A novel tool for improving the accuracy of major depressive disorder screening: A prospective study on andrology with external validation

Patient Health Questionnaire-9 (PHQ-9) is the most widely used tool for screening for major depressive disorder (MDD). Although its reliability and validity have been proven, missed or misjudged cases during MDD screening are often encountered. A nomogram that considers the weights of depressive symptoms was developed using data from premature ejaculation patients to improve screening accuracy. During a 33-month prospective study, a training cohort comprising 605 participants from Xijing Hospital was used to develop and internally validate the nomogram. A validation cohort comprising 461 patients from Xi'an Daxing Hospital was also used to externally test the nomogram. The nomogram was established by integrating the LASSO regression-based optimal predictors of MDD according to their coefficients in a multivariate logistic regression model. The nomogram was well-calibrated during internal and external validations. Moreover, it showed a better discriminatory capacity and yielded more net benefits in both validations than PHQ-9. With better performance, the nomogram may help reduce the number of missed or misjudged cases during MDD screening. This study is the first to weigh the direct indicators of MDD under the DSM-5 criteria, presenting a fresh concept that can be applied to other populations to enhance screening accuracy.