Table 1.
Baseline characteristics of newly diagnosed patients with COPD categorised by baseline LRTI frequency and severity
| Overall | None | 1 mild | ≥2 mild | 1 moderate | ≥2 moderate | ≥1 severe | |
| Patient, n (%) | 215 234 (100) | 158 074 (73.4) | 18 081 (8.4) | 6133 (2.8) | 19 787 (9.2) | 6227 (2.9) | 6932 (3.2) |
| Median study follow-up in years (Q1–Q3) | 4.4 (1.9–7.8) | 4.5 (2.0–7.9) | 3.1 (1.5–5.7) | 2.9 (1.3–5.2) | 6.4 (3.3–9.3) | 6.5 (3.3–9.5) | 2.4 (0.9–4.8) |
| Mean age (SD) | 66.9 (11.4) | 66.6 (11.3) | 67.4 (11.5) | 67.8 (11.6) | 66.9 (11.2) | 67.2 (11.4) | 71.5 (12.0) |
| Sex | |||||||
| Male | 114 738 (53.3) | 86 166 (54.5) | 8998 (49.8) | 2921 (47.6) | 9991 (50.5) | 2915 (46.8) | 3747 (54.1) |
| Female | 100 496 (46.7) | 71 908 (45.5) | 9083 (50.2) | 3212 (52.4) | 9796 (49.5) | 3312 (53.2) | 3185 (46.0) |
| Smoking status | |||||||
| Ex-smoker | 107 787 (50.1) | 84 066 (53.2) | 9407 (52.0) | 3274 (53.4) | 10 508 (53.1) | 3324 (53.4) | 4128 (59.6) |
| Current smoker | 107 447 (49.9) | 74 008 (46.8) | 8674 (48.0) | 2859 (46.6) | 9279 (46.9) | 2903 (46.6) | 2804 (40.5) |
| GOLD grade of airflow limitation | |||||||
| 1 | 51 151 (23.8) | 38 450 (24.3) | 4370 (24.2) | 1441 (23.5) | 4627 (23.4) | 1336 (21.5) | 927 (13.4) |
| 2 | 78 736 (36.6) | 57 432 (36.3) | 6757 (37.4) | 2287 (37.3) | 7793 (39.4) | 2537 (40.7) | 1930 (27.8) |
| 3 | 24 985 (11.6) | 17 764 (11.2) | 2086 (11.5) | 724 (11.8) | 2705 (13.7) | 859 (13.8) | 847 (12.2) |
| 4 | 3814 (1.8) | 2781 (1.8) | 282 (1.6) | 99 (1.6) | 361 (1.8) | 138 (2.2) | 153 (2.2) |
| Missing | 56 548 (26.3) | 41 647 (26.4) | 4586 (25.4) | 1582 (25.8) | 4301 (21.7) | 1357 (21.8) | 3075 (44.4) |
| mMRC score | |||||||
| 1 | 34 191 (15.9) | 25 687 (16.3) | 3201 (17.7) | 1000 (16.3) | 2854 (14.4) | 779 (12.5) | 670 (9.7) |
| 2 | 59 658 (27.7) | 43 767 (27.7) | 5580 (30.9) | 1967 (32.1) | 5297 (26.8) | 1579 (25.4) | 1468 (21.2) |
| 3 | 32 330 (15.0) | 22 858 (14.5) | 3118 (17.2) | 1161 (18.9) | 2938 (14.9) | 1001 (16.1) | 1254 (18.1) |
| 4 | 13 249 (6.2) | 9050 (5.7) | 1319 (7.3) | 487 (7.9) | 1188 (6.0) | 434 (7.0) | 771 (11.1) |
| 5 | 2559 (1.2) | 1652 (1.1) | 279 (1.5) | 94 (1.5) | 235 (1.2) | 78 (1.3) | 221 (3.2) |
| Missing | 73 247 (34.0) | 55 060 (34.8) | 4584 (25.4) | 1424 (23.2) | 7275 (36.8) | 2356 (37.8) | 2548 (36.8) |
| Myocardial infarction | 15 062 (7.0) | 10 599 (6.7) | 1367 (7.6) | 467 (7.6) | 1408 (7.1) | 491 (7.9) | 730 (10.5) |
| Stroke | 17 311 (8.0) | 12 381 (7.8) | 1553 (8.6) | 588 (9.6) | 1399 (7.1) | 458 (7.4) | 932 (13.4) |
| Heart failure | 9136 (4.2) | 6045 (3.8) | 951 (5.3) | 335 (5.5) | 726 (3.7) | 303 (4.9) | 776 (11.2) |
| Lung cancer | 412 (0.2) | 285 (0.2) | 42 (0.2) | <20 | 42 (0.2) | <20 | <20 |
