Table 2.
Estimated marginal means, standard deviations, 95% confidence intervals, percentage changes, and effect sizes (Cohen's d) for primary and secondary outcomes by treatment condition using pooled imputations.
| Estimated marginal means |
Percentage changes from pre-treatment |
Within-group effect sizes from pre-treatment |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| Pre-treatment | Post-treatment | 16-Week follow-up | 26-Week follow up | To post-treatment | To 26-week follow-up | p-Valuea | To post-treatment | To 26-week follow-up | |
| Primary outcomes | |||||||||
| PHQ-9 | |||||||||
| No extension | 13.48 (5.47) | 6.88 (5.31) | 6.23 (4.78) | 5.94 (4.81) | 49.0 [42.6, 55.4] | 56.0 [49.9, 62.0] | 1.22 [1.02, 1.43] | 1.46 [1.25, 1.67] | |
| Extension | 13.82 (5.44) | 7.06 (5.79) | 6.38 (5.39) | 6.34 (5.48) | 48.9 [42.7, 55.1] | 54.1 [48.2, 60.0] | 0.64 | 1.20 [1.00, 1.41] | 1.37 [1.16, 1.58] |
| No booster | 13.36 (5.36) | 7.24 (5.33) | 6.31 (4.84) | 6.25 (5.05) | 45.8 [39.6, 52.0] | 53.2 [47.1, 59.4] | 1.14 [0.94, 1.35] | 1.36 [1.15, 1.57] | |
| Booster | 13.93 (5.54) | 6.71 (5.75) | 6.30 (5.33) | 6.04 (5.26) | 51.8 [45.6, 58.1] | 56.7 [51.0, 62.3] | 0.37 | 1.28 [1.07, 1.48] | 1.46 [1.25, 1.67] |
| GAD-7 | |||||||||
| No extension | 12.68 (4.83) | 6.56 (5.09) | 5.42 (4.34) | 5.10 (4.12) | 48.3 [42.0, 54.5] | 59.8 [54.0, 65.5] | 1.23 [1.03, 1.44] | 1.69 [1.47, 1.90] | |
| Extension | 12.95 (5.14) | 6.66 (5.51) | 5.82 (5.27) | 5.55 (4.78) | 48.6 [42.3, 54.9] | 57.1 [51.4, 62.8] | 0.49 | 1.18 [0.97, 1.38] | 1.49 [1.28, 1.70] |
| No booster | 12.72 (5.09) | 6.96 (5.31) | 5.61 (4.71) | 5.38 (4.45) | 45.3 [38.7, 51.8] | 57.7 [51.8, 63.5] | 1.10 [0.90, 1.31] | 1.53 [1.31, 1.75] | |
| Booster | 12.91 (4.89) | 6.27 (5.28) | 5.62 (4.94) | 5.27 (4.48) | 51.4 [45.3, 57.6] | 59.2 [53.6, 64.8] | 0.69 | 1.30 [1.10, 1.51] | 1.63 [1.41, 1.84] |
| Secondary outcomes | |||||||||
| SDS | |||||||||
| No extension | 17.96 (7.24) | 12.25 (8.44) | 8.85 (8.24) | 7.97 (8.39) | 31.8 [24.4, 39.3] | 55.6 [48.2, 63.1] | 0.73 [0.53, 0.92] | 1.27 [1.07, 1.48] | |
| Extension | 18.30 (6.63) | 10.87 (8.25) | 8.98 (8.46) | 7.71 (8.08) | 40.6 [34.2, 47.0] | 57.9 [50.8, 65.0] | 0.63 | 0.99 [0.79, 1.19] | 1.43 [1.22, 1.64] |
| No booster | 17.80 (7.17) | 12.12 (8.12) | 9.16 (8.18) | 7.08 (7.66) | 31.9 [24.8, 39.1] | 60.2 [53.1, 67.3] | 0.74 [0.54, 0.94] | 1.44 [1.23, 1.66] | |
| Booster | 18.44 (6.71) | 11.03 (8.57) | 8.68 (8.50) | 8.56 (8.69) | 40.2 [33.5, 46.9] | 53.6 [46.3, 60.8] | 0.15 | 0.96 [0.76, 1.16] | 1.27 [1.07, 1.47] |
| PDSS-SR | |||||||||
| No extension | 7.93 (6.21) | 4.26 (4.51) | 3.48 (4.35) | 2.76 (3.63) | 46.2 [36.4, 56.0] | 65.2 [58.1, 72.3] | 0.67 [0.48, 0.87] | 1.01 [0.81, 1.21] | |
| Extension | 8.76 (6.22) | 5.02 (4.86) | 3.76 (4.76) | 3.50 (4.17) | 42.7 [34.2, 51.1] | 60.0 [52.6, 67.5] | 0.24 | 0.67 [0.47, 0.86] | 0.99 [0.79, 1.19] |
