Table 2. Changes in Sleep Parameters Over Time.
| Measure | Mean sleep parameter (SE)a | Change from time 1 to time 2 | Change from time 1 to time 3 | Change from time 2 to time 3 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Time 1 (baseline) | Time 2 (9 wk after time 1) | Time 3 (6 mo after time 2) | Change in scoreb | P valuec | P value vs PEd | P value vs SHUTie | Change in score | P valuec | P value vs PEd | P value vs SHUTie | Change in score | P valuec | P value vs PEd | P value vs SHUTie | |
| Insomnia Severity Index (P < .001)f | |||||||||||||||
| All participants | 18.8 (0.2) | 12.6 (0.3) | 11.1 (0.3) | −6.2 | <.001 | NA | NA | −7.6 | <.001 | NA | NA | −1.4 | <.001 | NA | NA |
| SHUTi-BWHS | 18.7 (0.4) | 11 (0.5) | 9.4 (0.6) | −7.8 | <.001 | <.001 | .48 | −9.3 | <.001 | <.001 | .44 | −1.5 | .002 | .85 | .85 |
| SHUTi | 18.3 (0.4) | 10 (0.6) | 8.4 (0.6) | −8.3 | <.001 | <.001 | NA | −10.0 | <.001 | <.001 | NA | −1.7 | .002 | .85 | NA |
| PE | 19.2 (0.3) | 16.7 (0.5) | 15.6 (0.5) | −2.5 | <.001 | NA | NA | −3.6 | <.001 | NA | NA | −1.1 | .01 | NA | NA |
| Sleep onset latency, min (P = .001) | |||||||||||||||
| All participants | 42.3 (1.6) | 27.5 (1.2) | 27.4 (1.3) | −14.8 | <.001 | NA | NA | −15.0 | <.001 | NA | NA | −0.2 | .89 | NA | NA |
| SHUTi-BWHS | 38.0 (2.7) | 21.9 (2.1) | 20.3 (2.2) | −16.1 | <.001 | .02 | .14 | −17.7 | <.001 | .01 | .54 | −1.6 | .47 | .66 | .66 |
| SHUTi | 47.5 (2.7) | 25.9 (2.3) | 27.3 (2.4) | −21.6 | <.001 | <.001 | NA | −20.2 | <.001 | .00 | NA | 1.4 | .57 | .66 | NA |
| PE | 41.6 (2.6) | 34.8 (2.0) | 34.5 (2.1) | −6.7 | .01 | NA | NA | −7.0 | .01 | NA | NA | −0.3 | .89 | NA | NA |
| Wake after sleep onset, min (P = .03) | |||||||||||||||
| All participants | 39.7 (1.8) | 26.4 (1.6) | 24.9 (1.7) | −13.3 | <.001 | NA | NA | −14.8 | <.001 | NA | NA | −1.6 | .25 | NA | NA |
| SHUTi-BWHS | 41.2 (3.2) | 25.4 (2.7) | 21.5 (2.9) | −15.8 | <.001 | .08 | .80 | −19.7 | <.001 | .01 | .64 | −3.9 | .10 | .70 | .70 |
| SHUTi | 37.4 (3.2) | 20.4 (2.9) | 19.8 (3.1) | −17.0 | <.001 | .07 | NA | −17.6 | <.001 | .04 | NA | −0.6 | .81 | .89 | NA |
| PE | 40.5 (3.1) | 33.5 (2.6) | 33.3 (2.7) | −7.1 | .02 | NA | NA | −7.2 | .01 | NA | NA | −0.2 | .94 | NA | NA |
| Total sleep time, h (P = .02) | |||||||||||||||
| All participants | 5.8 (0.1) | 6.1 (0.1) | 6.3 (0.1) | 0.3 | <.001 | NA | NA | 0.5 | <.001 | NA | NA | 0.2 | <.001 | NA | NA |
| SHUTi-BWHS | 6.0 (0.1) | 6.0 (0.1) | 6.3 (0.1) | 0.1 | .47 | .04 | .07 | 0.3 | .003 | .24 | .03 | 0.3 | .003 | .34 | .45 |
| SHUTi | 5.7 (0.1) | 6.1 (0.1) | 6.4 (0.1) | 0.4 | <.001 | .81 | NA | 0.8 | <.001 | .24 | NA | 0.4 | <.001 | .11 | NA |
