Table 1.
Clinical characteristics of women with AS and controls: Korean HIRA claims database
| Characteristic | Before matching |
After matchinga (1:10) |
|||||
|---|---|---|---|---|---|---|---|
| With AS | Without AS | p valueb | d c | With AS | Without AS | d c | |
| No. of deliveries | 1,293 (100) | 4,238,896 (100) | 1,293 (100) | 12,926 (100) | |||
| Year of delivery | < 0.001 | 0.498 | 0.000 | ||||
| 2007–2010 | 204 (15.8) | 1,123,099 (36.4) | 204 (15.8) | 2,040 (15.8) | |||
| 2011–2013 | 456 (35.3) | 1,310,325 (31) | 456 (35.3) | 4,560 (35.3) | |||
| 2014–2017 | 633 (48.9) | 455,453 (32.8) | 633 (48.9) | 6,326 (48.9) | |||
| Maternal age, yr | 32 ± 3.4 | 31.1 ± 4.1 | < 0.001 | 0.357 | 32 ± 3.4 | 32 ± 3.4 | 0.012 |
| 20–24 | 12 (0.9) | 236,460 (5.6) | 12 (0.9) | 120 (0.9) | |||
| 25–29 | 260 (20.1) | 1,208,897 (28.5) | 260 (20.1) | 2,600 (20.1) | |||
| 30–34 | 708 (54.8) | 1,988,052 (46.9) | 708 (54.8) | 7,080 (54.8) | |||
| 35–39 | 287 (22.2) | 710,732 (16.8) | 287 (22.2) | 2,870 (22.2) | |||
| 40–44 | 25 (1.9) | 92,288 (2.2) | 25 (1.9) | 250 (1.9) | |||
| 45–49 | 1 (0.1) | 2,467 (0.1) | 1 (0.1) | 6 (0.1) | |||
| Parity | < 0.001 | 0.108 | 0.169 | ||||
| Nulliparous | 749 (57.9) | 2,227,398 (52.6) | 749 (57.9) | 6,403 (49.5) | |||
| Multiparous | 544 (42.1) | 2,011,498 (47.5) | 544 (42.1) | 6,523 (50.5) | |||
| Comorbidityd | |||||||
| Hypertension | 25 (1.93) | 53,890 (1.3) | 0.034 | 0.053 | 25 (1.93) | 173 (1.3) | 0.047 |
| Diabetes mellitus | 33 (2.6) | 96,963 (2.3) | 0.524 | 0.017 | 33 (2.6) | 347 (2.7) | 0.008 |
| Uveitis | 204 (15.8) | 5,228 (0.1) | < 0.001 | 0.605 | 204 (15.8) | 22 (0.2) | 0.602 |
| IBD | 138 (10.7) | 1,845 (0.0) | < 0.001 | 0.486 | 138 (10.7) | 2 (0.0) | 0.488 |
| Psoriasis | 19 (1.5) | 15,825 (0.4) | < 0.001 | 0.115 | 19 (1.5) | 48 (0.4) | 0.115 |
| Drug exposured | |||||||
| NSAIDs | 506 (39.1) | 304,590 (7.2) | < 0.001 | 0.818 | 506 (39.1) | 876 (6.8) | 0.834 |
| Corticosteroid | 270 (20.9) | 17,122 (0.4) | < 0.001 | 0.704 | 270 (20.9) | 50 (0.4) | 0.705 |
| DMARDs | 223 (17.3) | 1,368 (0.0) | < 0.001 | 0.644 | 223 (17.3) | 6 (0.1) | 0.643 |
| TNF inhibitors | 136 (10.5) | 393 (0.0) | < 0.001 | 0.484 | 136 (10.5) | 1 (0.0) | 0.484 |
Values are presented as number (%) or mean ± SD.
AS, ankylosing spondylitis; HIRA, Health Insurance Review and Assessment Service; IBD, inf lammatory bowel disease; NSAID, nonsteroidal anti-inflammatory drug; DMARD, disease-modifying anti-rheumatic drug; TNF, tumour necrosis factor.
a
Matched by maternal age and year of delivery.
b
p value estimated by chi-square test.
c
Standardised difference: standardised difference less than 0.1 indicated a negligible difference.
d
12 months prior to delivery.