Background: Severe acute respiratory syndrome (SARS) has become a global public health emergency.

Objective: To evaluate the characteristics and outcomes of patients with SARS in Hong Kong and to identify predictors of mortality.

Design: Retrospective cohort study.

Setting: Quarantine hospital for patients with SARS in Hong Kong.

Patients: 267 consecutive patients hospitalized from 26 February to 31 March 2003 for probable or confirmed SARS.

Measurements: Clinical, laboratory, and radiographic measures; 3-month mortality rate.

Results: According to our case definition, there were 227 cases of confirmed SARS and 40 cases of probable SARS. Common presenting symptoms were fever (99% of patients), chills (74%), malaise (63%), and myalgia (50%). Laboratory findings included lymphopenia (73%), thrombocytopenia (50%), hyponatremia (60%), and elevated levels of lactate dehydrogenase (47%) and C-reactive protein (75%). During hospitalization, incidence of diarrhea (53%), anemia (53%), and acute renal failure (6%) increased. Sixty-nine patients (26%) required intensive care because of respiratory failure. The 3-month mortality rate was 12% (95% CI, 8% to 16%). Factors contributing to mortality were respiratory failure, acute renal failure, and nosocomial sepsis. On multivariate Cox regression, age older than 60 years (relative risk, 5.10 [CI, 2.30 to 11.31]; P < 0.001) and lactate dehydrogenase level greater than 3.8 micro kat/L at presentation (relative risk, 2.20 [CI, 1.03 to 4.71]; P = 0.04) were independent predictors of mortality.

Conclusion: Because of the longer follow-up period in our cohort, the mortality rate in these patients is higher than rates reported in previous studies. Advanced age and high lactate dehydrogenase level at presentation predict mortality. *For members of the Princess Margaret Hospital SARS Study Group, see the Appendix.