Table 1.
Baseline characteristics
| Baseline comparison | Endometriosis cohort (N = 6851) | Control cohort (N = 6851) | p value |
|---|---|---|---|
| Demographic characteristics | |||
| Age at index date (years), mean ± SD | 38.65 ± 6.51 | 38.65 ± 6.51 | – |
| Region, N (%) | – | ||
| Northeast | 831 (12.13%) | 831 (12.13%) | |
| Midwest | 1633 (23.84%) | 1633 (23.84%) | |
| South | 3255 (47.51%) | 3255 (47.51%) | |
| West | 1132 (16.52%) | 1132 (16.52%) | |
| Health insurance type, N (%) | < 0.01* | ||
| Preferred provider organization | 3882 (56.66%) | 3931 (57.38%) | |
| Point of service | 1603 (23.40%) | 1376 (20.08%) | |
| Othera | 1366 (19.94%) | 1544 (22.54%) | |
| Financial status | |||
| Annual salary (2018 USD), mean ± SD | 60,079.66 ± 54,779.4 | 64,080.65 ± 55,580.2 | < 0.01* |
| 25th percentile | 34,215.46 | 33,754.41 | |
| Median | 49,446.27 | 50,361.54 | |
| 75th percentile | 72,590.34 | 78,737.13 | |
| Industry type, N (%) | – | ||
| Manufacturing industry | 583 (8.51%) | 583 (8.51%) | |
| Service industry | 5236 (76.43%) | 5236 (76.43%) | |
| Healthcare industry | 768 (11.21%) | 768 (11.21%) | |
| Other industry | 264 (3.85%) | 264 (3.85%) | |
| Medication useb, N (%) | |||
| Combined oral contraceptives | 1378 (20.11%) | 1386 (20.23%) | 0.86 |
| NSAIDs | 2221 (32.42%) | 1393 (20.33%) | < 0.01* |
| Opioids | 3057 (44.62%) | 1784 (26.04%) | < 0.01* |
| Non-opioidsc | 179 (2.61%) | 113 (1.65%) | < 0.01* |
| Leuprolide | 213 (3.11%) | 17 (0.25%) | < 0.01* |
| GnRH agonists other than leuprolide | 3 (< 0.1%) | 0 (0.00%) | > 0.99 |
| DMPA | 149 (2.17%) | 91 (1.33%) | < 0.01* |
| Progestin other than DMPA | 837 (12.22%) | 355 (5.18%) | < 0.01* |
| Danazol | 4 (< 0.1%) | 0 (0.00%) | > 0.99 |
| Surgeries, N (%) | |||
| Laparoscopy | 209 (3.05%) | 56 (0.82%) | < 0.01* |
| Hysterectomy | 44 (0.64%) | 40 (0.58%) | 0.66 |
| Laparotomy | 24 (0.35%) | 5 (< 0.1%) | < 0.01* |
| Oophorectomy | 11 (0.16%) | 1 (< 0.1%) | < 0.01* |
| Salpingectomy | 3 (< 0.1%) | 2 (< 0.1%) | 0.65 |
| Other surgeries | 0 (0.00%) | 0 (0.00%) | > 0.99 |
| Conditions and symptoms, N (%) | |||
| Abdominal pain | 2247 (32.80%) | 781 (11.40%) | < 0.01* |
| Pelvic pain | 2480 (36.20%) | 325 (4.74%) | < 0.01* |
| Dysmenorrhea | 1282 (18.71%) | 109 (1.59%) | < 0.01* |
| Excessive or frequent menstruationd | 2171 (31.69%) | 300 (4.38%) | < 0.01* |
| Infertility | 615 (8.98%) | 129 (1.88%) | < 0.01* |
| Ovarian cysts | 1774 (25.89%) | 206 (3.01%) | < 0.01* |
| Vaginitis | 748 (10.92%) | 485 (7.08%) | < 0.01* |
| Charlson Comorbidity Index (CCI)e, mean ± SD | 0.16 ± 0.49 | 0.12 ± 0.40 | < 0.01* |
DMPA depo-medroxyprogesterone acetate, GnRH gonadotropin-releasing hormone, NSAIDs nonsteroidal anti-inflammatory drugs, SD standard deviation, USD United States dollars
*p < 0.05
a"Other" health insurance types included indemnity, health maintenance organization, independent practice organization, lock-in, exclusive provider organization, pharmacy network plans, unknown, and no coverage
bUse of relevant medications was identified by the General Product Identifier or Healthcare Common Procedure Coding System code associated with a medication
cAll non-opioid drugs listed are also non-narcotics
dExcessive or frequent menstruation included menometrorrhagia, menorrhagia, and metrorrhagia
eThe 17 conditions included in the CCI were identified using International Statistical Classification of Diseases and Related Health Problems, versions 9 or 10 (ICD-9 and ICD-10) diagnosis codes reported by Quan et al. [16]