Kidney Function and Systolic Blood Pressure

New Insights from Cystatin: Data from the Heart and Soul Study

Many people who have chronic kidney disease (CKD) also have hypertension. Controlling hypertension is extremely important in treating CKD. The relationship between kidney function and blood pressure components has been studied in people with diagnosed CKD, diabetes, or hypertension, but has not been studied in people with hypertension whose kidney function is in the normal range. It is therefore unclear whether kidney function in the normal range is associated with systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure. This research compares SBP, DBP and pulse pressure among people who have a wide range of kidney functions.

The authors studied 906 participants in the Heart and Soul study, a prospective cohort designed to examine the influence of psychological factors on coronary artery disease. The authors used cystatin C and 24-h creatinine clearance to evaluate the association between kidney function and each blood pressure component among the participants.

Key Findings:

  • Results demonstrated a strong association between kidney function and both SBP and pulse pressure throughout a wide range of kidney function levels.
  • Kidney function was not associated with DBP.
  • Small changes in kidney function, even within the normal range, were associated with SBP and pulse pressure.

The authors state that limitations to the study include their inability to discern the pathway of the SBP to kidney function association (i.e., whether kidney dysfunction leads to elevated SBP, or elevated SBP leads to kidney dysfunction).

The authors conclude that kidney function may be a more important determinant of SBP control than previously thought, even among people without clinical CKD. They state that cystatin C may offer new insights into the association of CKD and hypertension, and that this association may have important implications in the treatment of hypertension.