Table 2.
Baseline characteristics of patients with COVID-19 stratified by vaccine status and controls from the Hong Kong Hospital Authority after propensity-score weighting
| Hong Kong Hospital Authority (April 1, 2020 to October 31, 2022) | ||||||
|---|---|---|---|---|---|---|
| Controls (N = 3,828,075) | COVID-19 | |||||
| Baseline characteristics | Unvaccinated (N = 3,809,700) | Incomplete vaccination (N = 3,801,677) | Fully vaccinated (N = 3,818,571) | Received booster dose (N = 3,854,149) | SMD | |
| N/mean (%/SD) | N/mean (%/SD) | N/mean (%/SD) | N/mean (%/SD) | N/mean (%/SD) | ||
| Age (years) | 54.1 (18.19) | 52.4 (20.79) | 53.4 (19.75) | 54.0 (18.02) | 54.1 (16.90) | 0.040 |
| Sex, male | 1,690,639 (44.2) | 1,681,641 (44.1) | 1,692,265 (44.5) | 1,689,322 (44.2) | 1,716,080 (44.5) | 0.005 |
| Charlson Comorbidity Index | 1.65 (1.82) | 1.59 (1.95) | 1.64 (1.86) | 1.65 (1.86) | 1.74 (2.06) | 0.032 |
| Pre-existing morbidities | ||||||
| Respiratory disease | 69,540 (1.8) | 97,239 (2.6) | 91,668 (2.4) | 81,724 (2.1) | 84,607 (2.2) | 0.024 |
| Diabetes | 444,079 (11.6) | 428,379 (11.2) | 438,048 (11.5) | 446,612 (11.7) | 472,078 (12.2) | 0.014 |
| Cardiovascular disease | 291,084 (7.6) | 331,874 (8.7) | 307,673 (8.1) | 292,762 (7.7) | 304,869 (7.9) | 0.019 |
| Myocardial Infarction | 27,309 (0.7) | 30,844 (0.8) | 27,559 (0.7) | 28,154 (0.7) | 31,849 (0.8) | 0.007 |
| Chronic heart failure | 37,531 (1.0) | 53,104 (1.4) | 43,631 (1.1) | 43,140 (1.1) | 42,721 (1.1) | 0.016 |
| Peripheral vascular disease | 10,610 (0.3) | 13,600 (0.4) | 10,275 (0.3) | 9430 (0.2) | 11,916 (0.3) | 0.009 |
| Cerebrovascular disease | 132,775 (3.5) | 179,833 (4.7) | 153,715 (4.0) | 136,713 (3.6) | 136,145 (3.5) | 0.031 |
| COPD | 69,276 (1.8) | 96,613 (2.5) | 91,266 (2.4) | 81,544 (2.1) | 84,507 (2.2) | 0.024 |
| Dementia | 9916 (0.3) | 38,782 (1.0) | 28,411 (0.7) | 17,978 (0.5) | 8948 (0.2) | 0.055 |
| Paralysis | 7705 (0.2) | 11,966 (0.3) | 9190 (0.2) | 8585 (0.2) | 9048 (0.2) | 0.010 |
| Diabetes without chronic complication | 423,588 (11.1) | 405,241 (10.6) | 418,941 (11.0) | 427,648 (11.2) | 447,257 (11.6) | 0.013 |
| Diabetes with chronic complication | 30,253 (0.8) | 29,564 (0.8) | 25,827 (0.7) | 28,255 (0.7) | 39,233 (1.0) | 0.016 |
| Chronic kidney disease | 45,952 (1.2) | 48,784 (1.3) | 45,533 (1.2) | 48,248 (1.3) | 70,173 (1.8) | 0.022 |
| Mild liver disease | 5453 (0.1) | 5909 (0.2) | 5303 (0.1) | 6099 (0.2) | 7418 (0.2) | 0.006 |
| Moderate-severe liver disease | 3666 (0.1) | 3509 (0.1) | 2822 (0.1) | 4673 (0.1) | 6894 (0.2) | 0.014 |
| Ulcers | 37,358 (1.0) | 41,500 (1.1) | 39,446 (1.0) | 42,146 (1.1) | 46,942 (1.2) | 0.011 |
