ObjectivesThis study aims to compare the clinical manifestations, laboratory findings, outcomes and overall survival time of patients with COVID-19 with and without comorbidities.DesignRetrospective design.SettingThis study was undertaken at two hospitals in Damascus.ParticipantsA total of 515 Syrian patients met the inclusion criterion, laboratory-confirmed COVID-19 infection following the Centers for Disease Control and Prevention. Exclusion criteria were suspected and probable cases that were not confirmed with a positive reverse transcription-PCR assay, and patients who self-discharged from the hospital against medical advice.Primary and secondary outcome measuresFirst, assess the impacts of comorbidities on COVID-19 infection in four areas (clinical manifestations, laboratory findings, severity and outcomes). Second, calculate the overall survival time for patients with COVID-19 with comorbidities.ResultsOf 515 patients included, 316 (61.4%) were male and 347 (67.4%) had at least one coexisting chronic disease. Patients with comorbidities compared with no comorbidities were more vulnerable to poor outcomes such as severe infection (32.0% vs 9.5%, p<0.001), severe complications (34.6% vs 9.5%, p<0.001), the need for mechanical ventilation (28.8% vs 7.7%, p<0.001) and death (32.0% vs 8.3%, p<0.001). Multiple logistic regression showed that age ≥65 years old, positive smoking history, having ≥2 comorbidities and chronic obstructive pulmonary disease were risk factors linked to severe COVID-19 infection in patients with comorbidities. Overall survival time was lower among patients with comorbidities (vs no comorbidities), patients with ≥2 comorbidities (vs one comorbidity), and patients with hypertension, chronic obstructive pulmonary disease, malignancy or obesity (vs other comorbidities) (p<0.05).ConclusionThis study revealed that COVID-19 infection had poor outcomes among those with comorbidities. Severe complications, mechanical ventilation usage and death were more prevalent among patients with comorbidities compared with those with no comorbidities.