Objective  To investigate the early clinical features of severe cases with coronavirus disease 2019 (COVID-19) and analyze its early risk factors.

  Methods  From January to March in 2020, the severe and critical cases with COVID-19 diagnosed in the Fifth Medical Center of Chinese PLA General Hospital served as observation group, and patients with moderate and mild COVID-19 served as control group. The general data, clinical manifestations and blood testing results were collected and analyzed to identify the early risk factors of severe COVID-19.

  Results  A total of 63 cases with COVID-19 were enrolled in this study. Of the 21 severe or critically severe patients (severe group), there were 11 males (52.4%) and 10 females (47.6%), with an average age of (61.6±16.4) years. Of the 42 mild or moderate patients, there were 25 males (59.5%) and 17 females (40.5%), with an average age of (40.7±15.7) years. The incidences of chills (22.8% vs 4.7%), fatigue (71.4% vs 21.4%), hemoptysis (14.3% vs 0), chest tightness or suffocation (28.6% vs 2.4%) in patients of the severe group were significantly higher than those of the control group (all P < 0.05). Compared with the mild group, a significant decrease was found in the absolute value of peripheral blood lymphocytes (0.92±0.47×10⁹/L vs 1.64±0.67×10⁹/L), CD4⁺ 167 (MdIQR: 107, 283/μL vs 520238, 597/μL) and CD8⁺ T lymphocyte count (MdIQR: 108103, 210/μL vs 425290, 533/μL) in patients of the severe group, and an obviously increase in C reactive protein (MdIQR: 20.849.66, 37.00 mg/L vs 4.551.60, 9.30 mg/L), erythrocyte sedimentation rate (MdIQR: 41.0 32.0, 59.0 mm/h vs 11.57.0, 25.0 mm/h), procalcitonin (MdIQR: 0.090.05, 0.26 ng/mL vs 0.04(0.03, 0.06) ng/mL), IL-6 (MdIQR: 19.708.91, 44.02 pg/mL vs 8.215.40, 16.70 pg/mL), serum ferritin (MdIQR: 644.9408.7, 1 066.0 U/L vs 281.7580.98, 430.40 U/L and lactate dehydrogenase (MdIQR: 309.1±120.2 U/L vs 212.2±81.5 U/L), and the differences were statistically significant (all P < 0.05). Logistic regression analysis revealed that age ≥ 60 years (OR=24.320, 95% CI: 2.272 - 260.293), C reactive protein ≥ 16 mg/L (OR=24.320, 95% CI: 2.272 - 260.293), CD4⁺ T lymphocytes count ≤ 300/μL (OR=14.428, 95% CI: 2.000 - 104.074), and serum ferritin level ≥ 500 U/L (OR=15.513, 95% CI: 1.735 - 138.702) were independent risk factors for the occurrence of severe COVID-19.

  Conclusion  Patients with severe or critically severe COVID-19 are dominated by the elderly over 60 years. The main early manifestations are fever, chills, fatigue, cough, chest tightness or suffocation, and hemoptysis. Age, CRP, CD4 cell count and serum ferritin contribute to early warnings of the disease severity.