in costs () ofall
vascular events by prior disease and age
STATIN
PLACEBO
Baseline
feature
Prior disease
Any CHD
2158
2675
No prior CHD
?
2

0.8
CVD
1281
1641
3
PVD
1866
2563
Diabetes
1076
1445
Age
lt 65
1572
2066
?
2

0.8
2
65 - 70
1958
2369
gt 70
2115
2710
ALL PATIENTS
1819
2319
0.78 (0.73-0.84)
0.4
0.6
0.8
1.0
1.2
1.4
14
Similar relative reduction in costs () of all
vascular events by risk group
STATIN
PLACEBO
Risk
group
1 (low risk)
784
1219
2
1364
1746
?
2

4.0
3
1773
2120
4
4
2168
2610
5 (high risk)
3000
3903
ALL PATIENTS
1819
2319
0.78 (0.73-0.84)
0.4
0.6
0.8
1.0
1.2
1.4
15
Similar absolute difference in statin costs by
risk group
Statin costs ()
2
5
4
3
1
Risk group
16
Similar absolute difference in statin costs by
disease and age
Statin costs ()
Any CHD
65 lt 70
70
No CHD
lt 65
Age (years)
Prior disease
17
Vascular event cost-savings by risk group
100
Current simvastatin price
50
25
18
Vascular event cost-savings by risk group
100
Current simvastatin price
50
25
19
Vascular event cost-savings by risk group
100
Current simvastatin price
50
25
20
Cost per MVE avoided by risk group
Overall 11,000
21
Cost per vascular death avoided by risk group
Overall 66,000
22
On-going health economic analyses

• Extrapolation to effects beyond trial period
• Assessment of cost per QALY
• Adapt analyses to other countries

23
CONCLUSIONS Economic evaluation of HPS

• Simvastatin allocation reduced vascular
  hospitalisation costs by 22 regardless of
  patient characteristics
• Cost-effectiveness is chiefly determined by an
  individuals overall risk of vascular events
  (rather than by single risk factors, such as LDL)
• Statin treatment is cost-effective for a wide
  range of high-risk individuals (and will become
  increasingly so as statin prices fall)