Table 2.
Odds ratios for venous thromboembolism in users of oral contraceptives containing drospirenone compared with those containing levonorgestrel
| Exposure | No (%) cases | No (%) controls | Crude* odds ratio (95% CI) | Adjusted† odds ratio (95% CI) |
|---|---|---|---|---|
| Overall | ||||
| Levonorgestrel | 65 (15) | 368 (85) | 1.0 | 1.0 |
| Drospirenone | 121 (28) | 313 (72) | 2.3 (1.6 to 3.2) | 2.4 (1.7 to 3.4) |
| Levonorgestrel 20 users only | ||||
| Levonorgestrel-20 | 20 (13) | 131 (87) | 1.0 | 1.0 |
| Drospirenone | 121 (28) | 313 (72) | 2.7 (1.6 to 4.7) | 3.2 (1.8 to 5.5) |
| Levonorgestrel 30 users only | ||||
| Levonorgestrel-30 | 45 (16) | 237 (84) | 1.0 | 1.0 |
| Drospirenone | 121 (28) | 313 (72) | 2.1 (1.4 to 3.1) | 2.2 (1.5 to 3.4) |
| New episodes of use only | ||||
| Levonorgestrel | 42 (14) | 253 (86) | 1.0 | 1.0 |
| Drospirenone | 102 (28) | 264 (72) | 2.5 (1.7 to 3.8) | 2.7 (1.7 to 4.1) |
| Users of unknown duration only | ||||
| Levonorgestrel | 23 (17) | 115 (83) | 1.0 | 1.0 |
| Drospirenone | 19 (28) | 49 (72) | 2.0 (0.91 to 4.3) | 2.1 (0.96 to 4.7) |
| New episodes of use with no previous episode | ||||
| Levonorgestrel | 20 (17) | 97 (83) | 1.0 | 1.0 |
| Drospirenone | 52 (33) | 106 (67) | 2.7 (1.5 to 5.1) | 2.8 (1.5 to 5.2) |
| New episodes of use with previous episode | ||||
| Levonorgestrel | 22 (12) | 156 (88) | 1.0 | 1.0 |
| Drospirenone | 50 (24) | 158 (76) | 2.3 (1.3 to 4.0) | 2.6 (1.4 to 4.6) |
*For overall analysis, crude odds ratio is a conditional odds ratio; for stratified analyses, crude odds ratios are adjusted for age and index year.
†Also adjusted for duration.