Findings from an SGH study change the way COVID-19 patients are managed.

Chest x-rays may not be needed for COVID-19 patients with mild or no symptoms, a Singapore General Hospital (SGH) study has found. The findings can help hospitals overwhelmed by the pandemic to zero in on managing COVID-19 patients better.

The study is also significant as it examined a large sample population, comprising younger COVID-19 patients with mild or no symptoms during a relatively early period of the pandemic. The patients were diagnosed with the disease using reverse transcription polymerase chain reaction (RTPCR) test, a molecular diagnostic test using samples collected from nasal swabs. Not all had undergone chest radiographs or x-rays before the study.

“Most COVID-19 patients do not develop lung infection. Unless they show signs of deterioration, putting everyone through a chest x-ray may not be necessary. Chest x-rays should therefore be reserved for those who display symptoms or have other medical risk factors,” said Dr Charles Goh, Consultant, Department of Nuclear Medicine and Molecular Imaging, SGH, and senior author of the publication.

The study was published in peer-reviewed journal Radiology in December 2020, less than a year after COVID-19 was diagnosed in Singapore. It supports recommendations issued by international thoracic radiology group Fleischner Society, and further validates the guidelines’ application in Asian patients.

According to Dr Benjamin Kuo, Medical Officer, Department of Diagnostic Radiology, Changi General Hospital, “effective use of resources during these unprecedented times is crucial. We believe that our findings will be of help to other countries around the world that are still dealing with large-scale community outbreaks, as the resources required for an x-ray can perhaps be redirected to other areas with more pressing needs”.

Dr Kuo, the paper’s lead author, was attached to SGH’s Department of Diagnostic Radiology at the time of the study.

In the early days of the pandemic, x-rays and scans were regularly used on people suspected of being infected with the COVID-19 virus. Pneumonia, one of the symptoms of the disease, can indicate disease severity and complications.

SGH and its sister SingHealth institutions operated a community care facility (CCF) for COVID-19 patients with mild symptoms at the Singapore Expo. This provided an opportunity to collect, analyse and study the data of 5,621 patients admitted to the CCF in May 2020.

The patients, aged between 17 and 60 years, were not expected to see their conditions deteriorate as they were well with mild or no symptoms. The study used various criteria, and only patients aged 36 years and older admitted to the CCF from 3 to 31 May 2020 were included. The final tally was 1,964 patients, all of whom underwent x-ray screening as part of their initial medical assessment.

Of the 1,964, 39 patients (or 2 per cent) had x-rays suggesting lung infections. Seventeen of the 39 were assessed to be at low risk of deteriorating and were discharged from the CCF subsequently. Another 14 were transferred to hospitals for closer monitoring. The remaining eight were also hospitalised for respiratory symptoms or other abnormalities in their vital signs. One of them needed intensive care, and another was admitted to the high dependency ward. Three needed supplemental oxygen while a fourth received intravenous medication. However, all recovered well.

An overwhelming 1,925 of the 1,964 patients had normal x-rays; 1,899 of the patients remained stable until discharge, while 26 were transferred to hospitals for further treatment.

Of the 3,657 patients excluded from undergoing x-ray on CCF admission, 3,605 remained stable until discharge. Six were sent to hospital later for respiratory symptoms, and just one of them had a lung infection. All six recovered well, and did not need oxygen therapy or intravenous medications.

As the study showed that very few patients with mild or no symptoms needed x-rays, Dr Goh said that “management of patients can now be directed by their clinical signs and symptoms instead. Healthcare workers in other countries can change practices and be confident about not performing chest radiographs in clinically well patients”.

In the early days of the pandemic, chest x-rays and CT scans were used in many parts of the world to diagnose COVID-19. While COVID-19 patients may have abnormalities on either a chest x-ray or CT scan, many other lung problems can cause similar irregularities.

Having signs of infection on an x-ray image will not mean that the patient has COVID-19. Conversely, the absence of an abnormal x-ray does not necessarily exclude COVID-19, as the study has shown.

Still, chest x-rays are useful in determining the treatment plan in older COVID-19 patients, even if they do not show any symptoms. “If the chest x-ray shows signs of infection, it can be assumed that the patient will need more intensive management in a hospital,” said Dr Goh.

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