Clinical, analytical and bioimpedance characteristics of persistently overhydrated haemodialysis patients.

BACKGROUND: Fluid overload is an important and modifiable cardiovascular risk factor for haemodialysis patients. So far, the diagnosis was based on clinical methods alone. Nowadays, we have new tools to assess more objectively the hydration status of the patients on haemodialysis, as BCM (Body Composition Monitor). A Relative Overhydration (AvROH) higher than 15% (it means, Absolute Overhydration or AWOH higher than 2.5 Litres) is associated to greater risk in haemodialysis. However, there is a group of maintained hyperhydrated patients. The aim of the present study is to identify the characteristics of patients with maintained hyperhydrated status (AvROH higher than 15% or AWOH higher than 2.5 liters). The secondary aim is to show the hemodynamic and analytical changes that are related to the reduction in hyperhydration status.

METHODS: Longitudinal cohort study during six months in 2959 patients in haemodialysis (HD) that are grouped according to their hydration status by BCM. And we compare their clinical, analytical and bioimpedance spectroscopy parameters.

RESULTS: The change in overhydration status is followed by a decrease in blood pressure and the need for hypotensive drugs (AHT) and erythropoiesis stimulating agents (ESA). The target hydration status is not reached by two subgroups of patients. First, in diabetic patients with a high comorbidity index and high number of hypotensive drugs (AHT) but a great positive sodium gradient during dialysis sessions; and, younger non-diabetic patients with longer time on hemodialysis and positive sodium gradient, lower fat tissue index (FTI) but similar lean tissue index (LTI) and albumin than those with a reduction in hyperhydration status.

CONCLUSION: Those patients with a reduction in hyperhydration status, also show a better control in blood pressure and anemia with less number of AHT and ESA. The maintained hyperhydrated patients, diabetic patients with many comorbidities and young men patients with longer time on hemodialysis and non-adherence treatment, can profit from a constant monitoring of their hydration state as well as an individualized treatment (dialysis and drugs).