Prevalence of Overhydration in Patients on Maintenance Haemodialysis As Determined by Body Composition Monitor and Effects of Attaining Target Dry Weight

Introduction: Fluid overload in chronic kidney disease (CKD) is an independent risk factor for all-cause mortality. The volume of ultrafiltrate removed during haemodialysis is usually assessed clinically. Assessment of overhydration by body composition monitor (BCM) using bioimpedance spectroscopy is an objective method. This study was conducted to identify the prevalence of overhydration in CKD patients on maintenance haemodialysis and thereby assess the effects of BCM targeted dry weight attainment. Methods: All patients included in the study were assessed for one month before enrolment for blood pressure, intradialytic events during each dialysis and BP medications. Overhydration was defined as the ratio of overhydration to extracellular water (OH/ECW) > 1.1. Overhydrated patients were brought to BCM targeted dry weight by increasing ultrafiltrate to 500mL/week more than their routine intradialytic weight gain. The effect of attaining BCM target dry weight on blood pressure and intradialytic events were analysed. Results: Out of 110 patients, overhydration was seen in 30 (27.2%); only 20 had clinically evident overhydration. Body composition monitor guided dry weight was achieved in 28 of the 30 patients after a mean duration of 20 weeks. After achieving the target dry weight, there was a significant reduction in intradialytic hypertension events (2.37 vs 1.82 events per session, p-value 0.01). Surprisingly, there was a reduction in episodes of intradialytic hypotension as well, though this did not reach statistical significance. There was a clinically significant reduction in mean systolic and diastolic blood pressures (mean of 5.7mmHg and 2.8mmHg, respectively). Conclusion: The study underlines the importance of BCM-based hydration status assessment and target dry weight attainment in better control of intradialytic events and blood pressure in patients on maintenance haemodialysis.