Hospitalization Following Outpatient Diagnosis of Respiratory Syncytial Virus in Adults

Abstract

Importance: Respiratory syncytial virus (RSV) is a leading cause of acute respiratory tract infections among adults and is estimated to cause approximately 159 000 hospitalizations among adults aged 65 years and older in the US each year. Estimates of hospitalization among adults with outpatient medically attended RSV (MA-RSV) infections are required to design interventional studies that aim to prevent hospitalization.

Objective: To assess absolute risk of 28-day, all-cause hospitalization following outpatient MA-RSV infections in adults.

Design, setting, and participants: In this cohort study, data from 3 different deidentified databases containing electronic health records (EHR) linked to closed claims data (Optum's deidentified Integrated Claims-Clinical dataset, TriNetX Linked, and Veradigm Network EHR [VNEHR] database linked with claims) were analyzed separately across 6 RSV years (October 1, 2016, to September 30, 2022) in adults with commercial or government insurance. Outpatient (eg, clinics and emergency departments) MA-RSV infections were identified based on clinical laboratory data or RSV-specific International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes. Data were analyzed from March 2023 to April 2024.

Main outcomes and measures: The main outcome was all-cause 28-day hospitalization following outpatient MA-RSV infections among all adults and a high-risk subgroup (defined as age ≥65 years or with asthma, chronic obstructive pulmonary disease [COPD], or congestive heart failure [CHF]).

Results: In this cohort study of 67 239 MA-RSV infections in adults (2771 from Optum, 7442 from TriNetX, and 57 026 from VNEHR), most occurred among females (62%-67%) and comorbidity prevalences were 20.0% to 30.5% for COPD, 14.6% to 24.4% for CHF, 14.6% to 24.4% for asthma; 14.0% to 54.5% of individuals were aged 65 years or older. The proportion hospitalized was 6.2% (95% CI, 5.3%-7.1%) in Optum, 6.0% (95% CI, 5.4% to 6.5%) in TriNetX, and 4.5% (95% CI, 4.3%-4.6%) in VNEHR. Among the high-risk subgroup, the proportion hospitalized was 7.6% (95% CI, 6.5%-8.9%) in Optum, 8.5% (95% CI, 7.6%-9.4%) in TriNetX, and 6.5% (95% CI, 6.2%-6.8%) in VNEHR.

Conclusions and relevance: In this cohort study of adults with outpatient MA-RSV infections from 3 large deidentified US databases across 6 RSV seasons, approximately 1 in 20 adults experienced all-cause hospitalization within 28 days. The results of this study highlight the public health need for RSV prevention and treatment.

Figure 1.. Study Design

The same methods were used to identify eligible respiratory syncytial virus (RSV) outpatient infections for the 2018 to 2019, 2019 to 2020, 2020 to 2021, and 2021 to 2022 RSV seasons. ED indicates emergency department. ^aAll-available data is defined as using all observable data present in the database for a patient at the time of outpatient infection.

Figure 2.. Study Inclusion Flowcharts

^aAn immediate hospital admission occurring on the same day as the index visit (or 1 day after an emergency department [ED] index visit) did not allow for adequate time to communicate the respiratory syncytial virus (RSV) diagnosis to the patient and consider outpatient management. ^bContinuous enrollment for at least 180 days before the visit date and at least 28 days continuous enrollment after the visit date (censored for death) was required for inclusion into the study. ^cOnly the first outpatient visit for RSV per person per RSV season was included as an index visit for this study.

Figure 3.. Absolute Risk of All-Cause Hospitalization Stratified by Year and High-Risk Subgroup Among Adults With Outpatient Medically Attended Respiratory Syncytial Virus

EHR indicates electronic health record. ^aConditions included asthma, chronic obstructive pulmonary disease, and congestive heart failure