Research Article

A Nomogram Prediction of Length of Hospital Stay in Patients with COVID-19 Pneumonia: A Retrospective Cohort Study

Table 1

Summary statistics of patient demographics and clinical characteristics (by quartile of LOS).

Total≤10 days ()11–18 days ()≥19 days () value

Demographic characteristics
 Age, years (IQR)51.5 (38–64)41.0 (31,62.5)49 (37–60)63 (57–74.8)≤0.001
 Male sex, (%)41 (42.3)9 (34.6)18 (36.7)14 (63.6)0.069
Clinical findings
 Pneumonia, (%)
  Mild69 (71.1)23 (88.5)39 (79.6)7 (31.8)≤0.001
  Severe17 (17.5)3 (11.5)8 (16.3)6 (27.3)
  Critical11 (11.3)0 (0.0)2 (4.1)9 (40.9)
 Fever (°C), (%)
  <37.324 (24.7)11 (42.3)11 (22.4)2 (9.1)0.045
  37.3–38.550 (51.5)13 (50.0)24 (49.0)13 (59.1)
  >38.523 (23.7)2 (7.7)14 (28.6)7 (31.8)
 Cough58 (59.8%)13 (46.4%)31 (62%)15 (68.2%)0.423
 Sputum25 (25.8%)5 (19.2%)12 (24.5%)8 (36.4%)0.384
 Vomiting4 (4.1%)1 (3.8%)2 (4.1%)1 (4.5%)0.993
 Diarrhea2 (2.1%)1 (3.8%)0 (0%)1 (4.5%)0.238
 Lung CT(a)85 (87.6%)21 (80.8%)44 (91.8%)19 (86.4%)0.384
 Coexisting illnesses
  Kidney disease3 (3.1%)1 (3.80%)2 (4.1%)0 (0.0%)0.455
  Hypertension22 (22.7%)2 (15.4%)9 (18.4%)9 (40.9%)0.081
  Hyperlipidemia3 (3.1%)1 (3.8%)1 (2.0%)1 (4.5%)0.825
  Diabetes8 (8.2%)2 (7.7%)4 (8.2%)3 (13.6%)0.984
  Heart disease10 (10.3%)2 (7.7%)5 (10.2%)2 (10.5%)0.798
  Lung disease7 (7.2%)2 (7.7%)4 (8.2%)1 (4.5%)0.844
  Surgery22 (22.7%)4 (15.4%)12 (24.5%)6 (27.3%)0.564
Laboratory indicators
 White blood cell count, ×109/L4.4 (3.5–5.9)4.1 (3.5–5.8)4.4 (3.5–5.7)5.0 (3.2–6.9)0.583
  <440 (41.2%)12 (46.2%)20 (40.8%)8 (36.4%)0.787
  ≥457 (58.8%)14 (53.8%)29 (59.2%)14 (63.6%)
 Hemoglobin, g/dL136 (125–144)131 (120.3–144.3)135 (126–143.5)139 (129–149)0.157
194 (160–238)206 (161–298.3)193 (144.5–245)191 (147.5–226.3)0.257
  <1005 (5.2%)0 (0.0%)2 (4.1%)5 (10.2%)0.071
  100–30080 (82.5%)20 (76.9%)42 (85.7%)6 (23.1%)
  >30012 (12.4%)6 (23.1%)5 (10.2%)1 (4.5%)
1.1 (0.77–1.53)1.26 (0.93–1.61)1.18 (0.80–1.54)0.81 (0.70–1.21)0.026
  <0.826 (26.8%)5 (19.2%)11 (22.4%)10 (45.5%)0.90
  ≥0.871 (73.2%)21 (80.8%)38 (77.6%)12 (54.5%)
