Risk factors and medical resource utilization in US adults hospitalized with influenza or respiratory syncytial virus in the Hospitalized Acute Respiratory Tract Infection study

Abstract

Background: Influenza and respiratory syncytial virus (RSV) are associated with substantial morbidity and mortality in the United States. We assessed risk factors for severe disease and medical resource utilization (MRU) among US adults hospitalized with influenza or RSV in the Hospitalized Acute Respiratory Tract Infection (HARTI) study.

Methods: HARTI was a prospective global (40 centers, 12 countries) epidemiological study of adults hospitalized with acute respiratory tract infections conducted across the 2017-2019 epidemic seasons. Patients with confirmed influenza or RSV were followed up to 3 months post-discharge. Baseline characteristics, prevalence of core risk factors (CRFs) for severe disease (age ≥65 years, chronic heart or renal disease, chronic obstructive pulmonary disease, or asthma), and MRU were summarized descriptively.

Results: The US cohort included 280 influenza-positive and 120 RSV-positive patients. RSV patients were older (mean: 63.1 vs. 59.7 years) and a higher proportion had CRFs (87.5% vs. 81.4%). Among those with CRFs (influenza, n = 153; RSV, n = 99), RSV patients required longer hospitalizations (median length of stay: 4.5 days) and a greater proportion (79.8%) required oxygen supplementation during hospitalization compared with influenza patients (4.0 days and 59.5%, respectively). At 3 months post-discharge, a greater proportion of RSV patients with CRFs reported use of antibiotics, antitussives, bronchodilators, and inhaled and systemic steroids versus those with influenza and CRFs. Many patients with CRFs reported hospital readmission at 3 months post-discharge (RSV: 13.4%; influenza: 11.9%).

Conclusions: MRU during and post-hospitalization due to RSV in adults is similar to or greater than that of influenza. Enhanced RSV surveillance and preventive and therapeutic interventions are needed.

Keywords: hospitalization; influenza; prospective study; respiratory infections; respiratory syncytial virus; risk factors.

FIGURE 1

Study design. ADL, activities of daily living; ARTI, acute respiratory tract infection; EQ‐5D‐5L, EuroQol 5 Dimensions 5 Levels; hMPV, human metapneumovirus; IADL, instrumental activities of daily living; MRU, medical resource utilization; PCR, polymerase chain reaction; RiiQ™, Respiratory Intensity and Impact Questionnaire; RSB, Respiratory Symptoms Bother and Change in Health Status Questionnaire; RSV, respiratory syncytial virus; SoC, standard‐of‐care. ^†When a nasal swab was collected as part of SoC, a mid‐turbinate swab was collected from the opposite nostril and then used for the SoC test. Rapid PCR analysis was used to identify respiratory pathogens from the SoC nasal and mid‐turbinate swabs. ^‡Leftover nasal swab or blood samples were stored for potential future exploratory research. ^§For patients discharged within 48 h of screening, only one visit was conducted (at discharge). ^¶Patient‐reported questionnaires included the Barthel ADL, Lawton IADL, RiiQ™, RSB, EQ‐5D‐5L, and MRU questionnaires.

FIGURE 2

Baseline CRFs and ARTIs leading to hospitalization (main study). (A) Percentage of patients with CRFs at baseline and (B) ARTIs reported by patients leading to hospitalization. ARTI, acute respiratory tract infection; COPD, chronic obstructive pulmonary disease; CRF, core risk factor; RSV, respiratory syncytial virus. ^†Other ARTIs primarily consisted of viral influenza‐like ARTIs.

FIGURE 3

Key MRU parameters during hospitalization. CRF, core risk factor; COPD, chronic obstructive pulmonary disease; ICU, intensive care unit; LoS, length of stay; LTCF, long‐term care facility; RSV, respiratory syncytial virus. ^†CRFs included any one or a combination of the following: age ≥65 years, chronic heart disease, COPD, chronic renal disease, and asthma. ^‡The one patient with influenza discharged to a LTCF was in an LTCF prior to hospitalization. Of the eight patients with RSV who were discharged to LTCFs, four patients reported LTCF residence prior to hospitalization.

FIGURE 4

Medication use post‐discharge (substudy). Percentage of patients reporting use of (A) antibiotics, (B) antitussives, (C) bronchodilators, (D) inhaled steroids, (E) systemic steroids, or (F) oxygen at 1, 2, and 3 months post‐discharge. CRF, core risk factor; COPD, chronic obstructive pulmonary disease; RSV, respiratory syncytial virus. ^†CRFs included any one or a combination of the following: age ≥65 years, chronic heart disease, COPD, chronic renal disease, and asthma.

FIGURE 5

MRU post‐discharge (substudy). Percentage of patients reporting (A) hospital readmission, (B) use of medical consultations,^† and (C) professional home care^‡ at 1, 2, and 3 months post‐discharge. CRF, core risk factor; COPD, chronic obstructive pulmonary disease; MRU, medical resource utilization; RSV, respiratory syncytial virus. ^†Medical consultations included utilization of a pulmonologist or respiratory physiotherapist. ^‡Professional home care included utilization of a general practitioner, nurse, or respiratory physiotherapist. ^§CRFs included any one or a combination of the following: age ≥65 years, chronic heart disease, COPD, chronic renal disease, and asthma.