Vitality and recurrent event risk in acute myocardial infarction survivors

Low vitality, characterized by fatigue and lack of energy, is common among survivors of acute myocardial infarction (AMI) and has been shown to be associated with increased risk of primary and secondary cardiac events. The goal of this study was to determine whether an association between vitality and recurrent cardiac events (nonfatal MI, cardiac death) among acute MI survivors persists after controlling for possible physiological and psychological confounders.

Incident AMI survivors (n = 1328) from Erie and Niagara (New York) county hospitals were enrolled and followed up to 9 years. Vitality was measured by the Short Form-36 on a 0-100 scale approximately 4 months post-AMI. Cox proportional hazards models were developed to assess the vitality-recurrent event association controlling for traditional cardiovascular disease risk factors, index MI severity, and psychological correlates of vitality.

Low-vitality individuals at baseline were more likely females, of higher BMI, smoking, diabetic, less physically active, and to have worse depression scores. Vitality was not strongly associated with MI severity markers. Lower vitality scores were associated with increased risk of recurrent cardiac events: adjusted hazard ratios (95% CI) for vitality scores 51-79, 21-50, and < or =20 (compared with > or =80) were 1.2 (0.8, 1.8), 1.4 (0.9, 2.2), and 2.9 (1.5, 5.4), respectively (Ptrend = 0.005).

Low vitality was associated with increased risk of recurrent cardiac events among AMI survivors after controlling for physiological and psychological confounders. Mechanistic links with vitality should be sought as interventional targets.