Monocyte count×109/L0.31 (0.21–0.44)0.34 (0.22–0.42)0.25 (0.16–0.39)0.32 (0.19–0.51)0.928
2.69 (1.84–4.09)2.37 (1.86–3.42)2.69 (1.84–3.83)3.71 (1.68–5.38)0.067
  <1.821 (21.6%)5 (19.2%)10 (20.4%)6 (27.3%)0.206
  1.8–6.370 (72.2%)21 (80.8%)36 (73.5%)13 (59.1%)
  >6.36 (6.2%)0 (0%)3 (6.1%)3 (13.6%)
 Lymphocyte percentage26.1 (17.9–34.5)33 (21.7–37.8)26.1 (19.3–34.3)18.7 (19.3–34.5)0.002
  <2029 (29.9%)3 (11.5%)14 (28.6%)12 (54.5%)0.007
  20–4058 (59.8%)19 (73.1%)29 (59.2%)10 (45.5%)
  >4010 (10.3%)4 (15.4%)6 (12.2%)0 (0.0%)
 Neutrophil percentage64.0 (51.8–72.3)55.4 (49.2–69.1)64 (53.1–72.7)70.4 (60.4–79.6)0.002
  <7578 (80.4%)25 (96.2%)39 (79.6%)14 (63.6%)0.018
  ≥7519 (19.6%)1 (3.8%)10 (20.4%)8 (36.4%)
 NLR2.4 (1.4, 3.9)1.7 (1.3–3.1)2.3 (1.6–3.8)3.61 (1.8–6.3)0.004
  <2.7556 (57.7%)18 (69.2%)31 (63.3%)7 (31.8%)0.018
  2.7541 (42.3%)8 (30.8%)18 (36.7%)15 (68.2%)
 LMR3.7 (2.8, 5.3)4.1 (2.9, 6.3)3.9 (2.8, 5.4)3.0 (2.3,4.8)0.268
  <2.6320 (20.8%)5 (19.2%)7 (14.3%)8 (38.1%)0.096
  ≥2.6376 (79.2%)21 (80.8%)42 (85.7%)8 (61.9%)
 PLR177.3 (124.8–246.2)132.7 (118.5–172.3)188.1 (124.8–156.6)221.5 (163.6–182.5)0.018
  <16041 (42.3%)15 (57.7%)21 (42.9%)5 (22.7%)0.045
  ≥16056 (57.7%)11 (42.3%)28 (57.1%)17 (77.3%)
 Prothrombin time, s12.6 (12.1–131.1)12.8 (12.2–13.4)12.4 (11.9–12.87)12.75 (12.1–13.42)0.417
 Prothrombin activity, percentage75 (71–80)73.5 (68.5–79.0)76.0 (73.0–82.0)74.0 (68.5–78.5)0.459
  <7546 (48.4%)15 (57.7%)19 (39.6%)12 (57.1%)0.219
  ≥7549 (51.6%)11 (43.3%)29 (60.4%)9 (42.9%)
 C-reactive protein, mg/L14.7 (3.4–37.4)12.7 (2.0–18.3)16.8 (3.3, 41.15)19.4 (10.0–54.13)0.314
 Procalcitonin, ug/L0.11 (0.10–0.14)0.10 (0.08–0.15)0.11 (0.06, 0.15)0.12 (0.10–0.14)0.256
 Fibrinogen, g/L3.2 (2.5–4.3)3.0 (2.5–4.3)3.2 (2.5–4.1)3.2 (2.5–4.4)0.549
 ALT, U/L28 (20–45)26.5 (20–39)26 (20–42)42 (19.7–52.7)0.126
  <4065 (67.0%)21 (80.8%)35 (71.4%)9 (40.9%)0.009
  ≥4032 (33.0%)5 (19.2%)14 (28.6%)13 (59.1%)
 AST, U/L30 (21.5–42)25.5 (20.5–34)28.0 (21–40)42.5 (22.75–64.5)0.004
  <4070 (72.2%)24 (92.3%)38 (77.6%)3 (36.4%)≤0.001
  ≥4027 (27.8%)2 (7.7%)11 (22.4%)14 (63.6%)
 AST/ALT1.04 (0.76–1.35)0.96 (0.60, 1.43)1.02 (0.73–1.30)1.30 (0.89, 1.71)0.108
