Baseline characteristics of patients with interstitial lung disease
| Variable | Poor sleep quality (PSQI>5) | Good sleep quality (PSQI≤5) | p-value |
| Subjects n | 67 | 34 | |
| Age years | 68.3±10.4 | 71.6±10.3 | 0.13 |
| Males n (%) | 35 (54%) | 21 (62%) | 0.52 |
| BMI kg·m−2 | 28.1 (25.2–32.9) | 27.9 (23.8–32.5) | 0.57 |
| FEV1 % pred | 65.1±19.2 | 68.7±20.4 | 0.40 |
| FVC % pred | 63.3±18.8 | 65.9±20.5 | 0.54 |
| STOP-Bang au | 4.0±1.6 | 3.6±1.4 | 0.19 |
| ESS au | 7 (4–8) | 4 (2–7) | 0.003 |
| Neck circumference cm | 39.7±4.8 | 39.3±3.7 | 0.75 |
| mMRC au | 2.3±1.1 | 1.9±1.0 | 0.08 |
| SGRQ-Symptoms | 57.2±20.7 | 39.4±19.2 | <0.0001 |
| SGRQ-Activities | 75.8±19.4 | 66.7±19.0 | 0.03 |
| SGRQ-Impacts | 48.0±20.2 | 35.7±19.7 | 0.005 |
| SGRQ-Total au | 58.0±16.0 | 46.1±16.8 | 0.001 |
| HADS-Anxiety au | 7.1±4.6 | 4.4±3.4 | 0.004 |
| 0–7 n/N (%) | 37/65 (57%) | 28/34 (82%) | |
| 8–21 n/N (%) | 28/65 (43%) | 6/34 (18%) | |
| HADS-Depression au | 6.8±3.8 | 4.4±3.9 | 0.004 |
| 0–7 n/N (%) | 37/65 (57%) | 29/34 (85%) | |
| 8–21 n/N (%) | 28/65 (43%) | 5/34 (15%) |
Data are presented as mean±sd or median (interquartile range), unless stated otherwise. PSQI: Pittsburgh Sleep Quality Index; BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; ESS: Epworth Sleepiness Scale; mMRC: modified Medical Research Council Dyspnoea Scale; SGRQ: St George's Respiratory Questionnaire; HADS: Hospital Anxiety and Depression Scale (0–7=normal, 8–10=borderline abnormal, 11–21=abnormal); au: arbitrary units.