A Prospectively Validated Nomogram for Predicting the Risk of PHQ-9 Score ≥15 in Patients With Erectile Dysfunction: A Multi-Center Study

Abstract

Background: Although erectile dysfunction (ED) often occurs simultaneously with depression, not all patients with ED suffer major depression (MD), with a PHQ-9 score ≥15 indicating MD. Because the PHQ-9 questionnaire includes phrases such as "I think I am a loser" and "I want to commit suicide," the psychological burdens of ED patients are likely to increase inevitably after using the PHQ-9, which, in turn, may affect ED therapeutic effects. Accordingly, we endeavored to develop a nomogram to predict individual risk of PHQ-9 score ≥15 in these patients.

Methods: The data of 1,142 patients with ED diagnosed in Xijing Hospital and Northwest Women and Children's Hospital from January 2017 to May 2020 were analyzed. While the Least Absolute Shrinkage and Selection Operator regression was employed to screen PHQ-9 score ≥15 related risk factors, multivariate logistic regression analysis was performed to verify these factors and construct the nomogram. The training cohort and an independent cohort that comprised 877 prospectively enrolled patients were used to demonstrate the efficacy of the nomogram.

Results: The IIEF-5 score, PEDT score, physical pain score, frequent urination, and feeling of endless urination were found to be independent factors of PHQ-9 score ≥15 in patients with ED. The nomogram developed by these five factors showed good calibration and discrimination in internal and external validation, with a predictive accuracy of 0.757 and 0.722, respectively. The sensitivity and specificity of the nomogram in the training cohort were 0.86 and 0.52, respectively. Besides, the sensitivity and specificity of the nomogram in the validation cohort were 0.73 and 0.62, respectively. Moreover, based on the nomogram, the sample was divided into low-risk and high-risk groups.

Conclusion: This study established a nomogram to predict individual risk of PHQ-9 score ≥15 in patients with ED. It is deemed that the nomogram may be employed initially to avoid those with a low risk of MD completing questionnaires unnecessarily.

Keywords: erectile dysfunction; major depression; nomogram; prognostic factor; risk factor.

Figure 1

The flow chart of this study.

Figure 2

Variable screening using the least absolute shrinkage and selection operator (LASSO) binary logistic regression model. (A) LASSO coefficient profile of features. This graph shows the relationship between the penalty coefficient log (λ) and the retained charicteristics. The number of intersecting curves represent the number of charicteristics retained at that log (λ) value. (B) The relationship between log (λ) and binomial deviance. Based on the 10-fold crossvalidation method, the relationship between log (λ) and binomial deviance is drawn. The dotted vertical lines were drawn at the optimal values by using the minimum criteria and the minimum criterion of 1 SE.

Figure 3

Nomogram for predicting individual risk of major depression in patients with erectile dysfunction. (IIEF-5, 5-item International Index Erectile Function; PEDT, premature ejaculation diagnostic tool; PPS, physical pain score; FU, frequent urination; FEU, feeling of endless urination).

Figure 4

The ROC curves and the dotted line represents of the derivation cohort and validation cohort. (A) The ROC curves of the nomogram, IIEF-5 score, PEDT score, physical pain score, frequent urination and feeling of endless urination in derivation cohort. (B) The ROC curves of the nomogram, IIEF-5 score, PEDT score, physical pain score, frequent urination and feeling of endless urination in validation cohort. (C) The calibration plot of the nomogram in derivation cohort. (D) The calibration plot of the nomogram in validation cohort. The dotted line represents the calibration of an ideal nomogram (the predicted risk perfectly corresponds to the actual rate). The red solid line represents the apparent accuracy of the nomogram without correction for overfitting, while the black solid line represents the bootstrap-corrected nomogram. (Nom, nomogram; IIEF-5, 5-item International Index Erectile Function; PEDT, premature ejaculation diagnostic tool; PPS, physical pain score; FU, frequent urination; FEU, feeling of endless urination).

Figure 5

Dose-response association between total points. The presence of major depression in patients with erectile dysfunction with five knots located at the 5th, 27.5th, 50th, 72.5th, and 95th percentiles. (Ref, reference; OR, odds ratio).