Case fatality rate of severe acute respiratory syndromes in Beijing.
ABSTRACT To describe the case fatality rate of SARS in Beijing.
Data of SARS cases notified from Beijing Center for Disease Control and Prevention (BCDC) and supplemented by other channels were collected. The data were analyzed by rate calculation.
The case fatality rate of SARS in Beijing was 7.66%, and had an ascending trend while the age of cases was getting older, and a descending trend while the epidemic development. The case fatality rate in Beijing was lower than that in other main epidemic countries or regions.
The risk of death increases with the increment of age of SARS patients. Beijing is successful in controlling and treating SARS.
BIOMEDICAL AND ENVIRONMENTAL SCIENCES 18, 220-226 (2005)
Case Fatality Rate of Severe Acute Respiratory Syndromes in Beijing
QI CHEN*, WAN-NIAN LIANG†,1, GAI-FEN LIU, MIN LIU#, XUE-QIN XIE‡, JIANG WU‡,
XIONG HE‡, AND ZE-JUN LIU‡
* School of Health Management and Education, Capital University of Medical Sciences, Beijing 100054, China;
#School of Public Health, Peking University, Beijing 100083, China; †Capital University of Medical
Sciences & Beijing Municipal Health Bureau, Beijing 100054, China; ‡Beijing Municipal
Centers for Disease Prevention and Control, Beijing 100013, China
Objective To describe the case fatality rate of SARS in Beijing. Methods Data of SARS cases notified from Beijing
Center for Disease Control and Prevention (BCDC) and supplemented by other channels were collected. The data were
analyzed by rate calculation. Results The case fatality rate of SARS in Beijing was 7.66%, and had an ascending trend
while the age of cases was getting older, and a descending trend while the epidemic development. The case fatality rate in
Beijing was lower than that in other main epidemic countries or regions. Conclusions The risk of death increases with the
increment of age of SARS patients. Beijing is successful in controlling and treating SARS.
Key words: SARS; Case fatality rate; Beijing
Severe acute respiratory syndrome (SARS), a
highly transmissible atypical pneumonia, is a new
clinical entity caused by a novel coronavirus. In
November 2002, SARS emerged in Guangdong
Province of China, and soon was transmitted into
Hongkong Special Administrative Region, Vietnam,
etc. In March 2003, SARS was imported into Beijing,
and the outbreak reached its peak in late April.
Beijing became one of the cities severely attacked by
SARS all over the world. When a large number of
SARS cases emerged in Beijing, Beijing municipal
authorities took the decisive measures to increase the
admission rate and the cure rate, in order to decrease
the case fatality rate and the attack rate of health care
workers. The case fatality rate was not only
concerned by the medical field but also by the health
administrators and publics. Up to August 16, 2003,
all the SARS patients were discharged from hospitals.
So it was possible to calculate the SARS case fatality
rate in Beijing. It is of great importance and value to
analyze the difference of SARS case fatality rate
between different populations and the variations of
the case fatality rate in different epidemic stages. It
could be served as the basis for the decision making of
how to prevent and control SARS among populations.
MATERIALS AND METHODS
All data of SARS cases were collected from
daily notification of Ministry of Health, P. R. China
and the database of infectious diseases established by
the Beijing Municipal Centers for Disease Prevention
and Control. In the dataset collected by Beijing
Municipal Centers for Disease Prevention and
Control, 2521 were clinically diagnosed as SARS
cases according to the interim diagnostic criteria set
by the Ministry of Health of China. All data from
foreign countries were downloaded from the WHO
Valid data of the 2521 cases were input into a
data file with Microsoft Excel-2000 software and
analyzed with SPSS version 10.0, and figures were
made with Microsoft Excel-2000 software. The case
fatality rate was calculated with the following
Case fatality rate=the number of cases died of
SARS/the clinically diagnosed SARS cases×100%.
1 Correspondence should be addressed to Wan-Nian LIANG.
Biographical note of the first author: Qi CHEN, male, born in 1977, master degree, majoring in epidemiology and health statistics.
Copyright © 2005 by China CDC
CASE FATALITY RATE IN BEIJING IN 2003
There were 2521 clinically diagnosed SARS
cases in the data collected by the Beijing Municipal
Centers for Disease Prevention and Control. Of the
cases, 1279 were males and 1242 were females,
accounting for 50.73% and 49.72%, respectively, and
there was no statistical gender significance. 30.98%
of the cases were aged 20-29 years.
Comparison of Case Fatality Rate Between Different
Populations in Beijing
In this study, the case fatality rate was compared
between the different populations by gender, age,
occupation, area, contact history with SARS patients,
classification of admitted hospital, interval from
onset to admission, different epidemic stages. A
comparison was also made between the case fatality rate
in Beijing and other regions.
Gender and Age
Of all the 2521 cases, 193 died of SARS, the
overall fatality rate of SARS was 7.66%. All the
cases were divided into 10 groups by age with the
interval of every 10 years. Two thousand five
hundred and eighteen eligible cases were analyzed, 3
survived cases were excluded because their age was
not clear. The number of cases and case fatality rate
in each age group are shown in Fig. 1. During the
epidemic of SARS in Beijing, the cases were mainly
distributed in the 20-, 30-, 40- age groups which
accounted for 72.36% of the total cases. The case
fatality rate increased with age. The fatality rate of
the groups younger than 49 years old, including the
20-, 30-, 40- age groups, was lower than the crude
fatality rate 7.66%. The case fatality rate in the 5
groups older than 50 was higher than 15%. Generally,
the case fatality rate increased with the age, but there
was a slight decrease in the 80-year-old group. Two
cases in the 90-year-old group died.
