Table 1.
Demographic and Clinical Characteristics of 47 Critically Ill Adolescents and Adults Hospitalized With 2009 Pandemic Influenza A(H1N1) Virus Infection, by Patient Outcome—Canada, 2009–2011
| Variable | Total | Survived | Died |
|---|---|---|---|
| Patients | 47 (100) | 39 (83) | 8 (17) |
| Demographic characteristics | |||
| Influenza season of illness | |||
| Pandemic spring wave (Apr–Jul 2009) | 12 (26) | 10 (26) | 2 (25) |
| Pandemic fall wave (Aug 2009–May 2010) | 29 (62) | 23 (59) | 6 (75) |
| Oct 2010–Apr 2011 | 6 (13) | 6 (15) | 0 (0) |
| Age, y | 47 (17–80) | 48 (17–80) | 56 (17–74) |
| <50 | 26 (55) | 22 (56) | 4 (50) |
| 50–64 | 13 (28) | 13 (33) | 0 (0) |
| ≥65 | 8 (17) | 4 (10) | 4 (50) |
| Sex | |||
| Male | 16 (34) | 14 (36) | 2 (25) |
| Female | 31 (66) | 25 (64) | 6 (75) |
| Race | |||
| White | 29 (62) | 25 (64) | 4 (50) |
| Asian descent | 3 (6) | 2 (5) | 1 (13) |
| First Nations | 14 (30) | 11 (28) | 3 (38) |
| Other/unknown | 1 (2) | 1 (3) | 0 (0) |
| Received influenza vaccine | 4 (9) | 2 (5) | 2 (25) |
| High-risk conditions | |||
| Age ≥65 y | 8 (17) | 4 (10) | 4 (50) |
| Chronic lung condition | 19 (40) | 17 (44) | 2 (25) |
| Cardiovascular condition | 16 (34) | 11 (28) | 5 (63) |
| Renal condition | 9 (19) | 6 (15) | 3 (38) |
| Hepatic condition | 1 (2) | 1 (3) | 0 (0) |
| Immunosuppression | 9 (19) | 9 (23) | 0 (0) |
| Diabetes mellitus | 9 (19) | 6 (15) | 3 (38) |
| First Nations | 14 (30) | 11 (28) | 3 (38) |
| Obesity (BMI ≥40a) | 11 (23) | 10 (26) | 1 (13) |
| Pregnant | 3 (6) | 2 (5) | 1 (13) |
| Other | 7 (15) | 6 (15) | 1 (13) |
| Any of the above | 40 (85) | 31 (79) | 7 (88) |
| Clinical characteristics | |||
| Invasive mechanical ventilation use | 39 (91) | 32 (89) | 7 (100) |
| ECMO use | 1/39 (3) | 0/32 (0) | 1/7 (14) |
| Received influenza antiviral therapy | 47 (100) | 39 (100) | 8 (100) |
| Received corticosteroid therapy | |||
| Overall | 25 (53) | 21 (54) | 4 (50) |
| Low dose | |||
| Received (≤50 mg/d, prednisone equivalent) | 14/25 (56) | 13/21 (62) | 1/4 (25) |
| Duration, d | 5 (3–7) | 4 (3–6) | 8 (NA) |
| High dose | |||
| Received (>50 mg/d, prednisone equivalent) | 15/25 (60) | 13/21 (62) | 2/4 (50) |
| Duration, d | 5 (3–8) | 5 (3–8) | 9 (7–11) |
| Pneumonia | 13/28 (46) | 11/24 (46) | 2/4 (50) |
| Sepsis | 8 (17) | 7 (18) | 1 (13) |
| Shock | 19 (40) | 15 (38) | 4 (50) |
| Septic | 8 (42) | 7 (47) | 1 (25) |
| Nonseptic | 11 (58) | 8 (53) | 3 (75) |
| Clinical event duration, d | |||
| From symptom onset to hospitalization | 5 (3–8) | 5 (3–8) | 6 (2–8) |
| From hospitalization to ventilation | 1 (1–2) | 1 (1–2) | 3 (1–4) |
| From hospitalization to ICU admission | 1 (1–2) | 1 (1–2) | 2 (1–4) |
| From symptom onset to discharge or death | 28 (18–45) | 31 (18–52) | 24 (16–31) |
| ICU stayb | 14 (9–26) | 14 (9–26) | 17 (12–26) |
| Hospital stay | 21 (15–31) | 24 (16–51) | 17 (15–25) |
Data are no. or proportion (%) of patients or median value (interquartile range).
Abbreviations: ECMO, extracorporal membrane oxygenation; ICU, intensive care unit; NA, not available.
a
Body mass index (BMI) is calculated as the weight in kilograms divided by the height in meters squared.
b
One patient, a survivor, did not have a known date of ICU discharge.