BACKGROUND: Studies seeking to estimate the burden of @entity683 among hospitalized adults often use case definitions that require presence of @entity55 . The goal of this study was to assess the extent to which restricting @entity683 testing to adults hospitalized with @entity55 could underestimate the total burden of hospitalized @entity683 disease. METHODS: We conducted a modelling study using the complete State Inpatient Databases from Arizona, California, and Washington and regional @entity683 surveillance data acquired from CDC from January 2003 through March 2009. The exposures of interest were positive laboratory tests for @entity683 (H1N1), @entity683 (H3N2), and @entity683 B from two contiguous US Federal Regions encompassing the study area. We identified the two outcomes of interest by ICD-9-CM code: respiratory and circulatory hospitalizations, as well as @entity3124 ( @entity1576 , severe @entity295 , and in-hospital death). We linked the hospitalization datasets with the virus surveillance datasets by geographic region and month of hospitalization. We used negative binomial regression models to estimate the number of @entity683 -associated events for the outcomes of interest. We sub-categorized these events to include all outcomes with or without @entity55 diagnosis codes. RESULTS: We estimated that there were 80,834 (95% CI 29,214-174,033) @entity683 -associated respiratory and circulatory hospitalizations and 26,760 (95% CI 14,541-47,464) @entity683 -associated @entity3124 . When a @entity55 diagnosis was excluded, the estimated number of @entity683 -associated respiratory and circulatory hospitalizations was 24,816 (95% CI 6,342-92,624). The estimated number of @entity683 -associated @entity3124 was 8,213 (95% CI 3,764-20,799). Around 30% of both @entity683 -associated respiratory and circulatory hospitalizations, as well as @entity683 -associated @entity3124 did not have @entity55 diagnosis codes. CONCLUSIONS: Surveillance studies which only consider hospitalizations that include a diagnosis of @entity55 may underestimate the total burden of @entity683 hospitalizations.

XXXX Surveillance among Hospitalized Adults May Underestimate the Burden of Severe Influenza Disease.

@entity295 :: ('MESH:D018805', 'Disease') :: ['sepsis'] @entity55 :: ('MESH:D011014', 'Disease') :: ['pneumonia'] @entity3124 :: ('MESH:D016638', 'Disease') :: ['critical illness hospitalizations'] @entity683 :: ('MESH:D007251', 'Disease') :: ['influenza', 'influenza A'] @entity1576 :: ('MESH:D012131', 'Disease') :: ['acute respiratory failure']
@entity55 :: (MESH:D011014,Disease) :: ['Influenza Pneumonia']
