Profound Anemia in Hospitalized Community Acquired Pneumonia Patients is Associated with Increased Mortality and is Prevalent in All Patients’ Age-groups. A Retrospective Analysis of 15,121 Patients

Background. Community acquired Pneumonia (CAP) is a widespread and potentially lethal disease. Acute anemia is a common phenomenon featuring many such instances. However, the prevalence and clinical implications of anemia in younger CAP patients is unknown. This study aimed to assess the prevalence and clinical outcomes of anemia in patients with CAP treated in a modern-time treated CAP (with current treatment strategies?). Methods. This was a retrospective analysis of CAP patients that were hospitalized during 2010–2024 in a large, tertiary medical center. Results. Following approval by the Institutional Review Board, we retrieved data relating to 17,336 adult patients hospitalized with CAP, of whom relevant clinical data were available for 15,121 patients. The median age was 77 years (IQR 22.2) and 55.2% of the cohort were males. Female patients were more common in the lower hemoglobin patients’ groups (43.9% amongst Hg ≥ 10g/dL, 49.6% in the 8g/dL ≤ Hb < 10g/dL group and 51.7% in the Hb < 8g/dL group of patients; p < 0.05). Interestingly, the median age of patients with severe anemia (73.6 years [IQR 19.6]) was lower than that of the other groups: 78.6 [IQR 18.4] in the 8g/dL ≤ Hb < 10g/dL group and 76.7 [IQR 22.9] in the Hg ≥ 10g/dL group (p < 0.001). Profound anemia and advanced age were identified as independent risk factors for both short- and long-term mortality. Conclusions. Profound anemia affects hospitalized CAP patients across all age groups and remains an independent risk factor for adverse clinical outcomes in the second decade of the 21st century.