Dry weight assessment by combined ultrasound and bioimpedance monitoring in low cardiovascular risk hemodialysis patients: a randomized controlled trial

Fluid overload is associated with adverse outcomes in hemodialysis (HD) patients. The precise assessment of hydration status in HD patients remains a major challenge for nephrologists. Our study aimed to explore whether combining two bedside methods, lung ultrasonography (LUS) and bioimpedance, may provide complementary information to guide treatment in specific HD patients. In total, 250 HD patients from two dialysis units were included in this randomized clinical trial. Patients were randomized 1:1 to have a dry weight assessment based on clinical (control) or LUS with bioimpedance in case of clinical hypovolemia (active)-guided protocol. The primary outcome was to assess the difference between the two groups on a composite of all-cause mortality and first cardiovascular event (CVE)-including death, stroke, and myocardial infarction. During a mean follow-up period was 21.3 +/- 5.6 months, there were 54 (21.6%) composite events in the entire population. There was a nonsignificant 9% increase in the risk of this outcome in the active arm (HR = 1.09, 95% CI 0.64-1.86, p = 0.75). Similarly, there were no differences between the two groups when analyzing separately the all-cause mortality and CVE outcomes. However, patients in the active arm had a 19% lower relative risk of pre-dialytic dyspnea (rate ratio-0.81, 95% CI 0.68-0.96), but a 26% higher relative risk of intradialytic cramps (rate ratio-1.26, 95% CI 1.16-1.37). This study shows that a LUS-bioimpedance-guided dry weight adjustment protocol, as compared to clinical evaluation, does not reduce all-cause mortality and/or CVE in HD patients. A fluid management protocol based on bioimpedance with LUS on indication might be a better strategy.