title: Association Between Serum Cortisol and Chronic Kidney Disease in Patients with Essential Hypertension.
abstract: OBJECTIVE
  Serum cortisol level is elevated in patients with essential hypertension. We aimed at investigating the association of serum cortisol levels with parameters of renal function in essential hypertension.
  
  
  METHODS
  One hundred and seventy-eight patients with essential hypertension participated in the study. Fasting serum samples were collected at 8:00 am. Renal function was measured as estimated glomerular filtration rate (eGFR) calculated by the Chronic Kidney Disease Epidemiology Collaboration creatinine- cystatin C equation (eGFRcr-cys). Correlation analysis and stepwise regression analysis were used to detect the relationship between cortisol and eGFRcr-cys. The distributions of serum cortisol were split by the tertiles and subjects were stratified into those with low, median and high levels accordingly.
  
  
  RESULTS
  Serum cortisol levels were significantly higher in subjects whose eGFRcr-cys<90 ml/min/1.73 m2 than subjects whose eGFRcr-cys>90 ml/min/1.73 m2 (394.0±93.4 vs. 343.2±98.4 nmol/L, P=0.001). Age, systolic blood pressure, and serum total cholesterol, uric acid, cortisol levels were significantly associated with eGFRcr-cys, serum levels of creatinine and cystatin C. After adjusting for clinical factors, serum cortisol level had a statistically significant negative association with the eGFRcr-cys (β=-0.19, P=0.027), and positive associations with cystatin C (β=0.31, P=0.001) and creatinine (β=0.14, P=0.044). With the increment of cortisol tertile, the eGFRcr-cys significantly decreased (93.18±14.36 vs. 84.61±14.67 vs. 81.29±12.36 ml/min/1.73 m2 for low, median and high tertile, respecively, P=0.001).
  
  
  CONCLUSIONS
  Serum cortisol level was negatively correlated with eGFRcr-cys in subjects with essential hypertension. Further studies are needed to investigate whether cortisol plays a role in hypertensive nephropathy development.
authors.affiliation: Department of Endocrinology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Li
authors.forename: Xiaojiao
authors.initials: X
authors.lastname: Xiang
authors.forename: Jinbo
authors.initials: J
authors.lastname: Hu
authors.forename: Richa
authors.initials: R
authors.lastname: Goswami
authors.forename: Shumin
authors.initials: S
authors.lastname: Yang
authors.forename: Aipin
authors.initials: A
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.forename: Qifu
authors.initials: Q
authors.lastname: Li
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Bi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000075222:Essential Hypertension; D005919:Glomerular Filtration Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood* / Q000502:physiology; D006973:Hypertension / Q000097:blood*; D006977:Hypertension, Renal / Q000097:blood; D008875:Middle Aged; D009393:Nephritis / Q000097:blood; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology
chemical_list: D006854:Hydrocortisone