A Nomogram for Predicting Secondary Hyperparathyroidism after Bariatric Surgery: A Retrospective Study on Short-Term Outcome.

Background: Secondary hyperparathyroidism (SHPT) is a condition that may occur after bariatric surgery. This study aimed to evaluate clinical factors that could predict SHPT after bariatric surgery and to construct a nomogram.

Methods: Data for 294 patients were retrieved and divided into training and validation cohorts (206 and 88 patients, respectively). Univariate analysis and multivariate logistic regression were used to evaluate prognostic factors to establish a nomogram. Receiver operating characteristic (ROC) curves, calibration curves and decision curves were drawn to determine the predictive ability of our model.

Results: Preoperative parathyroid hormone (PTH), fasting blood glucose (Glu0h), high-density lipoprotein cholesterol (HDL-C), creatinine, and 25(OH) vitamin D (25(OH)D) were identified as essential factors in SHPT, and their combination in the multivariate regression had good performance. Based on the multivariate model, we established a nomogram with a low degree of overfitting, as validated in the training (area under the curve: 0.743) and validation (area under the curve: 0.726) cohorts, which showed good discrimination. The calibration and decision curves also indicated that with a definite threshold, using the nomogram to predict SHPT was more beneficial.

Conclusions: The nomogram constructed in this study performed well in predicting short-term SHPT after bariatric surgery.