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Table 1 Characteristics of hospitalized severe acute respiratory infection (SARI) patients and laboratory-confirmed influenza patients in 10 sentinel surveillance hospitals in 10 provinces, China, February 1, 2011 to October 27, 2013

From: Characterizing the epidemiology, virology, and clinical features of influenza in China’s first severe acute respiratory infection sentinel surveillance system, February 2011 – October 2013

Characteristics

All SARI patients (%) [n = 5,268]a

SARI patients with confirmed influenza (%) [n = 299]a

SARI patients without confirmed influenza (%) [n = 4,678]a

pvalue

Male sex

3,091 (58.7)

193 (64.5)

2,725 (58.3)

0.202

Age, median (interquartile range [IQR], years)

12.0 (2.0-58.0)

20.0 (3.0-67.0)

11.0 (2.0-56.0)

0.003 *

Age group

 <6 months

357(6.8)

11 (3.7)

335 (7.2)

<0.001 *

 6 - 11 months

392 (7.4)

15 (5.0)

362 (7.7)

 12 - 23 months

458 (8.7)

24 (8.0)

411 (8.8)

 2 - 4 years

928 (17.6)

51 (17.1)

836 (17.9)

 5 - 9 years

412 (7.8)

37 (12.4)

351 (7.5)

 10 - 14 years

137 (2.6)

7 (2.3)

125 (2.7)

 15 - 49 years

976 (18.5)

38 (12.7)

886 (18.9)

 50 - 64 years

554 (10.5)

35 (11.7)

476 (10.2)

 ≥65 years

1050 (19.9)

81 (27.1)

896 (19.2)

Underlying chronic medical conditions

At least oneb

1407 (26.7)

111 (37.1)

1296 (27.7)

<0.001 *

 Cardiovascular disease

792 (15.0)

64 (21.5)

728 (15.6)

<0.001 *

 Chronic obstructive pulmonary diseasec

198 (3.8)

23 (7.7)

175 (3.7)

0.064

 Diabetes mellitus

244 (4.6)

22 (7.4)

222 (4.7)

0.215

 Chronic bronchitis

205 (3.9)

22 (7.4)

183 (3.9)

0.049 *

 Cancer/Tumor

138 (2.6)

13 (4.3)

125 (2.7)

0.043 *

 Asthma

85 (1.6)

2 (0.7)

83 (1.8)

0.040 *

Vaccinated with seasonal influenza vaccine during past year

47 (1.1)

6 (2.7)

41 (1.1)

0.041 *

Clinical history and physical examination

 Fever

4440 (84.3)

284 (95.0)

4156 (88.8)

<0.001 *

 Highest temperature after onset, median (interquartile range [IQR], °C)

39.0 (38.5-39.5)

39.0 (38.6-39.6)

39.0 (38.5-39.5)

0.072

 Abnormal breath sounds on auscultation

2950 (60.0)

196 (65.6)

2754 (58.9)

0.071

 Cough

4235 (80.4)

256 (85.6)

3979 (85.1)

0.592

 Sore throat

1661 (31.5)

103 (34.4)

1558 (33.3)

0.028 *

 Difficulty breathing

1449 (27.5)

112 (37.5)

1387 (29.6)

0.012 *

Clinical pneumonia

    

 Abnormal chest X-ray performance

2868 (54.4)

176 (58.9)

2692 (57.5)

0.992

 Diagnosis of clinical pneumonia

1189 (22.6)

66 (22.1)

1123 (24.0)

0.925

Clinical course, median (IQR), days

 From illness onset to hospital admission

3 (1–6)

2.5 (1–5)

3 (1–6)

0.802

 Length of stay in hospital

8 (6–12.5)

9 (6.75-14)

8 (5–12)

0.593

Admission to ICUd

61 (1.2)

5 (1.7)

56 (1.2)

0.840

Deathe

98 (1.9)

12 (4.0)

86 (1.8)

0.013 *

  1. aData are presented as no. (%) of patients unless otherwise indicated. Denominators for testing are indicated. Percentages may not total 100 because of rounding. As a proportion of SARI case patients did not have influenza testing results, the sum of all patients with and without confirmed influenza is not equal to the total number of SARI patients.
  2. bAt least one underlying medical condition defined as: admission diagnosis of any of the following: chronic obstructive pulmonary disease, asthma, cardiovascular disease, diabetes mellitus, chronic bronchitis, or cancer/tumor.
  3. cChronic obstructive pulmonary disease defined as a lung disease characterized by chronic obstruction of lung airflow that interferes with normal breathing and is not fully reversible.
  4. dICU denotes intensive care unit.
  5. eDuring hospitalization.
  6. *The symbol bold data means p<0.05.