 Total bilirubin, mmol/L9.60 (7.10–13.05)8.80 (6.13–12.10)9.20 (6.80–12.60)12.35 (9.38–14.75)0.046
 Albumin, g/L36.8 (33–39.8)37.60 (33.8–40)36.6 (33.4–39.9)36.2 (32.5–40)0.158
  <3536 (37.1%)8 (30.8%)17 (34.7%)11 (50.0%)0.350
  ≥3561 (62.9%)18 (69.2%)32 (65.3%)11 (50.0%)
 Glomerular filtration rate, (mL/min)99.5 (91–113.75)109.35 (94.8–119.7)105.3 (94.2–117.6)94.5 (80.3–97.4)0.001
 Carbon dioxide combining power, mmol/L26.8 (24.4–28.9)25.70 (24.4–28.3)27.2 (24.7–28.9)27 (23–28.9)0.428
 Creatine kinase, U/L72 (46–118)59 (42–100.3)72 (46–118)118 (59.3–353)0.203
  <18583 (85.6%)25 (96.2%)43 (87.8%)15 (68.2%)0.022
  ≥18514 (14.4%)1 (3.8%)6 (12.2%)7 (31.8%)
 Creatine kinase isoenzymes, CK-MB, ng/mL0.34 (0.16–0.73)0.29 (0.08–0.61)0.28 (0.13–0.69)0.57 (0.27–1.10)0.008
  <566 (68.0%)17 (65.4%)39 (79.6%)10 (45.5%)0.016
  ≥531 (32.0%)9 (34.6%)10 (20.4%)12 (54.5%)
 Myoglobin, μg/L45 (30–66)34 (27.5–50)38 (29–60.5)66 (49.5–187.5)≤0.001
  <10084 (86.6%)24 (92.3%)46 (93.9%)14 (63.6%)0.004
  ≥10013 (13.4%)2 (7.7%)3 (6.1%)8 (36.4%)
 Lactate, mmol/L1.2 (0.9–1.7)1.0 (0.9–1.2)1.24 (0.9–1.7)1.6 (1.2–1.9)0.004
  <1.769 (73.4%)22 (88.0%)37 (78.7%)10 (45.5%)0.02
  ≥1.725 (26.6%)3 (12.0%)10 (21.3%)12 (54.5%)
 PF ratio, mmHg433.5 (311.4–527.4)471.3 (293.5–530.8)446 (370.8–572.9)340 (223.4–447.4)0.02
  <300207490.003
  ≥30077194513
Treatment
 Antibiotics30 (30.9%)11 (42.3%)13 (26.5%)6 (27.3%)0.340
 Antiviral treatment37 (38.1%)10 (38.5%)19 (38.8%)8 (36.4%)0.981
 Chinese medicine treatment74 (76.3%)22 (84.6%)36 (73.5%)16 (72.7%)0.505
 Corticosteroids19 (19.6%)0 (0.0%)8 (16.3%)11 (50.0%)≤0.001
 Oxygen therapy34 (35.1%)4 (15.4%)19 (38.8%)11 (50.0%)0.032
 Ventilator6 (6.2%)0 (0.0%)2 (4.1%)4 (18.2%)0.024

(a)Positive result: CT images showing multiple patchy ground-glass opacities along the peribronchial and subpleural lungs; NLR: neutrophil-to-lymphocyte ratio; LMR: lymphocyte-to-monocyte ratio; PLR: platelet-to-lymphocyte ratio; ALT: alanine aminotransferase; AST: aspartate aminotransferase; PF ratio: PaO2/FiO2 ratio. Significance codes: “”0.001, “”0.01, “”0.05.