Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Anhui Medical University, Furong Road no 678, Hefei, Anhui, 230601, China.
Institute of Respiratory Diseases, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, 230601, China.
BMC Pulm Med. 2024 Sep 27;24(1):472. doi: 10.1186/s12890-024-03297-y.
Previous research has discovered that surfactant protein A (SP-A) is involved in the pathophysiology processes of certain lung illnesses. However, no definitive clinical studies have delved into the function of SP-A in individuals afflicted with community-acquired pneumonia (CAP). A prospective cohort study was used to investigate the relationships between blood SP-A levels and the severity and prognosis among CAP patients.
This study included 260 patients with CAP. Clinical traits and demographic data were examined during hospitalization. The concentrations of serum SP-A and serum interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA). In addition, to evaluate the severity of CAP, a variety of scores, including the CURB-65, PSI, SMART-COP, and APACHE II, were employed.
The serum levels of SP-A at admission exhibited a gradual decline as the severity scores of CAP increased. Through Spearman correlation analysis, we observed an association between serum SP-A and some clinical indicators among CAP patients. Furthermore, results from a multiple linear regression model suggested changes in PSI scores (-17.868 scores, 95% CI: -32.743, -2.993) affect serum SP-A more than CURB-65 (-0.547 scores, 95% CI: -0.964, -0.131), SMART-COP (-1.097 scores, 95% CI: -1.889, -0.304) and APACHE II (-3.475 scores, 95% CI: -5.874, -1.075) with age, hypertension, diabetes mellitus, cerebral infarction, coronary heart disease, and bronchitis adjusted. In addition, the prognosis in CAP patients was monitored. Throughout their hospital stay, higher serum levels of SP-A decreased the risks of mechanical ventilation (RR: 0.315; 95% CI: 0.106, 0.937), vasoactive agents (RR: 0.165; 95% CI: 0.034, 0.790), intensive care unit (ICU) admissions (RR: 0.218; 95% CI: 0.066, 0.717) and longer hospital stays (RR: 0.397; 95% CI: 0.167, 0.945).
In CAP patients, inverse dose-response correlations exist between serum SP-A levels with severity scores as well as prognosis at admission, suggesting that SP-A may take part in the CAP pathophysiological processes. Moreover, lower serum SP-A on admission is associated with an elevated prognostic risk of mechanical ventilation, the use of vasoactive agents, longer hospital stays, ICU admission, and mortality. Therefore, as a biomarker, SP-A may have the potential to predict the severity and poor prognosis of CAP patients.
既往研究发现，表面活性蛋白 A（SP-A）参与某些肺部疾病的病理生理学过程。然而，尚无明确的临床研究深入探讨 SP-A 在社区获得性肺炎（CAP）患者中的作用。本研究采用前瞻性队列研究方法，旨在探讨 CAP 患者血 SP-A 水平与疾病严重程度和预后之间的关系。
本研究纳入 260 例 CAP 患者。患者住院期间对其临床特征和人口统计学数据进行了检查。采用酶联免疫吸附试验（ELISA）检测血清 SP-A 和血清白细胞介素-6（IL-6）浓度。此外，还采用 CURB-65、PSI、SMART-COP 和 APACHE II 等多种评分评估 CAP 严重程度。
入院时血清 SP-A 水平随 CAP 严重程度评分的升高而逐渐降低。Spearman 相关性分析显示，CAP 患者的血清 SP-A 与某些临床指标之间存在相关性。此外，多元线性回归模型结果表明，PSI 评分变化（-17.868 分，95%CI：-32.743，-2.993）对血清 SP-A 的影响大于 CURB-65（-0.547 分，95%CI：-0.964，-0.131）、SMART-COP（-1.097 分，95%CI：-1.889，-0.304）和 APACHE II（-3.475 分，95%CI：-5.874，-1.075）（均调整年龄、高血压、糖尿病、脑梗死、冠心病和支气管炎等因素）。此外，还对 CAP 患者的预后进行了监测。在整个住院期间，血清 SP-A 水平较高的患者机械通气（RR：0.315；95%CI：0.106，0.937）、血管活性药物（RR：0.165；95%CI：0.034，0.790）、入住重症监护病房（RR：0.218；95%CI：0.066，0.717）和住院时间延长（RR：0.397；95%CI：0.167，0.945）的风险降低。
在 CAP 患者中，入院时血清 SP-A 水平与严重程度评分及预后呈负相关，提示 SP-A 可能参与 CAP 的病理生理过程。此外，入院时血清 SP-A 水平较低与机械通气、血管活性药物使用、住院时间延长、入住重症监护病房和死亡的预后风险升高相关。因此，作为一种生物标志物，SP-A 可能有助于预测 CAP 患者的严重程度和不良预后。
