Risk Factor Analysis Of The Patients With Single Pulmonary Nodule And Establishment Of A Prediction Model For The Probability Of Malignancy

Objective:To analyze risk factors of malignancy in patients with single pulmonary nodule (diameter≤3cm) using univariate analysis and multivariate logistic regression, and establish a prediction model for the probability of malignancy.Methods:Clinical data of264patients with single pulmonary nodule who underwent surgical resection with definite postoperative pathological diagnosis from January2011to December2013in the Sir Run Run Shaw Hospital were retrospectively analyzed. Univariate analysis was performed to analyze risk factors including age, gender, symptoms, history and quantity of smoking, history of tumor, Family history of tumor, diameter, location, ground-glass opacity, lobulation, speculation, pleural indentation and cavity. Independent risk factors were screened with multivariate logistic regression analysis. A mathematical prediction model was built to estimate the probability of malignancy and then examined.Result:Age(t=-3.710, P=0.000), heavy smoking history(χ2=9.108, P=0.003), nodule diameter(P=0.000), ground-glass opacity(χ2=27.721, P=0.000), speculation (χ2=25.940, P=0.000), lobulation (χ2=9.270, P=0.002), pleural indentation (χ2.297, P=0.038), cavity (χ2=5.034, P=0.025) were shown statistical difference in the univariate analysis between benign and malignant single pulmonary nodule groups. Multivariate logistic regression analysis showed that patient age (OR=1.042, P=0.013), nodule diameter (OR=1.072, P=0.011), ground-glass opacity (OR=33.979, P=0.000) and speculation (OR=1.546, P=0.000) were independent predictors of malignancy in patients with single pulmonary nodule (P<0.05). The mathematical prediction model to estimate the probability of malignancy was:Logit(P)=e7(1+ez), Z=-3.416+(0.041*age)+(0.069*nodule diameter)+(3.526*ground-glass opacity)+(1.546*speculation), and e was natural logarithm. Both Hosmer-Lemeshow test(χ2=7.531, P=0.481) and maximum likelihood ratio test (Cox-Snell R2=0.276, Nagelkerke R2=0.481) showed satisfactory goodness of fit. When the cut-off value was0.70, the diagnostic accuracy was79.6%, sensitivity was82.0%, specifi city was78.1%, positive predictive value was90.1%, and negative predictive value was56.1%.Conclusions:Patient age, nodule diameter, ground-glass opacity and speculation are independent predictors of malignancy in patients with small pulmonary nodules. The mathematical prediction model can estimate the probability of malignancy for patients with small pulmonary nodules.