摘要目的:探讨弥散功能对慢性阻塞性肺疾病(慢阻肺)合并肺癌的预测价值。方法:本研究为病例对照研究。采用非随机对照的方法，分析2008年3月至2021年10月兰州大学第一医院收治的421例慢阻肺合并肺癌患者的临床资料，并与慢阻肺患者(708例)及肺癌患者(438例)比较；比较肺癌患者不同临床分期的弥散功能，并分析弥散功能与临床分期的相关性；采用多因素logistic回归分析弥散功能与慢阻肺合并肺癌的关系；根据受试者工作特征(ROC)曲线分析弥散功能对慢阻肺合并肺癌的预测价值。结果:慢阻肺合并肺癌组男性占比、吸烟比例及吸烟指数均高于慢阻肺组和肺癌组，年龄高于肺癌组，体质量指数低于慢阻肺组( P值均<0.05)；慢阻肺合并肺癌组鳞癌占比高，肺癌组腺癌占比高( P值均<0.05)。慢阻肺合并肺癌组与肺癌组肿瘤最大直径、侵犯大气道及肺动脉受压占比差异均无统计学意义。慢阻肺合并肺癌组肺通气功能、小气道功能、残气量及残/总比、肺功能GOLD分级与慢阻肺组比较差异无统计学意义；与肺癌组比较，慢阻肺合并肺癌组通气功能、小气道功能显著降低，残气量、残/总比增高( P值均<0.05)；慢阻肺合并肺癌组弥散功能低于慢阻肺组和肺癌组，不同程度弥散功能下降者占比均高于慢阻肺组和肺癌组( P值均<0.05)。慢阻肺合并肺癌组与肺癌组非小细胞肺癌患者TNM分期越高，弥散功能越低。Spearman相关分析显示，弥散功能与慢阻肺合并肺癌组及肺癌组非小细胞肺癌患者TNM分期呈负相关( P值均<0.05)。调整性别、年龄、体质量指数、吸烟史及吸烟指数后，多因素logistic回归分析结果显示，弥散功能重度下降组慢阻肺患者发生肺癌风险是弥散功能正常组的2.771倍(95% CI：1.211~6.338， P＝0.016)。ROC曲线分析结果提示，一氧化碳弥散量(D LCO)、一氧化碳弥散量占预计值百分比(D LCO%pred)、单位肺泡容积一氧化碳弥散量(D LCO/VA)、单位肺泡容积一氧化碳弥散量占预计值百分比(D LCO/VA%pred)预测慢阻肺合并肺癌的最佳阈值分别为7.12 mmol·min -1·kPa -1、87.95%、1.24 mmol·min -1·kPa -1·L -1、101.25%，敏感度、特异度分别为65.6%、46.8%，62.5%、60.2%，49.2%、73.6%，64.8%、58.8%，曲线下面积分别为0.582、0.653、0.651、0.647，以D LCO%pred预测作用最好；第1秒用力呼气容积占预计值百分比联合D LCO、D LCO%pred、D LCO/VA及D LCO/VA%pred的曲线下面积分别为0.582、0.656、0.651、0.647，敏感度、特异度分别为35.4%、76.7%，76.2%、47.0%，52.0%、71.6%，64.4%、59.5%。 结论:弥散功能与慢阻肺合并肺癌有关，对慢阻肺患者合并肺癌有一定的预测价值。

abstractsObjective:To explore the predictive value of diffusing capacity for chronic obstructive pulmonary disease (COPD) complicated with lung cancer.Methods:This was a case-control study.The clinical data of 421 patients with COPD complicated with lung cancer who were admitted to the First Hospital of Lanzhou University from March 2008 to October 2021 were collected by non-randomized control method, and the clinical data were compared with those of the patients with COPD (708 cases) and lung cancer (438 cases).The diffusing capacity of different clinical stages of lung cancer was compared, and the correlation between diffusing capacity and clinical stage was analyzed.Multivariate logistic regression was used to analyze the relationship between diffusing capacity and lung cancer in COPD patients.The predictive value of diffusing capacity for COPD complicating lung cancer was explored by receiver operating characteristic (ROC) curve analysis.Results:The proportion of male, smoking rate, and smoking index in COPD complicating lung cancer group were higher than those in the COPD and lung cancer groups (all P<0.05).The age of COPD complicating lung cancer group was older than that of the lung cancer group, and body mass index (BMI) was lower than that of the COPD group (all P<0.05).Compared with the lung cancer group, in the COPD complicating lung cancer group, the proportion of squamous cancer was higher while the frequency of adenocarcinoma was lower (all P<0.05).There were no significant differences in the maximum tumor diameter, the proportion of large airway invasion, and pulmonary artery compression between the COPD complicating lung cancer group and the lung cancer group.There were no differences in lung ventilation function, small airway function, residual volume, residual/total ratio, and GOLD grade between COPD complicating lung cancer group and COPD group.Compared with lung cancer group, in COPD complicating lung cancer group, lung ventilation function and small airway function were significantly decreased while residual volume and residual/total ratio were increased (all P<0.05).The diffusing capacity of COPD complicating lung cancer group was lower than that of COPD and lung cancer groups, and the proportion of patients with decreased diffusion function in different degrees in COPD complicating lung cancer group was significantly higher than that in COPD group and lung cancer group (all P<0.05).The higher the TNM stage of the NSCLC patients in the COPD complicating lung cancer group and the lung cancer group, the lower the diffusing capacity.Spearman correlation analysis showed that the diffusing capacity was negatively correlated with the TNM stage of the NSCLC patients in the COPD complicating lung cancer group and lung cancer group.Multivariate logistic regression analysis showed that the risk of lung cancer in COPD group with severely decreased diffusing capacity was 2.771 times higher than that in normal diffusing capacity group after adjusting for gender, age, BMI, smoking history, and smoking index (95% CI: 1.211-6.338, P=0.016).ROC curve suggested that the optimal thresholds of diffusing capacity of carbon monoxide (D LCO), D LCO percent predicted value (D LCO%pred), diffusing capacity of carbon monoxide per liter of alveolar volume(D LCO/VA), and D LCO/VA percent predicted value (D LCO/VA%pred) for predicting COPD complicating lung cancer were respectively 7.12 mmol·min -1·kPa -1, 87.95%, 1.24 mmol·min -1·kPa -1·L -1, 101.25%; the sensitivity and specificity were 65.6% and 46.8%, 62.5% and 60.2%, 49.2% and 73.6%, 64.8% and 58.8%, respectively; the areas under the curve were 0.582, 0.653, 0.651 and 0.647, respectively.D LCO%pred had the best prediction effect.The AUCs of FEV 1%pred combined with D LCO, D LCO%pred, D LCO/VA, and D LCO/VA%pred were 0.582, 0.656, 0.651, 0.647, respectively; and the sensitivity and specificity were 35.4% and 76.7%, 76.2% and 47.0%, 52.0% and 71.6%, 64.4% and 59.5%, respectively. Conclusions:Diffusing capacity is associated with COPD complicating lung cancer, and has certain predictive value for COPD complicating lung cancer.