| No booster | 8.42 (6.21) | 4.57 (4.75) | 3.91 (4.97) | 3.04 (3.98) | 45.8 [36.6, 54.9] | 63.9 [56.6, 71.3] | 0.70 [0.50, 0.89] | 1.03 [0.83, 1.23] | |
| Booster | 8.27 (6.25) | 4.71 (4.66) | 3.35 (4.13) | 3.22 (3.87) | 43.0 [33.8, 52.3] | 61.1 [53.4, 68.9] | 0.56 | 0.64 [0.45, 0.84] | 0.97 [0.78, 1.17] |
| SIAS-6/SPS-6 | |||||||||
| No extension | 25.68 (10.32) | 12.13 (10.41) | 14.92 (12.11) | 13.00 (11.88) | 52.8 [46.6, 58.9] | 49.4 [42.4, 56.3] | 1.31 [1.10, 1.51] | 1.14 [0.93, 1.34] | |
| Extension | 26.64 (10.11) | 13.25 (10.37) | 15.70 (12.65) | 13.80 (11.67) | 50.2 [44.5, 56.0] | 48.2 [41.6, 54.8] | 0.78 | 1.30 [1.10, 1.51] | 1.17 [0.97, 1.38] |
| No booster | 25.93 (10.19) | 12.64 (10.42) | 15.61 (12.13) | 12.88 (11.17) | 51.2 [45.2, 57.2] | 50.3 [43.7, 56.9] | 1.29 [1.08, 1.50] | 1.22 [1.01, 1.43] | |
| Booster | 26.37 (10.26) | 12.73 (10.39) | 15.01 (12.61) | 13.89 (12.32) | 51.7 [45.8, 57.6] | 47.3 [40.3, 54.3] | 0.50 | 1.32 [1.11, 1.52] | 1.10 [0.90, 1.30] |
| PCL-5 | |||||||||
| No extension | 34.70 (17.40) | 25.09 (16.75) | 17.62 (16.68) | 14.72 (14.41) | 27.7 [18.5, 36.9] | 57.6 [49.4, 65.7] | 0.56 [0.32, 0.80] | 1.25 [0.99, 1.50] | |
| Extension | 32.29 (17.65) | 24.27 (17.46) | 18.06 (17.70) | 15.05 (15.18) | 24.8 [15.1, 34.6] | 53.4 [44.8, 62.0] | 0.43 | 0.46 [0.22, 0.70] | 1.04 [0.79, 1.30] |
| No booster | 32.41 (17.69) | 23.53 (16.95) | 17.40 (16.21) | 13.97 (14.35) | 27.4 [17.9, 36.8] | 56.9 [48.3, 65.4] | 0.51 [0.27, 0.75] | 1.14 [0.88, 1.40] | |
| Booster | 34.57 (17.39) | 25.79 (17.19) | 18.26 (18.09) | 15.76 (15.16) | 25.4 [15.6, 35.2] | 54.4 [46.1, 62.7] | 0.64 | 0.51 [0.27, 0.74] | 1.15 [0.90, 1.40] |
| EQ-VAS | |||||||||
| No extension | 59.18 (19.39) | 71.63 (20.16) | 69.31 (16.98) | 69.71 (16.91) | 30.5 [22.6, 38.4] | 25.8 [18.8, 32.8] | 0.63 [0.44, 0.82] | 0.58 [0.39, 0.77] | |
| Extension | 56.80 (19.69) | 71.48 (19.44) | 69.88 (16.71) | 69.31 (18.27) | 34.0 [27.0, 40.9] | 29.0 [22.1, 35.8] | 0.52 | 0.75 [0.55, 0.94] | 0.66 [0.46, 0.85] |
| No booster | 57.92 (18.87) | 72.96 (17.55) | 69.70 (16.81) | 70.29 (17.05) | 35.7 [29.0, 42.5] | 29.4 [22.9, 35.9] | 0.82 [0.63, 1.02] | 0.69 [0.49, 0.88] | |
| Booster | 58.06 (20.22) | 70.22 (21.64) | 69.49 (16.89) | 68.77 (18.07) | 29.0 [20.8, 37.2] | 25.5 [18.3, 32.8] | 0.43 | 0.58 [0.39, 0.77] | 0.56 [0.37, 0.75] |
Note. ICBT = Internet-delivered Cognitive Behaviour Therapy; PHQ-9 = Patient Health Questionnaire-9; GAD-7 = Generalized Anxiety Disorder-7; SDS = Sheehan Disability Scale; PDSS-SR = Panic Disorder Severity Scale Self-Report; SIAS-6 = Social Interaction Anxiety Scale 6-item; SPS-6 = Social Phobia Scale 6-item; PCL-5 = PTSD Checklist for DSM-5; EQ VAS = EuroQol Visual Analogue Scale.
a
Test of whether percentage changes from pre-treatment to week 26 are the same for both groups (no extension versus extension, no booster versus booster).