Changes in Heart Failure Self-care Behaviors and Intrathoracic Impedance over 6 Months.

Abstract

Background Poor heart failure (HF) self-care has been shown by others to be associated with lung fluid accumulation measured by intrathoracic impedance. No studies, however, have examined how HF self-care is associated with intrathoracic impedance over time. Objective Examine the association of self-care behaviors and intrathoracic impedance using Medtronic Optivol Index threshold crossings as a marker of pulmonary congestion over 6 months. Method Patients with symptomatic HF and a Medtronic Optivol-enabled device had two 90 day periods of impedance data collected that corresponded with two waves of data collection on HF self-care (measured with the European HF Self-care Behavior Scale (EHFScBS)), as well as sociodemographic and clinical data. Changes in Optivol threshold crossings data (categorized as more frequent (31%) vs. fewer (69%) episodes of congestion) and self-care were calculated between the two phases of measurement. Multivariate logistic regression was use to quantify the likelihood of the self-care behaviors predicting an increase in threshold crossing over the 6 months. Results Participants (n=47) were mostly male (57%), on average 62 years old with predominantly non-ischemic (81%), NYHA Class III/IV HF (64%). Adjusting for sociodemographic and clinical factors, improvement in HF self-care care over time was associated significantly with lower odds of having more frequent threshold crossings over time (odds ratio=0.74; 95% confidence interval, 0.55–0.99; p=0.039). Conclusion Positive changes in HF self-care over time may decrease the odds of having more fluid accumulation or pulmonary congestion events. Our study supports self-care as an essential aspect of HF self-management. Furthermore, longitudinal and experimental studies are needed to examine the temporal and causal relationship between objective markers of HF pathophysiology and self-care behaviors.