TABLE 2.
Risk factors for death among cases of invasive group A streptococcal disease in Alaska, 2001 to 2013
| Risk factor | Group | % case fatality (ratio) | Rate ratioa | P value |
|---|---|---|---|---|
| Period | 2001–2005 | 10.2 (16/157) | Ref | 0.89 |
| 2006–2009 | 10.5 (15/143) | 1.0 | ||
| 2010–2013 | 11.6 (25/215) | 1.1 | ||
| Sex | Female | 11.7 (27/231) | 1.1 | 0.59 |
| Male | 10.2 (29/284) | Ref | ||
| Age | ≤64 years | 8.7 (36/415) | Ref | 0.001b |
| 65+ years | 20.0 (20/100) | 2.3 | ||
| Ethnicity | Alaska Native | 8.9 (21/237) | 0.7 | 0.18 |
| Non-Alaska Native | 12.6 (35/278) | Ref | ||
| emm type | 1, 3, and 12 | 24.5 (25/102) | 3.4 | <0.0001b |
| All others | 7.2 (23/319) | Ref | ||
| Endocarditis | Yes | 35.7 (5/14) | 2.5 | 0.01 |
| No | 10.2 (51/501) | Ref | ||
| Empyema | Yes | 4.6 (1/22) | 0.4 | 0.49 |
| No | 11.2 (55/493) | Ref | ||
| Toxic shock syndrome | Yes | 12.5 (2/16) | 1.2 | 0.70 |
| No | 10.8 (54/499) | Ref | ||
| Pneumonia | Yes | 14.9 (15/101) | 1.5 | 0.15 |
| No | 9.9 (41/413) | Ref | ||
| Necrotizing fasciitis | Yes | 10.0 (4/40) | 0.9 | 1.00 |
| No | 11.0 (52/475) | Ref | ||
| Septic arthritis | Yes | 4.6 (2/44) | 0.4 | 0.21 |
| No | 11.5 (54/471) | Ref | ||
| Cellulitis | Yes | 6.0 (13/217) | 0.4 | 0.002b |
| No | 14.4 (43/298) | Ref |
a
Ref, reference.
b
All remained significant in a multivariate logistic regression: age class (P = 0.007); emm type 1, 3, or 12 (P < 0.0001); and cellulitis (P = 0.007).