The Effects of Fluid Management Approaches on Renin–Angiotensin–Aldosterone System Activity and Blood Pressure Control in Patients on Dialysis

BACKGROUND: Chronic fluid imbalance in maintenance hemodialysis can increase cardiovascular risk through activation of the renin-angiotensin-aldosterone pathway. This study compared the endocrine and hemodynamic effects of three fluid management strategies in adults receiving maintenance hemodialysis in a prospective two-center observational cohort study. METHODS: Six hundred patients were assigned to fluid management by clinical assessment, bioimpedance-guided monitoring, or absolute blood volume monitoring, with 200 patients in each group. Plasma renin activity, angiotensin II, aldosterone, systolic and diastolic blood pressure, and arterial stiffness were measured at baseline and Weeks 6 and 12. Between-group and over-time differences were analyzed using adjusted longitudinal and covariance-based models. Additional analyses examined variation by age, fluid status pattern, and sodium self-management. RESULTS: By Week 12, plasma renin activity, angiotensin II, and aldosterone increased in the clinical assessment group showed smaller increases or minimal change in the bioimpedance-guided group and declined in the absolute blood volume monitoring group. The absolute blood volume monitoring group also showed the greatest improvement in blood pressure and arterial stiffness over follow-up. In addition, this group had the lowest frequency of intradialytic hypotension and the strongest improvement in patient self-management measures. CONCLUSIONS: Absolute blood volume monitoring was associated with greater short-term suppression of endocrine activation and better hemodynamic outcomes than clinical assessment or bioimpedance-guided monitoring during the 12-week follow-up period.