Objective To analyze the value of heparin-binding protein (HBP) and interleukin-17A (IL-17A) levels in bronchoalveolar lavage fluid in predicting prognosis of elderly patients with severe pneumonia.

Methods A total of 105 elderly patients with severe pneumonia in the hospital from May 2022 to May 2024 were selected and divided into death group (n=32) and survival group (n=73) based on their survival outcomes within 28 days after admission. The levels of HBP and IL-17A in bronchoalveolar lavage fluid were compared between the two groups; the Logistic regression analysis was conducted to explore the influencing factors for prognosis in elderly patients with severe pneumonia; the receiver operating characteristic (ROC) curve was plotted to analyze the predictive efficiencies of HBP and IL-17A in bronchoalveolar lavage fluid for the prognosis of elderly patients with severe pneumonia.

Results The levels of HBP and IL-17A in bronchoalveolar lavage fluid in the death group were significantly higher than those in the survival group (P < 0.01). There were significant differences in the Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) score and blood lactate (Lac) level between the two groups (P < 0.01). Logistic regression analysis showed that HBP (OR=3.084, 95%CI, 1.326 to 4.694), IL-17A (OR=4.521, 95%CI, 2.164 to 7.841), APACHE Ⅱ score (OR=2.039, 95%CI, 1.069 to 2.859), and Lac (OR=2.627, 95%CI, 1.168 to 3.058) were influencing factors for the prognosis of elderly patients with severe pneumonia (P < 0.05). When the optimal cut-off values were set at 15.92 ng/mL for HBP and 109.34 pg/mL for IL-17A, the area under the curve (AUC) for the combined prediction of prognosis by HBP and IL-17A in bronchoalveolar lavage fluid was 0.852, with a 95%CI of 0.801 to 0.948. The AUC for the combined prediction of prognosis by HBP and IL-17A in bronchoalveolar lavage fluid was significantly higher than that for single tests (Z=2.906, 2.416, P=0.007, 0.014).

Conclusion Increased levels of HBP and IL-17A in bronchoalveolar lavage fluid, decreased APACHE Ⅱ score, and increased Lac are influencing factors for the prognosis of elderly patients with severe pneumonia. Combined detection of HBP and IL-17A in bronchoalveolar lavage fluid has high sensitivity in predicting the prognosis of elderly patients with severe pneumonia.