Table 2.
Distribution of PREMIS Item Responses, Condom Use, and Ring Adherence by Study Visit
| PREMIS Items | 3-Months Visit | 12-Months Visit | 3-Months Visit | 12-Months Visit | p-valuea |
|---|---|---|---|---|---|
| (see Appendix A) | (n=1261) | (n=2085) | (Participants who completed PREMIS at both visits, n=1010) | ||
| 1. Expectation of personal benefit | 0.1294 | ||||
| Median | 70 | 75 | 70 | 80 | |
| 25th, 75th percentile | 50.0, 100.0 | 50.0, 99.0 | 50.0, 100.0 | 50.0, 100.0 | |
| Min, Max | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | |
| 2. Which group are you in, n (%)b | 0.1577 | ||||
| Missing | 6 (0.5) | 9 (0.4) | 2 (0.2%) | 7 (0.7%) | |
| Vaginal ring containing dapivirine | 301 (24.0) | 596 (28.7) | 245 (24.3%) | 245 (24.5%) | |
| Vaginal ring containing placebo | 97 (7.7) | 146 (7.0) | 76 (7.5%) | 53 (5.3%) | |
| Do not know/not sure | 857 (68.3) | 1334 (64.3) | 687 (68.2%) | 705 (70.3%) | |
| 3. Study group decision, n (%)b | 0.6099 | ||||
| Missing | 5 (0.4) | 9 (0.4) | 1 (0.1%) | 7 (0.7%) | |
| A study doctor chose the group | 27 (2.1) | 84 (4.0) | 24 (2.4%) | 13 (1.3%) | |
| Randomly (by chance) | 1016 (80.9) | 1613 (77.7) | 825 (81.8%) | 834 (83.2%) | |
| Other, specify | 1 (0.1) | 3 (0.1) | 1 (0.1%) | ||
| Do not know/not sure | 212 (16.9) | 376 (18.1) | 160 (15.9%) | 155 (15.5%) | |
| 4. Rings reduce HIV risk, n (%)b | 0.0017 | ||||
| Missing | 6 (0.5) | 12 (0.6) | 1 (0.1%) | 8 (0.8%) | |
| Yes | 842 (67.1) | 1423 (68.6) | 685 (67.9%) | 717 (71.6%) | |
| No | 64 (5.1) | 84 (4.1) | 56 (5.6%) | 28 (2.8%) | |
| Maybe | 231 (18.4) | 382 (18.4) | 179 (17.7%) | 168 (16.8%) | |
| Do not know/not sure | 118 (9.4) | 184 (8.9) | 89 (8.8%) | 89 (8.9%) | |
| 4a. Aggregate benefit for dapivirine ring | |||||
| Median | 70 | 70 | 70 | 79 | 0.1885 |
| 25th, 75th percentile | 50.0, 99.0 | 50.0, 95.0 | 50.0, 99.0 | 50.0, 99.0 | |
| Min, Max | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | |
| 4b. Aggregate benefit for placebo | 0.0589 | ||||
| Median | 20 | 25 | 15 | 20 | |
| 25th, 75th percentiles | 0.0, 50.0 | 0.0, 50.0 | 0.0, 50.0 | 0.0, 50.0 | |
| Min, Max | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | |
| Expectation of maximum aggregate benefitc | <.0001 | ||||
| Median | 70 | 70 | 70 | 80 | |
| 25th, 75th percentile | 50.0, 99.0 | 50.0, 95.0 | 50.0, 99.0 | 50.0, 98.0 | |
| Min, Max | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | 0.0, 100.0 | |
| Condom use, n (%)b | --- | ||||
| Not asked or missing | 266 (21.1) | 536 (25.7) | 205 (20.3%) | 235 (23.3%) | |
| Neither | 499 (50.2) | 772 (49.8) | 413 (51.3%) | 420 (54.3%) | |
| Male or female condom or both | 496 (49.8) | 777 (50.2) | 392 (48.7%) | 354 (45.7%) | |
| Drug concentration - residual dapivirine level | --- | ||||
| Median | 21.3 | 21.3 | 21.3 | 21.3 | |
| 25th, 75th | 20.5, 22.5 | 20.4, 22.5 | 20.4, 22.6 | 20.3, 22.3 | |
| Min, Max | 0.0, 26.6 | 0.0, 26.6 | 0.0, 26.3 | 17.6, 26.1 | |
| Adherence to Ring d, n (%) | --- | ||||
| Missing | 56 (8.9) | 50 (4.8) | 46 (9.0) | 14 (2.7) | |
| No | 76 (12.0) | 138 (13.1) | 61 (11.9) | 56 (10.9) | |
| Yes | 500 (79.1) | 864 (82.1) | 406 (79.1) | 443 (86.4) | |
| Treatment arm, n (%) | --- | ||||
| Dapivirine | 632 (50.2) | 974 (50.7) | 497 (49.2%) | 497 (49.2%) | |
| Placebo | 628 (49.8) | 948 (49.3) | 513 (50.8%) | 513 (50.8%) | |
a
P-values from tests of agreement: Wilcoxon signed-rank test for continuous and ordinal categorical variables, and McNemar’s test for 2×2 tables or Bowker’s test of symmetry for square tables larger than 2×2;
b
Percent for “Not asked or missing” is based the total sample since women who did not report sexual activity over the past week were not asked about condom use; percent for other response options is calculated based on the non-missing data.
c
The higher of the participant’s responses to items 4a and 4b.
d
Adherence was defined as “Yes” = residual dapivirine of <23.5 mg and “No” = residual of ≥23.5;