The first consecutive 5000 patients with Coronavirus Disease 2019 from Qatar; a nation-wide cohort study

Hamad Medical Corporation (HMC) encompasses multiple hospital facilities and provides all COVID-19 medical care for the 2.8 million population of Qatar. In response to the COVID-19 pandemic, existing clinical services were re-organized and two brand new hospital facilities were opened ahead of their originally planned dates. In total, non-ICU bed capacity was increased from 2143 to 3469 (61.9% increase), and ICU beds from 130 to 529 (306.9% increase). From a healthcare delivery perspective, HMC defines adults as those aged above 14 years.

SARS-CoV-2 infection was diagnosed by real-time polymerase chain reaction (RT-PCR) assays TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, Waltham, Massachusetts) or Cobas SARS-CoV-2 Test (Roche Diagnostics, Rotkreuz, Switzerland) on respiratory tract specimens. Severity of COVID-19 was classified according to the WHO guidelines [11]. SARS-CoV-2 testing was offered to all individuals presenting with symptoms suggestive of COVID-19, known close contacts of confirmed cases including healthcare workers, and all returning travelers.

Patients with asymptomatic SARS-CoV-2 infection or mild COVID-19 without significant co-morbidities were isolated in dedicated community facilities until they had two consecutive negative SARS-CoV-2 RT-PCR results from upper airway samples taken more than 24 h apart. COVID-19 patients with significant co-morbidities or moderate to severe disease were hospitalized for inpatient management. Standard care for hospitalized patients involved supportive care and investigational antiviral therapy. Individual regimens were selected by the treating physicians based on severity of disease, the presence of contra-indications or potential drug-drug interactions, and the patients’ preferences. Twenty five individuals included in this study had been elsewhere reported [12].

We used the HMC COVID-19 database to identify the first consecutive 5000 patients with RT-PCR-confirmed COVID-19 who would complete 60 days of follow up from date of diagnosis by June 17, 2020. During the period between May 24 and June 18, 2020, clinical and laboratory data were retrieved from HMC’s electronic healthcare system. Final status 60 days after COVID-19 diagnosis was ascertained against the electronic healthcare system and Qatar’s national deaths records.

The report was prepared according the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) recommendations [13].

The primary endpoint was all-cause mortality within 60 days after RT-PCR confirmation of SARS-CoV-2 infection. For hospitalized patients, we also assessed risk factors for admission to ICU.

We summarized categorical data as numbers and percentages and compared them using Pearson’s chi-squared or Fisher’s exact test, as appropriate. Continuous data are presented as medians and interquartile ranges (IQR) and compared among groups using Wilcoxon rank-sum test. The majority (82 patients, 75.2%) of admissions to ICU occurred within of the first 48 h from hospitalization. We therefore used logistic regression to explore predictors of admission to ICU.

Baseline variables were included in the univariable logistic regression analysis if their between groups differences were associated with P values of < 0.05. Independent variables in the multivariable regression model were chosen based on their association with P values of < 0.1 in the univariable logistic regression, and on their ready availability before any COVID-19-related clinical evaluation. Due to the number of events in the study, we limited the number of independent variables in the multivariable regression analysis to eight to avoid overfitting the model. The final multivariable logistic regression model included age, male sex, body mass index (BMI), defined as body weight in kilograms divided by squared height in meters, and co-existing diabetes mellitus, systemic hypertension, coronary artery disease, chronic liver disease, and chronic kidney disease. Multiple imputations approach was applied for variables with > 5% missingness.

Out of 4869 individuals aged > 14 included in this report, 1409 (28.9%) were hospitalized. The majority (1167, 82.8%) were males and the median age was 39 years (IQR 30–50). Nationalities from WHO’s South-East Asia Region (791, 56.1%) and Eastern Mediterranean Region (485, 34.4%) were most frequent. Diabetes (327, 23.2%) and hypertension (292, 20.7%) were the most common co-existing medical conditions. Fever (58.3%) and cough (59.1%) were the most common presenting symptoms. Median BMI was 26.8 kg/m² (IQR 23.9–29.8). Most patients (1233, 87.5%) did not require oxygen therapy within the first 24 h of hospitalization. Hydroxychloroquine (1044, 74.1%), azithromycin (898, 63.7%), and lopinavir-ritonavir (522, 37%) were the most commonly used investigational antiviral agents.

