Table 1 Patient and hospital characteristics on the index date

Demographic characteristics

Age, mean ± SD [median]

76.8 ± 8.9 [77.0]

75.9 ± 8.9 [76.0]

77.8 ± 8.8 [79.0]

< 0.0001

76.2 ± 8.9 [76.0]

77.8 ± 8.8 [79.0]

< 0.0001

< 65 years old, n (%)

2,231 (11.3)

1,336 (13.1)

895 (9.4)

< 0.0001

735 (12.3)

895 (9.4)

< 0.0001

65–74 years old, n (%)

5,876 (29.7)

3,326 (32.5)

2,550 (26.7)

< 0.0001

1,898 (31.7)

2,550 (26.7)

< 0.0001

75–84 years old, n (%)

6,510 (32.9)

3,256 (31.8)

3,254 (34.1)

0.0006

1,936 (32.4)

3,254 (34.1)

0.0262

≥ 85 years old, n (%)

5,156 (26.1)

2,317 (22.6)

2,839 (29.8)

< 0.0001

1,409 (23.6)

2,839 (29.8)

< 0.0001

Gender, n (%)

Female

13,321 (67.4)

6,016 (58.8)

7,305 (76.6)

< 0.0001

3,390 (56.7)

7,305 (76.6)

< 0.0001

Male

6,451 (32.6)

4,219 (41.2)

2,232 (23.4)

< 0.0001

2,588 (43.3)

2,232 (23.4)

< 0.0001

Unknown

1 (0.0)

0 (0.0)

1 (0.0)

-

0 (0.0)

1 (0.0)

-

Race, n (%)

White

16,234 (82.1)

8,302 (81.1)

7,932 (83.2)

0.0002

4,768 (79.8)

7,932 (83.2)

< 0.0001

Black

1,799 (9.1)

831 (8.1)

968 (10.1)

< 0.0001

535 (8.9)

968 (10.1)

0.0140

Asian

646 (3.3)

434 (4.2)

212 (2.2)

< 0.0001

284 (4.8)

212 (2.2)

< 0.0001

Other

909 (4.6)

569 (5.6)

340 (3.6)

< 0.0001

339 (5.7)

340 (3.6)

< 0.0001

Unknown

185 (0.9)

99 (1.0)

86 (0.9)

0.6320

52 (0.9)

86 (0.9)

0.8373

Comorbidities

CCI score,^amean ± SD [median]

2.5 ± 2.1 [2.0]

2.2 ± 2.1 [2.0]

2.8 ± 2.1 [2.0]

< 0.0001

2.5 ± 2.2 [2.0]

2.8 ± 2.1 [2.0]

< 0.0001

≥ 3, N (%)

8,398 (42.5)

3,730 (36.4)

4,668 (48.9)

< 0.0001

2,555 (42.7)

4,668 (48.9)

< 0.0001

CCI comorbidities^b

AIDS/HIV

21 (0.1)

9 (0.1)

12 (0.1)

0.4139

7 (0.1)

12 (0.1)

0.8799

Cancer

2,102 (10.6)

1,217 (11.9)

885 (9.3)

< 0.0001

765 (12.8)

885 (9.3)

< 0.0001

Any malignancy, including lymphoma and leukemia except malignant neoplasm of the skin

1,295 (6.5)

793 (7.7)

502 (5.3)

< 0.0001

492 (8.2)

502 (5.3)

< 0.0001

Metastatic solid tumor

807 (4.1)

424 (4.1)

383 (4.0)

0.6516

273 (4.6)

383 (4.0)

0.0968

Cerebrovascular disease

1,811 (9.2)

626 (6.1)

1,185 (12.4)

< 0.0001

426 (7.1)

1,185 (12.4)

< 0.0001

Chronic pulmonary disease

5,036 (25.5)

2,324 (22.7)

2,712 (28.4)

< 0.0001

1,421 (23.8)

2,712 (28.4)

< 0.0001

Congestive heart failure

5,803 (29.3)

2,565 (25.1)

3,238 (33.9)

< 0.0001

1,762 (29.5)

3,238 (33.9)

< 0.0001

Dementia

4,465 (22.6)

1,536 (15.0)

2,929 (30.7)

< 0.0001

1,014 (17.0)

