Characteristics and Outcomes of Patients with Severe Acute Respiratory Syndrome (SARS) in Hong Kong

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The summary below is from the full report titled "Outcomes and Prognostic Factors in 267 Patients with Severe Acute Respiratory Syndrome in Hong Kong." It is in the 4 November 2003 issue of Annals of Internal Medicine (volume 139, pages 715-723). The authors are K.W. Choi, T.N. Chau, O. Tsang, E. Tso, M.C. Chiu, W.L. Tong, P.O. Lee, T.K. Ng, W.F. Ng, K.C. Lee, W. Lam, W.C. Yu, J.Y. Lai, S.T. Lai, and the Princess Margaret Hospital SARS Study Group.

What is the problem and what is known about it so far?

Severe acute respiratory syndrome (SARS) is a serious illness caused by a virus called a coronavirus. SARS was first described in Asia in February 2003. It was discovered in Chinese patients who had fever and severe breathing problems. In spring 2003, SARS quickly spread among humans with close person-to-person contact. More than 8000 people in Asia, Europe, and North and South America became sick with SARS. Some places, such as Hong Kong, set up quarantine hospitals to handle the large numbers of patients with the illness. By July 2003, the SARS outbreak was contained. Because SARS is a newly discovered viral illness, most doctors don't know how patients presented with the illness or what their outcomes were.

Why did the researchers do this particular study?

To describe the characteristics, course, and outcomes of patients with SARS.

Who was studied?

267 people admitted to a hospital in Hong Kong for suspected SARS.

How was the study done?

The researchers reviewed medical records of patients who were admitted to the hospital for probable SARS from February 26 to March 31, 2003. During this time, health care workers used standard forms to record patient findings and results of laboratory and x-ray tests. All patients had tests (nasopharyngeal aspirates and blood tests) to detect coronavirus and antibodies to coronavirus. All but 1 patient received several therapies, including antibiotics, an antiviral drug, and steroids. Patients were followed for at least 3 months from their first day of hospitalization.

What did the researchers find?

Laboratory tests confirmed coronavirus infection in 227 of the 267 patients with suspected SARS. Most of these patients had presented with fever (99%), chills (74%), and muscle aches (about 50%). Some had had cough (about 40%), shortness of breath (about 20%), or abnormal sounds (rales) on lung examinations (about 20%). Almost all had had abnormal chest x-rays that showed features similar to pneumonia. Many had had low numbers of blood cells that make antibodies and fight infection (lymphocytes). During hospitalization, about 50% had diarrhea, about 50% had anemia, and about 25% required intensive care for severe problems with breathing. Twelve percent died within 3 months. Age older than 60 years and elevated levels of lactate dehydrogenase (a blood test that indirectly reflects cell death) were associated with increased risk for death.

What were the limitations of the study?

Study data were obtained from review of medical records. Some patients may have had symptoms and findings that were not recorded in the records. Patients received antiviral agents (ribavirin), antibiotics, and steroids. These treatments, rather than SARS, may have caused some of the findings that occurred during hospitalization.

What are the implications of the study?

Some patients with SARS may not present with breathing problems or cough even though they have abnormal chest x-rays. Diarrhea may be common during the course of SARS, and older age is associated with increased risk for death.