Objective: The aim of this study is to investigate the factors affecting cost in patients with severe community-acquired pneumonia (CAP) who admitted to the intensive care unit (ICU).

Material and Methods: This retrospective cohort study was conducted at Süreyyapaşa Chest Diseases Training and Research Hospital, Dokuz Eylül University Hospital, Ankara University Hospital, Akdeniz University Hospital ICU between January 2013 - December 2016. A total of 291 sequential patients with severe CAP were included in the study. Patients’ demographic and clinical data, need for invasive mechanical ventilation (IMV) or non-invasive mechanical ventilation (NIMV), intensive care severity scores including APACHE-II (Acute Physiology And Chronic Health Evaluation), SOFA (Sepsis-related Organ Failure Assessment), Quick SOFA and pneumonia severity index (PSI) and CURB-65 scores were obtained from medical records and recorded for all cases.

Results: The mean age of 291 patients was 68.4 ± 16.8 years, and 61% were female. Median length of intensive care unit stay was 7 days (1^st-3^rd percentiles: 4-11 days). Forty-six percent of patients had chronic obstructive pulmonary disease (COPD), and 42% had hypertension. Mean cost of each hospitalization was found as 2722 $ (5578 TL). The highest cost was found in 50-59 years-aged patient group, lowest cost was found in the <50 years-aged patients. Statistically significant relationship was found between ICU severity scores and health cost. The cost of patients in PSI group-V, APACHE-II score >20 points, and CURB-65 score ≥3 points were higher. The cost of patients in PSI class V, APACHE II (>20 points) and CURB-65 score were higher. Presence of COPD, atrial fibrillation, congestive heart failure, hypoalbuminemia, mental state deterioration, in-hospital mortality, severe sepsis, septic shock, mechanical ventilation requirement, haloperidol and vasopressor usage were associated with higher cost; while use of florokinolon was associated with lower cost.

Conclusion: The presence of certain comorbidities and high disease severity in patients with severe CAP hospitalized into ICU increase the cost of in-patient treatment. The need for mechanical ventilation during treatment and presence of sepsis / septic shock were other factors that increase the cost.