The prognostic importance of D-dimer in elderly population with community-acquired penumonia: a retrospective analysis.

INTRODUCTION: The aim of this study was to evaluate the association between admission D-dimer levels and clinical outcomes in elderly patients with community-acquired pneumonia.


METHODS: This retrospective cohort study included elderly patients diagnosed with CAP between February 2025 and February 2026. Demographic characteristics, clinical findings, and laboratory parameters were obtained from hospital records. Serum D-dimer levels were measured at admission using a latex-enhanced turbidimetric immunoassay. Disease severity was assessed using the Pneumonia Severity Index (PSI). D-dimer levels were compared between CAP patients and healthy controls and analyzed according to PSI risk groups, hospitalization status, and intensive care unit (ICU) admission
RESULTS: A total of 104 elderly individuals were included in the study, consisting of 56 patients with CAP and 48 healthy controls. There were no significant differences between the groups in terms of age, sex distribution, body weight, hemoglobin, hematocrit, or platelet counts (p > 0.05). However, white blood cell counts were significantly higher in the CAP group (p = 0.001). Serum D-dimer levels were markedly elevated in patients with CAP compared with the control group (median 2.25 µg/mL vs 0.02 µg/mL, p = 0.001). Among CAP patients, D-dimer levels increased progressively with higher PSI classes, ranging from 1.08 ± 0.45 µg/mL in PSI class I to 2.23 ± 1.32 µg/mL in PSI class V. In addition, D-dimer levels were lowest in outpatients and significantly higher in hospitalized and ICU patients. Post-hoc analysis showed significant differences between outpatients and hospitalized patients as well as between outpatients and ICU patients, whereas no significant difference was observed between inpatient and ICU groups.
DISCUSSION AND CONCLUSION: Serum D-dimer levels are significantly elevated in elderly patients with community-acquired pneumonia and are associated with increasing disease severity. The progressive rise in D-dimer levels across PSI classes and clinical care settings suggests that D-dimer may serve as a useful adjunct biomarker for risk stratification in elderly CAP patients.

Keywords: pneumonia, elderly, chest