Background The recent outbreak of COVID-19 has rapidly spread worldwide. A large proportion of COVID-19 patients with chronic underlying complications have been reported to be in severe condition and show unpromising clinical outcomes. But whether chronic comorbidities are risk factors affecting the severity of COVID-19 has not been well described. Methods We included COVID-19 patients who had been admitted to Tongji Hospital, Tongji medical college of HUST (Wuhan, China) from January, 27, 2020 to March, 8, 2020 in this retrospective cohort study. The final date of follow-up was March, 30, 2020. All patients were diagnosed with COVID-19 according to Prevention and control Scheme for Novel Coronavirus Pneumonia published by National Health Commission of the People' s Republic of China and WHO interim. Demographic data, medical history, clinical symptoms and signs, laboratory findings, chest computed tomography (CT), treatment and clinical outcomes were extracted from electronic medical records with standardized data collection forms and compared among different groups. Results 1031 COVID-19 inpatients were included in this study, of whom 866 were discharged and 165 were dead in hospital. 73% of 165 dead patients had complicated chronic comorbidities. Of the 1031 patients, 514 (50%) were combined with chronic comorbidities, and showed CFR 2.8 times as that of patients without any underlying disease. The number of patients with hypertension accounted for three fourths of those with concomitant underlying diseases. The univariable regression revealed that patients in the simple hypertension group showed overall risk higher than those in the simple diabetes mellitus group. In the age-grouped research, patients in the hypertension senile group were proved to be at the highest risk, which might be associated with the level of LDH and eGFR. In this retrospective cohort study, 166 (43%) patients with hypertension took CCB during the hospitalization, the odds ratio of CFR in patients with hypertension taking CCB group was 0.68 (P = 0.155), compared to those not. Conclusion Our data shows that the clinical manifestations of most hospitalized patients with COVID-19 are actually systemic syndromes, although COVID-19 is defined as novel coronavirus pneumonia in China. Hypertension is not just a chronic underlying comorbidity, but also a risk factor affecting the severity of COVID-19 and does play a critical role in improving patients' clinical outcomes. Therefore, hypertension management in patients with COVID-19 should be a major challenge in the diagnostic and therapeutic strategies, including optimal management of blood pressure and pathophysiological status.