| PE | 5.7 (0.1) | 6.2 (0.1) | 6.3 (0.1) | 0.4 | <.001 | NA | NA | 0.5 | <.001 | NA | NA | 0.1 | .24 | NA | NA |
| Time in bed, h (P < .001)f | |||||||||||||||
| All participants | 8.0 (0.1) | 7.5 (0.1) | 7.8 (0.1) | −0.5 | <.001 | NA | NA | −0.2 | <.001 | NA | NA | 0.3 | <.001 | NA | NA |
| SHUTi-BWHS | 8.2 (0.1) | 7.3 (0.1) | 7.5 (0.1) | −0.9 | <.001 | <.001 | .22 | −0.7 | <.001 | <.001 | .01 | 0.2 | .02 | .51 | .12 |
| SHUTi | 8.0 (0.1) | 7.3 (0.1) | 7.8 (0.1) | −0.7 | <.001 | <.001 | NA | −0.3 | .03 | .002 | NA | 0.5 | <.001 | .03 | NA |
| PE | 7.9 (0.1) | 8.0 (0.1) | 8.2 (0.1) | 0.1 | .20 | NA | NA | 0.3 | .01 | NA | NA | 0.1 | .12 | NA | NA |
| Sleep efficiency, % (P < .001) g | |||||||||||||||
| All participants | 72.2 (0.7) | 81.2 (0.6) | 81.5 (0.6) | 9.0 | <.001 | NA | NA | 9.3 | <.001 | NA | NA | 0.3 | .51 | NA | NA |
| SHUTi-BWHS | 73.1 (1.1) | 83.5 (1.0) | 84.5 (1.1) | 10.4 | <.001 | <.001 | .27 | 11.4 | <.001 | <.001 | .61 | 1.0 | .26 | .93 | .93 |
| SHUTi | 70.9 (1.1) | 83.1 (1.1) | 83.1 (1.1) | 12.2 | <.001 | <.001 | NA | 12.3 | <.001 | <.001 | NA | 0.0 | .97 | .98 | NA |
| PE | 72.7 (1.1) | 77.0 (1.0) | 77.0 (1.0) | 4.3 | <.001 | NA | NA | 4.3 | <.001 | NA | NA | 0.0 | .99 | NA | NA |
| Pittsburgh Sleep Quality Index (P < .001) | |||||||||||||||
| All participants | 12.7 (0.2) | 9.2 (0.2) | 8.7 (0.2) | −3.6 | <.001 | NA | NA | −4.0 | <.001 | NA | NA | −0.5 | .02 | NA | NA |
| SHUTi-BWHS | 12.3 (0.3) | 8.1 (0.3) | 7.5 (0.4) | −4.2 | <.001 | <.001 | .43 | −4.8 | <.001 | <.001 | .29 | −0.6 | .07 | .86 | .86 |
| SHUTi | 12.7 (0.3) | 8 .0 (0.4) | 7.5 (0.4) | −4.8 | <.001 | <.001 | NA | −5.3 | <.001 | <.001 | NA | −0.5 | .16 | .86 | NA |
| PE | 13.1 (0.3) | 11.4 (0.3) | 11.1 (0.4) | −1.7 | <.001 | NA | NA | −2.0 | <.001 | NA | NA | −0.3 | .35 | NA | NA |
Abbreviations: BWHS, Black Women’s Health Study; NA, not applicable; PE, patient education; SHUTi, Sleep Healthy Using the Internet.
Means presented are least squares means from mixed-effects linear regression model.
Estimated within-group change from mixed-effects linear regression model.
P value for within-group change.
P value for change between indicated group and PE group from mixed-effects linear regression model with Hochberg correction for multiple comparisons.
P value for change between indicated group and SHUTi group from mixed-effects linear regression model with Hochberg correction for multiple comparisons.
P value for comparing the 3 study groups on change over time, from the group × time interaction in mixed-effects linear regression model.
Calculated as total time spent asleep divided by total time spent in bed, multiplied by 100.