Baseline cohort characteristics
| Characteristic | No. (%) of patients* | Standardized difference | |
|---|---|---|---|
| With endometriosis n = 166 853 | Without endometriosis n = 333 706 | ||
| Age, yr, mean ± SD | 36.4 ± 8.0 | 36.4 ± 8.0 | 0 |
| Income quintile | |||
| Q1 (lowest) | 31904 (19.1) | 64631 (19.4) | 0.006 |
| Q2 | 33899 (20.3) | 65962 (19.8) | 0.014 |
| Q3 | 34446 (20.6) | 67767 (20.3) | 0.008 |
| Q4 | 35030 (21.0) | 68629 (20.6) | 0.011 |
| Q5 (highest) | 31153 (18.7) | 65824 (19.7) | 0.027 |
| Rural residence | 21282 (12.8) | 42559 (12.8) | 0 |
| Immigrant | 22898 (13.7) | 48478 (14.5) | 0.023 |
| Nulliparity | 108964 (65.3) | 198877 (59.6) | 0.118 |
| Comorbidities at index date | |||
| Obesity | 16124 (9.7) | 27780 (8.3) | 0.047 |
| Diabetes | 4576 (2.7) | 7803 (2.3) | 0.026 |
| Hypertension | 12937 (7.8) | 18799 (5.6) | 0.085 |
| Pelvic pain | 66102 (39.6) | 52519 (15.7) | 0.554 |
| Fibroids | 32950 (19.7) | 11388 (3.4) | 0.528 |
| Infertility | 40766 (24.4) | 28881 (8.7) | 0.435 |
| Premature menopause | 18298 (11.0) | 17171 (5.1) | 0.215 |
| Surgical history at index | |||
| Bilateral oophorectomy | 15978 (9.6) | 1549 (0.5) | 0.427 |
| Hysterectomy | 46710 (28.0) | 7660 (2.3) | 0.768 |
| Endometriosis characteristics | |||
| Index year | |||
| 1993–1999 | 64628 (38.7) | 129256 (38.7) | 0 |
| 2000–2007 | 58818 (35.3) | 117636 (35.3) | 0 |
| 2008–2015 | 43407 (26.0) | 86814 (26.0) | 0 |
| Method of diagnosis | |||
| Medical only | 25920 (15.5) | NA | NA |
| Surgical at any time | 140933 (84.5) | NA | NA |
Note: NA = not applicable, SD = standard deviation.
↵* Unless indicated otherwise.