Open AccessComparative Outcomes of Adults Hospitalized With Seasonal Influenza A or B Virus Infection: Application of the 7-Category Ordinal Scale
Author(s) -
Yeming Wang,
Guohui Fan,
Peter Horby,
F G Hayden,
Qian Li,
Qiaoling Wu,
Xiaohui Zou,
Hui Li,
Qingyuan Zhan,
Chen Wang,
Bin Cao
Publication year - 2019
Publication title -
open forum infectious diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.546
H-Index - 35
ISSN - 2328-8957
DOI - 10.1093/ofid/ofz053
Subject(s) - medicine , hazard ratio , confidence interval , observational study , proportional hazards model , prospective cohort study , pediatrics
Background The objective of this study was to investigate the difference in disease severity between influenza A and B among hospitalized adults using a novel ordinal scale and existing clinical outcome end points. Methods A prospective, observational study was conducted over the 2016–2018 influenza seasons in a central hospital. The primary outcome was the rate of clinical improvement, defined as a decline of 2 categories from admission on a 7-category ordinal scale that ranges from 1 (discharged with normal activity) to 7 (death), or hospital discharge up to day 28. Results In total, 574 eligible patients were enrolled, including 369 (64.3%) influenza A cases and 205 (35.7%) influenza B cases. The proportion of patients with a worse ordinal scale at admission was higher in influenza A than influenza B (P = .0005). Clinical improvement up to 28 days occurred in 82.4% of patients with influenza A and 90.7% of patients with influenza B (P = .0067). The Cox model indicated that influenza B patients had a higher clinical improvement probability than influenza A cases (adjusted hazard ratio [HR], 1.266; 95% confidence interval [CI], 1.019–1.573; P = .0335). A similar pattern was observed in weaning oxygen supplement (adjusted HR, 1.285; 95% CI, 1.030–1.603; P = .0261). In-hospital mortality for influenza A was marginally higher than influenza B (11.4% vs 6.8%; P = .0782). Conclusions Our findings indicated that hospitalized patients with influenza A were more ill and had delayed clinical improvement compared with those with influenza B virus infection.