Table 3.
Sleep outcome results by treatment condition
| CBT-I | MEC | Difference | ||||
|---|---|---|---|---|---|---|
| Outcome | n | Mean (95% CI) | n | Mean (95% CI) | Mean (95% CI) | p-value* |
| Insomnia Severity Index | ||||||
| Baseline | 53 | 15.6 (14.8, 16.4) | 53 | 16.8 (15.8, 17.9) | −1.2 (−2.6, 0.1) | |
| Week 8 - baseline | 47 | −9.9 (−11.2, −8.7) | 41 | −4.7 (−6.1, −3.3) | −5.2 (−6.1, −3.3) | <0.001 |
| Week 24 - baseline | 44 | −10.7 (−11.9, −9.4) | 37 | −6.7 (−8.4, −5.0) | −4.0 (−6.0, −1.9) | <0.001 |
| Pittsburgh Sleep Quality Index | ||||||
| Baseline | 51 | 8.9 (8.2, 9.6) | 53 | 9.4 (8.6, 10.3) | 0.5 (−1.6, 0.6) | |
| Week 8 - baseline | 47 | −4.0 (−5.0, −3.1) | 41 | −1.4 (−2.1, −0.7) | −2.7 (−3.9, −1.5) | <0.001 |
| Week 24 - baseline | 44 | −4.3 (−5.1, −3.5) | 38 | −2.7 (−3.5, −1.9) | −1.6 (−2.7, −0.5) | <0.001 |
| Diary Sleep Latency (mins) | ||||||
| Baseline | 51 | 54.4 (43.8, 65.0) | 52 | 51.1 (42.0, 60.2) | 3.3 (−10.5, 17.1) | |
| Week 8 – baseline | 43 | −31.5 (−39.2, −23.8) | 33 | −12.2 (−22.8, −1.7) | −19.3 (−31.8, −6.8) | <0.001 |
| Week 24 – baseline | 39 | −25.3 (−32.8, −17.8) | 29 | −13.4 (−25.1, −1.8) | −11.9 (−24.9, 1.2) | 0.007 |
| Diary Wake Time After Sleep Onset (mins)** |
||||||
| Baseline | 51 | 71.7 (60.7, 82.7) | 52 | 83.0 (69.2, 96.8) | −11.3 (−28.8, 6.2) | |
| Week 8 – baseline | 43 | −37.4 (−48.3, −26.6) | 33 | −17.0 (−33.5, −0.5) | −20.4 (−39.1, −1.7) | <0.001 |
| Week 24 - baseline | 39 | −32.8 (−43.9, −21.7) | 29 | −26.0 (−40.3, −11.8) | −6.7 (−24.2, 10.7) | 0.02 |
| Diary Total Sleep Time (hrs) | ||||||
| Baseline** | 51 | 6.6 (6.3, 6.8) | 52 | 6.4 (6.1, 6.7) | 0.1 (−0.3, 0.5) | |
| Week 8 – baseline | 43 | 0.4 (−0.1, 0.9) | 33 | 0.2 (−0.1, 0.5) | 0.2 (−0.3, 0.8) | 0.14 |
| Week 24 - baseline | 39 | 0.7 (0.4, 0.9) | 29 | 0.5 (0.1, 0.9) | 0.1 (−0.3, 0.6) | 0.17 |
| Diary Sleep Efficiency** | ||||||
| Baseline | 51 | 75.8 (73.1, 78.6) | 52 | 74.6 (71.5, 77.7) | 1.3 (−2..8, 5.3) | |
| Week 8 – baseline | 43 | 12.1 (9.4, 14.8) | 33 | 5.1 (1.3, 8.9) | 7.0 (2.6, 11.5) | <0.001 |
| Week 24 - baseline | 39 | 10.7 (8.3, 13.0) | 29 | 7.5 (3.5, 11.6) | 3.1 (−1.5, 7.8) | 0.007 |
CBT-I = Cognitive Behavior Therapy for Insomnia; MEC = Menopause Education Condition
*
p-values from contrasts of CBTI vs. MEC in a repeated measures linear model of outcome as a function of intervention arm, week (8, 24), and baseline outcome value.
**
Daily sleep diary variables were computed as following: Time in Bed (TIB) = difference between final bed and final rise time the following morning; Sleep Latency (SL) = estimated time to fall asleep at night after turning out the light; Wake Time After Sleep Onset (WASO) = estimated total time awake each night; Total Sleep Time (TST) = TIB – (SL + WASO); Sleep Efficiency = TST / TIB