Baseline characteristics and prior healthcare service use of matched treatment and control cohorts
| Treatment cohort (n=9951) | Control cohort (n=9951) | SMD | |
| Sociodemographic characteristics | |||
| Age, mean±SD | 48.96±14.18 | 48.98±14.17 | 0 |
| Sex | |||
| Female | 5257 (52.8) | 5257 (52.8) | 0 |
| Male | 4694 (47.2) | 4694 (47.2) | 0 |
| Education quintile | |||
| Missing | 556 (5.6) | 541 (5.4) | 0.01 |
| Q1 (lowest) | 690 (6.9) | 661 (6.6) | 0.01 |
| Q2 | 1485 (14.9) | 1461 (14.7) | 0.01 |
| Q3 | 1989 (20) | 1977 (19.9) | 0 |
| Q4 | 2523 (25.4) | 2548 (25.6) | 0.01 |
| Q5 (highest) | 2708 (27.2) | 2763 (27.8) | 0.01 |
| Employment quintile | |||
| Missing | 556 (5.6) | 541 (5.4) | 0.01 |
| Q1 (lowest) | 2196 (22.1) | 2234 (22.5) | 0.01 |
| Q2 | 2013 (20.2) | 1876 (18.9) | 0.03 |
| Q3 | 1787 (18) | 1915 (19.2) | 0.03 |
| Q4 | 1745 (17.5) | 1746 (17.5) | 0 |
| Q5 (highest) | 1654 (16.6) | 1639 (16.5) | 0 |
| Rurality + neighbourhood income quintile | |||
| Missing | 19 (0.2) | 19 (0.2) | 0 |
| Rural | 2381 (23.9) | 2383 (23.9) | 0 |
| Urban Q1 (lowest) | 2196 (22.1) | 2166 (21.8) | 0.01 |
| Urban Q2 | 1579 (15.9) | 1597 (16) | 0 |
| Urban Q3 | 1431 (14.4) | 1477 (14.8) | 0.01 |
| Urban Q4 | 1336 (13.4) | 1321 (13.3) | 0 |
| Urban Q5 (highest) | 1009 (10.1) | 988 (9.9) | 0.01 |
| Migrant status | |||
| Immigrant* | 262 (2.6) | 267 (2.7) | 0 |
| Non-immigrant | 9689 (97.4) | 9684 (97.3) | 0 |
| Smoking characteristics | |||
| Frequency of smoking | |||
| Daily | 9745 (97.9) | 9133 (91.8) | 0.28 |
| Occasional | 206 (2.1) | 818 (8.2) | 0.28 |
| Cigarettes per day, mean±SD | 17.82±9.77 | 17.56±9.56 | 0.03 |
| Age first tried smoking, mean±SD | 15.82±4.81 | 15.69±4.67 | 0.03 |
| Duration smoking (years), mean±SD | 33.14±14.41 | 33.29±14.20 | 0.01 |
| Health comorbidities | |||
| Prevalent comorbidities | |||
| COPD | 2985 (30) | 2018 (20.3) | 0.23 |
| Hypertension | 2863 (28.8) | 2694 (27.1) | 0.04 |
| Diabetes | 1515 (15.2) | 1146 (11.5) | 0.11 |
| Asthma | 1882 (18.9) | 1474 (14.8) | 0.11 |
| Cancer | 448 (4.5) | 400 (4) | 0.02 |
| Myocardial infarction | 332 (3.3) | 248 (2.5) | 0.05 |
| Congestive heart failure | 235 (2.4) | 193 (1.9) | 0.03 |
| No. ADG comorbidities, mean±SD | 5.84±3.43 | 5.45±3.63 | 0.11 |
| 0–5 | 5149 (51.7) | 5177 (52) | 0.01 |
| 6–9 | 3314 (33.3) | 3355 (33.7) | 0.01 |
| 10+ | 1488 (15) | 1419 (14.3) | 0.02 |
| Rate of healthcare service use ppy† | |||
| Outpatient visits (mean±SD) | 6.61±8.62 | 6.16±7.64 | 0.06 |
| ED visits (mean±SD) | 0.89±1.40 | 0.83±1.50 | 0.04 |
| Hospitalisations (mean±SD) | 0.13±0.38 | 0.12±0.37 | 0.02 |
Number (%) are reported unless otherwise noted.
*Includes immigrants and refugees.
†During 2-year period up to index date.
ADG, Aggregated Diagnostic Groups; COPD, chronic obstructive pulmonary disease; ED, emergency department; ppy, per person year; Q, quintile; SMD, standardised mean difference.