Baseline data of matched cohorts with and without bDMARD treatment with P values of group differences
| bDMARD | Control | P value | ||
| n | 1352 | 1352 | ||
| Age | Years | 55±12 | 53±12 | <0.001 |
| Female proportion | 36% | 36% | 0.689 | |
| CCI | 2.8±1.8 | 2.6±1.8 | 0.008 | |
| Time since AS diagnosis | Years | 12±8 | 12±8 | 0.831 |
| Methotrexate | Years | 6±18 | 4±11 | <0.001 |
| Sulfasalazine | Years | 4±13 | 4±13 | 0.409 |
| NSAID | Years | 20±19 | 20±24 | 0.833 |
AS, ankylosing spondylitis; bDMARD, biological disease-modifying antirheumatic drugs; CCI, Charlson Comorbidity Index; NSAID, non-steroidal anti-inflammatory drugs.