Table 1.
Characteristics of hospital encounters in the study sample, overall and according to readmission and extended length of stay.
| Characteristic | Overall | Not readmitted within 30 days | Readmitted within 30 days | Hospital stay less than 5 days | Hospital stay over 5 days |
|---|---|---|---|---|---|
| Number of hospitalizations | 1,485,880 | 1,274,858 | 211,022 | 1,234,148 | 251,732 |
| Age, median [Q1, Q3] | 59.0 [39.0, 73.0] | 59.0 [38.0, 73.0] | 62.0 [48.0, 76.0] | 58.0 [36.0, 72.0] | 66.0 [54.0, 78.0] |
| Female, n (%) | 826,025 (55.6) | 713,391 (56.0) | 112,634 (53.4) | 698,382 (56.6) | 127,643 (50.7) |
| Race/ethnicity, n (%) | |||||
| African American | 333,212 (22.4) | 276,208 (21.7) | 57,004 (27.0) | 276,476 (22.4) | 56,736 (22.5) |
| White | 1,055,180 (71.1) | 913,085 (71.7) | 142,095 (67.4) | 873,453 (70.8) | 181,727 (72.2) |
| Other | 96,592 (6.5) | 84,755 (6.7) | 11,837 (5.6) | 83,453 (6.8) | 13,139 (5.2) |
| Marital status, n (%) | |||||
| Divorced or separated | 134,841 (9.1) | 111,680 (8.8) | 23,161 (11.0) | 108,779 (8.8) | 26,062 (10.4) |
| Married or partnered | 594,375 (40.0) | 515,620 (40.5) | 78,755 (37.3) | 494,338 (40.1) | 100,037 (39.7) |
| Single | 554,116 (37.3) | 477,592 (37.5) | 76,524 (36.3) | 472,301 (38.3) | 81,815 (32.5) |
| Widowed | 175,822 (11.8) | 146,611 (11.5) | 29,211 (13.8) | 136,888 (11.1) | 38,934 (15.5) |
| Other | 26,200 (1.8) | 22,847 (1.8) | 3353 (1.6) | 21,347 (1.7) | 4853 (1.9) |
| Payer class, n (%) | |||||
| Medicaid | 221,969 (16.4) | 188,630 (16.3) | 33,339 (17.0) | 193,978 (17.2) | 27,991 (12.1) |
| Medicare | 725,125 (53.5) | 601,752 (51.9) | 123,373 (63.0) | 567,435 (50.5) | 157,690 (68.4) |
| Private health insurance | 329,842 (24.3) | 298,444 (25.7) | 31,398 (16.0) | 293,292 (26.1) | 36,550 (15.9) |
| Other | 78,269 (5.8) | 70,553 (6.1) | 7716 (3.9) | 69,940 (6.2) | 8329 (3.6) |
| Comorbidities, n (%) | |||||
| Cancer | 183,367 (12.3), | 142,205 (11.2) | 41,162 (19.5) | 140,188 (11.4) | 43,179 (17.2) |
| Metastatic solid tumor | 55,906 (3.8) | 41,867 (3.3) | 14,039 (6.7) | 42,339 (3.4) | 13,567 (5.4) |
| Solid organ transplant | 33,780 (2.3) | 24,928 (2.0) | 8852 (4.2) | 22,837 (1.9) | 10,943 (4.3) |
| AIDS/HIV | 4552 (0.3) | 3310 (0.3) | 1242 (0.6) | 3703 (0.3) | 849 (0.3) |
| Renal disease | 177,544 (11.9) | 133,099 (10.4) | 44,445 (21.1) | 129,114 (10.5) | 48,430 (19.2) |
| Mild liver disease | 93,947 (6.3) | 71,396 (5.6) | 22,551 (10.7) | 73,362 (5.9) | 20,585 (8.2) |
| Moderate or severe liver disease | 22,816 (1.5) | 15,542 (1.2) | 7274 (3.4) | 15,971 (1.3) | 6845 (2.7) |
| Diabetes with chronic complication | 125,118 (8.4) | 95,619 (7.5) | 29,499 (14.0) | 95,561 (7.7) | 29,557 (11.7) |
| Diabetes without chronic complication | 293,379 (19.7) | 232,187 (18.2) | 61,192 (29.0) | 226,901 (18.4) | 66,478 (26.4) |
| Hypertension | 939,048 (63.2) | 779,460 (61.1) | 159,588 (75.6) | 744,603 (60.3) | 194,445 (77.2) |
| Myocardial infarction | 69,914 (4.7) | 53,267 (4.2) | 16,647 (7.9) | 52,835 (4.3) | 17,079 (6.8) |
| Congestive heart failure | 215,510 (14.5) | 164,879 (12.9) | 50,631 (24.0) | 155,898 (12.6) | 59,612 (23.7) |
| Cerebrovascular disease | 193,243 (13.0) | 154,368 (12.1) | 38,875 (18.4) | 148,158 (12.0) | 45,085 (17.9) |
| Chronic obstructive pulmonary disease | 302,548 (20.4) | 240,195 (18.8) | 62,353 (29.5) | 238,907 (19.4) | 63,641 (25.3) |
| Pneumonia | 188,684 (12.7) | 142,066 (11.1) | 46,618 (22.1) | 142,437 (11.5) | 46,247 (18.4) |
