SP574
DYNAMICS OF FLUID STATUS AND INFLAMMATION IN AN INTERNAL HEMODIALYSIS PATIENT COHORT

Introduction and Aims: In hemodialysis patients fluid overload (FO) is a predictor of all-cause mortality and a relation with inflammation has been observed in previous studies. The magnitude and nature of this interaction and the effects of moderate FO and fluid depletion on survival are still unclear.

Methods: We conducted a retrospective cohort study in the European subset of the MONDO-Initiative database. Fluid status was assessed using bioimpedance and inflammation by C-reactive protein (CRP) measurements. We included patients with at least one measurement each during baseline. All-cause mortality was recorded during 12 months follow-up. In a second analysis patients were divided into 4 groups based on average fluid and inflammation status during two consecutive 3 months periods, in which the change or persistency of both variables was observed and all-cause mortality was noted during a subsequent 6 months follow up period in this analysis.

Results: We included 8883 patients (age 63 years, 57.2% male). FO was associated with risk of mortality, already apparent at moderate levels of pre- and post-dialysis FO (> +1.1L to +2.5L; hazard ratio (HR) 1.64 (95% confidence interval (CI) 1.35-1.98) and HR 1.72 (95% CI 1.45-2.05) respectively). Likewise, pre-dialysis FD (≤ -1.1L; HR 2.03 (95% CI 1.32-3.12)) was associated with increased mortality risk, whereas post-dialysis FD was associated with a survival benefit HR 0.74 (95% CI 0.62-0.90). In patients with severe pre-dialysis FO (> +2.5L to +5.0L) but without inflammation (CRP level ≤ 6.0 mg/L), the HR was 3.09 (95% CI 2.20-4.36) compared to an HR of 6.02 (95% CI 4.41-8.23) when inflammation was present. In the subset analysis the association with mortality was the highest in the groups of patients with persistent FO and inflammation (adjusted HR 9.44 (95% CI 5.67-15.72)), this increased risk of death remained elevated even after resolving both fluid overload and inflammation (HR 3.28 (95% CI 1.13-9.52)). The presence of inflammation was not significantly related with the occurrence of FO, also the reverse relation was not statistically significant.

Conclusions: Both pre-dialysis and post-dialysis FO and FD are associated with an increased risk of death, whereas post-dialysis FD is associated with a survival benefit. The concurrent presence of FO and inflammation is associated with the highest risk of death. Both parameters remain significant predictors of outcome during a 6 months period even after normalization.