2758. Identifying Populations at High-Risk for Influenza-Related Hospitalization: A Real-World Analysis of Commercially Insured Population in the United States

Background The disease burden of seasonal influenza (flu) is high and contributes to morbidity, mortality and healthcare utilization. While only 1–2% of flu cases are hospitalized, these events are costly. The objective of this study was to describe and quantify risk factors for flu hospitalization. Methods Patients with 1 flu diagnosis (Dx) over 4 seasons (October 1, 2014–May 31, 2018) in IQVIA’s Real-World Data Adjudicated Claims – US database were selected into the study; the earliest flu Dx was the index date. Patients were required to have ≥12 months continuous enrollment in their health plan before index (baseline), ≥30 days after index, and either a record of a flu test ± 14 days of index or a flu Dx in the primary position. Comorbidities during a fixed 12-month baseline period were categorized by AHRQ and CDC definitions. The study outcome of interest, flu-related hospitalization during the 30-day follow-up period, was defined as hospitalization with Dx of flu or a pre-defined flu-related complication in any position. A logistic regression model assessed the odds of flu-related hospitalization, adjusting for age, sex, region, payer, season of index Dx, evidence of flu vaccination, and comorbidities. Results More than 1.6 million medically-attended flu cases were identified, of which 18,509 (1%) had a hospitalization. 40% of patients were < 18 years of age, 47% were male, and 28%, 15%, 24%, and 33% were identified in the 2014–2017 flu seasons, respectively. More hospitalized patients were ages 50+ compared with non-hospitalized patients (57% vs. 20%) and 44% of hospitalized patients had 4 or more AHRQ/CDC comorbidities vs. 8% of non-hospitalized patients. In adjusted analyses, older age (65+ vs. 5–17; OR = 9.4, 95% CI 8.8–10.1) and leukemia/lymphoma/metastatic cancer (OR = 3.2, 95% CI = 2.9–3.5) were key drivers of hospitalization (Figure 1). Conclusion The risk of flu-related hospitalization is high for elderly populations and those with certain underlying co-morbidities among all age groups. While these findings reflect the burden of medically-attended flu in a younger, commercially insured population, additional research is needed to address the flu burden in high-risk populations. Disclosures All authors: No reported disclosures.