Association of obstructive sleep apnea with outcomes in hospitalized patients with pneumonia: a retrospective analysis of the nationwide inpatient sample

Purpose Obstructive sleep apnea (OSA) impairs mucociliary defense, reduces ventilatory reserve, promotes systemic inflammation, and predisposes patients to lower respiratory tract infections. Despite biological plausibility, the population-level association of comorbid OSA with pneumonia hospitalization outcomes remains poorly characterized. We aimed to evaluate associations between OSA and clinical outcomes in adults hospitalized with pneumonia using a nationally representative inpatient database. Methods Using the 2018–2020 Nationwide Inpatient Sample (NIS), we conducted a retrospective cohort study of adults (≥ 18 years) hospitalized with a primary diagnosis of pneumonia, stratified by OSA status. Multivariable logistic and linear regression models adjusted for age, sex, race/ethnicity, household income quartile, primary payer, Charlson Comorbidity Index, obesity, hospital type, hospital bed size, and geographic region. P-values were corrected for multiple comparisons (Bonferroni), and E-values were calculated to assess sensitivity to unmeasured confounding. Results Among 4,918,328 hospitalizations, 9.2% ( n = 450,580) had coexisting OSA. Despite a greater comorbidity burden, OSA was associated with lower in-hospital mortality (3.3% vs. 4.8%; aOR 0.74; 95% CI 0.71–0.77; p < 0.0001), lower sepsis (aOR 0.89; 95% CI 0.87–0.90), and lower septic shock (2.2% vs. 2.7%; aOR 0.80; 95% CI 0.76–0.84). Conversely, OSA was associated with higher acute respiratory failure (48.1% vs. 35.8%; aOR 1.56; 95% CI 1.54–1.59), noninvasive ventilation (NIV) use (14.8% vs. 5.0%; aOR 3.26; 95% CI 3.17–3.34), and acute kidney injury (AKI; 24.1% vs. 22.1%; aOR 1.13; 95% CI 1.11–1.15). Adjusted length of stay was slightly longer (β + 0.11 days; 95% CI 0.07–0.16), while adjusted hospital charges did not differ significantly. All associations except hospital charges remained significant after correction for multiple comparisons; E-values suggested that the sepsis and AKI associations could be explained by relatively weak unmeasured confounding. Conclusions Among adults hospitalized with pneumonia, comorbid OSA was associated with higher rates of acute respiratory failure, NIV use, and AKI, and with lower in-hospital mortality and sepsis. Because of the retrospective administrative design and the lack of data on pneumonia severity, OSA severity, and CPAP use, residual and unmeasured confounding cannot be excluded. These findings are hypothesis-generating, and prospective studies are needed.