Table 2 Multivariate analysis of the association of patient-level and hospital characteristics with retained placenta

Race/Ethnicity

 White

831 (810–852)

7,254,729 (52.8)

60,795 (56.3)

1 [Ref.]

 Black

682 (653–712)

2,048,815 (14.9)

14,065 (13.0)

0.92 (0.88–0.97)

0.001

 Hispanic

696 (658–736)

2,831,493 (20.6)

19,845 (18.4)

0.84 (0.80–0.89)

 < 0.001

 Asian and Pacific Islander

854 (802–910)

869,524 (6.3)

7,490 (6.9)

0.89 (0.84–0.95)

 < 0.001

 Native American

1,434 (1,230–1,670)

100,025 (0.7)

1,455 (1.3)

1.56 (1.35–1.81)

 < 0.001

 Others

685 (638–736)

635,510 (4.6)

4,385 (4.1)

0.88 (0.81–0.94)

 < 0.001

Age group, y

 18–24

607 (583–633)

3,264,213 (23.8)

19,950 (18.5)

1 [Ref.]

 25–34

689 (667–711)

4,030,952 (29.3)

27,970 (25.9)

1.10 (1.05–1.15)

 < 0.001

 35–44

857 (832–884)

3,962,983 (28.8)

34,275 (31.7)

1.34 (1.28–1.40)

 < 0.001

 45 or older

1,030 (997–1,065)

2,481,949 (18.1)

25,840 (23.9)

1.59 (1.52–1.67)

 < 0.001

Type of admission

 Elective

718 (697–740)

6,838,109 (49.9)

49,455 (45.9)

1 [Ref.]

 Non-elective

841 (815–868)

6,875,572 (50.1)

58,295 (54.1)

1.18 (1.13–1.23)

 < 0.001

Median household income for patient's ZIP Code

 First QT

687 (660–714)

3,834,708 (28.2)

26,515 (24.8)

1 [Ref.]

 Second QT

767 (742–792)

3,409,347 (25)

26,340 (24.6)

1.04 (0.99–1.08)

0.084

 Third QT

819 (792–847)

3,367,073 (24.7)

27,810 (26.0)

1.05 (1.00–1.09)

0.035

 Fourth QT

870 (837–904)

3,001,298 (22.0)

26,340 (24.6)

1.05 (0.99–1.10)

0.064

Health insurance

 Private insurance

831 (808–854)

7,054,080 (51.4)

59,100 (54.8)

1 [Ref.]

 Medicare

924 (794–1,075)

99,690 (0.7)

930 (0.9)

1.12 (0.95–1.31)

0.753

 Medicaid

719 (695–743)

5,836,591 (42.5)

42,270 (39.2)

0.99 (0.96–1.03)

0.171

 Self-pay

740 (673–814)

358,785 (2.6)

2,675 (2.5)

1.05 (0.95–1.15)

0.345

 No charge

757 (440–1,299)

9,180 (0.1)

70 (0.1)

1.12 (0.65–1.93)

0.672

 Other

779 (716–847)

367,005 (2.7)

2,880 (2.7)

1.02 (0.93–1.11)

0.680

Elixhauser Comorbidity Index

 0

719 (702–737)

10,221,782 (74.4)

74,065 (68.6)

1 [Ref.]

 1

911 (879–944)

2,747,214 (20.0)

25,250 (23.4)

1.22 (1.18–1.27)

 < 0.001

 2

1,074 (1,013–1,139)

617,970 (4.5)

6,710 (6.2)

1.40 (1.32–1.49)

 < 0.001

  ≥ 3

1,296 (1,175–1,429)

153,130 (1.1)

2,010 (1.9)

1.64 (1.48–1.81)

 < 0.001

Bedsize of hospital

 Large

818 (790–846)

6,960,882 (50.7)

57,400 (53.1)

1 [Ref.]

 Small

789 (755–825)

2,580,800 (18.8)

20,525 (19.0)

0.99 (0.94–1.05)

0.760

 Medium

712 (683–743)

4,198,414 (30.6)

30,110 (27.9)

0.94 (0.89–0.99)

0.032

Location/teaching status of hospital

 Urban teaching

816 (793–840)

9,633,882 (70.1)

79,270 (73.4)

1 [Ref.]

 Rural

783 (742–825)

1,217,756 (8.9)

9,605 (8.9)

1.03 (0.96–1.10)

0.398

 Urban nonteaching

659 (631–688)

2,888,458 (21.0)

19,160 (17.7)

0.84 (0.80–0.89)

 < 0.001

Region of hospital

 South

544 (519–571)

5,482,178 (39.9)

30,000 (27.8)

1 [Ref.]

 Northeast

795 (755–837)

2,244,920 (16.3)

17,985 (16.6)

1.35 (1.25–1.45)

 < 0.001

 Midwest

966 (925–1,009)

2,779,487 (20.2)

27,110 (25.1)

1.68 (1.58–1.79)

 < 0.001

 West

1,008 (967–1,051)

3,233,510 (23.5)

32,940 (30.5)

1.79 (1.67–1.92)

 < 0.001