Abstract 2938: Association between Periodic Limb Movements in Sleep and Increased Mortality Risk in Patients with Heart Failure
Periodic limb movements in sleep (PLMS) is a disorder characterized by regularly recurring movements of the lower extremities. PLMS can provoke arousals and disturb sleep and may be associated with complaints of insomnia, daytime fatigue and restless leg syndrome. There is some evidence that PLMS is related to the impairment of hypothalamic dopaminergic transmission, and that it may be a biological marker of abnormalities of dopaminergic function. Although PLMS is very commonly found in patients with heart failure (HF), its clinical significance is unknown. We hypothesized that the presence of PLMS may be related to increased mortality in patients with HF. We enrolled 193 patients with HF (left ventricular ejection fractions [LVEF] ≤ 45%) into a prospective epidemiological study. All subjects underwent polysomnography and those with ≥ 5 periodic limb movements per hr of sleep were defined as having a PLMS disorder. 75 patients (39%) were found to have a PLMS disorder. Patients with PLMS were significantly older and had lower LVEF. In addition, we found that there was a significant correlation between the periodic leg movement index and NYHA functional class (Ptrend < 0.001) but no relationship with apnea-hypopnea index, a measure of sleep apnea severity. During a mean (± SD) of 32 ± 26 months of follow-up, the mortality rate was significantly higher in patients with PLMS than those without it (10.7 versus 3.9 deaths per 100 patient years, P = 0.003). Furthermore, on multivariate analysis after adjusting for age, LVEF and NYHA functional classes, both the presence and the severity of PLMS were an independent predictor for mortality in patients with HF (the presence, HR 2.19, 95% CI 1.07– 4.47, P = 0.032). This is the first study in which a strong association between PLMS and increased mortality risk in patients with HF has been described. Although our results do not establish a cause-effect relationship between PLMS and mortality in HF, they do suggest that further research is needed to determine the pathophysiology and clinical consequences of PLMS in patients with HF.