Characteristics of the study population
| N=21 | |||
|---|---|---|---|
| Age (years) mean (SD) (range) | 68.8 (9.8) (51 to 91) | ||
| Sex | N/21 (%) | ||
| Men | 8 (38) | ||
| Women | 13 (62) | ||
| Ethnicity | |||
| European | 14 (67) | ||
| Māori | 6 (29) | ||
| Asian | 1 (5) | ||
| Smoking history | |||
| Current smoker | 1 (5) | ||
| Ex-smoker | 18 (86) | ||
| Never smoker | 2 (10) | ||
| COPD severity (FEV1% predicted) | |||
| ≥80% (mild) | 3 (14) | ||
| 50–79% (moderate) | 14 (66) | ||
| 30–49% (severe) | 2 (10) | ||
| <30% (very severe) | 2 (10) | ||
| COPD mortality risk* | |||
| BODE score: 0-2 | 4 (19) | ||
| 3–4 | 8 (38) | ||
| 5–6 | 6 (29) | ||
| 7–10 | 3 (14) | ||
| Continuous long-term domiciliary oxygen therapy | 2 (10) | ||
| Comorbidities† | |||
| Bronchiectasis | 3 (14) | ||
| Heart failure | 6 (29) | ||
| Diabetes | 7 (33) | ||
| Anxiety on treatment | 5 (24) | ||
| Atrial fibrillation | 8 (38) | ||
| Ischaemic heart disease | 5 (24) | ||
| Clinical characteristics | Mean (SD) | Median (IQR) | Min to max |
| FEV1 (L) | 1.3 (0.5) | 1.3 (0.9 to 1.6) | 0.6 to 2.6 |
| FEV1 (% predicted) | 60.3 (21.1) | 57.1 (50 to 72.4) | 14.6 to 110.3 |
| FVC (L) | 2.85 (0.9) | 2.75 (2.2 to 3.0) | 1.8 to 4.9 |
| FVC (%predicted) | 103.5 (26.9) | 102.5 (85.3 to 126.7) | 53.4 to160.4 |
| FEV1/FVC | 0.47 (0.14) | 0.47 (0.36 to 0.56) | 0.22 to 0.68 |
| TLC (L) | 6.38 (1.99) | 5.68 (5.2 to 7.0) | 3.57 to 11.3 |
| RV (L) | 3.39 (1.52) | 3.06 (2.6 to 3.4) | 1.67 to 8.52 |
| SpO2 at rest (%) | 95.4 (2.3) | 96 (93 to 97) | 89 to 99 |
| 6MWT (m) | 300 (110) | 290 (212 to 349) | 132 to 508 |
| BMI (kg/m2) | 29.1 (7.6) | 28.0 (23.9 to 32.5) | 20.1 to 53.0 |
| Questionnaires | |||
| CCQ | 2.11 (0.83) | 1.9 (1.7 to 2.8) | 0.4 to 3.3 |
| HADS anxiety | 5.8 (2.8) | 6 (4 to 7) | 1 to 11 |
| HADS depression | 4.1 (2.3) | 3 (3 to 6) | 1 to 10 |
| HADS total | 9.9 (4.6) | 9 (7 to 12) | 2 to 21 |
*BODE score: the body mass index, airflow obstruction, dyspnoea and exercise capacity index in COPD.29
†Some participants had multiple comorbidities.
6MWT, 6-min walk test; BMI, body mass index; CCQ, clinical COPD questionnaire; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; HADS, hospital anxiety and depression score; RV, residual volume; SpO2, oxygen saturation measured by a pulse oximeter; TLC, total lung capacity.