Baseline demographic and clinical characteristics in total cohort and in each smoking category
| Total cohort (n=16 479) | Cohort with known smoking status prior to study commencement (n=15 040, 91.3%) | ||||
| Descriptive statistics | Missing | Active smokers (n=5787, 38.5%) | Ex-smokers (n=8941, 59.4%) | Never-smokers (n=312, 2.1%) | |
| Male | 8847 (53.7%) | NA | 2986 (51.6%) | 5018 (56.1%) | 102 (32.7%) |
| Age years | 70.1±11.1 | NA | 65.8±10.8 | 72.8±10.1 | 74.9±13.1 |
| IMD rank decile | 6 (3–8) | 61 (0.4%) | 6 (3–8) | 6 (2–9) | 7 (2–9) |
| BMI kg·m−2 | 27.2±6.0 | 1929 (11.7%) | 26.3±6.2 | 27.8±5.8 | 26.5±5.5 |
| FEV1 % pred | 60.7±20.0 | 3186 (19.4%) | 60.4±19.1 | 60.6±20.4 | 65.0±22.5 |
| FEV1 L | 1.51±0.63 | 3256 (19.8%) | 1.57±0.65 | 1.48±0.61 | 1.35±0.59 |
| FEV1/FVC % | 59.4±14.9 | 4586 (27.8%) | 58.9±14.4 | 59.7±15.1 | 64.2±16.1 |
| Comorbidities# n | 2.6±1.8 | NA | 2.4±1.7 | 2.8±1.8 | 2.9±1.7 |
| Inhaled LABA | 6386 (38.8%) | NA | 2157 (37.3%) | 3960 (44.3%) | 109 (34.9%) |
| Inhaled LAMA | 4573 (27.8%) | NA | 1621 (28.0%) | 2795 (31.3%) | 44 (14.1%) |
| Inhaled ICS | 7315 (44.4%) | NA | 2501 (43.2%) | 4484 (50.2%) | 150 (48.1%) |
| Months from COPD diagnosis to study start | 61 (26–108) | 337 (2.0%)¶ | 56 (23–96) | 69 (34–116) | 72 (36–133) |
| Months from last recorded smoking status to study start | 4 (2–9) | 1439 (8.7%) | 3 (1–8) | 5 (2–10) | 8 (2–13) |
Data are presented as n (%), mean±sd or median (interquartile range), unless otherwise stated. IMD: index of multiple deprivation (a weighted standardised measure of socioeconomic status); BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; LABA: long-acting β₂-agonist; LAMA: long-acting antimuscarinic bronchodilator; ICS: inhaled corticosteroid; #: anxiety/depression, asthma, bronchiectasis, cerebrovascular disease, chronic kidney disease, connective tissue disease, dementia, diabetes mellitus, gastro-oesophageal reflux, heart failure, hyperlipidaemia, hypertension, ischaemic heart disease, lung cancer, obstructive sleep apnoea, osteoporosis, peripheral vascular disease, rhino-sinusitis; ¶: exact date of chronic obstructive pulmonary disease (COPD) diagnosis unavailable for 2% of cohort.