Clinical characteristics, laboratory abnormalities and CT findings of COVID-19 patients and risk factors of severe disease: a systematic review and meta-analysis

Ann Palliat Med. 2021 Feb;10(2):1928-1949. doi: 10.21037/apm-20-1863. Epub 2021 Jan 27.


Background: The coronavirus disease 2019 (COVID-19) is an emerging pandemic of global public health concern. We aimed to summarize the characteristics of COVID-19 patients in the early stage of the pandemic and explore the risk factors of disease progression.

Methods: We conducted a systematic review with meta-analysis, searching three databases for studies published between January 1, 2020, and March 18, 2020. We used random-effects models to calculate the 95% confidence intervals of pooled estimated prevalence and the odds ratio between the severe and nonsevere cases.

Results: Ninety studies involving 16,526 COVID-19 patients were included. Hypertension (19.1%) and diabetes (9.5%) were the most common comorbidities. The most prevalent clinical symptoms were fever (78.4%), cough (58.5%), and fatigue (26.4%). Increased serum ferritin (74.2%), high C-reactive protein (73.3%), and high erythrocyte sedimentation rate (ESR) (72.2%) were the most frequently reported laboratory abnormalities. Most patients had bilateral lung involvement (82.2%) and showed peripheral (66.9%) and subpleural (62.1%) distribution, with multifocal involvement (73.1%). And the most common CT features were vascular enlargement (64.3%), ground-glass opacity (GGO) (60.7%), and thickened interlobular septa (55.1%). Respiratory failure was the most common complication (30.7%) and the overall case-fatality rate (CFR) was 4.2%. Moreover, male, history of smoking, and comorbidities might influence the prognosis. Most clinical symptoms such as fever, high fever, cough, sputum production, fatigue, shortness of breath, dyspnoea, and abdominal pain were linked to the severity of disease. Some specific laboratory indicators implied the deterioration of disease, such as leucocytosis, lymphopenia, platelet, alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, creatinine, creatine kinase (CK), lactic dehydrogenase (LDH), C-reactive protein, procalcitonin (PCT), and D-dimer. Besides, the risk of bilateral pneumonia, consolidation, pleural effusion, and enlarged mediastinal nodes was higher in severe cases.

Conclusions: Most COVID-19 patients have fever and cough with lymphopenia and increased inflammatory indices, and the main CT feature is GGO involved bilateral lung. Patients with comorbidities and worse clinical symptoms, laboratory characteristics, and CT findings tend to have poor disease progression.

Keywords: CT findings; Coronavirus disease 2019 (COVID-19); clinical characteristics; laboratory abnormalities; risk factors.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Biomarkers / blood
  • COVID-19 / blood
  • COVID-19 / diagnosis*
  • COVID-19 / pathology
  • Comorbidity
  • Cough
  • Fever
  • Humans
  • Inflammation
  • Lung / diagnostic imaging
  • Lung / pathology
  • Lymphopenia
  • Retrospective Studies
  • Risk Factors
  • Tomography, X-Ray Computed


  • Biomarkers