A Nomogram Diagnostic Model for Eustachian Tube Dysfunction in Patients with Tympanic Membrane Perforation

Abstract

Objectives: Eustachian tube dysfunction (ETD) is a common disease associated with chronic otitis media. A standard diagnostic tool for ETD in patients with tympanic membrane perforation is still lacking. We developed and validated a new diagnostic model for ETD in patients with tympanic membrane perforation.

Methods: A prospective study was conducted in patients who had tympanic membrane perforation from February to August 2023. We collected clinical characteristics and examination results including otoscopy, nasal endoscopy, tubomanometry, and 5-item Eustachian Tube Score (ETS-5). Univariate and multivariate logistic regression analysis was performed to determine the independent diagnostic factors. Based on this, the nomogram model was constructed. The discrimination and calibration of the nomogram were evaluated using the area under the curve (AUC), the C-index, the calibration curve, and the decision curve analysis (DCA).

Results: A total of 40 participants were enrolled in the study. ETS-5 score and Eustachian tube opening mucosa inflammation in the nasopharynx were significant predictors in identifying ETD. Based on the above independent predictors, a diagnostic nomogram was successfully established. The sensitivity and specificity of the diagnostic model were 80.0% and 90.0%, respectively. The AUC and the C-index of the diagnostic model were both 0.901, which suggested that the model had a good discrimination power. The calibration curve indicated a good calibration degree of the model. DCA showed that the proposed model was useful for clinical practice.

Conclusion: The nomogram model is effective and reliable in identifying ETD in patients with tympanic membrane perforation.

Keywords: Eustachian tube dysfunction; chronic otitis media; diagnostic model; tympanic membrane perforation.

Graphical abstract

Figure 1.

The nomogram diagnostic model to identify ETD in patients with tympanic membrane perforation. In the nomogram, each factor is assigned a score (the numbers in brackets) based on its corresponding values or degrees (the numbers or classes on the axis). These scores are obtained by drawing a vertical line from each factor to the score axis. By calculating the total scores of the 2 factors, the likelihood of diagnosing a patient with ETD is visually demonstrated on the corresponding probability axis. ETD, Eustachian tube dysfunction; ETS-5, 5-item Eustachian Tube Score; ET, Eustachian tube.

Figure 2.

The ROC curve and the area under the curve of the nomogram model and independent diagnostic factors. ROC, receiver-operative characteristics; ETS-5, 5-item Eustachian Tube Score; ET, Eustachian tube.

Figure 3.

The calibration belt for the nomogram. The curve shows that the predicted probability is consistent with the actual probability and is close to the ideal line, indicating good consistency and a high degree of calibration for the nomogram model. ETD, Eustachian tube dysfunction.

Figure 4.

The decision curve analysis for the nomogram. The y-axis represents the standardized net benefit, calculated by taking the difference between the proportion of true positive patients and the proportion of false positive patients. A risk threshold on x-axis is specified, which we would undertake treatment if the probability of ETD calculated by the nomogram model is over this specific risk threshold. The thick colorful lines represent the nomogram model, ETS-5 model, and ET mucosa inflammation model, respectively. The black solid line represents the assumption that no one is treated. The gray solid line represents the assumption that all patients are treated regardless of the diagnostic results. All models have superior net benefits than both treating no one and treating all patients in all domains of threshold probability. The nomogram model provides a higher net benefit than other models. ETD, Eustachian tube dysfunction; ETS-5, 5-item Eustachian Tube Score; ET, Eustachian tube.