Compared with those who did not require ICU admission, ICU patients were significantly more likely to be males (P 0.005), have higher median age (P < 0.001) and to have multiple co-morbidities (P < 0.001) (Table 1). They also had significantly higher median BMI (28.2 versus 26.6, P < 0.001) and were more likely to present with fever, cough and dyspnea (P < 0.001 for each). Within the first 24 h of hospitalization, ICU patients had significantly higher median heart rate (95 versus 86 per minute, P < 0.001), and respiratory rate (26.5 versus 19 per minute, P < 0.001), significantly lower oxygen saturation (94% versus 98%, P < 0.001) (Table 1). In addition, baseline blood investigations from ICU patient were significantly more likely to show lower median peripheral lymphocyte count (1.0 versus 1.7 ×  10⁹/L, P < 0.001), and higher median serum creatinine (90 versus 80 μmol/L, P < 0.001), and C-reactive protein (CRP) (107.7 versus 7, P < 0.001). Complications such as acute kidney injury (43.5% versus 1.5%), and myocardial injury (14.8% versus 0.3%, P < 0.001) were more common in ICU compared with non-ICU patients. Other baseline characteristics, management, and complications variables in hospitalized COVID-19 adults included in this study are shown in Table 1.

In univariable analysis, the odds of admission to ICU were significantly higher in older patients, males compared with females, and in those with diabetes, hypertension, coronary artery disease, or chronic lung, liver, or kidney disease, and in those with higher BMI (Table 2). The presence of cough, dyspnea, or fever, elevated baseline heart rate or respiratory rate, decreased oxygen saturation, lower lymphocyte count, and increased serum creatinine, CRP, and alanine transaminase (ALT) were also associated with admission to ICU (Table 2).

In the multivariable logistic regression, we found that older age, male sex, co-existing diabetes or chronic kidney disease, and higher BMI were all independently associated with increased risk of need for ICU admission (Table 2).

A total of 14 patients (0.28%) died within 60 days of follow up. The median age of fatal COVID-19 cases was 59.5 years (IQR 55.8–68). Most deceased patients were males (13, 92.9%) and most (8, 57.1%) had two or more co-morbidities (see Table S2 in Supplementary Material).

Two patients died without hospitalization. The first was a 59-year-old man with a history of hypertension and heavy smoking. He had asymptomatic SARS-CoV-2 infection and was isolated in a community facility pending viral clearance. He developed severe chest pain and cardiopulmonary arrest 17 days after COVID-19 diagnosis. The second patient was a 74-year-old man with end-stage kidney disease, hypertension, diabetes and coronary artery disease. He developed cardiopulmonary arrest shortly after presenting to the emergency department in severe respiratory distress. A post-mortem examination to confirm the cause of death was not performed in either case.

The remaining 12 deaths all occurred in patients who were in ICU with severe acute respiratory distress syndrome requiring prolonged invasive mechanical ventilation. Deaths occurred after a median of 24 days (IQR 14–49) from COVID-19 diagnosis. Ten (86.5%) deaths occurred in patients aged 55 or older. The remaining two were in patients aged 54 years and 24 years. The former had diabetes, hypertension, and obesity (BMI 38.7). The latter patient presented with fulminant hepatitis and his hepatitis B serology was positive for surface IgM antibodies. He died within 11 days with encephalopathy and multi-organ failure.

The study included 26 pregnant women with SARS-CoV-2 infection with median age of 29 years (IQR 25.5–33). Nineteen (73.1%) were hospitalized, including one (3.8%) in ICU, and all were discharged within the follow up period. Ten (38.5%) pregnant women with COVID-19 gave birth during the follow up period; all resulting in healthy babies with negative SARS-CoV-2 tests (see Table S3 in Supplementary Material).

A total of 135 patients in this cohort were healthcare workers. Their median age was 35 years (28–43) and the majority were males (101, 74.8%). The most frequent professional background of affected healthcare workers was nursing (49, 36.3%), and allied healthcare (27, 20%) (see Table S4 in Supplementary Material). Out of 63 (46.6%) who required hospitalization, three (2.2%) required admission to ICU. All healthcare workers in this study were alive and out of hospital at end of follow up (see Table S4 in Supplementary Material).

There were 131 individuals aged 14 years or less in the study, of which 69 (52.7%) were males. Median age was 7 years (IQR 4–10). Children were mostly diagnosed in the context of contact screening (75/123, 61%), and were not hospitalized (116, 88.5%). The majority (120, 91.6%) of children, including all seven infants, had family members with confirmed COVID-19 (see Table S5 in Supplementary Material).