Introduction
Materials and methods
Study sample and elicitation mode
DCE
Attributes and attribute levels
Attributes and levels | Beta coefficients in regression analysis |
---|---|
Route of drug administration: | |
Tablet once a month (TABLETmonthly) | |
Tablet once a week (TABLETweekly) | β1
|
Injection by GP every four months (INJECTIONfourmonths) | β2
|
Injection by GP every month (INJECTIONmonthly) | β3
|
10–year risk redution of a hip fracture (%) (EFFECTIVENESS): | β4
|
5 | |
10 | |
25 | |
50 | |
Nausea (for up to two hours after intake) (NAUSEA): | β5
|
No (0) | |
Yes (1) | |
Total treatment duration (years) (TIME) | β6
|
1 | |
2 | |
5 | |
10 | |
Total cost to you (€) (COST) | β7
|
0 | |
120 | |
240 | |
720 |
Study design and questionnaire
Analyses
-
V represents the utility derived for preventive osteoporosis drug treatment.
-
β0 is a constant reflecting the respondents’ preference for receiving osteoporosis drug treatment relative to no osteoporosis drug treatment.
-
β1 to β7 are coefficients that indicate the relative importance of each attribute (Table 1). β1 to β3 are dummy variables of the attribute ‘route of drug administration’, with tablet once a month as the base level.
Results
Respondents
All patients (%) | Low fracture risk patients (%) | High fracture risk patients (%) |
P valuea
| ||||
---|---|---|---|---|---|---|---|
Group | 120 | (100) | 60 | (50.0) | 60 | (50.0) | |
Age (years) | <0.001* | ||||||
60–64 | 28 | (23.3) | 21 | (35.0) | 7 | (11.7) | |
64–69 | 18 | (15.0) | 11 | (18.3) | 7 | (11.7) | |
70–74 | 20 | (16.7) | 17 | (28.3) | 3 | (5.0) | |
75–79 | 28 | (23.3) | 10 | (16.7) | 28 | (30.0) | |
80 and older | 26 | (21.1) | 1 | (1.7) | 25 | (41.7) | |
Household | <0.001* | ||||||
Single | 53 | (44.2) | 17 | (28.3) | 36 | (60.0) | |
With partner | 67 | (55.8) | 43 | (71.7) | 24 | (40.0) | |
Educational level | 0.215 | ||||||
Low | 63 | (52.5) | 31 | (51.7) | 32 | (53.3) | |
Intermediate | 46 | (38.3) | 26 | (43.3) | 20 | (33.3) | |
High | 11 | (9.2) | 3 | (5.0) | 8 | (13.3) |
DCE results
Attribute | Beta coefficient |
P value | 95% CI | |
---|---|---|---|---|
Constant (drug treatment) | 1.23 | <0.001* | 0.81 | 1.66 |
Drug administration (basel level tablet once a month): | ||||
Table once a week | −0.31 | <0.001* | −0.45 | −0.17 |
Injection every four months | −0.21 | 0.027* | −0.41 | −0.02 |
Injection once a month | −0.44 | <0.001* | −0.64 | −0.25 |
Effectiveness (10% risk reduction) | 0.28 | <0.001* | 0.23 | 0.34 |
Side effect nausea | −1.10 | <0.001* | −1.30 | −0.89 |
Treatment duration (1 year) | −0.04 | <0.001* | −0.06 | −0.02 |
Cost (100) | −0.15 | <0.001* | −0.18 | −0.11 |
Trade-offs
Attribute | Willingness to adhere to the drug treatment longer (years) | WTP for total treatment (€) | Interpretation note |
---|---|---|---|
Constant (no drug treatment) | 32.7 | 847 | For drug treatment vs. no drug treatment |
Drug administration (base level tablet once a month): | |||
Tablet once a week | 8.2 | 212 | For change from tablet once a week to tablet once a month |
Injection every 4 months | 5.7 | 147 | For change from injection every 4 months to tablet once a month |
Injection once a month | 11.7 | 304 | For change from injection once a month to tablet once a month |
Effectiveness | 7.5 | 195 | For 10% reduction in 10–year risk of a hip fracture |
Side effect nausea | 29.0 | 752 | For change from side effect to no side effect |
Treatment duration | 26 | For 1–year decrease in total drug treatment duration | |
Cost | 3.9 | For 100 euro decrease in drug treatment cost |
High versus low Fracture risk patients
Attribute | Beta coefficient of low risk patients | Beta coefficient of high risk patients |
P value |
---|---|---|---|
Constant (drug treatment) | 1.178 | 1.316 | 0.748 |
Drug administration (basel level tablet once a month): | |||
Table once a week | −0.360 | −0.255 | 0.464 |
Injection every 4 months | −0.125 | −0.317 | 0.323 |
Injection once a month | −0.445 | −0.454 | 0.966 |
Effectiveness (1% risk reduction) | 0.023 | 0.034 | 0.050* |
Side effect nausea | −1.046 | −1.161 | 0.582 |
Treatment duration (1 year) | −0.033 | −0.045 | 0.583 |
Cost (100) | −0.002 | −0.001 | 0.435 |