| Dementia | 56,876 (3.8) | 45,461 (3.6) | 11,415 (5.4) | 41,554 (3.4) | 15,322 (6.1) |
| Anxiety | 181,440 (12.2) | 146,263 (11.5) | 35,177 (16.7) | 150,668 (12.2) | 30,772 (12.2) |
| Depression | 259,323 (17.5) | 207,914 (16.3) | 51,409 (24.4) | 212,806 (17.2) | 46,517 (18.5) |
| Psychosis | 52,085 (3.5) | 39,086 (3.1) | 12,999 (6.2) | 38,544 (3.1) | 13,541 (5.4) |
| Receiving dialysis | 17,791 (1.2) | 12,604 (1.0) | 5187 (2.5) | 10,658 (0.9) | 7133 (2.8) |
| Selected discharge laboratory results, n (%) | |||||
| Low hemoglobin level (<12 g/dL) | 248,387 (16.7) | 204,139 (16.0) | 44,248 (21.0) | 200,374 (16.2) | 48,013 (19.1) |
| Low sodium level (<135 mEq/L) | 38,847 (2.6) | 31,439 (2.5) | 7408 (3.5) | 29,467 (2.4) | 9380 (3.7) |
| Hospital encounter information, median [Q1, Q3] or n (%) | |||||
| Previous hospitalizations | 1.0 [0.0, 2.0] | 0.0 [0.0, 2.0] | 2.0 [0.0, 6.0] | 1.0 [0.0, 2.0] | 1.0 [0.0, 3.0] |
| Emergency department (ED) admission | 725,843 (48.8) | 603,317 (47.3) | 122,526 (58.1) | 618,055 (50.1) | 107,788 (42.8) |
| Any ED visits in the past 6 months | 644,102 (43.3) | 511,323 (40.1) | 132,779 (62.9) | 521,248 (42.2) | 122,854 (48.8) |
| Total ED visits in the past 6 months | 0.0 [0.0, 1.0] | 0.0 [0.0, 1.0] | 1.0 [0.0, 3.0] | 0.0 [0.0, 1.0] | 0.0 [0.0, 2.0] |
| Admission class, n (%) | |||||
| Ambulatory surgical procedures | 8081 (0.5) | 7464 (0.6) | 617 (0.3) | 8060 (0.7) | 21 (0.0) |
| Emergency | 7058 (0.5) | 6417 (0.5) | 641 (0.3) | 7055 (0.6) | 3 (0.0) |
| Hospice | 1486 (0.1) | 1463 (0.1) | 23 (0.0) | 1357 (0.1) | 129 (0.1) |
| Inpatient | 1,185,985 (80.0) | 1,011,772 (79.6) | 174,213 (82.7) | 937,614 (76.2) | 248,371 (98.7) |
| Observation | 261,942 (17.7) | 228,559 (18.0) | 33,383 (15.8) | 260,955 (21.2) | 987 (0.4) |
| Outpatient | 10,559 (0.7) | 9415 (0.7) | 1144 (0.5) | 10,513 (0.9) | 46 (0.0) |
| Psychiatric inpatient | 3381 (0.2) | 2936 (0.2) | 445 (0.2) | 2198 (0.2) | 1183 (0.5) |
| Other | 4074 (0.3) | 3799 (0.3) | 275 (0.1) | 3082 (0.3) | 992 (0.4) |
| Discharge location, n (%) | |||||
| Expired | 18,615 (1.4) | 18,615 (1.6) | 0 (0.0) | 10,907 (1.0) | 7708 (3.3) |
| General acute care hospital | 19,855 (1.5) | 17,490 (1.5) | 2365 (1.2) | 16,105 (1.4) | 3750 (1.6) |
| Home | 959,559 (71.1) | 833,797 (72.2) | 125,762 (64.8) | 862,810 (77.1) | 96,749 (42.0) |
| Home care services | 134,970 (10.0) | 109,327 (9.5) | 25,643 (13.2) | 93,833 (8.4) | 41,137 (17.9) |
| Hospice | 14,318 (1.1) | 13,765 (1.2) | 553 (0.3) | 8879 (0.8) | 5439 (2.4) |
| Intermediate care facility | 9046 (0.7) | 7451 (0.6) | 1595 (0.8) | 5215 (0.5) | 3831 (1.7) |
| Left against medical advice | 13,864 (1.0) | 10,599 (0.9) | 3265 (1.7) | 13,374 (1.2) | 490 (0.2) |
| Long-term care facility | 14,592 (1.1) | 12,210 (1.1) | 2382 (1.2) | 5403 (0.5) | 9189 (4.0) |
| Skilled nursing facility | 145,882 (10.8) | 115,106 (10.0) | 30,776 (15.8) | 87,530 (7.8) | 58,352 (25.3) |
| Transfer to a psychiatric hospital | 6828 (0.5) | 6276 (0.5) | 552 (0.3) | 6197 (0.6) | 631 (0.3) |
| Transfer to another hospital | 4482 (0.3) | 4032 (0.3) | 450 (0.2) | 3797 (0.3) | 685 (0.3) |
| Other | 7109 (0.5) | 6240 (0.5) | 869 (0.4) | 4740 (0.4) | 2369 (1.0) |
| Outcomes of interest | |||||
| 30-day readmissions, n (%) | 211,022 (14.2) | 0 (0.0) | 211,022 (100.0) | 158,577 (12.8) | 52,445 (20.8) |
| Length of stay in days, median [Q1, Q3] | 2.9 [1.7, 5.3] | 2.8 [1.6, 5.1] | 3.9 [2.0, 7.0] | 2.4 [1.4, 3.9] | 10.6 [8.3, 15.0] |