Table 1.
Comparison of general characteristics of patients between two groups (Mean ± SD)
| Variables | COPD group (N = 648) | COPD overlap OSA group(N = 194) | χ2/t value | P | ||||
|---|---|---|---|---|---|---|---|---|
| AHI < 5 events / h | 5 events / h ≤ AHI < 15 events / h | Total | 15 events / h ≤ AHI < 30 events / h | AHI ≥ 30 events / h | Total | |||
| Gender (male,%) | 200(69.93%) | 253(69.89%) | 453(69.91%) | 87(70.73%) | 54(76.06%) | 141(72.68%) | 0.427 | 0.513 |
| Age y (mean ± SD) | 62 ± 7 | 64 ± 9 | 63 ± 8 | 63 ± 9 | 64 ± 9 | 62 ± 7 | 1.57 | 0.117 |
| BMI (kg/m2) (mean ± SD) | 21 ± 3 | 22 ± 4 | 22 ± 4 | 23 ± 4 | 24 ± 4 | 24 ± 4 | − 6.11 | < 0.001 |
| Neck circumference (cm) (mean ± SD) | 36.5 ± 2.2 | 37.3 ± 3.1 | 37.0 ± 2.6 | 37.5 ± 35 | 38.6 ± 3.6 | 38.1 ± 3.5 | 3.97 | < 0.001 |
| Smoking index (package year) | 32.5 ± 27.8 | 37.5 ± 27.0 | 35.5 ± 27.5 | 38.5 ± 25.5 | 40.5 ± 22.6 | 39.2 ± 24.8 | − 1.68 | 0.093 |
| Smoke status(never,%) | 123(43.01%) | 133(36.74%) | 248(38.27%) | 42(34.15%) | 25(35.21%) | 67(34.54%) | 5.53 | 0.06 |
| FEV1 (L) (mean ± SD) | \ | 1.1 ± 0.8 | 1.0 ± 0.8 | 1.2 ± 1.0 | 1.4 ± 1.3 | 1.3 ± 1.1 | − 4.18 | < 0.001 |
| FEV1% of expected value (mean ± SD) | 42.0 ± 28.5 | 45.5 ± 30.0 | 44.5 ± 29.5 | 52.5 ± 32.6 | 60.0 ± 39.5 | 55.0 ± 36.5 | − 4.11 | < 0.001 |
| FEV1% of predicted value < 50% ( n) | 169(59.09%) | 190(52.49%) | 359(55.40%) | 51(41.46%) | 24(33.80%) | 75(38.66%) | 10.047 | 0.002 |
| FEV1/FVC(%) | 38.0 ± 21.0 | 40.0 ± 20.0 | 39.0 ± 21.0 | 43.0 ± 23.0 | 55.0 ± 25.0 | 49.0 ± 240 | − 5.624 | < 0.001 |
| AHI (events / h) | 2.5 ± 2.2 | 9.1 ± 5.2 | 6.2 ± 5.7 | 19.8 ± 7.3 | 37.8 ± 20.0 | 26.7 ± 14.7 | − 28.987 | < 0.001 |
| Acute exacerbation in the past year (frequency) | 2.1 ± 1.5 | 2.2 ± 2.1 | 2.1 ± 2.0 | 2.1 ± 2.0 | 2.1 ± 2.0 | 2.0 ± 2.1 | 0.60 | 0.546 |
| Hospitalization in the past year (frequency) | 0.5 ± 1.1 | 1.3 ± 2.2 | 1.3 ± 1.5 | 1.2 ± 2.1 | 1.1 ± 2.0 | 1.2 ± 2.0 | 0.75 | 0.453 |
| mMRC scores (mean ± SD) | 2.0 ± 0.4 | 1.0 ± 2.2 | 1.5 ± 1.3 | 1.8 ± 2.0 | 1.5 ± 1.3 | 1.6 ± 1.1 | − 0.97 | 0.331 |
| CAT scores (mean ± SD) | 14.7 ± 6.5 | 16.8 ± 7.3 | 15.9 ± 7.2 | 17.3 ± 8.2 | 19.2 ± 8.4 | 18.4 ± 8.4 | − 4.08 | < 0.001 |
| ESS scores (mean ± SD) | 4.1 ± 4.0 | 5.2 ± 4.1 | 5.1 ± 4.0 | 6.2 ± 5.1 | 8.1 ± 9.0 | 7.8 ± 5.9 | − 7.32 | < 0.001 |
| SBQ scores(mean ± SD) | 3.1 ± 2.0 | 4.4 ± 3.2 | 4.2 ± 3.0 | 5.5 ± 4.0 | 7.0 ± 4.0 | 6.0 ± 4.0 | − 7.50 | < 0.001 |
| HADS-A scores | 4.5 ± 3.2 | 6.5 ± 4.1 | 5.7 ± 3.8 | 7.6 ± 4.0 | 10.5 ± 7.5 | 9 .3 ± 6.1 | − 9.92 | < 0.001 |
| HADS-D scores | 4.4 ± 2.7 | 6.3 ± 4.3 | 5.5 ± 3.6 | 7.2 ± 4.5 | 11.0 ± 7.2 | 9.5 ± 6.4 | − 11.10 | < 0.001 |
| CCI scores (mean ± SD) | 2.0 ± 1.0 | 3.0 ± 2.0 | 2.7 ± 1.4 | 3.0 ± 1.5 | 4.0 ± 2.0 | 3.4 ± 1.7 | 0 | 1 |
| Hypertension (n,%) | 71(24.83%) | 119(32.87%) | 190(29.32%) | 52(42.28%) | 41(57.75%) | 93(47.94%) | 8.001 | 0.005 |
| Cor Pulmonale (n,%) | 15(5.24%) | 22(6.08%) | 37(5.71%) | 9(7.32%) | 6(8.45%) | 15(7.73%) | 0.937 | 0.333 |
| Coronary heart disease(n,%) | 22(7.69%) | 45(12.43%) | 67(10.34%) | 14(11.38%) | 6(8.45%) | 20(10.31%) | 7.305 | 0.007 |
| Diabetes (n,%) | 15(5.24%) | 61(16.85%) | 76(11.73%) | 24(19.51%) | 20(28.17%) | 44(22.68%) | 13.845 | < 0.001 |
Gender, FEV1% of predicted value < 50%, Hypertension, cor pulmonale,coronary heart disease and diabetes are presented as n; other values are the mean with SD; COPD chronic obstructive pulmonary disease; OSA obstructive sleep apnea; SD standard deviation; BMI body mass index; FEV1 forced expiratory volume in 1 s; FVC forced vital capacity; AHI apnea–hypopnea index; mMRC Modified British Medical Research Council; CAT COPD assessment test; ESS Epworth sleepiness scale; CCI Charlson comorbidity index; SBQ STOP-Bang; HADS-A Hospital Anxiety and Depression Scale for anxiety; HADS-D Hospital Anxiety and Depression Scale for depression