Analysis of risk factors for contralateral occult inguinal hernia and construction and validation of a nomogram prediction model

Objective Early screening and treatment of contralateral occult inguinal hernia remains a significant challenge. This study aimed to investigate risk factors for contralateral occult inguinal hernia, construct and validate a risk prediction model, and provide evidence-based support for early screening and individualized intervention in high-risk patients. Methods Clinical data from patients diagnosed with unilateral inguinal hernia before surgery who underwent laparoscopic transabdominal preperitoneal hernia repair at our hospital between January 2018 and December 2025 were retrospectively analyzed. The patients were randomly split into a training set (1054 cases) and a validation set (453 cases) at a 7:3 ratio using a computer-generated random number sequence. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for contralateral occult inguinal hernia, and a nomogram was constructed based on the regression results. Receiver operating characteristic (ROC) curve, calibration curve, and decision curve were used to evaluate the discrimination, calibration, and clinical utility in the training and validation sets. Result Multivariate logistic regression analysis showed that age, smoking, diabetes mellitus (DM), hernia type, and risk factors for intra-abdominal hypertension (IAH). were independent risk factors for contralateral occult inguinal hernia (P < 0.05). A nomogram prediction model was constructed based on the five factors above, with an AUC of 0.80 (95% CI: 0.76–0.83) in the training set and 0.83 (95% CI: 0.79–0.88) in the validation set. The calibration curves for both the training and validation sets closely matched the ideal curve, and the decision curve showed that the model has good clinical net benefit. Conclusion Age, smoking, DM, hernia type, and risk factors for IAH are independent risk factors for contralateral occult inguinal hernia. The nomogram prediction model constructed in this study can effectively evaluate the risk of contralateral occult inguinal hernia, providing a useful tool for early screening and personalized treatment strategies in high-risk populations.