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Volume
7: No. 5, September 2010
ORIGINAL RESEARCH
Cost-Effectiveness Analysis of Efforts to Reduce Risk of Type 2 Diabetes and Cardiovascular Disease in Southwestern Pennsylvania, 2005-2007
This model shows 6 possible health states: 1) no diabetes, risk-factor–negative; 2) risk-factor–positive, not enrolled in
a modified Diabetes Prevention Program (mDPP); 3) risk-factor–positive, enrolled in
an mDPP; 4) stable diabetes; 5) complicated diabetes; and 6) death. For each
model cycle, patients either remain in the same health state (indicated with
short curved arrows) or move (搕ransition�) to another health state (indicated
with straight arrows or long curved arrows). The following transitions are
permitted. From health state 1, patients may remain in health state 1 or
transition to health states 2, 3, 4, or 6. From health state 2, patients may
remain in health state 2 or transition to health states 1, 4, or 6. From health
state 3, patients may remain in health state 3 or transition to health states 1,
4, or 6. From health state 4, patients may remain in health state 4 or
transition to health states 5 or 6. From health state 5, patients may remain in
health state 5 or transition to health state 6.
Figure 1. Model analyzing cost-effectiveness of a
modified Diabetes Prevention Program, southwestern Pennsylvania, 2005-2007.
Ovals indicate health states. Subjects may remain in a health state (short
curved arrow) or may move to a different health state (straight arrow or long
curved arrow) during each model cycle.
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Figure 2 shows the 1-way sensitivity analysis for 8 model parameters. For each parameter, we summarize the parameter values (baseline value; range: minimum, maximum) and provide the corresponding cost-effectiveness ratios
(CERs).
For example, the first parameter listed is “Probability of reducing risk factors without an mDPP.” The baseline probability was 12.1%, but in sensitivity analyses, we varied this value from a low of 3.2% to a high of 25.9%. At the baseline value, the cost-effectiveness ratio was $3,420. If this probability decreases to 3.2%, then the cost-effectiveness ratio is $783 per QALY; if the probability increases to 25.9%, then the cost-effectiveness ratio is $18,580. We
summarize this information as follows:
- Probability of reducing risk factors without an mDPP: 12.1%; range, 3.2%-25.9%
($3,420; range, $783-$18,580)
Analogous summaries for the remaining 7 parameters are
- Probability of enrollment in an mDPP: 47.0%; range, 9.2%-86.7% ($3,420; range, $16,707-$1,911)
- Probability of reducing risk factors with an mDPP: 16.2%; range, 4.2%-34.4%
($3,420; range, $13,087-$0)
- Probability of screening risk-factor–positive: 31.0%; range, 7.2%-63.5%
($3,420; range, $14,046-$1,818)
- Utility for risk-factor–positive patients with an mDPP: 0.75; range, 0.73-0.77
($3,420; range, $13,178-$1,926)
- Probability of diabetes for risk-factor–positive patients without an mDPP: 10.8%; range, 2.9%-23.3%
($3,420; range, 8,505-$0)
- Probability of diabetes for risk-factor–positive patients with an mDPP: 4.8%; range, 1.3%-10.5%
($3,420; range, $7,085-$1,911)
- Utility for risk-factor–positive patients without an mDPP: 0.73; range, 0.71-0.75
($3,420; range, $2,280-$7,301)
The parameters are listed based on the variation in CERs, with the parameter
causing the most variation listed first.
| Model Parameter |
Parameter Value |
Cost-Effectiveness, $ per QALY |
| Base case |
Min value |
Max value |
Base case |
Low CER |
High CER |
| Probability of reducing risk factors without an mDPP |
12.1% |
3.2% |
25.9% |
3,420 |
783 |
18,580 |
| Probability of enrollment in an mDPP |
47.0% |
9.2% |
86.7% |
3,420 |
1,911 |
16,707 |
| Probability of reducing risk factors with an mDPP |
16.2% |
4.2% |
34.4% |
3,420 |
0 |
13,087 |
| Probability of screening risk-factor–positive |
31.0% |
7.2% |
63.5% |
3,420 |
1,818 |
14,046 |
|
Utility for risk-factor–positive patients with an mDPP |
0.75 |
0.73 |
0.77 |
3,420 |
1,926 |
13,178 |
| Probability of diabetes for risk-factor–positive
patients without an mDPP |
10.8% |
2.9% |
23.3% |
3,420 |
0 |
8,505 |
| Probability of diabetes for risk-factor–positive
patients with an mDPP |
4.8% |
1.3% |
10.5% |
3,420 |
1,911 |
7,085 |
| Utility for risk-factor–positive
patients without an mDPP |
0.73 |
0.71 |
0.75 |
3,420 |
2,280 |
7,301 |
Figure 2. One-way sensitivity analyses assessing cost-effectiveness of
a modified Diabetes Prevention Program (mDPP), southwestern Pennsylvania, 2005-2007.
Horizontal bars depict the range of cost-effectiveness ratios for the values
shown for each parameter. The vertical dotted line depicts the base case
cost-effectiveness ratio. Variation of all other parameters not shown in the
figure did not increase the cost-effectiveness ratio above $7,000 per QALY
gained. Abbreviations: QALY, quality-adjusted life-year; Min, minimum; Max, maximum; CER,
cost-effectiveness ratios; mDPP, modified Diabetes Prevention Program.
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This acceptability curve depicts the likelihood of a modified Diabetes Prevention Program lifestyle intervention being favored for a given cost-effectiveness ceiling threshold (willingness to pay).
| Willingness to Pay, $ |
Probability of Cost-Effectiveness, % |
| 0 |
12 |
| 5,000 |
50 |
| 10,000 |
67 |
| 15,000 |
75 |
| 20,000 |
79 |
| 25,000 |
82 |
| 30,000 |
84 |
| 35,000 |
85 |
| 40,000 |
86 |
| 45,000 |
87 |
| 50,000 |
87 |
| 55,000 |
87 |
| 60,000 |
88 |
| 65,000 |
88 |
| 70,000 |
88 |
| 75,000 |
88 |
| 80,000 |
89 |
| 85,000 |
89 |
| 90,000 |
89 |
| 95,000 |
89 |
| 100,000 |
89 |
Figure 3. Probabilistic (Monte Carlo) sensitivity analyses assessing cost-effectiveness of
a modified Diabetes Prevention Program (mDPP), southwestern Pennsylvania, 2005-2007. The acceptability curve depicts the likelihood of an mDPP
lifestyle intervention being favored for a given cost-effectiveness ceiling
threshold (willingness to pay).
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