CONCLUSIONS
We found that 19% of patients with RSV-associated hospitalization
experienced severe outcomes, including 6.7% who died during
hospitalization. The proportion of deaths associated with RSV infection
is consistent with previous studies of similar populations
(8%1, 5.6%4). ICU admission and/or
mechanical ventilation have been shown to be associated with increased
morbidity and mortality, longer lengths of hospital stay as well as
hospital-associated infections.9 Furthermore, ICU
admissions were found to be three to four times more costly than
admissions to non-ICU units.10
Previous studies have compared morbidity and mortality in adult patients
with RSV-related and influenza-related
hospitalizations.11,12 Hospitalized adults in Hong
Kong with RSV infection had comparable 30- and 60-day mortality compared
to those with influenza, but significantly higher rates of mechanical
ventilation (11.1% vs. 6.2%, p=0.003), and extended care in subacute
hospitals following discharge (25.2% vs. 19.7%,
p=0.027).11 Analysis of Medicaid data in Tennessee
found that RSV infection and influenza accounted for a similar estimated
number of hospitalizations.12
We found that nearly half of the patients admitted from assisted living,
a skilled nursing or long-term care facility, rehabilitation facility,
or hospice had severe RSV outcomes. While age and specific comorbidities
were not associated with severe disease, those living in a facility
prior to admission had 4.43 times the odds of severe disease compared to
those living independently or with assistance in the community.
Similarly, when controlling for age and comorbidities, those who lived
in a facility had 6.64 times the odds of severe RSV infection compared
to those living independently or with assistance. These findings suggest
that living situation may be a proxy measure of frailty and, in turn, a
risk for severe disease.13 Chronic disease, multiple
comorbidities, and functional disability are associated with frailty,
and frailty has been shown to contribute to older adults’ vulnerability
to adverse outcomes from influenza.14,15 Other studies
have shown that those in assisted living have higher rates of
frailty,16 although it should be noted that there are
inconsistent measures of frailty. Future interventions for RSV such as
vaccines or antiviral therapy should target this vulnerable high-risk
population.
Furthermore, we found that 15.1% of adults who survived hospitalization
required an increased level of care as reflected in their living
situation at discharge when compared with that on admission. Overall, 36
patients (9.7%) went from living in the community to living in a
facility. Other studies have shown that hospitalization is an
independent risk factor for declines in functional status among older
adults which can be associated with a need for increased level of
care.17 The yearly median cost of assisted living was
estimated to be $48,612 in 2019.18 Thus, studies of
healthcare costs associated with RSV hospitalizations should include
those incurred after discharge as the need for an increased level of
support after discharge will add RSV-related healthcare costs to those
already incurred from hospitalization.
This study had limitations. This study was performed in an urban,
academically affiliated medical center and the findings may not be
generalizable. Although patients had laboratory-confirmed RSV infection
and at least two symptoms of ARI, their outcomes, including severe
outcomes, may have been secondary to exacerbations of their comorbid
conditions. Assessment of comorbidities were collected as reported in
the admission notes, but were not verified by treatment, did not account
for disease severity, or management during hospitalization. Living
situation was self-reported or reported by a family member and not
otherwise verified. Living situation might not be due to health-related
issues, e.g., patients could be living with a family member due to
financial constraints or to assist with childcare.
There are currently no specific therapies or approved vaccines for
prevention of RSV infection in adults. These data further highlight the
need for prevention strategies for RSV infection in older populations,
especially those living in residential living facilities. While frail,
older adults may have a diminished capacity to respond to vaccines,
prevention of RSV transmission in congregate settings is highly
desirable and feasible. Infection prevention strategies combined with
vaccination could reduce morbidity and mortality as well as healthcare
costs. Future studies should further assess the association of living
situation and adverse outcomes as well as the association of RSV-related
hospitalizations and longer-term deterioration in functional status.