Cryptogenic organizing pneumonia (COP) is a form of non-specific lung injury characterized by the formation of alveolar granulomas. While it typically responds well to glucocorticoid therapy, the condition is prone to relapse upon dose reduction or discontinuation of treatment. Recurrence of COP is associated with a poor prognosis and significantly impacts patients' quality of life. Consequently, analyzing the clinical characteristics and identifying risk factors for recurrence are crucial for early recognition and minimizing the likelihood of relapse.

By analyzing the clinical data of patients with COP, we aim to identify potential risk factors associated with disease recurrence. This research will enhance the understanding of COP recurrence mechanisms and provide valuable insights for clinical doctors to develop more effective prevention strategies.

We retrospectively collected data from 95 patients who were diagnosed with COP through a combination of clinical, radiological, and pathological assessments at the Affiliated Central Hospital of Shandong First Medical University from 2014 to 2023. All patients were followed up at 1, 3, and 6 months after discharge, with the results interpreted jointly by specialized pulmonologists and radiologists. Patients were divided into two groups based on recurrence status: the recurrence group and the non-recurrence group. We analyzed the general information, clinical manifestations, laboratory tests, and imaging findings of the two groups. Univariate analysis was performed, and significant indicators were further subjected to multivariate Logistic regression analysis to identify independent risk factors for COP recurrence.

A total of 95 patients with COP were included in this study, comprising 49 males and 46 females, with ages ranging from 18 to 85 years. The main clinical manifestations were dry cough, chest tightness, dyspnea, and respiratory distress. Chest imaging primarily showed multifocal or large areas of consolidation in both lungs. Laboratory tests showed no significant specificity, but some patients had elevated inflammatory markers, including white blood cell count, neutrophil count, C-reactive protein, and erythrocyte sedimentation rate. Pathological findings included granulation tissue formation in the alveolar ducts and alveolar spaces, often accompanied by massive accumulation of foamy macrophages, inflammatory cell infiltration, alveolar epithelial proliferation, fibrous tissue proliferation, and widened alveolar septa. Among the 95 patients, 24 experienced recurrence. Univariate analysis revealed that white blood cell count, neutrophil count, C-reactive protein, alanine aminotransferase, lactate dehydrogenase, γ-glutamyl transferase (γ-GT) , erythrocyte sedimentation rate, arterial oxygen partial pressure, time from onset to diagnosis, and fever were associated with COP recurrence. Multivariate Logistic regression analysis identified higher lactate dehydrogenase (OR=1.003, 95%CI=1.003-1.037, P=0.024) , higher erythrocyte sedimentation rate (OR=1.084, 95%CI=1.037-1.132, P=0.002) , lower arterial oxygen partial pressure (OR=0.882, 95%CI=0.817-0.952, P=0.001) , and longer time from onset to diagnosis (OR=1.017, 95%CI=1.003-1.031, P=0.016) as independent risk factors for COP recurrence.

Higher lactate dehydrogenase, higher erythrocyte sedimentation rate, lower arterial oxygen pressure, and longer time from onset to diagnosis are independent risk factors for COP recurrence.

隐源性机化性肺炎（COP）是一种病理特征为肺泡内肉芽肿形成的非特异性肺损伤性疾病，对糖皮质激素治疗反应良好，但减量或停药时易复发。COP复发会导致预后不良，影响患者生活质量。因此，对COP临床特征及复发危险因素进行分析，对早期识别、减少复发尤为重要。

通过对COP患者临床资料的分析，筛选出可能的复发危险因素，加强临床医生对COP复发的认识和预防。

回顾性收集2014—2023年在山东第一医科大学附属中心医院就诊，并经临床-影像-病理共同诊断为COP的患者95例，患者出院后1个月、3个月、6个月进行随访，随访结果均由专业的呼吸内科医师和影像学医师共同判读。按照复发与否分为复发组和未复发组，对两组患者的一般临床信息、临床表现、实验室检查指标及影像学特点等进行分析，采用单因素及多因素Logistic回归分析探讨COP复发的危险因素。

本研究共收集95例COP患者，其中男49例，女46例，年龄18~85岁；临床表现主要为干咳、胸闷气促、呼吸困难；胸部影像学主要表现为双肺多发或大片实变影；实验室检查无明显特异性，部分患者可有炎症指标如白细胞计数、中性粒细胞计数、C反应蛋白、红细胞沉降率增高。病理表现为肺泡管和肺泡腔内肉芽组织形成，可同时伴有大量泡沫细胞聚集、炎性细胞浸润、肺泡上皮增生、纤维组织增生、肺泡间隔增宽。有24例患者出现复发，单因素分析显示白细胞计数、中性粒细胞计数、C反应蛋白、丙氨酸氨基转移酶、乳酸脱氢酶、γ-谷氨酰基转移酶（γ-GT）、红细胞沉降率、动脉血氧分压、诊断时间、发热与COP复发相关。多因素Logistic回归分析结果显示，乳酸脱氢酶升高（OR=1.003，95%CI=1.003~1.037，P=0.024）、红细胞沉降率升高（OR=1.084，95%CI=1.037~1.132，P=0.002）、动脉血氧分压降低（OR=0.882，95%CI=0.817~0.952，P=0.001）、诊断时间长（OR=1.017，95%CI=1.003~1.031，P=0.016）为COP复发的危险因素。

乳酸脱氢酶、红细胞沉降率、动脉血氧分压、诊断时间是COP复发的危险因素。