Self-Efficacy as a Marker of Cardiac Function and Predictor of Heart Failure Hospitalization and Mortality in Patients With Stable Coronary Heart Disease: Findings From the Heart and Soul Study

As mortality from coronary heart disease (CHD) improves in the acute setting, improving care and outcomes for those with stable CHD assumes greater importance for public health. Avoiding hospitalization for heart failure (HF) is an important goal for this population, and understanding predictors of HF is the first step toward targeted prevention measures. In addition to cardiac physiology, psychosocial factors may contribute to HF hospitalizations (Howie-Esquivel & Dracup, 2007; Jiang et al., 2007; Sherwood et al., 2007), through both increased physiologic stress and through patient behaviors such as inadequate medication adherence (Murray et al., 2007; Tu et al., 2005). Self-efficacy is a psychological construct based on social–cognitive theory, which describes the interaction between behavioral, personal, and environmental factors in health and chronic disease (Bandura, 1977, 1997; Lorig & Holman, 2003). The theory of self-efficacy proposes that patients’ confidence in their ability to perform certain health behaviors influences their engagement in and actual performance of those behaviors (e.g., diet and exercise adherence), which in turn influence health outcomes. Indeed, the construct of self-efficacy has extended far beyond the psychological arena, and has been demonstrated to affect health behaviors and chronic disease management in many chronic diseases settings (Aljasem, Peyrot, Wissow, & Rubin, 2001; Arnold et al., 2005; Bernal, Woolley, Schenaul, & Dickinson, 2000; Clark & Dodge, 1999; Holden, 1991; Kavanagh, Gooley, & Wilson, 1993; McCaul, Glasgow, & Schafer, 1987). Importantly, self-efficacy is a modifiable characteristic; many health behavior interventions have been shown to improve patients’ self-efficacy (Lorig & Holman, 2003; Lorig et al., 2001; Maddigan et al., 2004; Oka, DeMarco, & Haskell, 2005). In patients with cardiovascular disease, studies of self-efficacy have largely focused on its role in successful cardiac rehabilitation (Berkhuysen, Nieuwland, Buunk, Sanderman, & Rispens, 1999; Carlson et al., 2001; Ewart, Taylor, Reese, & DeBusk, 1983; Foster et al., 1995; Gardner et al., 2003; Izawa et al., 2005). In addition, one previous study found that self-efficacy predicted health status in 198 patients undergoing cardiac angiography (Sullivan, LaCroix, Russo, & Katon, 1998). In our previous work, we found that greater cardiac self-efficacy was associated with better health status in a cross-sectional study of patients with CHD (Sarkar, Ali, & Whooley, 2007). We chose to examine HF for two reasons. First, HF requires complex self-management activities including not only medication adherence but also frequent weighing, and, for some patients, self-titration of diuretic medications. Because higher self-efficacy has been associated with better self-management across multiple chronic disease settings, we hypothesized that self-efficacy would be especially relevant to avoiding hospitalization for HF (Curtin et al., 2008; Sarkar, Fisher, & Schillinger, 2006; Subramanian, Hopp, Mitchinson, & Lowery, 2008; Wolf et al., 2007). Second, the symptoms of HF often vary substantially from day to day. Thus, day-to-day management of HF and its symptoms is much more challenging (and more likely to be influenced by self-efficacy) than management of CHD, in which day-to-day symptom levels do not usually fluctuate and hospitalizations are much more sudden/episodic. Therefore, we sought to determine whether baseline cardiac self-efficacy would predict subsequent hospitalizations for HF within a population of 1024 outpatients with established CHD (CHD), and to assess whether this relationship would be independent of known demographic factors, psychosocial characteristics, and baseline cardiac function. In addition, because mortality is the ultimate endpoint for patients with CHD, we report the association between baseline self-efficacy and all-cause mortality in this cohort, with adjustment for other factors as above.