Table 2:
Baseline characteristics, stratified by Modified World Health Organization Classification
| Modified World Health Organization classification | |||||
|---|---|---|---|---|---|
| Overall (N=8,004,184) (Weighted N = 14,995,122) |
No heart disease (N=7,959,609) (Weighted N = 14,911,251) |
WHO I-II (N=24,947) (Weighted N = 46,541) |
WHO II/III-IV (N=19,628) (Weighted N = 37,330) |
P* | |
| Mean (Standard Deviation) or % | |||||
| Patient Demographics | |||||
| Age in years at admission | 28.8 (5.8) | 28.8 (5.8) | 30.2 (5.9) | 29.8 (6.0) | <0.001 |
| Primary expected payer† | <0.001 | ||||
| Medicare | 119,392 (0.8) | 117,712 (0.8) | 635 (1.4) | 1,045 (2.8) | |
| Medicaid | 6,300,543 (42.1) | 6,268,908 (42.1) | 15,512 (33.4) | 16,124 (43.2) | |
| Private | 7,902,339 (52.8) | 7,855,343 (52.7) | 28,396 (61.1) | 18,600 (49.9) | |
| Self-pay | 220,180 (1.5) | 219,297 (1.5) | 446 (1.0) | 437 (1.2) | |
| No charge | 7,558 (0.1) | 7,528 (0.1) | 11 (0.0) | 19 (0.1) | |
| Other | 427,594 (2.9) | 425,058 (2.9) | 1,478 (3.2) | 1,057 (2.8) | |
| Zip Code Median Household Income† | <0.001 | ||||
| Quartile 1 (Lowest) | 4,107,300 (27.6) | 4,085,289 (27.6) | 11,134 (24.1) | 10,877 (29.3) | |
| Quartile 2 | 3,894,478 (26.1) | 3,873,575 (26.1) | 11,221 (24.3) | 9,681 (26.1) | |
| Quartile 3 | 3,780,479 (25.4) | 3,758,884 (25.4) | 12,423 (26.9) | 9,172 (24.7) | |
| Quartile 4 (Highest) | 3,116,885 (20.9) | 3,098,057 (20.9) | 11,467 (24.8) | 7,361 (19.8) | |
| Hospital Characteristics | |||||
| Hospital Bed Size | <0.001 | ||||
| Small | 2,514,262 (16.8) | 2,503,663 (16.8) | 6,294 (13.5) | 4,305 (11.5) | |
| Medium | 4,295,153 (28.6) | 4,275,238 (28.7) | 11,865 (25.5) | 8,050 (21.6) | |
| Large | 8,185,708 (54.6) | 8,132,350 (54.5) | 28,382 (61.0) | 24,976 (66.9) | |
| Hospital location / teaching status | <0.001 | ||||
| Metropolitan non-teaching | 3,178,062 (21.2) | 3,165,133 (21.2) | 7,804 (16.8) | 5,125 (13.7) | |
| Metropolitan teaching | 10424392 (69.5) | 10358423 (69.5) | 35,668 (76.6) | 30,302 (81.2) | |
| Non-metropolitan hospital | 1,392,668 (9.3) | 1,387,695 (9.3) | 3,070 (6.6) | 1,904 (5.1) | |
| Comorbid Conditions | |||||
| Advanced maternal age | 2,624,113 (17.5) | 2,604,334 (17.5) | 11,210 (24.1) | 8,570 (23.0) | <0.001 |
| Asthma | 785,843 (5.2) | 774,202 (5.2) | 5,189 (11.1) | 6,453 (17.3) | <0.001 |
| Bariatric surgery | 41,532 (0.3) | 41,056 (0.3) | 245 (0.5) | 231 (0.6) | <0.001 |
| Bleeding disorder | 327,773 (2.2) | 323,751 (2.2) | 2,009 (4.3) | 2,013 (5.4) | <0.001 |
