Table 1.
Characteristics of participants with a new diagnosis of chronic obstructive pulmonary disease (COPD). Data are number (%) of participants unless stated otherwise
| Characteristic | History of using illicit opioids (n=3903) |
Comparison group (n=19 515) |
| Median (IQR) years of observation | 3.0 (1.2-5.7) | 3.6 (1.7-6.6) |
| Median (IQR) age at diagnosis (years) | 48.8 (43.4-54.4) | 49.1 (43.7-54.9) |
| Sex | ||
| Male | 2507 (64.2) | 12 535 (64.2) |
| Female | 1396 (35.8) | 6980 (35.8) |
| Body mass index | ||
| Underweight (<18.5) | 434 (11.1) | 739 (3.8) |
| Healthy (18.5-25) | 1623 (41.6) | 6473 (33.2) |
| Overweight (25-30) | 880 (22.5) | 5874 (30.1) |
| Obese (30-40) | 689 (17.7) | 4982 (25.5) |
| Severely obese (≥40) | 146 (3.7) | 1025 (5.3) |
| Missing | 131 (3.4) | 422 (2.2) |
| Median (IQR) | 24.2 (20.5-29.1) | 26.8 (23.0-31.3) |
| Tobacco smoking at diagnosis | ||
| Never | 61 (1.6) | 2276 (11.7) |
| Ex-smoker | 433 (11.1) | 4106 (21.0) |
| Current | 3359 (86.1) | 12 803 (65.6) |
| Missing | 50 (1.3) | 330 (1.7) |
| No of comorbidities | ||
| 0 | 1258 (32.2) | 8522 (43.7) |
| 1-2 | 1019 (26.1) | 5465 (28.0) |
| 3-4 | 893 (22.9) | 3371 (17.3) |
| 5-7 | 580 (14.9) | 1820 (9.3) |
| ≥8 | 153 (3.9) | 337 (1.7) |
| Median (IQR) | 2 (0-4) | 1 (0-3) |
| COPD GOLD spirometry stage: forced exhaled volume in 1 second (FEV1) (% predicted) | ||
| Mild (≥80%) | 611 (15.7) | 4476 (22.9) |
| Moderate (50-80%) | 1298 (33.3) | 7654 (39.2) |
| Severe (30-50%) | 605 (15.5) | 1966 (10.1) |
| Very severe (<30%) | 191 (4.9) | 340 (1.7) |
| Missing | 1198 (30.7) | 5079 (26.0) |
| Median (IQR) | 63.0 (46.0-78.0) | 70.0 (57.0-83.0) |
| MRC dyspnoea scale | ||
| Grade 0 (least severe) | 331 (8.5) | 4199 (21.5) |
| Grade 1 | 957 (24.5) | 5278 (27.0) |
| Grade 2 | 747 (19.1) | 2384 (12.2) |
| Grade 3 | 377 (9.7) | 783 (4.0) |
| Grade 4 (most severe) | 73 (1.9) | 114 (0.6) |
| Missing | 1418 (36.3) | 6757 (34.6) |
| Index of multiple deprivation* | ||
| 1 (least deprived) | 187 (4.8) | 2109 (10.8) |
| 2 | 304 (7.8) | 2866 (14.7) |
| 3 | 520 (13.3) | 3511 (18.0) |
| 4 | 937 (24.0) | 4687 (24.0) |
| 5 (most deprived) | 1952 (50.0) | 6325 (32.4) |
| Missing | 3 (0.1) | 17 (0.1) |
IQR=interquartile range; MRC=UK Medical Research Council.
*Participants are matched by general practitioner surgery. Different deprivation scores indicate that participants in the opioid group disproportionately live in poor neighbourhoods around the same surgeries.