Estimating the Proportion of Asymptomatic COVID-19 Cases in an Italian Region with Intermediate Incidence during the First Pandemic Wave: An Observational Retrospective Study
Table 1
Comparison of characteristics between asymptomatic and symptomatic SARS-CoV-2 infections, Apulia region, Italy, February-July 2020.
Characteristics
Asymptomatic SARS-CoV-2 infections (no. 903)
Symptomatic SARS-CoV-2 infections (no. 3,633)
Total (no. 4,536)
Logistic regression analysis
Binary
Multivariate
No.
%
No.
%
No.
%
OR
95% CI
OR
95% CI
Sex
Female
483
53.49
1,734
47.73
2,217
48.88
Ref.
Ref.
Male
420
46.51
1,899
52.27
2,319
51.12
0.79
0.69-0.92
0.002
0.69
0.54-0.86
0.002
Age group, years
0-9
28
3.10
47
1.29
75
1.65
Ref.
Ref.
10-19
53
5.87
80
2.20
133
2.93
1.11
0.62-1.99
0.721
0.89
0.83-0.96
0.001
20-29
98
10.85
284
7.82
382
8.42
0.58
0.34-0.97
0.040
30-39
125
13.84
370
10.18
495
10.91
0.56
0.34-0.94
0.029
40-49
137
15.17
499
13.74
636
14.02
0.46
0.28-0.76
0.003
50-59
189
20.93
696
19.16
885
19.51
0.45
0.28-0.75
0.002
60-69
100
11.07
560
15.41
660
14.55
0.3
0.18-0.50
<0.001
70-79
63
6.98
436
12.00
499
11.00
0.24
0.14-0.41
<0.001
80-89
77
8.53
467
12.85
544
11.99
0.28
0.16-0.46
<0.001
≥90
33
3.65
194
5.34
227
5.00
0.27
0.16-0.52
<0.001
Single comorbidities
None
189
56.42
676
35.39
865
38.53
Ref.
Ref.
Cardiovascular disease
83
24.78
733
38.38
816
36.35
0.41
0.37-0.54
<0.001
Diabetes
14
4.18
244
12.77
258
11.49
0.21
0.12-0.36
<0.001
Chronic pulmonary disease
11
3.28
232
12.15
243
10.82
0.17
0.09-0.32
<0.001
Cancer
9
2.69
141
7.38
150
6.68
0.23
0.11-0.46
<0.001
Neurological diseases
22
6.57
178
9.32
200
8.91
0.44
0.28-0.71
0.001
Chronic kidney disease
3
0.90
110
5.76
113
5.03
0.1
0.03-0.31
<0.001
Obesity
5
1.49
89
4.66
94
4.19
0.2
0.08-0.5
0.001
Other metabolic diseases
10
2.99
58
3.04
68
3.03
0.62
0.31-1.22
0.170
Liver disease
2
0.60
33
1.73
35
1.56
0.22
0.05-0.91
0.037
HIV
2
0.60
26
1.36
28
1.25
0.27
0.06-1.17
0.081
At least one comorbidity
146
43.58
1,234
64.61
1,380
61.427
0.42
0.33-0.53
<0.001
0.55
0.41-0.73
<0.001
Ref.: reference group. 2,245 cases (335 asymptomatic and 1,910 symptomatic infections) for whom the information was available.
