The prediction of lymphocyte count and neutrophil count on the efficacy of Xuebijing adjuvant treatment for severe community-acquired pneumonia: A post hoc analysis of a randomized controlled trial

Background: Adjuvant Xuebijing therapy exhibited a protective effect on severe community-acquired pneumonia (SCAP) in previous studies. Blood inflammatory biomarkers related to the disease subtype and severity of SCAP might be associated with the effects of Xuebijing on clinical outcomes of SCAP. Purpose: To investigate whether neutrophils or lymphocytes are a useful biomarker of the therapeutic effect of Xuebijing on mortality and inflammation damage index. Study Design: A post hoc analysis of a randomized, placebo-controlled and double-blinded clinical trial of Xuebijing in patients with SCAP (Clinical Trial Registration: ChiCTR-TRC-13003534). Methods: We compared 28-day mortality (primary outcome) and four clinical scores (secondary outcome), including pneumonia severity index (PSI) score, sequential organ failure assessment (SOFA) score, acute physiology and chronic health evaluation II (APACHE II) score, and systemic inflammatory response syndrome (SIRS) score, according to the baseline strata of neutrophil count and lymphocyte count. Results: A total of 675 patients were included in the analyses, of which 334 received Xuebijing and 341 received the placebo. Xuebijing was more effective in SCAP patients with higher lymphocyte counts and lower neutrophil counts. In the lymphocyte-dominated inflammation (LDI) subgroup, defined as neutrophil count <13 x 10(9) cells/l and lymphocyte count >= 0.65 x 10(9) cells/l, Xuebijing reduced 28-day mortality by 15% while mortality of the neutrophil-dominated inflammation (NDI) subgroup decreased by 4.7% (p = 0.050). There was also greater improvement in the PSI, SOFA, APACHE II, and SIRS scores following Xuebijing treatment in the LDI subgroup compared with the NDI subgroup. Conclusions: Xuebijing treatment shows stronger protective effects in SCAP patients with higher lymphocyte and lower neutrophil counts. Our findings may facilitate the selection of the most appropriate treatments for individual patients with SCAP, including who will receive Xuebijing injections.