Abstract: Objective Informing and providing help for the clinicians to judge the state of SARS cases punctually and actually by analyzing the risk factors of serious SARS cases.Methods Making comparison of 40 serious cases with 43 ordinary SARS cases retrospectively.Results In ordinary cases 98.2% of the cases were under 40 years old.All serious cases were over 50 years old.Most serious SARS cases had longer fever time with an average of 7.7 days.36.4% of the cases got fever lasted for more than 3 days or rose after descending on steroid therapy.45.0% of the cases companied with diarrhea for the average period of 6 days.The lymphocyte counting (L-cell<1.0×10⁹/L) took 91.7% and 38.0% separately in serious and ordinary cases with 41.2% of the serious cases showed steady descending in 15 days.The decrease of T cell subgroup,CD₄ and CD₃ in serious SARS cases (81.3% and 52.9% separately) was much higher than that in ordinary cases (50.0% and 22.2% separately).Conclusion The risk factors of serious SARS cases include age over 50 years,continuous fever with no effect on steroid therapy for 3 days or the temperature raises after descending,diarrhea over 6 days,lymphocyte counting descending steadily in 2 weeks period and serum enzyme raise twice over normal level.

Key words: SARS, Risk factors