Table 3.
Choice-Based Conjoint Utilities Importancea
| Medicare beneficiaries | Commercially insured patients | |||
|---|---|---|---|---|
| Medication attributes and levels | Average utility, utils (SD) | Average importance score (SD) | Average utility, utils (SD) | Average importance score (SD) |
| Route of administrationb | ||||
| Oral | 65.2 (63.3) | 31.1 (14.8) | 57.7 (47.0) | 23.0 (11.3) |
| Self-injection | 46.4 (54.7) | 18.3 (49.2) | ||
| Infusion | –111.6 (81.8) | –76.0 (59.5) | ||
| Frequency of administration | ||||
| Once or twice daily | –36.5 (31.1) | 12.3 (5.4) | –32.0 (36.9) | 12.1 (5.2) |
| Once weekly | 13.8 (19.7) | 7.7 (19.9) | ||
| Every other week | 14.8 (28.7) | 7.3 (24.9) | ||
| Once every 12 weeks | 7.9 (34.3) | 17.1 (34.3) | ||
| Chance of serious infections during 1 year of treatment | ||||
| 1 of 100 patients | –7.8 (18.6) | 6.6 (3.2) | 0.0 (28.9) | 7.6 (4.2) |
| 2 of 100 patients | 6.8 (22.4) | 8.3 (25.3) | ||
| 3 of 100 patients | 1.0 (22.2) | –8.3 (20.1) | ||
| Cost to Medicare/commercially insured patients | ||||
| $80/$50 copay monthly | 61.1 (45.1) | 19.5 (11.5) | 88.6 (63.4) | 30.6 (17.1) |
| $100/$150 copay monthly | 3.3 (21.9) | 25.3 (21.4) | ||
| $160/$600 copay monthly | –64.4 (51.8) | –113.9 (75.5) | ||
| Patients achieving clear or almost clear skin | ||||
| 25 of 100 patients | –20.8 (28.5) | 8.7 (6.3) | –19.7 (21.4) | 7.2 (3.5) |
| 45 of 100 patients | 0.2 (20.4) | 9.4 (17.2) | ||
| 60 of 100 patients | 20.6 (31.5) | 10.3 (20.3) | ||
| Ability to reduce daily joint pain and joint swelling | ||||
| 40 of 100 patients | –24.6 (26.6) | 8.5 (5.3) | –19.4 (25.1) | 9.8 (5.9) |
| 50 of 100 patients | 2.7 (15.7) | 11.1 (26.8) | ||
| 60 of 100 patients | 21.9 (24.4) | 8.3 (39.7) | ||
| Improvement in the ability to perform daily tasks and activities | ||||
| 20% improvement | –44.2 (29.7) | 13.3 (7.3) | –28.4 (33.7) | 9.7 (8.1) |
| 45% improvement | 44.2 (29.7) | 28.4 (33.7) | ||
Results based on hierarchical Bayesian model estimates of utilities and importance of attributes and levels. The sum of the average utilities within an attribute is set to equal zero. The relative importance of each attribute is characterized by considering how much difference each attribute could make in the total utility of a drug. That difference is the range in the attribute's utility values. Percentages are calculated from relative ranges, obtaining a set of attribute importance values that add to 100%. The higher the score, the more important the attribute was to the respondents.
Among respondents to the Medicare survey, those receiving injection or infusion preferred self-injection, followed by oral and then infusion, whereas those not receiving injection or infusion preferred oral, followed by self-injection and then infusion (P <.01). The differences were not statistically significant for respondents to the commercial insurance survey.
SD indicates standard deviation.