Characteristics of cases and matched controls
| Characteristics | Cases (n = 50656) | Controls (n = 50656) | Crude OR (95% CI) |
|---|---|---|---|
| *Patients without a diagnosis of RA or lung disease but with use of disease specific drugs for RA or COPD were excluded (n = 1940 case–control pairs excluded). | |||
| CI, confidence interval; COPD, chronic obstructive pulmonary disease; DMARDs, disease modifying anti-rheumatic drugs; HRT, hormone replacement therapy; NA, not applicable; NSAIDs, non-steroidal anti-inflammatory drugs; OR, odds ratio; RA, rheumatoid arthritis. | |||
| Sex | |||
| Male | 21 952 (43.3%) | 21 952 (43.3%) | NA |
| Female | 28 704 (56.7%) | 28 704 (56.7%) | NA |
| Age (years) | |||
| 50–59 | 4 884 (9.6%) | 4 950 (9.8%) | NA |
| 60–69 | 12 177 (24.0%) | 12 361 (24.4%) | NA |
| 70–79 | 18 129 (35.8%) | 18 296 (36.1%) | NA |
| 80–89 | 13 036 (25.7%) | 12 742 (25.2%) | NA |
| ⩾90 | 2 430 (4.8%) | 2 307 (4.6%) | NA |
| Matching by disease indication | |||
| RA | 1 515 (3.0%) | 1 515 (3.0%) | NA |
| COPD | 16 440 (32.5%) | 16 440 (32.5%) | NA |
| Other* | 31 240 (61.7%) | 31 240 (61.7%) | NA |
| Body mass index (kg/m2) | |||
| <20 | 1 872 (3.7%) | 2 101 (4.1%) | 1.00 (reference) |
| 20–25 | 11 256 (22.2%) | 12 235 (24.2%) | 0.96 (0.90 to 1.03) |
| 25–30 | 12 207 (24.1%) | 11 831 (23.4%) | 1.13 (1.09 to 1.17) |
| ⩾30 | 5 779 (11.4%) | 4 569 (9.0%) | 1.39 (1.33 to 1.46) |
| Unknown | 19 542 (38.6%) | 19 920 (39.3%) | 1.05 (1.02 to 1.09) |
| Smoking | |||
| Yes | 9 997 (19.7%) | 8 609 (17.0%) | 1.20 (1.16 to 1.24) |
| Unknown | 13 719 (27.1%) | 14 940 (29.5%) | 0.90 (0.87 to 0.93) |
| Use of prescription drugs in the year before the index date | |||
| NSAIDs | 14 415 (28.5%) | 12 694 (25.1%) | 1.20 (1.16 to 1.23) |
| DMARDs | 265 (0.5%) | 255 (0.5%) | 1.05 (0.87 to 1.26) |
| HRT | 1 169 (2.3%) | 1 236 (2.4%) | 0.93 (0.85 to 1.02) |
| Bronchodilators | 9 870 (19.5%) | 8 737 (17.2%) | 1.28 (1.23 to 1.33) |
| Antidiabetic drugs | 2 681 (5.3%) | 1 371 (2.7%) | 2.02 (1.89 to 2.16) |
| Cardiac glycosides | 2 093 (4.1%) | 962 (1.9%) | 2.26 (2.09 to 2.44) |
| Antihypertensive drugs | 19 464 (38.4%) | 13 964 (27.6%) | 1.68 (1.63 to 1.72) |
| Nitrates | 1 735 (3.4%) | 435 (0.9%) | 4.10 (3.69 to 4.57) |
| Oral anticoagulants | 4.371 (8.6%) | 3 224(6.4%) | 1.42 (1.35 to 1.49) |
| Antiplatelet drugs | 285 (0.6%) | 139 (0.3%) | 2.07 (1.69 to 2.54) |
| Lipid lowering drugs | 374 (0.7%) | 302 (0.6%) | 1.24 (1.07 to 1.45) |
| Antiarrhythmics | 783 (1.5%) | 439 (0.9%) | 1.80 (1.60 to 2.02) |
| Number of hospital admissions in year before index date | |||
| None | 44 480 (87.8%) | 45 151 (89.1%) | 1.00 (reference) |
| 1 | 4 019 (7.9%) | 3 774 (7.5%) | 1.08 (1.04 to 1.14) |
| >1 | 2 157 (4.3%) | 1 731 (3.4%) | 1.27 (1.19 to 1.36) |
| Number of visits to a general practitioner in year before index date | |||
| None | 44 480 (87.8%) | 45 151 (89.1%) | 1.00 (reference) |
| 1 | 4 019 (7.9%) | 3 774 (7.5%) | 1.21 (1.06 to 1.40) |
| >1 | 2 157 (4.3%) | 1 731 (3.4%) | 1.77 (1.40 to 2.23) |