[Establishment and assessment of a nomogram for predicting the risk of primary aldosteronism]

Objective: To develop and validate a nomogram prediction model for primary aldosteronism based on clinical and laboratory indicators, and to explore its application value. Methods: This retrospective study enrolled 691 hypertensive patients hospitalized at the First Affiliated Hospital of Dalian Medical University between January 2019 and November 2023. According to the results of confirmatory test for primary aldosteronism, patients were divided into primary aldosteronism group (n=205) and essential hypertension group (n=486). General clinical and laboratory indicators were collected for correlation analysis to evaluate inter-indicator associations. All participants were randomly split into a training set (n=414) and a validation set (n=277) at a 6∶4 ratio. LASSO regression was performed on the training set to screen potential predictive variables for primary aldosteronism, which were subsequently entered into a multivariate logistic regression model to identify variables associated with disease. Based on the variables above, a nomogram prediction model was constructed. The discrimination of this model was evaluated using the receiver operating characteristic curve, and its calibration was assessed with calibration curves and the mean absolute error. Results: The age of the enrolled patients was (48.54±12.21) years, and 370 (53.5%) were male. Correlation analysis showed weak to moderate correlations among most indicators. LASSO regression identified nine candidate variables, and multivariable logistic regression ultimately determined that hypertension duration >5 years (OR=2.826, 95%CI 1.537-5.196), serum potassium (OR=0.364, 95%CI 0.232-0.570), direct renin concentration (OR=0.031, 95%CI 0.010-0.089), plasma aldosterone concentration (OR=4.158, 95%CI 2.520-6.862), and the monocyte-lymphocyte ratio (OR=1.569, 95%CI 1.136-2.618) were associated with the risk of primary aldosteronism (all P<0.05). A nomogram was built from these five variables. The area under the curve was 0.921 (95%CI 0.895-0.947) in the training set and 0.869 (95%CI 0.823-0.915) in the validation set, indicating good discrimination. The calibration curves closely followed the ideal reference line, with mean absolute errors of 0.009 and 0.036 in the training and validation sets. Conclusions: The nomogram prediction model derived from hypertension duration >5 years, serum potassium, direct renin concentration, plasma aldosterone concentration, and the monocyte-lymphocyte ratio demonstrated satisfactory discrimination and calibration, which could be used for early prediction of the risk of primary aldosteronism in the hypertensive population, providing a reference basis for disease screening, diagnosis, and treatment.