Clinical characteristics, risk factors, and rate of severity of a nationwide COVID-19 Saudi cohort.

Objective: To evaluate COVID19 patients' clinical characteristics, risk factors, and COVID-19 severity at baseline and over one month following hospitalization. Design setting and participants: This prospective cohort study of 598 Saudi COVID19 patients recruited from 4 major medical institutions nationwide between June 01, 2020, and February 28, 2021. Patients were stratified into different demographic characteristics and COVID-19 severity scale. Results: Of the 598 hospitalized adult COVID19 patients (mean [range] age, 57 [46 to 65] years; 59% male), 300 (50.16%) had severe clinical COVID-19. Comorbidity was high among hospitalized patients (73.5 %), with diabetes mellitus (n=; 46%) and hypertension (n=; 41%) being the most common prevalent. In a multivariate logistic regression model, patient demographics and clinical factors such as age (odds ratio [OR], 1.014 per year; 95% CI, 1.003-1.025), male sex (OR, 1.63; 95% CI, 1.02-2.62), diabetes mellitus (OR, 1.63; 95% CI, 1.06-2.49), obesity (OR, 1.93; 95% CI, 1.26-2.94), oxygen saturation<92% (OR, 4.83; 95% CI, 2.96-7.86), and high neutrophil to lymphocyte ratio (OR, 3.74 per unit; 95% CI, 1.96-7.14) were independently associated with higher COVID-19 severity. Moreover, more than 60% of male patients and middle-aged patients (40-60 years) were associated with the use of COVID-19 medications, including favipiravir and dexamethasone, during their hospital stay. Additionally, the rate of invasive mechanical ventilation was the highest in female patients (61.5%) and in middle-aged patients (46.2%). However, the death rate was slightly higher in males (56%) than in female patients and in elderly patients (52%). In Cox proportional analysis, age associated with increased risk of 60-days mortality (Hazard ratio; HR, 1.05 per year; 95% CI, 1.018-1.098). Additionally, the Riyadh region associated with more COVID-19 cases required invasive respiratory support (57.7%) and Jeddah was associated with more deceased COVID-19 cases (44%). Conclusions: The data shows that comorbidity is associated with hospitalization among COVID-19 patients, which indicates the level of severity. Infection during the winter season (November), male gender, elderly, and those with pre-existing diabetes mellitus or obesity were associated with higher COVID-19 clinical severity.