Table 5. Differences in Baseline Symptom Severity Scores Between the Two Latent Classes for General Sleep Disturbance Scale Total Score.
| Characteristic | Lower Sleep Disturbance 224 (88.5%) | Higher Sleep Disturbance 29 (11.5%) | Statistics |
| Mean (SD) | Mean (SD) | ||
| Psychological Symptoms at Baseline | |||
| STAI-S | 30.4 (10.9) | 35.1 (9.2) | .029 |
| STAI-T | 33.5 (9.9) | 38.3 (9.0) | .014 |
| CES-D Total | 8.0 (7.9) | 14.9 (7.7) | <.001 |
| Pittsburgh Sleep Quality Index (PSQI) Scores at Baseline | |||
| Subjective sleep quality | 0.9 (0.7) | 1.4 (0.7) | <.001 |
| Sleep latency | 0.9 (0.9) | 1.4 (1.0) | .008 |
| Sleep duration | 0.9 (0.9) | 1.4 (1.0) | .003 |
| Habitual sleep efficiency | 0.7 (1.0) | 0.9 (1.0) | NS |
| Sleep disturbance | 1.3 (0.5) | 1.8 (0.6) | <.001 |
| Use of sleeping medication | 0.6 (1.1) | 0.9 (1.3) | NS |
| Daytime dysfunction | 0.7 (0.6) | 1.2 (0.7) | <.001 |
| PSQI Global score | 5.9 (3.5) | 8.9 (3.4) | <.001 |
| General Sleep Disturbance Scale Scores at Baseline | |||
| Quality | 2.3 (1.7) | 3.8 (1.9) | <.001 |
| Sleep onset latency | 1.4 (2.0) | 2.3 (2.0) | .025 |
| Quantity | 4.3 (1.3) | 5.1 (1.2) | .001 |
| Sleep medication | 0.3 (0.6) | 0.4 (0.6) | NS |
| Mid-sleep awakenings | 4.3 (2.6) | 5.7 (1.9) | .001 |
| Early awakenings | 2.1 (2.2) | 3.7 (2.2) | <.001 |
| Excessive daytime sleepiness | 1.7 (1.3) | 2.7 (1.3) | <.001 |
| Total GSDS score | 36.7 (17.7) | 55.0 (17.8) | <.001 |
| Actigraphy Parameters at Baseline | |||
| Sleep period time (minutes) | 485.5 (75.2) | 476.2 (72.1) | NS |
| Total sleep time (minutes) | 403.2 (79.6) | 372.8 (106.5) | NS |
| Sleep efficiency | 83.1 (11.9) | 77.7 (18.4) | .037 |
| Wake after sleep onset (% of TST) | 13.3 (11.1) | 18.4 (17.4) | .037 |
| Wake number | 16.9 (8.8) | 15.5 (8.9) | NS |
| Wake duration (minutes) | 3.7 (2.4) | 7.2 (12.0) | NS |
| Sleep onset latency (minutes) | 13.6 (11.9) | 23.7 (42.1) | NS |
| % Daytime sleep | 6.6 (10.8) | 10.3 (20.0) | NS |
| Fatigue and Energy Scores at Baseline | |||
| Evening fatigue | 4.1 (2.1) | 5.5 (1.3) | <.001 |
| Morning fatigue | 2.1 (1.9) | 3.8 (1.8) | <.001 |
| Evening energy | 4.5 (1.8) | 3.9 (1.8) | NS |
| Morning energy | 6.0 (2.0) | 4.8 (1.8) | .003 |
| Attentional fatigue | 7.3 (1.7) | 6.3 (2.0) | .005 |
| n (%) | n (%) | ||
| Pain (% yes) | 93 (41.5) | 28 (96.6) | <.001 |
Abbreviations: STAI-S = Spielberger State-Trait Anxiety Inventory – State subscale; STAI-T = Spielberger State-Trait Anxiety Inventory – Trait subscale; CES-D = Center for Epidemiological Studies – Depression scale; GSDS = General Sleep Disturbance Scale; TST = Total sleep time.