2,929 (30.7)

< 0.0001

Diabetes without chronic complications

4,266 (21.6)

2,243 (21.9)

2,023 (21.2)

0.2284

1,345 (22.5)

2,023 (21.2)

0.0580

Diabetes with complications

3,992 (20.2)

1,782 (17.4)

2,210 (23.2)

< 0.0001

1,226 (20.5)

2,210 (23.2)

0.0001

Hemiplegia or paraplegia

427 (2.2)

131 (1.3)

296 (3.1)

< 0.0001

95 (1.6)

296 (3.1)

< 0.0001

Mild liver disease

890 (4.5)

531 (5.2)

359 (3.8)

< 0.0001

381 (6.4)

359 (3.8)

< 0.0001

Moderate or severe liver disease

430 (2.2)

242 (2.4)

188 (2.0)

0.0581

197 (3.3)

188 (2.0)

< 0.0001

Myocardial infarction

2,942 (14.9)

1,404 (13.7)

1,538 (16.1)

< 0.0001

979 (16.4)

1,538 (16.1)

0.6789

Peptic ulcer disease

360 (1.8)

139 (1.4)

221 (2.3)

< 0.0001

109 (1.8)

221 (2.3)

0.0380

Peripheral vascular disease

2,066 (10.4)

928 (9.1)

1,138 (11.9)

< 0.0001

604 (10.1)

1,138 (11.9)

0.0004

Renal disease

6,529 (33.0)

3,019 (29.5)

3,510 (36.8)

< 0.0001

2,034 (34.0)

3,510 (36.8)

0.0004

Rheumatic disease

933 (4.7)

482 (4.7)

451 (4.7)

0.9495

276 (4.6)

451 (4.7)

0.7490

Other selected comorbidities^b

Cataracts

95 (0.5)

42 (0.4)

53 (0.6)

0.1398

23 (0.4)

53 (0.6)

0.1378

Glaucoma

625 (3.2)

277 (2.7)

348 (3.6)

0.0002

167 (2.8)

348 (3.6)

0.0038

Hearing problems

759 (3.8)

349 (3.4)

410 (4.3)

0.0012

207 (3.5)

410 (4.3)

0.0095

High blood pressure

15,849 (80.2)

7,974 (77.9)

7,875 (82.6)

< 0.0001

4,790 (80.1)

7,875 (82.6)

0.0001

Migraine/headache

392 (2.0)

224 (2.2)

168 (1.8)

0.0313

111 (1.9)

168 (1.8)

0.6633

Kidney stone

597 (3.0)

403 (3.9)

194 (2.0)

< 0.0001

259 (4.3)

194 (2.0)

< 0.0001

Benign prostate hyperplasia

2,086 (10.5)

1,294 (12.6)

792 (8.3)

< 0.0001

813 (13.6)

792 (8.3)

< 0.0001

Hospital characteristics

Number of beds, n (%)

≥ 500

6,032 (30.5)

2,972 (29.0)

3,060 (32.1)

< 0.0001

1,792 (30.0)

3,060 (32.1)

0.0059

Region, n (%)

Midwest

4,721 (23.9)

2,386 (23.3)

2,335 (24.5)

0.0540

1,395 (23.3)

2,335 (24.5)

0.1042

Northeast

3,271 (16.5)

1,826 (17.8)

1,445 (15.1)

< 0.0001

1,089 (18.2)

1,445 (15.1)

< 0.0001

South

11,046 (55.9)

5,578 (54.5)

5,468 (57.3)

< 0.0001

3,198 (53.5)

5,468 (57.3)

< 0.0001

West

735 (3.7)

445 (4.3)

290 (3.0)

< 0.0001

296 (5.0)

290 (3.0)

< 0.0001

Teaching hospital, n (%)

7,909 (40.0)

3,998 (39.1)

3,911 (41.0)

0.0053

2,411 (40.3)

3,911 (41.0)

0.4062

Population served, n (%)

Urban

16,638 (84.1)

8,494 (83.0)

8,144 (85.4)

< 0.0001

5,134 (85.9)

8,144 (85.4)

0.3913

Rural

3,135 (15.9)

1,741 (17.0)

1,394 (14.6)

< 0.0001

844 (14.1)

1,394 (14.6)

0.3913