Since being first reported in Wuhan, China, in December 8, 2019, the outbreak of the novel coronavirus, now known as COVID-19, has spread globally. Some case studies regarding the characteristics and outcome of patients with COVID-19 have been published recently. We conducted a meta-analysis to evaluate the risk factors of COVID-19.Medline, SinoMed, EMBASE, and Cochrane Library were searched for clinical and epidemiological studies on confirmed cases of COVID-19.The incidence of fever, cough, fatigue, and dyspnea symptoms were 85.6 % (95CI 81.3-89.9 %), 65.7 % (95CI 60.1-71.4 %), 42.4 % (95CI 32.2-52.6 %) and 21.4 % (95CI 15.3-27.5 %). The prevalence of diabetes was 7.7 % (95CI 6.1-9.3 %), hypertension was 15.6 % (95CI 12.6-18.6 %), cardiovascular disease was 4.7 % (95CI 3.1-6.2 %), and malignancy was 1.2 % (95CI 0.5-1.8 %). The complications, including ARDS risk, ranged from 5.6-13.2 %, with the pooled estimate of ARDS risk at 9.4 %, ACI at 5.8 % (95CI 0.7-10.8 %), AKI at 2.1 % (95CI 0.6-3.7 %), and shock at 4.7 % (95CI 0.9-8.6 %). The risks of severity and mortality ranged from 12.6 to 23.5% and from 2.0 to 4.4 %, with pooled estimates at 18.0 and 3.2 %, respectively. The percentage of critical cases in diabetes and hypertension was 44.5 % (95CI 27.0-61.9 %) and 41.7 % (95CI 26.4-56.9 %), respectively.Fever is the most common symptom in patients with COVID-19. The most prevalent comorbidities are hypertension and diabetes which are associated with the severity of COVID-19. ARDS and ACI may be the main obstacles for patients to treatment recovery. The case severe rate and mortality is lower than that of SARS and MERS.