Risk Factors for Mortality among 2009 A/H1N1 Influenza Hospitalizations in Maricopa County, Arizona, April 2009 to March 2010
Table 3
Unadjusted case fatality ratios among A/H1N1 influenza inpatients by pandemic wave, Maricopa County, April 1, 2009 through March 31, 2010.
Variable
Overall hospitalized case fatality ratio
Pandemic wave
valuea
Spring
Fall
Total A/H1N1 deaths (% of total A/H1N1 cases)
65/532 (12.2)
11/144 (7.6)
54/388 (13.9)
0.049
Race/ethnicity
Hispanics
18/202 (8.9)
5/60 (8.3)
13/142 (9.2)
0.85
Whites, non-Hispanic
36/197 (18.3)
4/52 (7.7)
32/145 (22.1)
0.021
Black, non-Hispanic
5/62 (8.1)
2/13 (15.4)
3/49 (6.1)
0.31
Native American
4/34 (11.8)
0/9 (0.0)
4/25 (16.0)
0.20
Asian
2/5 (40.0)
0/0 (0.0)
2/5 (40.0)
N/A
Gender
Female
36/297 (12.1)
5/80 (6.2)
31/217 (14.3)
0.060
Male
29/235 (12.3)
6/64 (9.4)
23/171 (13.5)
0.40
Age (years)
<18
11/243 (4.5)
2/62 (3.2)
9/181 (5.0)
0.57
18–49
24/175 (13.7)
3/41 (7.3)
21/134 (15.7)
0.17
≥50
30/114 (26.3)
6/41 (14.6)
24/73 (32.9)
0.034
Wave 1 (spring) refers to April 1, 2009 through August 15, 2009; fall wave refers to August 16, 2009 through March 31, 2010. Data are percentages of cases unless otherwise specified.
aDetermined by the Chi-square test statistic. values show the univariate comparisons of proportions between spring and fall waves.
