Epidemiology and Clinical Characteristics of People with Confirmed SARS-CoV-2 Infection during the Early COVID-19 Pandemic in Saudi Arabia

Abstract

This study provides epidemiologic and clinical characteristics of 492 consecutive patients diagnosed with SARS-CoV-2 infection at King Faisal Specialist Hospital and Research Centre in Saudi Arabia between March and September 2020. Data were collected from electronic case reports. The cohort was 54% male, with 20.4% aged >60 years, 19.9% aged 31−40 years, and 17% aged 41−50 years. The median incubation period was 16 days, with upper and lower 95% quartiles of 27 and 10 days, respectively. Most patients (79.2%) were symptomatic. Variables significantly different between symptomatic and asymptomatic patients were age, blood oxygen saturation percentage, hemoglobin level, lymphocyte count, neutrophil to lymphocyte (NTL) ratio, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level. Asymptomatic patients were mostly younger, with lower body mass index and ALT and AST levels but higher lymphocyte counts, NTL ratio, and CD4, CD8, natural killer cell, IgG, and IgM levels. Factors associated with increased risk of mortality were age (>42 years) and comorbidities, particularly diabetes mellitus and hypertension. Patients who were not given an antiviral regimen were associated with better prognosis than patients who received an antiviral regimen (HR, 0.07; 95% CI, 0.011−0.25). These findings will help clinicians and policymakers adopt best management and treatment options for SARS-CoV-2 infection.

Keywords: COVID-19; COVID-19 treatment regimens; SARS-CoV-2; Saudi Arabia; epidemiology.

Figure 1

Age group distribution of COVID-19 cases by symptom status (asymptomatic vs. symptomatic) shown as percentages. Most patients in this cohort with confirmed COVID-19 were older than 60 years (19%); 21% of the cohort was asymptomatic, whereas 79% was symptomatic. The highest percentage of asymptomatic patients (5%) was observed in the age group of 30 to 39 years.

Figure 2

Box plots of patient blood test results after diagnosis by illness severity as assessed by the need for mechanical ventilation (MV). (A) White blood cell count by illness severity, with higher counts observed for more severe illness. (B) Neutrophil absolute count by illness severity, with higher counts observed for more severe illness. (C) Lymphocyte absolute count by illness severity, with higher counts observed for milder illness. (D) Neutrophil to lymphocyte (NTL) ratio by illness severity, with higher ratios observed for more severe illness. (***) Significant p-value less than 0.001.

Figure 3

Instantons reproduction number (R_t) estimated using the EpiEstim package and modeled using a gamma distribution. Cases were detected for 155 days at KFSHRC. The average R value from 10 March to 11 August 2020, was 1.21. The red line shows the average median of R; dashed red line, confidence intervals; green line, incidence of cases reported; gray area, the lockdown period; and blue line, R = 1.

Figure 4

The estimated instantons reproduction number (R_t), using EpiEstim package and model using gamma distribution. Cases were detected for 155 days in Saudi Arabia. The average R-value from 10 March to 11 August 2020, was 1.23. The red line shows the average median of R, the dashed red line shows the confidence intervals, while the green line shows the incidence of cases reported, the grey area represents the time of lockdown, while the blue line represents the R = 1.