Baseline characteristics of the biological-naïve and biological-exposed cohorts of patients with RA and matched individuals from the general population 2002–2011
| General population comparators (n=175 972) | Biological-naïve RA (n=37 982) | Biological-exposed RA (n=10 800) | |
|---|---|---|---|
| Female, % | 71.7 | 71.4 | 75.6 |
| Age at start of follow-up, mean (±SD) | 62.7±13.9 | 63.1±14.1 | 56.4±13.3 |
| Years follow-up, mean (±SD) | 7.0±3.0 | 5.9±3.2 | 4.5±2.8 |
| Country of birth | |||
| Born in Nordic country, % | 93.4 | 95.3 | 90.6 |
| Born in Europe (non-Nordic), % | 4.3 | 2.9 | 3.4 |
| Born outside of Europe, % | 2.3 | 1.8 | 6.1 |
| Comorbidities* | |||
| Cancer, % | 13.2 | 13.6 | 10.9 |
| Diabetes, % | 4.8 | 6.0 | 6.3 |
| COPD, % | 1.6 | 2.7 | 1.9 |
| Education | |||
| 9 years or less | 37.5 | 41.5 | 26.9 |
| 10–12 years | 39.3 | 38.8 | 44.3 |
| >12 years | 21.7 | 17.5 | 26.2 |
| Missing | 1.5 | 1.9 | 2.7 |
*History of each comorbidity defined as any international classification of diseases code for each diagnosis before start of follow-up.
RA, rheumatoid arthritis; COPD chronic obstructive pulmonary disease.