Table 1.
Descriptive statistics on total influenza‐like‐illness (ILI) hospital admissions, International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD‐10) code distribution, and most frequent Healthcare Resource Group (HRG) code
| Age group | Total ILI hospital admissions (%) (N = 29,403) | ILI ICD‐10 code distribution (%)a | Most frequently assigned HRG code | ||
|---|---|---|---|---|---|
| J10 (N = 20,328) | J11 (N = 9,086) | Prepandemic (2004–2008) | Pandemic and postpandemic (2009–2011) | ||
| 0–4 years | 6,847 (19%) | 4,407 (78%) | 1,207 (22%) | Upper respiratory tract disorder | Other viral illness |
| 5–14 years | 2,869 (8%) | 1,856 (76%) | 579 (24%) | Upper respiratory tract disorder | Other viral illness |
| 15–24 years | 4,430 (13%) | 2,615 (66%) | 1,342 (34%) | Lower respiratory tract disorder | Other viral illness without critical care |
| 25–44 years | 9,241 (26%) | 5,133 (66%) | 2,649 (34%) | Lower respiratory tract disorder | Other viral illness with critical care |
| 45–64 years | 7,364 (20%) | 4,175 (71%) | 1,743 (29%) | Lower respiratory tract disorder | Other viral illness with critical care |
| 65+ years | 5,324 (14%) | 2,412 (58%) | 1,566 (42%) | Lower respiratory tract disorder | Other viral illness with critical care |
a
The total number ILI hospital admissions (N = 29,403) is less than the combined total of ILI admissions with ICD‐10 codes J10 and J11 (N = 20,328 + 9,086 = 29,414) because 11 patients have both diagnoses J10 and J11 and thus are counted twice. No ILI admissions with ICD‐10 code J09 were found in our data set.