Assessment of Compliance with National and International Guidelines in the Empirical Management of Community-Acquired Pneumonia (CAP) in Lebanese Hospitals: A Multicenter Retrospective Cohort Study

Background: Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality globally, with serious implications in Lebanon. Both international and local guidelines advocate for empirical antibiotic treatments by illness severity, yet the extent to which these are followed in Lebanese hospitals is unclear. This research examined the adherence to CAP treatment guidelines and its association with clinical outcomes. Methods: We retrospectively studied adults admitted to two Lebanese referral hospitals (Mount Lebanon University Medical Center and Ain Wazein Medical Village) from April 2011 to March 2025 with CAP. Adherence to empirical antibiotic regimens was determined based on the guidelines from the Lebanese Society of Infectious Diseases and Clinical Microbiology, American Thoracic Society/Infectious Diseases Society of America, and British Thoracic Society/National Institute for Health and Care Excellence. The outcomes assessed were in-hospital mortality, Intensive Care Unit (ICU) admission, and length of hospital stay (LOS). We used logistic and linear regression analyses, adjusting for demographic and clinical variables. Results: A total of 337 patients were included with an average age of 61 years; 53.7% were male, 51.6% were admitted to the ICU, and the in-hospital mortality rate was 27%. In general, 65.6% of the treatment regimens adhered to at least one guideline. The combination of β-lactam and macrolide was the most common, used in 87.8% of cases, while monotherapy was administered in 31.8% of cases and included β-lactam, macrolide, fluoroquinolone, and other antibiotics; most monotherapies were non-adherent to guidelines, except for selected fluoroquinolone monotherapy cases that may be considered guideline-concordant under ATS/IDSA recommendations depending on clinical context. Adherence to guidelines did not significantly affect mortality rates (25.8% vs. 29.3%), ICU admissions (52.5% vs. 50.0%), or length of stay (11.4 vs. 9.3 days). Multivariate analysis revealed that older age (OR 1.025, 95% CI 1.008–1.042) and ICU admission (OR 1.024, 95% CI 1.012–1.039) were independent predictors of adverse outcomes, whereas guideline adherence, comorbidities, and inflammatory markers were not independently linked. Surprisingly, mortality was higher among younger patients (average age 58 vs. 67 years, p < 0.001). Conclusions: Although guideline-concordant empirical therapy was prevalent in this two-center Lebanese retrospective population, it did not independently correlate with length of stay following adjustment, ICU admission, or in-hospital mortality. Patient-related and clinical factors, such as the severity of the illness, may have an impact on observed differences in outcomes, which should be taken as relationships.