Difference between cystatin C- and creatinine-based estimated glomerular filtration rate and incident hypertension and the mediating role of Triglyceride Glucose Index.

Estimated glomerular filtration rate (eGFR) is usually calculated based on serum creatinine (eGFRScr) or cystatin C (eGFRCysC). This study aimed to investigate the association between cystatin C-creatinine eGFR discordance (ΔeGFRCysC-Scr) and new-onset hypertension and to assess the mediating role of triglyceride glucose (TyG) index based on the China Health and Retirement Longitudinal Study. The ΔeGFRCysC-Scr was calculated by eGFRCysC - eGFRScr. A Cox proportional risk model was used to assess the association between ΔeGFRCysC-Scr and risk of new-onset hypertension. The mediating role of TyG was assessed using mediation analysis, and thresholds were obtained via Receiver Operating Characteristic curve. A total of 4,644 participants (median age 59 years, 55.5% female) were finally included. During a mean follow-up period of 5.0 years, 613 new cases of hypertension occurred. Multivariable analysis showed that, individuals in negative-ΔeGFRCysC-Scr group (< -15) had a 24% increase risk of hypertension (Hazard ratio [HR] = 1.24; 95% confidence interval [95% CI]: 0.99, 1.56), while positive-ΔeGFRCysC-Scr group (≥15) had a 20% decrease risk of hypertension (HR = 0.80; 95% CI: 0.63, 1.02), compared with those in the reference group (-15 ≤ ΔeGFRCysC-Scr < 15 mL/min/1.73 m2). In addition, each 15 mL/min/1.73m2 increase in ΔeGFRCysC-Scr was associated with a 13.4% reduction in the risk of new-onset hypertension (HR= 0.87; 95% CI: 0.79, 0.95). TyG acted as a partial mediator, explaining 9.3% of the total effect. The present study demonstrates an association between ΔeGFRCysC-Scr and the risk of new-onset hypertension and reveals the important mediating role of TyG in this association.