Table 1 Baseline characteristics and in-hospital outcomes of COVID-19 during different surges
Characteristic†| Total (N = 1323) | Surge 1 (N = 667) | Surge 2 (N = 489) | Surge 3 (N = 167) | P* | |
|---|---|---|---|---|---|---|
Demographics | ||||||
Age (year) | 59.2 ± 16.5 | 57.6 ± 16.3 | 61.0 ± 16.6 | 60.7 ± 16.6 | 0.001 | |
Sex | ||||||
 Female | 515(38.9%) | 249(37.3%) | 197(40.3%) | 69(41.3%) | 0.473 | |
 Male | 808(61.1%) | 418(62.7%) | 292(59.7%) | 98(58.7%) | ||
BMI (kg/m2) | 27.4 ± 4.7 | 27.5 ± 4.9 | 27.3 ± 4.6 | 27.4 ± 4.6 | 0.917 | |
Comorbidities | ||||||
Hypertension | 595(45.0%) | 274(41.1%)** | 237(48.5%) | 84(50.3%) | 0.015 | |
Diabetes mellitus | 393(29.7%) | 197(29.5%) | 145(29.7%) | 51(30.5%) | 0.968 | |
Cardiac disease | 308(23.3%) | 147(22.0%) | 122(24.9%) | 39(23.4%) | 0.512 | |
Cerebrovascular disease | 58(4.4%) | 22(3.3%) | 28(5.7%) | 8(4.8%) | 0.133 | |
Chronic lung disease | 82(6.2%) | 50(7.5%) | 22(4.5%) | 10(6.0%) | 0.112 | |
Malignancy | 59(4.5%) | 28(4.2%) | 25(5.1%) | 6(3.6%) | 0.641 | |
Chronic kidney disease | 63(4.8%) | 33(4.9%) | 23(4.7%) | 7(4.2%) | 0.971 | |
Symptoms | ||||||
Fever | 721(54.5%) | 354(53.1%) | 271(55.4%) | 96(57.5%) | 0.518 | |
Cough | 825(62.4%) | 447(67.0%)** | 273(55.8%)** | 105(62.9%) | 0.001 | |
Dyspnea | 799(60.4%) | 361(54.1%)** | 325(66.5%)** | 113(67.7%) |  < 0.001 | |
Myalgia and arthralgia | 637(48.1%) | 273(40.9%)** | 261(53.4%)** | 103(61.7%)** |  < 0.001 | |
Headache | 223(16.9%) | 100(15.0%) | 89(18.2%) | 34(20.4%) | 0.154 | |
Nausea and vomiting | 354(26.8%) | 133(19.9%)** | 151(30.9%)** | 70(41.9%)** |  < 0.001 | |
Sore throat | 57(4.3%) | 31(4.6%) | 16(3.3%) | 10(6.0%) | 0.272 | |
Chest pain | 167(12.6%) | 62(9.3%)** | 70(14.3%) | 35(21.0%)** |  < 0.001 | |
Abdominal pain | 227(17.2%) | 160(24.0%)** | 44(9.0%)** | 23(13.8%) |  < 0.001 | |
Neurological manifestations | 110(8.3%) | 38(5.7%)** | 42(8.6%) | 30(18.0%)** |  < 0.001 | |
LOC | 83(6.3%) | 35(5.2%) | 35(7.2%) | 13(7.8%) | 0.288 | |
Vital signs on admission | ||||||
Heart rate | 91.2 ± 24.0 | 88.6 ± 16.4 | 93.7 ± 32.5 | 93.4 ± 15.5 |  < 0.001 | |
SBP (mmHg) | 126.3 ± 21.2 | 123.8 ± 20.5** | 128.3 ± 21.8 | 128.7 ± 21.4 |  < 0.001 | |
DBP (mmHg) | 76.6 ± 12.9 | 75.8 ± 11.7 | 76.9 ± 13.4 | 78.2 ± 15.0 | 0.131 | |
Respiratory rate | 21.0 ± 5.7 | 19.8 ± 5.6** | 22.3 ± 5.9 | 21.2 ± 4.6 |  < 0.001 | |
Temperature (oC) | 37.2 ± 0.9 | 37.2 ± 0.9 | 37.2 ± 0.9 | 37.1 ± 0.9 | 0.706 | |
Oxygen saturation (%) | 89.2 ± 8.1 | 90.7 ± 7.4** | 87.7 ± 8.8 | 88.1 ± 7.7 |  < 0.001 | |
Laboratory data on admission | ||||||
WBC (× 109/L) | 6.9[5.2–9.5] | 6.6[5.2–9.5] | 7.4[5.3–9.5] | 7.2[5.1–9.6] | 0.338 | |
Neutrophil (× 109/L) | 5.3[3.7–7.7] | 4.8[3.6–7.3] | 5.9[3.9–8.1] | 5.6[3.7–7.5] | 0.003 | |
Lymphocyte (× 109/L) | 1.1[0.8–1.6] | 1.2[0.9–1.7] | 1.0 [0.7–1.4] | 1.1[0.8–1.5] |  < 0.001 | |
