Correlation between Serum Homocysteine Level and Cystatin C Elevation in Patients with H-type Hypertension

[Objective] To investigate the correlation between serum levels of homocysteine (Hcy) and cystatin C (CysC), a sensitive marker of renal function, in patients with H-type hypertension. [Methods] A total of 857 patients with essential hypertension without moderate to severe renal impairment (estimated glomerular filtration rate ≥ 60 ml/(min-1.73 m2) by Modification of Diet in Renal Disease equation) visited the Seventh Affiliated Hospital of Sun Yat-sen University from May 2018 to May 2020 were selected as the research subjects. The observation group (n = 635) consisted of patients with H-type hypertension (essential hypertension with Hcy ≥ 10 mmol/l) and the control group (n = 222) consisted of patients with non-H-type hypertension (essential hypertension with Hcy < 10 mmol/l). Multivariate logistic regression analysis, curve fitting, and threshold analysis were used to evaluate the correlation between elevated CysC and serum Hcy levels. [Results]CysC in observation group was significantly higher than that in control group (0.96 ± 0.160 vs 0.84 ± 0.13 mmol/l; p < 0.001). Multivariate logistic regression analysis, curve fitting, and threshold analysis showed that there was a significant difference in the risk of CysC elevation between Hcy levels at 10-25 mmol/L and Hcy levels below 10 mmol/L; there was no significant difference in the risk of CysC elevation between Hcy levels above 25 mmol/L and Hcy levels below 10 mmol/L. The inflection point of Hcy was 15.23 mmol/L, and when Hcy was < 15.23 mmol/L, the probability of CysC elevation increased by 27\% for each 1 mmol/L increase in Hcy (OR 1.27, 95\% Cl: 1.12, 1.44; P = 0.0002). When Hcy was > 15.23 mmol/l, the probability of CysC elevation was reduced by 4\% for each 1 mmol/l increase in Hcy (OR 0.96, 95\% Cl: 0.92, 1.01; P = 0.1085). [Conclusions] The risk of CysC in patients with H-type hypertension is higher than that in patients with non-H-type hypertension when Hcy is between 10-25 mmol/L; and the probability of cystatin C elevation is the highest when Hcy is at 15.23 mmol/L.