The purpose of this study was to test the hypothesis that severity of sleep apnea (SA), assessed by frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index [AHI]), is related to sodium intake in patients with heart failure (HF).
Dependent edema and overnight rostral fluid shift from the legs correlate with the AHI in patients with HF in whom excessive sodium intake can cause fluid retention.
Sodium intake was estimated by food recordings in 54 HF patients who underwent overnight polysomnography.
Thirty-one of the 54 patients had SA, and their mean sodium intake was higher than that in those without SA (3.0 ± 1.2 g vs. 1.9 ± 0.8 g, p < 0.001). There was a significant correlation between the AHI and sodium intake (r = 0.522, p < 0.001). Multivariate analysis showed that the significant independent correlates of the AHI were sodium intake, male sex, and serum creatinine level.
These findings suggest that in patients with HF, sodium intake plays a role in the pathogenesis of SA.