{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,18]],"date-time":"2025-12-18T11:31:20Z","timestamp":1766057480362,"version":"3.48.0"},"reference-count":30,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2025,12,18]],"date-time":"2025-12-18T00:00:00Z","timestamp":1766016000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Infectious Disease Reports"],"abstract":"<jats:p>Background: Respiratory syncytial virus (RSV) pneumonia is an underrecognized cause of critical illness in adults. However, the influence of biological sex on intensive care unit (ICU) outcomes in this population remains unclear. Due to limited case numbers and incomplete covariate data, this study was designed as exploratory and hypothesis-generating. Methods: We conducted a retrospective exploratory cohort study using the MIMIC-IV database and identified 105 adult ICU patients with laboratory-confirmed RSV pneumonia. Clinical variables included sex, age, ICU length of stay, use of mechanical ventilation, and weaning status. Exploratory multivariable logistic regression was performed to assess associations with in-hospital mortality and weaning success, acknowledging substantial missingness of comorbidity data, severity scores, and treatment variables. This limited adjustment for confounding and statistical power. Results: Overall, in-hospital mortality was 33.3%. Mortality was significantly higher among women than men (51.6% vs. 7.0%; p &lt; 0.001), although the absolute number of deaths in men was very small. In adjusted models, female sex (OR 14.6, 95% CI 1.58\u2013135.3, p = 0.018), reflecting model instability due to sparse events, as well as longer ICU stay (OR 1.22 per day, p = 0.001) were independently associated with higher mortality. Female sex was also associated with lower odds of successful weaning (OR 0.07, 95% CI 0.01\u20130.63, p = 0.018). These effect estimates must be interpreted cautiously due to the very small number of deaths in men and the resulting wide confidence intervals. Age and ventilation duration were not significant predictors. Conclusions: In this preliminary ICU cohort, female sex and prolonged ICU stay were linked to higher mortality and lower weaning success in adults with RSV pneumonia. However, given the very small number of events\u2014particularly among male patients\u2014together with the modest sample size, limited covariate availability, and unstable effect estimates, the findings should be viewed as exploratory rather than confirmatory. Larger, well-powered, prospective multicenter studies are needed to validate and further characterize potential sex-related differences in outcomes of RSV-associated critical illness.<\/jats:p>","DOI":"10.3390\/idr17060151","type":"journal-article","created":{"date-parts":[[2025,12,18]],"date-time":"2025-12-18T11:08:28Z","timestamp":1766056108000},"page":"151","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Sex Differences in Outcomes of Critically Ill Adults with Respiratory Syncytial Virus Pneumonia: A Retrospective Exploratory Cohort Study"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8363-621X","authenticated-orcid":false,"given":"Josef","family":"Yayan","sequence":"first","affiliation":[{"name":"Department of Internal Medicine, Division of Pulmonary, Allergy and Sleep Medicine, HELIOS Clinic Wuppertal, Witten\/Herdecke University, Heusnerstr. 40, 42283 Wuppertal, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2862-3325","authenticated-orcid":false,"given":"Kurt","family":"Rasche","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Pulmonary, Allergy and Sleep Medicine, HELIOS Clinic Wuppertal, Witten\/Herdecke University, Heusnerstr. 40, 42283 Wuppertal, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"946","DOI":"10.1016\/S0140-6736(17)30938-8","article-title":"Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: A systematic review and modelling study","volume":"390","author":"Shi","year":"2017","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1128\/CMR.13.3.371","article-title":"Respiratory syncytial virus infection in adults","volume":"13","author":"Falsey","year":"2000","journal-title":"Clin. 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