Abstract 8268: Sickness Behavior Predicts Event Free Survival in Adults with Heart Failure
Stimulation of the immune system produces a non-specific cluster of symptoms referred to as sickness behavior. Numerous and diverse systemic conditions stimulate the immune system and produce this response, including heart failure (HF).
Purpose: The purpose of this study was to explore the ability of the sickness behavior symptom cluster to predict event-free survival 6 months later in adults with HF.
Methods: A sample of 280 adults with stage C HF was enrolled from 3 sites in the Northeastern US. Those with dementia, terminal illness, a recent history of drug or alcohol abuse, and night shift workers were excluded. NYHA functional class was measured at baseline. Sickness behaviors, defined as an aggregate of fatigue, sleepiness, and depression, were measured at baseline, aggregated using factor analysis. Hospitalizations were measured by self-report and validated in the medical record. Deaths were confirmed in the medical record or the US death records. The influence of sickness behavior on event free survival (hospitalization, death) was analyzed with multivariable Cox proportional hazards regression.
Results: A total of 97 events (6 deaths) occurred during the 6-months of follow-up in the 274 subjects with follow-up data available. When the analysis was stratified by NYHA class, sickness behavior was a significant predictor of the risk for death or hospitalization for subjects in NYHA class IV (n=48, RR=1.67, p=0.011) but not in the other NYHA classes.
Conclusion: Adults with NYHA class IV HF who manifest sickness behavior are more likely to be hospitalized or die than those without the sickness behavior symptom cluster. Study of the factors associated with sickness behavior may suggest targets for intervention. Further study of this indicator of immune dysfunction may help integrate disparate observations regarding fatigue, sleepiness, and depression in HF patients.
- © 2011 by American Heart Association, Inc.