Platelets (× 109/L) | 194.0[151.0–265.5] | 191.0[150.0–258.0] | 203.0[157.0–282.7] | 192.5[152.0–262.2] | 0.094 | |
Neutrophil-to-lymphocyte ratio | 4.5[2.7–8.1] | 3.8[2.5–6.5] | 5.9[3.4–10.1] | 4.7[3.0–7.0] |  < 0.001 | |
Platelet-to-lymphocyte ratio | 173.1[119.7–259.3] | 154.4[114.0–216.1] | 206.8[138.3–336.1]** | 178.1[121.7–259.9] |  < 0.001 | |
SII | 889.6[498.5–1745.4] | 762.1[445.8–1380.9] | 1221.4[610.2–2607.7]** | 913.2[518.1–1714.6] |  < 0.001 | |
Hemoglobin (g/dL) | 13.5[12.1–14.9] | 13.7[12.4–15.0] | 13.3[11.8–14.6] | 13.5[12.0–14.8] | 0.008 | |
Urea (mg/dL) | 34.0[24.0–53.0] | 32.0[23.0–49.0] | 39.0[27.0–60.0]** | 34.0[25.7–48.0] |  < 0.001 | |
BUN/creatinine ratio | 14.7[11.2–19.5] | 13.9[10.7–18.3] | 15.9[12.2–20.7] | 14.7[11.3–18.6] |  < 0.001 | |
Creatinine (mg/dL) | 1.1[0.9–1.3] | 1.1[0.9–1.3] | 1.1[0.9–1.3] | 1.1[0.9–1.3] | 0.157 | |
Sodium (mmol/L) | 136.3[133.1–139.4] | 136.0[132.8–139.4] | 137.0[133.8–139.9] | 135.9[132.7–138.2] | 0.009 | |
Potassium (mmol/L) | 4.3[4.0–4.7] | 4.3[3.4–4.6] | 4.4[4.0–4.9] | 4.4[3.9–4.7] |  < 0.001 | |
Calcium (mmol/L) | 8.8[8.3–9.2] | 8.7[8.2–9.1]** | 8.8[8.4–9.2] | 8.8[8.4–9.2] |  < 0.001 | |
Phosphorous (mmol/L) | 3.3[2.8–3.9] | 3.4[2.9–4.0] | 3.3[2.7–4.0] | 3.0[2.5–3.6] |  < 0.001 | |
Magnesium (mmol/L) | 2.2[2.0–2.5] | 2.2[2.0–2.5] | 2.1[1.9–2.4] | 2.2[1.9–2.6] |  < 0.001 | |
CRP (mg/L) | 62.1[27.1–99.5] | 56.0[19.8–98.3] | 81.4[37.4–99.5] | 49.5[28.8–111.8] | 0.001 | |
ESR (mm/h) | 50.0[28.0–81.0] | 44.0[26.0–75.0]** | 56.0[36.0–87.0] | 55.5[35.0–87.2] |  < 0.001 | |
LDH (U/L) | 603.5[472.7–793.0] | 536.0[435.0–700.0]** | 648.0[513.0–822.0] | 713.5[532.5–925.0] |  < 0.001 | |
hs-cTnI (pg/mL) | 5.3[1.5–17.8] | 6.0[1.5–19.8] | 5.2[1.5–16.1] | 4.4[1.5–16.4] | 0.650 | |
AST (U/L) | 53.0[39.7–71.0] | 50.0[38.0–67.7] | 56.0[42.0–71.2] | 55.5[41.0–76.7] | 0.010 | |
ALT (U/L) | 39.0[29.0–56.0] | 36.0[27.0–51.0] | 43.0[31.0–61.2] | 39.0[28.0–57.0] |  < 0.001 | |
ALP (U/L) | 175.0[137.0–232.0] | 171.0[131.0–224.0] | 175.5[142.7–237.0] | 180.5[137.2–425.5] | 0.108 | |
In-hospital outcomes | ||||||
Hospital length of stay (day) | 5.0[2.2–8.0] | 4.0[2.0–7.0]** | 6.0[3.0–9.0] | 6.0[4.0–9.0] |  < 0.001 | |
ICU admission | 217(16.4%) | 111(16.6%) | 81(16.6%) | 25(15.0%) | 0.866 | |
Severity | 896(67.7%) | 437(65.5%) | 349(71.4%) | 110(65.9%) | 0.094 | |
Mortality | 235(17.8%) | 114(17.1%) | 91(18.6%) | 30(18.0%) | 0.798 | |
ARDS | 373(28.2%) | 205(30.7%) | 46(23.7%)** | 52(31.1%) | 0.022 | |
Invasive ventilation | 169(12.8%) | 97(14.5%) | 53(10.8%) | 19(11.4%) | 0.149 | |
ACI | 303(22.9%) | 133(19.9%) | 121(24.7%) | 49(29.3%) | 0.017 | |
AKI | 173(13.1%) | 83(12.4%) | 65(13.3%) | 25(15.0%) | 0.676 | |
ALI | 147(11.1%) | 64(9.6%) | 62(12.7%) | 21(12.6%) | 0.209 | |
Multi-organ damage | 260(19.7%) | 127(19.0%) | 95(19.4%) | 38(22.8%) | 0.551 | |