| Rheumatoid arthritis and other inflammatory polyarthropathies | 15,516 (0.4) | 17,100 (0.4) | 16,950 (0.4) | 16,209 (0.4) | 18,742 (0.5) | 0.006 |
| Acquired immune deficiency syndrome (AIDS) | 8 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0.001 |
| Malignancy | 110,554 (2.9) | 94,420 (2.5) | 99,599 (2.6) | 112,459 (2.9) | 172,683 (4.5) | 0.048 |
| Metastatic solid tumor | 18,870 (0.5) | 9,682 (0.3) | 11,332 (0.3) | 21,434 (0.6) | 56,238 (1.5) | 0.062 |
| Medication history | ||||||
| Renin–angiotensin system agents | 543,451 (14.2) | 535,752 (14.1) | 550,713 (14.5) | 544,896 (14.3) | 561,725 (14.6) | 0.007 |
| Beta-blockers | 343,990 (9.0) | 354,237 (9.3) | 354,979 (9.3) | 345,695 (9.1) | 362,166 (9.4) | 0.008 |
| Calcium channel blockers | 764,595 (20.0) | 732,992 (19.2) | 766,221 (20.2) | 764,390 (20.0) | 782,898 (20.3) | 0.012 |
| Diuretics | 118,650 (3.1) | 117,662 (3.1) | 122,698 (3.2) | 120,500 (3.2) | 129,769 (3.4) | 0.008 |
| Nitrates | 85,421 (2.2) | 85,906 (2.3) | 87,713 (2.3) | 86,476 (2.3) | 90,767 (2.4) | 0.004 |
| Lipid-lowering agents | 781,588 (20.4) | 765,893 (20.1) | 784,093 (20.6) | 785,049 (20.6) | 803,700 (20.9) | 0.008 |
| Insulins | 66,414 (1.7) | 71,182 (1.9) | 69,032 (1.8) | 67,438 (1.8) | 76,617 (2.0) | 0.009 |
| Antidiabetic drugs | 415,093 (10.8) | 421,824 (11.1) | 423,609 (11.1) | 416,006 (10.9) | 431,842 (11.2) | 0.006 |
| Oral anticoagulants | 46,658 (1.2) | 48,834 (1.3) | 48,463 (1.3) | 47,388 (1.2) | 51,978 (1.3) | 0.005 |
| Antiplatelets | 305,831 (8.0) | 296,699 (7.8) | 309,166 (8.1) | 310,017 (8.1) | 321,256 (8.3) | 0.009 |
| Immunosuppressants | 18,178 (0.5) | 20,464 (0.5) | 19,832 (0.5) | 18,872 (0.5) | 20,145 (0.5) | 0.004 |
| Number of past healthcare visits | ||||||
| Hospital admission | 0.4 (3.80) | 0.5 (2.07) | 0.4 (2.11) | 0.4 (2.81) | 0.6 (6.78) | 0.036 |
| Doctor consultation | 2.8 (4.48) | 2.9 (5.95) | 2.9 (3.69) | 2.8 (3.59) | 2.9 (3.79) | 0.015 |
| Doses of COVID-19 vaccines received | ||||||
| 0 | 632,151 (16.5) | 3,809,700 (100.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | |
| 1 | 286,526 (7.5) | 0 (0.0) | 3,801,677 (100.0) | 0 (0.0) | 0 (0.0) | |
| 2 | 1,328,800 (34.7) | 0 (0.0) | 0 (0.0) | 3,818,571 (100.0) | 0 (0.0) | |
| 3 or above | 1,580,598 (41.3) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 3,854,149 (100.0) | |
SMD standard mean difference, COPD chronic obstructive pulmonary disease.
The number of individuals presented represents the pseudo-population of each stratum of patients with COVID-19 after propensity-score weighting; Age, Charlson Comorbidity Index, Inpatient hospital and Specialist and general outpatient visits are presented in mean ± SD; SMD ≤ 0.1 is considered a good balance between cohorts.