Volume 26, Number 2—February 2020
CME ACTIVITY - Research
Illness Severity in Hospitalized Influenza Patients by Virus Type and Subtype, Spain, 2010–2017
Concepción Delgado-Sanz
, Clara Mazagatos-Ateca, Jesús Oliva, Alin Gherasim, and Amparo Larrauri
, Clara Mazagatos-Ateca, Jesús Oliva, Alin Gherasim, and Amparo Larrauri
Table 1
Demographic and clinical characteristics of patients hospitalized for laboratory-confirmed severe influenza, by influenza virus type or subtype, Spain, influenza seasons 2010–11 to 2016–17*
| Characteristic |
Influenza virus type or subtype |
||||||
| pH1N1 |
A(H3N2) |
B |
|||||
| No. (%) |
No. (%) |
Crude RRR† (95% CI) |
No. (%) |
Crude RRR‡ (95% CI) |
|||
| Total no. patients |
4,568 (100) |
3,091 (100) |
NA |
1,326 (100) |
NA |
||
| Age group, y | |||||||
| <15 | 566 (12) | 333 (11) | Referent | 318 (24) | Referent | ||
| 15–64 | 2,767 (61) | 716 (23) | 0.44 (0.38–0.52) | 437 (33) | 0.28 (0.24–0.33) | ||
| >65 | 1,231 (27) | 2,035 (66) | 2.81 (2.41–3.27) | 567 (43) | 0.82 (0.69–0.97) | ||
| Missing data |
4 (0.1) |
7 (0.2) |
NA |
4 (0.3) |
NA |
||
| Sex | |||||||
| M | 2,589 (57) | 1,637 (53) | 0.86 (0.78–0.94) | 736 (56) | 0.96 (0.85–1.08) | ||
| F | 1,977 (43) | 1,453 (47) | Referent | 588 (44) | Referent | ||
| Missing data |
2 (0.1) |
1 (0.1) |
NA |
2 (0.2) |
NA |
||
| Underlying medical condition§ | 2,334 (68) | 2,055 (86) | 2.81 (2.45–3.22) | 754 (74) | 1.32 (1.13–1.55) | ||
| Missing data | 1,161 (25) | 700 (23) | NA | 310 (23) | NA | ||
| Class III obesity (BMI >40 kg/m2) | 447 (12) | 205 (8) | 0.66 (0.55–0.78) | 80 (7) | 0.59 (0.46–0.75) | ||
| Chronic respiratory diseases | 686 (22) | 680 (30) | 1.53 (1.35–1.73) | 238 (25) | 1.20 (1.01–1.42) | ||
| Chronic cardiovascular diseases | 800 (21) | 1,051 (40) | 2.49 (2.23–2.78) | 308 (28) | 1.45 (1.24–1.69) | ||
| Diabetes mellitus | 696 (18) | 755 (29) | 1.81 (1.61–2.04) | 225 (20) | 1.15 (0.97–1.36) | ||
| Renal diseases | 335 (9) | 394 (15) | 1.87 (1.60–2.18) | 132 (12) | 1.42 (1.14–1.75) | ||
| Chronic liver disease | 212 (6) | 147 (6) | 1.02 (0.82–1.26) | 58 (5) | 0.94 (0.70–1.27) | ||
| Immunosuppression |
632 (17) |
327 (13) |
0.72 (0.63–0.84) |
170 (16) |
0.92 (0.77–1.11) |
||
| Pregnancy¶ | 125 (24) | 11 (10) | 0.33 (0.17–0.64) | 18 (24) | 0.98 (0.56−1.73) | ||
| Missing data |
134 (20) |
30 (21) |
NA |
19 (20) |
NA |
||
| Antiviral treatment | 3,787 (86) | 2,241 (75) | 0.48 (0.42–0.54) | 800 (64) | 0.30 (0.26–0.34) | ||
| Missing data | 165 (4) | 86 (3) | NA | 86 (6) | NA | ||
| Oseltamivir | 3,709 (99.3) | 2,209 (99.7) | NA | 777 (99.4) | NA | ||
| Zanamivir | 16 (0.4) | 3 (0.1) | NA | 4 (0.5) | NA | ||
| Other |
11 (0.3) |
5 (0.2) |
NA |
1 (0.1) |
NA |
||
| Seasonal trivalent influenza vaccine | 514 (14) | 862 (36) | 3.45 (3.05–3.91) | 261 (27) | 2.18 (1.84–2.58) | ||
| Missing data | 961 (21) | 727 (24) | NA | 345 (26) | NA | ||
*BMI, body mass index; RRR, relative risk ratio; NA, not applicable.
†Influenza A(H3N2) compared with pH1N1 (reference).
‡Influenza B compared with pH1N1 (reference).
§Underlying medical conditions defined as >1 of the following: class III obesity (BMI >40 kg/m2), chronic respiratory diseases, chronic cardiovascular diseases, diabetes mellitus, renal diseases, chronic liver disease, or immunosuppression.
¶Pregnancy among women of childbearing age (15–49 years).
Page created: January 16, 2020
Page updated: January 16, 2020
Page reviewed: January 16, 2020
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