Monitoring Water Balance to Predict Hospitalization in Patients with Chronic Heart Failure: A Retrospective Study

Background: Patients with chronic heart failure often experience repeated acute exacerbations leading to high rates of rehospitalization. Therefore, the management of patients to prevent rehospitalization and retain their physical function is important. Brain natriuretic peptide (BNP) and N-terminal-pro BNP are used to estimate the conditions of patients with chronic heart failure, but some hospitals cannot measure these levels in real time. To overcome this, we used bioelectrical impedance analysis as an alternative. Methods and results: Between April 2017 and December 2019, we measured water balance in the outpatient department of Hirose Hospital in three groups: those who had been hospitalized for chronic heart failure (257 patients), those with chronic heart failure who had not been hospitalized (224 patients), and controls with other chronic diseases (275 patients). We found that water balance was significantly correlated to the history of hospitalization, and age was a confounding bias in this correlation, regardless of whether patients have been hospitalized with chronic heart failure. Moreover, patients who have high extracellular water content/total body water content ratios, even in a stable period, are at risk of becoming unstable and experiencing rehospitalization. Conclusion: Water balance monitoring could be a useful indicator to estimate patient condition in real time and predict improvement in chronic heart failure. This easy-to-use indicator may enable timely management of exacerbation of patient condition and reduce hospitalization events.