Table 5.
Time Trade-Off Utilities within Subgroups Categorized According to Preference for Either Oral or Long-Acting Injectable ARTa
| Health States | Participants who preferred oral treatmentb | Participants who preferred long-acting injectable treatmentb | Between-group difference score | |||
|---|---|---|---|---|---|---|
| Mean (SD) | 95% CI | Mean (SD) | 95% CI | Mean (SD) | 95% CI | |
| Total Sample (N = 201) | n = 78 | n = 123 | ||||
| A. Single tablet | 0.921 (0.111) | 0.896–0.946 | 0.900 (0.124) | 0.878–0.922 | 0.021 (0.119) | −0.013–0.055 |
| B. Two tablets | 0.916 (0.118) | 0.889–0.943 | 0.898 (0.126) | 0.875–0.920 | 0.018 (0.123) | −0.017–0.054 |
| C. Injections every month | 0.885 (0.139) | 0.853–0.916 | 0.910 (0.099) | 0.893–0.928 | −0.026 (0.116) | −0.062–0.010 |
| D. Injections every two months | 0.894 (0.139) | 0.863–0.925 | 0.920 (0.092) | 0.904–0.936 | −0.026 (0.113) | −0.061–0.009 |
| Subgroup of participants who differentiated between health states in the TTO taskc (N = 73) | n = 33 | n = 40 | ||||
| A. Single tablet | 0.933 (0.115) | 0.892–0.974 | 0.849 (0.169) | 0.795–0.903 | 0.085 (0.147) | 0.018–0.151 |
| B. Two tablets | 0.922 (0.132) | 0.875–0.969 | 0.841 (0.170) | 0.786–0.895 | 0.081 (0.154) | 0.009–0.154 |
| C. Injections every month | 0.848 (0.168) | 0.788–0.907 | 0.880 (0.115) | 0.843–0.917 | −0.032 (0.141) | −0.101–0.037 |
| D. Injections every two months | 0.870 (0.172) | 0.809–0.931 | 0.909 (0.102) | 0.877–0.942 | −0.040 (0.138) | −0.108–0.028 |
aTTO scores are on a scale anchored with 0 representing dead and 1 representing full health
bParticipants were categorized as preferring either oral or long-acting injectable ART based on their responses in the introductory ranking task that preceded the TTO utility elicitation. Participants were categorized as preferring oral treatment if they ranked an oral ART health state (A or B) as most preferred. Participants were categorized as preferring long-acting injectable treatment if they ranked a long-acting injectable ART health state (C or D) as most preferred
cThis subgroup of 73 participants had TTO utility scores reflecting differences in preference among the four health states (i.e., at least one health state had a utility that was different from the utility of another health state). Each of the other 128 participants did not differentiate among health states in the TTO task, which means they had the same utility for all four health states (e.g., one of these participants could have had a utility of 0.90 for all four health states, while another could have had a utility of 0.85 for all four health states)
ART antiretroviral treatment; CI confidence interval; LAI long-acting injectable; SD standard deviation; TTO time trade-off