Adipokine isthmin-1 is a potential predictor of abnormal urine Na+ excretion and insulin resistance for primary hypertension

Abstract Background Isthmin-1 (ISM1) plays an important role in maintaining glucose homeostasis and lipid metabolism. However, the relationship between circulating ISM1 and hypertension remains unclear. This study was aimed to investigate the association between serum ISM1 levels and blood pressure and evaluate value of circulating ISM1 for predicting abnormal Na+ excretion and insulin resistance. Methods Four hundred sixty-eight individuals newly diagnosed with primary hypertension and 582 healthy individuals were initially screened. 84 participants were eligible for this case–control study. Serum ISM1 levels were assessed using ELISA. Spearman correlation analysis and partial correlation analysis were conducted to confirm the correlation. Multiple linear regression analysis was used to assess the independent association of serum ISM1 concentration with blood pressure. The receiver operating characteristic (ROC) curve was employed to evaluate the sensitivity of ISM1 in predicting abnormal Na+ excretion and insulin resistance in hypertensive subjects. Results The serum ISM1 levels of hypertensive individuals were higher than that of healthy individuals. ISM1 levels were positively associated with systolic blood pressure (SBP), diastolic blood pressure (DBP) and brachial-ankle pulse wave velocity, but negatively associated with nocturnal urine Na+ concentration and excretion. These associations remained significant even after adjusting for age, body mass index, sex, heart rate, glucose, total cholesterol and estimated glomerular filtration rate. Multiple linear regression analysis revealed that SBP was an independent factor associated with serum ISM1 levels. The area under receiver operating characteristic curve (AUROC) for predicting low urine Na+ excretion and insulin resistance were 0.873 and 0.740, respectively. Conclusions Serum ISM1 levels were positively associated with SBP and DBP. ISM1 may serve as a potential biomarker of abnormal urine Na+ excretion and insulin resistance in primary hypertensive individuals. Trial registration Registered on chictr.org.cn 18/04/2024 (Registration number: ChiCTR2400083204).