Objective: To study the differences in clinical characteristics, risk factors, and complications across age-groups among the inpatients with the coronavirus disease 2019 (COVID-19). Methods: In this population-based retrospective study, we included all the positive hospitalized patients with COVID-19 at Wuhan City from December 29, 2019 to April 15, 2020, during the first pandemic wave. Multivariate logistic regression analyses were used to explore the risk factors for death from COVID-19. Canonical correlation analysis (CCA) was performed to study the associations between comorbidities and complications. Results: There are 36,358 patients in the final cohort, of whom 2,492 (6.85%) died. Greater age (odds ration [OR] = 1.061 [95% CI 1.057-1.065], p < 0.001), male gender (OR = 1.726 [95% CI 1.582-1.885], p < 0.001), alcohol consumption (OR = 1.558 [95% CI 1.355-1.786], p < 0.001), smoking (OR = 1.326 [95% CI 1.055-1.652], p = 0.014), hypertension (OR = 1.175 [95% CI 1.067-1.293], p = 0.001), diabetes (OR = 1.258 [95% CI 1.118-1.413], p < 0.001), cancer (OR = 1.86 [95% CI 1.507-2.279], p < 0.001), chronic kidney disease (CKD) (OR = 1.745 [95% CI 1.427-2.12], p < 0.001), and intracerebral hemorrhage (ICH) (OR = 1.96 [95% CI 1.323-2.846], p = 0.001) were independent risk factors for death from COVID-19. Patients aged 40-80 years make up the majority of the whole patients, and them had similar risk factors with the whole patients. For patients aged <40 years, only cancer (OR = 17.112 [95% CI 6.264-39.73], p < 0.001) and ICH (OR = 31.538 [95% CI 5.213-158.787], p < 0.001) were significantly associated with higher odds of death. For patients aged >80 years, only age (OR = 1.033 [95% CI 1.008-1.059], p = 0.01) and male gender (OR = 1.585 [95% CI 1.301-1.933], p < 0.001) were associated with higher odds of death. The incidence of most complications increases with age, but arrhythmias, gastrointestinal bleeding, and sepsis were more common in younger deceased patients with COVID-19, with only arrhythmia reaching statistical difference (p = 0.039). We found a relatively poor correlation between preexisting risk factors and complications. Conclusions: Coronavirus disease 2019 are disproportionally affected by age for its clinical manifestations, risk factors, complications, and outcomes. Prior complications have little effect on the incidence of extrapulmonary complications.Copyright © 2022 Zhang, Wu, He, Liu, Liu, Tang, Li, Yang, Liang, Xu, Wang and Wang.