| Asthma | 45 751 (21.3) | 33 480 (21.2) | 3540 (19.6) | 1285 (21.0) | 4505 (22.8) | 1745 (28.0) | 1196 (17.3) |
| GORD | 31 904 (14.8) | 22 403 (14.2) | 3154 (17.4) | 1217 (19.8) | 3005 (15.2) | 1067 (17.1) | 1058 (15.3) |
| Anxiety disorder | 46 184 (21.5) | 32 399 (20.5) | 4625 (25.6) | 1678 (27.4) | 4409 (22.3) | 1571 (25.2) | 1502 (21.7) |
| Depression | 55 323 (25.7) | 39 000 (24.7) | 5358 (29.6) | 1990 (32.5) | 5320 (26.9) | 1839 (29.5) | 1816 (26.2) |
| BMI group (in kg/m2) | |||||||
| <19 | 8395 (3.9) | 5996 (3.8) | 757 (4.2) | 226 (3.7) | 735 (3.7) | 247 (4.0) | 434 (6.3) |
| 19–24 | 62 392 (29.0) | 46 015 (29.1) | 5126 (28.4) | 1662 (27.1) | 5919 (29.9) | 1725 (27.7) | 1945 (28.1) |
| 25–29 | 64 885 (30.2) | 48 313 (30.6) | 5314 (29.4) | 1802 (29.4) | 5863 (29.6) | 1877 (30.1) | 1716 (24.8) |
| ≥30 | 58 796 (27.3) | 42 687 (27.0) | 5251 (29.0) | 1897 (30.9) | 5325 (26.9) | 1781 (28.6) | 1855 (26.8) |
| Missing | 20 766 (9.7) | 15 063 (9.5) | 1633 (9.0) | 546 (8.9) | 1945 (9.8) | 597 (9.6) | 982 (14.2) |
| IMD quintiles | |||||||
| 1 (least deprived) | 34 469 (16.0) | 25 774 (16.3) | 2744 (15.2) | 896 (14.6) | 3148 (15.9) | 909 (14.6) | 998 (14.4) |
| 2 | 38 946 (18.1) | 28 881 (18.3) | 3.122 (17.3) | 1036 (16.9) | 3589 (18.1) | 1111 (17.8) | 1207 (17.4) |
| 3 | 42 090 (19.6) | 31 054 (19.7) | 3436 (19.0) | 1206 (19.7) | 3837 (19.4) | 1202 (19.3) | 1355 (19.6) |
| 4 | 45 775 (21.3) | 33 531 (21.2) | 3913 (21.6) | 1325 (21.6) | 4120 (20.8) | 1335 (21.4) | 1551 (22.4) |
| 5 (most deprived) | 53 797 (25.0) | 38 714 (24.5) | 4852 (26.8) | 1669 (27.2) | 5076 (25.7) | 1669 (26.8) | 1817 (26.2) |
| Missing | 157 (0.1) | 120 (0.1) | 14 (0.1) | <5 | 17 (0.1) | <5 | <5 |
| Blood eosinophil levels | |||||||
| <300 cells/µL | 83 244 (38.7) | 60 574 (38.3) | 7377 (40.8) | 2659 (43.4) | 7340 (37.1) | 2329 (37.4) | 2965 (42.8) |
| ≥300 cells/µL | 37 720 (17.5) | 26 885 (17.0) | 3408 (18.9) | 1272 (20.7) | 3611 (18.3) | 1206 (19.4) | 1338 (19.3) |
| Missing | 94 270 (43.8) | 70 615 (44.7) | 7296 (40.4) | 2202 (35.9) | 8826 (44.7) | 2692 (43.2) | 2629 (37.9) |
The following baseline variables were identified at or close to index date and were identified as ‘current’: age, smoking status, IMD, BMI, mMRC, GOLD, asthma, eosinophil level. The following baseline variables were recorded any time prior to index date: depression, anxiety, GORD, lung cancer, myocardial infarction, heart failure, stroke.
BMI, body mass index; COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; GORD, gastro-oesophageal reflux disease; IMD, Index of Multiple Deprivation; LRTI, lower respiratory tract infection; mMRC, modified Medical Research Council.