Material and method
This observational clinical qualitative study was conducted at Bærum Hospital, Vestre Viken. Bærum Hospital is a local hospital for a population of about 190 000 inhabitants of Viken county (8). The purpose of the study was to systematically survey features such as age, comorbidity and frailty, symptoms and examination findings and the course of illness of patients admitted with COVID-19. All hospitalised patients diagnosed with COVID-19 infection before or during their stay in hospital were included successively in the study. COVID-19 was confirmed on qualitative detection of nucleic acid from SARS-CoV-2 in specimens of laryngeal and pharyngeal secretion using real time polymerase chain reaction (RT-PCR) (9).
When reviewing patients' medical records we registered age, sex, comorbidity and frailty prior to the present illness, laboratory findings, results of radiological scans, self-reported symptoms, vital signs, need for respiratory support, intensive care treatment and death while in hospital. Comorbidity was surveyed using the Charlson Comorbidity Index (CCI) (10). The tool gives points for age and chronic diseases such as cardiopulmonary disease, diabetes mellitus, dementia and malignant diseases. The CCI score has proved to predict mortality and has been validated on hospitalised patients (11). Frailty was assessed by means of the Clinical Frailty Scale (CFS). The tool can be used to assess the vulnerability and frailty of elderly people, on the basis of their mobility, cognitive function and need for help in daily activities 14 days prior to the onset of acute illness (12) and it has been proposed to use it as support for assessing the treatment level needed during the COVID-19 outbreak (13). CCI and CFS scores were assigned by the last author on the basis of data in the patient's records.
In addition, NEWS2, qSOFA, CRB-65 and Systemic Inflammatory Response Syndrome (SIRS) scores on admission were calculated on the basis of the first clinical examination after admission. NEWS2 scores and as a rule qSOFA scores were noted in the records. For the other clinical scoring systems and in cases of missing total scores, the last author calculated the total score using figures noted in patient records.
In NEWS2, the physiological parameters respiratory rate, peripheral oxygen saturation, systolic blood pressure, pulse rate, level of consciousness/confusion and temperature are given scores of 1–3 points. In addition, two points are given if the patient receives supplemental oxygen. A total score of ≥ 5 indicates severe acute illness (14). In qSOFA, one point is scored for respiratory rate ≥ 22/min, systolic blood pressure ≤ 100 mm Hg and altered mental status (Glasgow Coma Scale (GCS) score <15) (15). A qSOFA score of ≥ 2 may be a predictor of a poor prognosis for patients with infection (15). CRB-65 is used to assess illness severity and has been validated on persons hospitalised with pneumonia (16). New-onset confusion, respiratory rate ≥30/min, low blood pressure (systolic < 90 mm Hg or diastolic ≤ 60 mm Hg) and age ≥ 65 years score one point each. Patients with a score of ≥ 2 are most frequently in need of hospitalisation (17). We defined systemic inflammatory response syndrome (SIRS) as that at least two of four SIRS criteria should be met (temperature > 38 °C or < 36 °C, pulse rate > 90/min, respiratory rate > 20/min or hypocapnia with pCO2 < 4.3 kPa, leukocytes ≥ 12 · 109/l or < 4 · 109/l) (15).
Severe illness was defined as requiring hospitalisation. Critical illness was defined as treatment in the Intensive Care Department or death in hospital up to 31 March 2020.