Human Metapneumovirus, Respiratory Syncytial Virus and Influenza Associated Pneumonia Hospitalizations in Colorado Adults Aged Over 50 Years: 2016-2023

Abstract Background The objectives were to identify the frequency and risk factors for ICU admission and mortality associated with RSV, influenza, and HMPV pneumonia hospitalizations and to compare these rates with those admitted with other ARI caused by these viruses Methods This retrospective cohort study identified hospitalization encounters of adults’ aged 50 to 88 years with RSV, influenza and HMPV pneumonia between 2016 and 2023 in the Colorado Hospital Association database., . Multivariate logistic regression was used to estimate the adjusted odds of ICU admission and mortality. Results Of 2210 hospitalized patients with RSV pneumonia, 780 (35%) were admitted to the ICU and 205 (9.3%) died. For Influenza pneumonia these figures were 7174, 2332 (32.5%) and 545 (7.6%) and HMPV pneumonia 1482, 408 (27.5%) and 88 (5.9%) respectively. Dementia has the highest odds for ICU admission in patients with RSV pneumonia aOR 4.2 (1.34, 13.18), for influenza pneumonia it was chronic pulmonary disease aOR 2.99 (2.45, 3.66) and for HMPV pneumonia it was COPD without asthma aOR 5.04 (2.92, 8.7). Increasing age was associated with increasing rates of mortality for RSV and influenza. Chronic pulmonary disease, and COPD itself had > 2 fold higher rates of mortality in patients with pneumonia for all three viruses while obesity, , diabetes and chronic renal disease didn’t. Increasing numbers of comorbidities significantly increase ICU admission and mortality rates in all 3 groups. Conclusions Pneumonia is a severe manifestation of ARI with RSV, influenza and HMPV with differing risk factors for ICU admission and mortality.