FIG . 1. SARS cases and case fatality rate by age in Beijing.
FIG . 2. Age specific fatality rate among clinically diagnosed male and female cases in Beijing.
CHEN ET AL.
Fig. 2 shows the case fatality rate by gender and
age. Since 3 survived cases whose age was unclear
were excluded, 1276 male cases and 1242 female
cases were analyzed. Of the 2518 cases, 107 males
and 86 females died. The case fatality rate of males
and females was 8.39% and 6.92%, respectively, and
no significant difference was found between the
males and females (χ2=1.665, P=0.197). Male fatality
rate showed a decrease in the 80-year-old group,
which was different from the female group. This
contributed to the change in the crude fatality rate in
the 80-year-old group.
The case fatality rate by occupation is shown in
Table 1. Among the 2516 cases who reported their
occupation, 191 died. The case fatality rate of retired
workers was the highest among all the occupations,
followed by the soldiers. The case fatality rate of the
cases who were farmer, industrial worker, teacher or
household-chorers was higher than the overall fatality
rate 7.66%. There were no children in day-care
Case Fatality Rate of SARS Patients by Occupation in Beijing
No. Cases Survived No. Cases Died Occupation Total Case Fatality Rate %
Farmer 53 6 59 10.17
Industrial Worker 208 20 228 8.77
Teacher 43 4 47 8.51
Official/Clerk 287 16 303 5.28
Food Handler 24 1 25 4.00
Health Care Worker 397 10 407 2.46
Armed Policemen 55 1 56 1.79
Children in Day-care
Children Staying at Home
3 0 3 0.00
Others 270 33 303 10.89
Total 2325 191 2516 7.59
The cases were divided into different groups
according to the area where they lived. Among 2447
cases who reported their living areas, 185 died. The
case fatality rate in each group is shown in Table 2.
Contact History With SARS Patients
The fatality rate of cases having contacted with
SARS patients was higher than that of cases having
no contact history with SARS patients (Table 3).
Classification of Hospitals
During the SARS epidemic period, some hospitals
were designated to admit SARS patients by the
government. The fatality rate of SARS cases admitted
to special hospitals for SARS patients was lower than
that in other hospitals (Table 4).
Interval Between Onset of SARS and Hospital Visit
During the SARS epidemic period, some cases
visited the hospital immediately after the onset of
SARS-like symptoms while some cases did not for
some reasons. The cases were divided into two
groups according to the interval between the onset of
SARS and the date admitted to hospitals (Table 5).
CASE FATALITY RATE IN BEIJING IN 2003
Fatality Rate of SARS Cases by Living Areas in Beijing
No. Cases Survived No. Cases Died Living Area Total Case Fatality Rate (%)
Xicheng 280 32 312 10.26
Haidian 476 41 517 7.93
Comparison of SARS Case Fatality Rate by Contact History With SARS Patients
No. Cases Survived No. Cases Died Contacting History Total Case Fatality Rate (%)
Note. *χ2=5.217, P=0.022.
Comparison of SARS Case Fatality Rate by the Classification of Hospitals
No. Case Survived No. Cases Died Type of Hospital Total Case Fatality Rate (%)
Special for SARS
Note. *χ2=109.729, P=0.000.
Comparison of Case Fatality Rate by the Interval Between Onset of SARS and Admitted Date
No. Case Survived No. Case Died Interval (days) Total Case Fatality Rate (%)
Note. *χ2=6.100, P=0.014.
CHEN ET AL.
Case Fatality Rate in Different Epidemic Stages
According to the number of new SARS cases
diagnosed in various periods during the epidemic, the
cases were divided into 5 stages: imported stage
(March 1 to March 31), spreading stage (April 1 to
April 15), peak stage (April 16 to May 5), slowly
decreasing stage (May 6 to May 19), terminating
stage (May 20-). Among the 2443 cases who reported
their onset date, 178 cases died, the case fatality
rate was 7.29%. The number of cases died of SARS
and the case fatality rate in each stage are shown in
FIG. 3. Cases died of SARS and the case fatality rate in each epidemic stage in Beijing.
Comparison of Cases Fatality Rate Between Beijing
and Other Regions
Fig. 4 shows the number of cases died of SARS
and the case fatality rate in the main epidemic areas
of mainland China. The case fatality rate in Inner
Mongolia was the highest, followed by Tianjing and
Beijing. The case fatality rates in these 3 regions
were all higher than 7%.
The case fatality rates of SARS patients in
Beijing and other main areas are shown in Fig. 5. The
case fatality rate in Beijing was relatively lower than
that in Taiwan, Hongkong, Canada, Singapore, and
Vietnam (Fig. 5).
FIG. 4. Cases died of SARS and the case fatality rate in the main epidemic areas in mainland China.
Case fatality rate is the proportion of persons
who died of a particular disease within a population
affected by this disease within a specified period of
time. The case fatality rate is influenced by the
severity of the disease, the diagnosis time after onset
and the regimen of treatment. The case fatality rate is
generally used to reflect the severity of the disease,
the diagnostic ability and the effectiveness of medical
Comparison of Case Fatality Rate in Different
No difference in case fatality rate of SARS
between genders was found in our study, which is
different from that reported by J. Karlberg et al. ,
who found that the case fatality rate of SARS in
Hongkong was significantly (P<0.0001) higher in
males than in females (21.9% versus 13.2%), and it