Respiratory syncytial virus has a nearly 10% mortality rate similar to influenza in hospitalized adult patients, according to a recent study. The researchers also found patients with RSV were sicker at baseline than patients with influenza.
Findings published in a 2008 supplement to Managed Care magazine showed RSV in adults is estimated to cause about 180,000 hospital admissions each year at a cost of more than $1 billion. High-risk populations include the elderly, people with chronic cardiopulmonary disease and those with immunosuppression.
However, a better understanding of complications and outcomes in adults is needed, according to background information in the study, which was published in the October issue of Clinical Infectious Diseases.
For their study, researchers with the Chinese University in Hong Kong conducted a retrospective cohort study including 607 adult patients with virologically confirmed RSV infection who were admitted to three acute care hospitals in Hong Kong from 2009 to 2011. For comparison, they included a group of 547 patients hospitalized with influenza (except for pandemic H1N1) during the same time period. All patients were diagnosed using standard protocols, and patients chest X-rays were independently reviewed by radiologists.
The average age of patients with RSV was 75, and 87% of those patients had underlying comorbidities, according to the findings. Lower respiratory complications were diagnosed in 71.9%, including pneumonia (42.3% of those with lower respiratory complications), acute bronchitis (21.9%) and COPD/asthma exacerbation (27.3%), and cardiovascular complications were observed in 14.3% of RSV patients. Bacterial superinfections were present in 12.5% of the patients. While hospitalized, supplemental oxygen and ventilator support were needed by 67.9% and 11.1%, respectively.
The 30-day overall mortality rate for patients with RSV was 9.1%, and at 60 days it was 11.9%; the average length of stay for patients who survived was 12 days. The researchers discovered being older than 75, having radiographic pneumonia, requiring ventilator support, bacterial superinfection and elevated urea level and white blood cell count were independently associated with poorer outcomes and survival rates. Use of corticosteroids in patients with RSV was associated with a longer stay and secondary infections, they found.
The overall outcomes of survival and length of stay were not significantly different from those in influenza, the authors wrote.
When comparing the two groups, the results showed patients with RSV had more pulmonary (36% vs. 24%) and nonpulmonary comorbidities (74% vs. 66%) than those with influenza at baseline, according to a study review by Cheryl Lynn Horton, MD, in NEJM Journal Watch.
Both groups had similar mortality rates at 30 days (9% and 8%), but patients with influenza died sooner (median, seven vs. 13 days after admission), Horton wrote in the review.