| BMI greater or equal to 40 | 501,552 (3.3) | 497,045 (3.3) | 2,088 (4.5) | 2,419 (6.5) | <0.001 |
| Chronic hypertension | 499,773 (3.3) | 491,341 (3.3) | 3,324 (7.1) | 5,109 (13.7) | <0.001 |
| Chronic renal disease | 38,633 (0.3) | 37,375 (0.3) | 270 (0.6) | 988 (2.6) | <0.001 |
| Connective tissue or autoimmune disease | 30,824 (0.2) | 29,970 (0.2) | 352 (0.8) | 502 (1.3) | <0.001 |
| Gastrointestinal disease | 847,655 (5.7) | 837,319 (5.6) | 5,587 (12.0) | 4,749 (12.7) | <0.001 |
| Gestational Diabetes Mellitus | 1,143,423 (7.6) | 1,136,040 (7.6) | 3,997 (8.6) | 3,386 (9.1) | <0.001 |
| Gestational hypertension / preeclampsia without severe features | 1,240,779 (8.3) | 1,232,357 (8.3) | 4,541 (9.8) | 3,881 (10.4) | <0.001 |
| HIV/AIDS | 13,531 (0.1) | 13,406 (0.1) | 50 (0.1) | 75 (0.2) | <0.001 |
| Mental health disorder | 1,149,200 (7.7) | 1,135,363 (7.6) | 7,801 (16.8) | 6,036 (16.2) | <0.001 |
| Multiples gestation | 269,703 (1.8) | 267,374 (1.8) | 1,187 (2.6) | 1,142 (3.1) | <0.001 |
| Neuromuscular disease | 74,543 (0.5) | 73,461 (0.5) | 547 (1.2) | 535 (1.4) | <0.001 |
| Placenta accreta spectrum | 16,928 (0.1) | 16,729 (0.1) | 102 (0.2) | 98 (0.3) | <0.001 |
| Placenta previa | 69,523 (0.5) | 68,954 (0.5) | 338 (0.7) | 232 (0.6) | <0.001 |
| Placental abruption | 161,879 (1.1) | 160,470 (1.1) | 642 (1.4) | 767 (2.1) | <0.001 |
| Preeclampsia with severe features | 496,658 (3.3) | 489,464 (3.3) | 2,437 (5.2) | 4,756 (12.7) | <0.001 |
| Preexisting anemia | 1,971,304 (13.1) | 1,955,613 (13.1) | 8,131 (17.5) | 7,560 (20.3) | <0.001 |
| Preexisting diabetes mellitus | 203,955 (1.4) | 201,432 (1.4) | 969 (2.1) | 1,555 (4.2) | <0.001 |
| Preterm birth | 1,497,610 (10.0) | 1,481,719 (9.9) | 6,586 (14.2) | 9,304 (24.9) | <0.001 |
| Prior cesarean birth | 2,630,037 (17.5) | 2,611,406 (17.5) | 9,855 (21.2) | 8,775 (23.5) | <0.001 |
| Substance use disorder | 978,538 (6.5) | 970,828 (6.5) | 3,311 (7.1) | 4,399 (11.8) | <0.001 |
| Thyrotoxicosis | 39,656 (0.3) | 38,979 (0.3) | 392 (0.8) | 284 (0.8) | <0.001 |
| Delivery type | <0.001 | ||||
| Spontaneous vaginal | 9,494,266 (63.7) | 9,451,868 (63.8) | 25,389 (54.9) | 17,009 (46.0) | |
| Operative vaginal | 608,019 (4.1) | 604,398 (4.1) | 1,778 (3.8) | 1,844 (5.0) | |
| Cesarean | 4,802,249 (32.2) | 4,765,067 (32.2) | 19,046 (41.2) | 18,136 (49.0) | |
*
P-values by weighted linear regression for continuous variables and weighted chi2 test for binary/categorical variables
†
Missing values in Payer (8,744 observations) and ZIP Code Income Quartile (54,174 observations)