Table 1.
Comparison of COVID-positive inpatients by the period of admission
| Pre-delta | Delta | Omicron | P* | All | |
|---|---|---|---|---|---|
| N | 7112 | 860 | 1556 | 9528 | |
| Age, years | 57.7 ± 19.3 | 58.8 ± 19.3 | 61.0 ± 19.9 | < 0.0001 | 58.3 ± 19.4 |
| Male sex | 3630 (51.0%) | 458 (53.3%) | 783 (50.3%) | 0.37 | 4871 (51.1%) |
| BMI | 30.0 ± 7.4 | 29.9 ± 7.8 | 29.0 ± 7.9 | < 0.0001 | 29.8 ± 7.5 |
| Obesity (BMI > 30) | 2935 (43.4%) | 359 (43.3%) | 559 (38.0%) | 0.0007 | 3853 (42.5%) |
| Morbid obesity (BMI > 40) | 573 (8.5%) | 74 (8.9%) | 126 (8.6%) | 0.90 | 773 (8.5%) |
| Comorbidities | |||||
| Charlson’s comorbidity index (CCI) | 3.78 ± 3.57 | 4.25 ± 3.85 | 5.05 ± 3.90 | < 0.0001 | 4.03 ± 3.68 |
| Myocardial infarction | 606 (8.5%) | 115 (13.4%) | 226 (14.5%) | < 0.0001 | 947 (9.9%) |
| Congestive heart failure | 1058 (14.9%) | 180 (20.9%) | 390 (25.1%) | < 0.0001 | 1628 (17.1%) |
| Peripheral vascular disease | 749 (10.5%) | 112 (13.0%) | 254 (16.3%) | < 0.0001 | 1115 (11.7%) |
| Cerebrovascular disease | 894 (12.6%) | 139 (16.2%) | 279 (17.9%) | < 0.0001 | 1312 (13.8%) |
| Dementia | 882 (12.4%) | 106 (12.3%) | 250 (16.1%) | 0.0004 | 1238 (13.0%) |
| Chronic pulmonary disease | 1514 (21.3%) | 214 (24.9%) | 458 (29.4%) | < 0.0001 | 2186 (22.9%) |
| Connective tissue/rheumatic disease | 203 (2.9%) | 39 (4.5%) | 77 (4.9%) | < 0.0001 | 319 (3.3%) |
| Peptic ulcer disease | 197 (2.8%) | 27 (3.1%) | 72 (4.6%) | 0.0007 | 296 (3.1%) |
| Mild liver disease | 675 (9.5%) | 96 (11.2%) | 173 (11.1%) | 0.07 | 944 (9.9%) |
| Diabetes without complications | 1542 (21.7%) | 139 (16.2%) | 217 (13.9%) | < 0.0001 | 1898 (19.9%) |
| Diabetes with complications | 1104 (15.5%) | 172 (20.0%) | 361 (23.2%) | < 0.0001 | 1637 (17.2%) |
| Paraplegia and hemiplegia | 228 (3.2%) | 34 (4.0%) | 68 (4.4%) | 0.05 | 330 (3.5%) |
| Renal disease | 1399 (19.7%) | 211 (24.5%) | 490 (31.5%) | < 0.0001 | 2100 (22.0%) |
| Non-metastatic cancer | 355 (5.0%) | 60 (7.0%) | 130 (8.4%) | < 0.0001 | 545 (5.7%) |
| Moderate/severe liver disease | 89 (1.3%) | 3 (0.3%) | 34 (2.2%) | 0.0005 | 126 (1.3%) |
| Metastatic carcinoma | 123 (1.7%) | 17 (2.0%) | 55 (3.5%) | < 0.0001 | 195 (2.0%) |
| AIDS | 24 (0.3%) | 1 (0.1%) | 5 (0.3%) | 0.55 | 30 (0.3%) |
| Elixhauser’s comorbidity index (ECI) | 10.4 ± 11.5 | 12.7 ± 12.3 | 14.2 ± 12.7 | < 0.0001 | 11.2 ± 11.9 |
| COVID-related findings | |||||
| O2 saturation at admission ≤ 90% | 1610 (22.8%) | 182 (21.2%) | 260 (16.8%) | < 0.0001 | 2052 (21.7%) |
| COVID-19 pneumonia | 2743 (38.6%) | 655 (76.2%) | 918 (59.0%) | < 0.0001 | 4316 (45.3%) |
| Coagulopathy | 832 (11.7%) | 146 (17.0%) | 217 (13.9%) | < 0.0001 | 1195 (12.5%) |
| Vaccinated (at least 1 dose) | 63 (1.3%) | 372 (45.5%) | 881 (60.6%) | < 0.0001 | 1316 (18.7%) |
| Inpatient resource utilization | |||||
| LOS, days | 9.18 ± 10.68 | 9.70 ± 11.70 | 7.14 ± 6.23 | < 0.0001 | 8.90 ± 10.22 |
| Admitted to ICU | 2042 (28.7%) | 184 (21.4%) | 239 (15.4%) | < 0.0001 | 2465 (25.9%) |
| LOS in ICU, days | 9.75 ± 11.70 | 9.35 ± 16.33 | 5.15 ± 6.29 | < 0.0001 | 9.27 ± 11.78 |
| Invasive mechanical ventilation | 838 (11.8%) | 115 (13.4%) | 118 (7.6%) | < 0.0001 | 1071 (11.2%) |
| ECMO | 59 (0.8%) | 13 (1.5%) | 4 (0.3%) | 0.0034 | 76 (0.8%) |
| Disposition | |||||
| Short-term care facility | 63 (0.9%) | 17 (2.0%) | 15 (1.0%) | 0.0097 | 95 (1.0%) |
| Long-term care facility | 729 (10.3%) | 102 (11.9%) | 166 (10.7%) | 0.33 | 997 (10.5%) |
| Home (including home healthcare) | 5373 (75.5%) | 618 (71.9%) | 1189 (76.4%) | 0.0344 | 7180 (75.4%) |
| Hospice (including home hospice) | 158 (2.2%) | 42 (4.9%) | 65 (4.2%) | < 0.0001 | 265 (2.8%) |
| Expired | 789 (11.1%) | 81 (9.4%) | 121 (7.8%) | 0.0003 | 991 (10.4%) |
The parameters are given as mean ± SD or N (%); missing entries not included in calculation of percentages
BMI body mass index, CCI Charlson’s comorbidity index (CCI), ECI Elixhauser’s comorbidity index, LOS length of stay
*By chi-square (categorical parameters) or Kruskal–Wallis (continuous parameters) non-parametric test