Table 4.
Characteristics by Influenza Straina
| Variable | Influenza A (N = 1223) (67.5%) | Influenza B (N = 589) (32.5%) | P Value |
|---|---|---|---|
| Influenza Season | P < .001 | ||
| 2011/2012 N (%) | 49 (4.0%) | 118 (20.0%) | |
| 2012/2013 N (%) | 815 (66.6%) | 55 (9.3%) | |
| 2013/2014 N (%) | 359 (29.4%) | 416 (70.6%) | |
| Mean age | 79.5 (SD 8.6) | 81.4 (SD = 8.7) | P < .001 |
| Sex N (%) female | 612 (50.0%) | 328 (55.7%) | P < .05 |
| Vaccinated N (%) | 724 (59.2%) | 373 (63.3%) | P = .09 |
| Baseline frailty | 0.22 (SD 0.13) | 0.23 (SD = 0.14) | P = .05 |
| Admission frailty (N = 1190/573) | 0.29 (SD 0.14) | 0.29 (SD 0.15) | P = .97 |
| Frailty index at 30 days postdischarge (N = 1087/505) | 0.21 (SD 0.13) | 0.22 (SD 0.13) | P = .44 |
| Mortality (30 days postdischarge) N (%) | 136 (11.1%) | 84 (14.3%) | P = .06 |
| Recovered N (%) | 963 (78.7%) | 450 (76.4%) | P = .26 |
Abbreviations: SD, standard deviation.
aIndependent samples t tests (continuous variables) or χ 2 tests (categorical variables) were used to compare influenza A and influenza B.