单项和联合指标在结节病诊断中的预测价值评价

目的 评价结节病诊断中各单项和联合诊断指标的预测价值.方法 回顾性分析北京协和医院2001年1月至2007年9月间88例初步诊断为结节病的患者的临床资料,应用受试者工作特征曲线(ROC曲线)和Bayes方法 对BALF细胞分类中的淋巴细胞比例、淋巴细胞亚群CD4/CD8、血清血管紧张素转换酶(ACE)等3项指标及其联合指标的诊断预测价值进行评价.采用ROC曲线评价各指标的诊断价值并确定指标的界定值,采用判别分析和ROC曲线评价联合指标的诊断价值.结果 在88例初步诊断为结节病的患者中,经活检确诊结节病59例(67%),男性16例(27%),女性43例(73%),平均年龄(48±10)岁;排除结节病29例(33%),男性12例(41%),女性17例(59%),平均年龄(49±13)岁.单项指标淋巴细胞比例、CD4/CD8值和ACE的ROC曲线下面积分别为0.64、0.74和0.69,CD4/CD8值在3项指标中的诊断效率最高;通过ROC曲线的切点和坐标结合确定3项指标的最佳界定值是淋巴细胞比例≥30%,CD4/CD8值≥4.0,ACE≥40 U/L;其阳性预测值分别为76.7%、80.4%和76.8%,表明CD4/CD8值在3项指标中的预测价值最高.CD4/CD8值和ACE联合指标的曲线下面积为0.81,CD4/CD8值、ACE、淋巴细胞比例3项联合指标的曲线下面积为0.78,均大于单项指标的曲线下面积,前者的诊断效率优于后者.CD4/CD8值和ACE并联指标的阳性预测值为83.9%,串联指标的阳性预测值为90.5%,明显高于单项指标的相同评价指标,表明将CD4/CD8值和ACE联合起来诊断结节病的效率和预测价值均高于各单项指标.结论 BALF淋巴细胞亚群中CD4/CD8值仍然是辅助诊断结节病的有效单项指标,采用CD4/CD8值和ACE联合指标诊断结节病可提高诊断效率和预测价值.

Predictive value of single and combined indexes in the diagnosis of sarcoidosis

Objective To evaluate the predictive value of single and combined indexes in the diagnosis of sarcoidosis. Methods Eighty-eight patients suspected of having sarcoidosis were retrospectively investigated. The diagnostic predictive value of lymphocyte percentage and CD4/CD8ratio in bronchoalveolar lavage (BAL), angiotensin converting enzyme (ACE) and their combination was evaluated by ROC curve method and Bayes'rule. Results Final diagnosis of sarcoidosis by biopsy was available in 59 patients (67%), 16 were males (27%), 43 were females (73%), with a mean age of (48±10) years. The diagnosis of non-sarcoidosis was available in 29 patients (33%), 12 were males (41%), 17 were females (59%) ,with a mean age of (49±13) years. The ROC curve area of lymphocyte percentage, CD4/CD8 ratio and ACE were 0.64, 0.74 and 0.69 respectively; CD4/CD8 ratio had the best diagnostic efficiency. The optimized cut-offs of the three single indexes, lymphocyte percentage ≥30% ,CD4/CD8 ratio≥4.0 and ACE≥40 U/L, were determined by the tangential points and coordinates of the ROC curve. The positive predictive values were 76. 7%, 80. 4% and 76. 8% respectively; CD4/CD8 ratio had the best predictive value. The ROC curve area of the combined CD4/CD8 ratio and ACE was 0. 81, and the combination of lymphocyte percentage, CD4/CD8 ratio and ACE was 0.78. They were both higher than those of the respective single indexes. The combination of CD4/CD8 ratio and ACE had the best diagnostic efficiency.On the other hand, it had the best positive predictive value of 90. 5% in all the diagnostic indexes. Conclusion CD4/CD8 ratio in BAL is still a useful index in the auxiliary diagnosis of sarcoidosis. The combination of CD4/CD8 ratio and ACE can improve the diagnostic efficiency and predictive value of sarcoidosis.