Table 1.
Baseline characteristics of the total group of COPD patients (n=240) and separately of patients initiated in stable condition (n=117) and of patients initiated after an episode of ARF (n=123)
| Total group (n=240) | Stable COPD (n=117) | After ARFb (n=123) | P-value | |
|---|---|---|---|---|
| Age (years) | 62.5 (8.9) | 61.8 (9.1) | 63.2 (8.6) | 0.235 |
| Gender (M), n (%) | 104 (43) | 50 (43) | 54 (44) | 0.855 |
| Smoker, n (%) | 55 (23) | 24 (21) | 31 (25) | 0.369 |
| Pack yearsa | 39 (23–50) | 40 (27–45) | 38 (21–56) | 0.850 |
| Living alone, n (%) | 50 (23) | 19 (16) | 31 (25) | 0.087 |
| Exacerbations (n)a,c | 2 (0–3) | 1 (0–2) | 2 (1–4) | 0.001 |
| BMI (kg/m2) | 25.6 (5.9) | 26.5 (6.0) | 24.8 (5.6) | 0.033 |
| PaO2 (kPa) | 7.9 (1.4) | 8.1 (1.4) | 7.8 (1.5) | 0.269 |
| PaCO2 (kPa)a | 7.4 (6.8–8.4) | 7.2 (6.6–7.9) | 7.8 (7.1–9.0) | <0.001 |
| HCO3− (mmol/L) | 33.0 (1.5) | 31.7 (3.9) | 34.0 (4.7) | <0.001 |
| FVC (L) | 2.1 (0.7) | 2.2 (0.6) | 2.1 (0.7) | 0.188 |
| FEV1 (L)a | 0.63 (0.49–0.81) | 0.64 (0.49–0.79) | 0.62 (0.49–0.83) | 0.741 |
| FEV1/FVC (%) | 33 (9) | 31 (8) | 34 (10) | 0.051 |
| TLC (L) | 7.3 (1.5) | 7.3 (1.5) | 7.2 (1.6) | 0.918 |
| RV (L) | 4.8 (1.3) | 4.9 (1.3) | 4.7 (1.6) | 0.696 |
| RV/TLC (%)a | 69 (60–72) | 69 (62–72) | 66 (54–73) | 0.475 |
| SRI, total score | 49.9 (15.0) | 54.6 (14.3) | 47.9 (14.9) | 0.020 |
| HADS, total score | 15.3 (8.7) | 13.9 (7.1) | 16.0 (9.2) | 0.214 |
| LTOT, n (%) | 170 (72) | 80 (68) | 90 (73) | 0.352 |
| Medication, n (%) | ||||
| Inhaled corticosteroid | 210 (88) | 107 (92) | 103 (84) | 0.096 |
| Oral corticosteroid | 142 (59) | 59 (50) | 83 (68) | 0.006 |
| Beta agonist | 233 (98) | 113 (97) | 120 (98) | 0.379 |
| Anticholinergics | 227 (95) | 111 (95) | 116 (94) | 0.941 |
| Theophylline | 74 (31) | 35 (30) | 39 (32) | 0.732 |
| Diuretics | 105 (44) | 55 (47) | 50 (41) | 0.321 |
Notes: Last column shows P-value for comparison between patients initiated in stable condition and patients initiated after acute respiratory failure ceased but remaining hypercapnic. Data are presented as mean (SD) or
median (IQR);
NIV initiated after acute respiratory failure resolved and patients remained hypercapnic;
Number of exacerbations in 12 months prior to NIV initiation. The values in bold are considered statistically significant (P<0.05). HADS, a higher score indicates more symptoms of anxiety and depression.
Abbreviations: ARF, acute respiratory failure; HADS, Hospital Anxiety and Depression Scale; HCO3−, arterial bicarbonate; LTOT, long-term oxygen therapy; NIV, noninvasive ventilation; PaCO2, arterial carbon dioxide pressure; PaO2, arterial oxygen pressure; RV, residual volume; SRI, severe respiratory insufficiency questionnaire; TLC, total lung capacity.