HALP score and 30-day mortality: an observational analysis of clinical associations in Pneumonia.

Background: Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide. Given the limitations of traditional risk scoring systems, new biomarkers such as the HALP (hemoglobin, albumin, lymphocyte, and platelet) score have emerged. This study evaluated the prognostic value of the HALP score in predicting 30-day mortality in patients with CAP and explored possible mechanisms underlying this association. Methods: A retrospective single-center study was conducted, including 467 adult patients hospitalized with pneumonia. HALP, PSI (pneumonia severity index), CURB-65 (confusion, uremia, respiratory rate, blood pressure, age ≥ 65 years), and NEWS (national early warning score) scores were calculated. ROC analysis was used to assess the prognostic value of HALP, and causal mediation analysis was performed to investigate the factors influencing the HALP-mortality relationship. Results: The 30-day mortality rate was 21.4%. Patients who died were older, mostly male, and had worse clinical and laboratory parameters, including lower HALP scores. The HALP score demonstrated good predictive ability (area under the receiver operating characteristic curve 0.794). Mediation analysis revealed that PSI, CURB-65, NEWS scores, confusion, oxygen saturation, shock index, and radiological findings significantly mediated the association between HALP and mortality. Conclusion: The HALP score was associated with short-term mortality in patients with CAP. Lower HALP values were associated with greater clinical severity and higher mortality, suggesting that it may serve as a complementary tool alongside traditional risk scoring systems.