Difference between estimated glomerular filtration rate based on cystatin c versus creatinine and risk of hypertension: a prospective cohort study.

Objectives: The impact of the difference between cystatin C- and creatinine-based estimated glomerular filtration rate (eGFRdiff) on hypertension remains unknown. We investigated the association of eGFRdiff and the risk of developing hypertension.

Methods: A total of 3628 participants without hypertension at baseline in 2011 from the China Health and Retirement Longitudinal Study were enrolled. The eGFRdiff was calculated using both absolute difference (eGFRabdiff = eGFRcys-eGFRcr) and the ratio (eGFRrediff = eGFRcys/eGFRcr) between cystatin C- and creatinine-based estimated glomerular filtration rate. The association between eGFRdiff and hypertension risk was examined using restricted cubic spline (RCS) and multivariable logistic regression analysis.

Results: The mean (± SD) for eGFRabdiff and eGFRrediff were - 16.3 ± 16.5 mL/min/1.73 m, and 0.83 ± 0.17, respectively. During 4 years of follow-up, 605 incident hypertension cases were identified. Participants in the third quantile of eGFRabdiff had a lower risk of hypertension than participants in the first quantile of eGFRabdiff (OR 0.72, 95% CI 0.57-0.92, P = 0.01), adjusting for potential confounders. RCS showed an inversely linear relationship between eGFRabdiff and hypertension risk. In the fully adjusted model, each standard deviation increase in eGFRabdiff was associated with a 0.85-fold decrease in the risk of incident hypertension (OR 0.85, 95% CI 0.77-0.94, P = 0.002). Sensitivity analysis also confirmed the results. In exploratory analyses, the proportional effect of eGFRabdiff on hypertension risk was consistent across the six pre-specified subgroups (all P for interaction > 0.05). Similar results were observed for eGFRrediff.

Conclusions: A large negative difference in cystatin C-based and creatinine-based eGFR was significantly associated with the risk of hypertension. Our findings suggested that monitoring eGFRdiff could be clinically useful in identifying high-risk people for hypertension.