Zhou Aiyuan, Zhang Xiyan, Lu Rongli, Peng Wenzhong, Wang Yanan, Tang Haiyun, Pan Pinhua
Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
Heliyon. 2024 Jul 25;10(15):e35099. doi: 10.1016/j.heliyon.2024.e35099. eCollection 2024 Aug 15.
The presence of fibrotic interstitial lung disease (ILD) is relatively common in patients with emphysema. This has been designated combined pulmonary fibrosis and emphysema (CPFE). CPFE had worse prognosis than emphysema alone. Krebs von den Lungen-6 (KL-6) levels as a biomarker of alveolar type 2 epithelial cell injury, which is widely used to identify the presence of ILD, whether it can differentiate CPFE from COPD remains unknown.
259 patients from Xiangya Hospital with diagnosis of COPD, with or without ILD, and who had KL-6 tests were recruited for this retrospective analysis. Recorded data included demographic information, comorbidities, inflammatory biomarkers. Results of CT and pulmonary function tests were collected one week before or after KL-6 measurements.
Among 259 patients, 52 patients were diagnosed with CPFE. The mean age was 67.39 ± 8.14 yeas. CPFE patients had higher ratio of rheumatic diseases (21.2 % vs 7.2 %, = 0.003). CPFE patients exhibited higher values of FEV (1.97 vs 1.57, = 0.002) and FEV/FVC ratio (69.46 vs 57.64, < 0.001) compared to COPD patients. CPFE patients had higher eosinophil counts, percentage of eosinophils, lactate dehydrogenase, total bilirubin levels and lower platelet counts. Serum KL-6 levels were higher in CPFE group compared to COPD group (574.95 vs 339.30 U/mL, < 0.001). Multiple logistic regression showed that KL-6 level was an independent predictive factor for the presence of ILD among COPD patients. The AUC of serum KL-6 levels to differentiate CPFE was 0.711, with 95 % CI being 0.635 to 0.787. The cutoff point of KL-6 level was 550.95 U/mL with 57.7 % sensitivity and 79.7 % specificity for the discrimination of CPFE from COPD.
CPFE patients show higher KL-6 levels compared to isolated COPD, suggesting the potential of KL-6 as a practical screening tool for interstitial lung disease, specifically CPFE. A KL-6 threshold of 550.95 U/mL in COPD patients may indicate a high need for high-resolution chest computed tomography to detect fibrosis.
纤维化间质性肺疾病（ILD）在肺气肿患者中相对常见。这被称为合并性肺纤维化和肺气肿（CPFE）。CPFE的预后比单纯肺气肿更差。克雷布斯冯登肺-6（KL-6）水平作为肺泡Ⅱ型上皮细胞损伤的生物标志物，被广泛用于识别ILD的存在，但其能否区分CPFE和慢性阻塞性肺疾病（COPD）仍不清楚。
本回顾性分析纳入了259例来自湘雅医院、诊断为COPD（有或无ILD）且进行了KL-6检测的患者。记录的数据包括人口统计学信息、合并症、炎症生物标志物。CT和肺功能检查结果在KL-6测量前或后一周收集。
在259例患者中，52例被诊断为CPFE。平均年龄为67.39±8.14岁。CPFE患者的风湿性疾病比例更高（21.2%对7.2%，P=0.003）。与COPD患者相比，CPFE患者的第1秒用力呼气容积（FEV）值更高（1.97对1.57，P=0.002），FEV与用力肺活量（FVC）比值更高（69.46对57.64，P<0.001）。CPFE患者的嗜酸性粒细胞计数、嗜酸性粒细胞百分比、乳酸脱氢酶、总胆红素水平更高，血小板计数更低。CPFE组的血清KL-6水平高于COPD组（574.95对339.30 U/mL，P<0.001）。多因素逻辑回归显示，KL-6水平是COPD患者中ILD存在的独立预测因素。血清KL-6水平区分CPFE的曲线下面积（AUC）为0.711，95%置信区间为0.635至0.787。KL-6水平的截断点为550.95 U/mL，区分CPFE与COPD的敏感度为57.7%，特异度为79.7%。
与单纯COPD患者相比，CPFE患者的KL-6水平更高，这表明KL-6有可能作为间质性肺疾病，特别是CPFE的实用筛查工具。COPD患者中KL-6阈值为550.95 U/mL可能表明高度需要进行高分辨率胸部计算机断层扫描以检测纤维化。
