Bronchoalveolar Lavage in Immunocompetent Patients with Pneumonia: A Retrospective Cohort Study Shows No Survival Benefit

<b>Background:</b> Bronchoalveolar lavage (BAL) is frequently employed for diagnostic purposes in immunocompromised patients with pneumonia, yet its role in immunocompetent individuals remains debated. The study investigates whether BAL is associated with reduced mortality in immunocompetent patients hospitalized with pneumonia. <b>Methods:</b> A retrospective cohort study was conducted at SMC, including 13,180 immunocompetent patients hospitalized with pneumonia from 2007 to 2024. Patients who underwent BAL (n = 96) were matched 1: 4 to a control group (n = 384) using Propensity score matching based on age, gender, severity scores and comorbidities. Mortality was assessed at 30, 60, and 90 days using logistic regression models, adjusting for length of stay, inflammatory markers, albumin levels, smoking status, and BMI. <b>Results:</b> In the matched cohort, 30-day mortality did not differ significantly between groups (20.8% in BAL vs. 19.5% in controls, <i>p</i> = 0.886), and no significant association was observed after adjustment (OR = 0.95 [0.51-1.73]. However, both 60-day and 90-day mortality were significantly higher in the BAL group (39.6% vs. 24.7% and 45.8% vs. 26.8%, respectively; <i>p</i> < 0.01 for both), and these differences persisted after adjustment (60 days: OR = 1.74 [1.03-2.94]; 90 days: OR = 2.12 [1.27-3.54]). <b>Conclusions:</b> In this cohort of immunocompetent patients hospitalized with pneumonia, BAL was not associated with short-term survival. Clinicians should carefully weigh the potential risks and benefits of BAL in this population. Further studies are needed to identify patient subgroups that might benefit from BAL through enhanced diagnostic or therapeutic approaches.