Obstructive sleep apnea (OSA) in a community based heart failure program: prevalence and risk factors

Background: Sleep apneas (SA): obstructive (OSA) and central (CSA) are present in one third of patients (pts) with stable congestive heart failure (CHF), and are associated with increased morbidity and mortality. Management of SA has been shown to favorably alter outcomes in CHF pts. However, effectiveness of SA screening at a community level in stable CHF pts is currently unclear. This study presents our experience with screening for SA, and analysis of prevalence of and risk factors for SA in a community based CHF program. Methods: We screened CHF pts for possible SA by history and physical examination. Pts determined to have high pre-test probability of SA after clinical screening underwent a formal sleep study. We are presenting data from 92 pts who underwent sleep studies between January 2001 and August 2003. Respiratory disturbance index (RDI), Arousal event rate (AER), number of desaturations, arrhythmias, movement associated arousals (MAA) and other relevant variables were recorded during these studies. Simple and multiple logistic regression was done to determine factors associated with SA. Results: Pts' mean age was 65 years (Range 26–88), and 40/92 (43%) were females. Average body mass index (BMI) was 31.2 in males and 39.2 in females. Mean RDI was 14 (Range: 0–77, 95% CI: 9.3–18.8), mean AER was 9.1 per hour of sleep (Range 0-64, 95% CI: 6.3–11.9), mean frequency of bradycardias was 1.3 per study (Range 0–25, 95% CI: 0.4–2.3), and mean MAA was 5.8 per study (Range 0–123, 95% CI: 1.3–10.3). 45/92 (48.9%) pts had SA, of whom 79% had OSA, 9% had CSA and 12% had mixed SA. Male gender increased risk of SA in this population (Odds ratio (OR): 2.7, 95% CI: 1.2–6.4, p = 0.02). OR for SA in a male compared with female, after adjusting for BMI was 8.1 (95% CI: 2.2–30.4, p = 0.002). After adjusting for gender, elevated BMI increased risk of SA (OR: 1.12, 95% CI: 1.03–1.2, p = 0.004). Increasing age is weakly positively associated with sleep apnea, association significant after adjusting for BMI and gender (OR 1.06, p = 0.04). CHF etiology and ejection fraction were not associated with SA, with and without adjusting for BMI and gender. Conclusion: SA, and specifically OSA is extremely prevalent in a community based CHF population. Male gender, elevated BMI and advanced age increase the risk of OSA in the CHF population. Aggressive screening of pts at risk for SA is important as it could facilitate timely diagnosis and management of SA, and thereby reduce worsened outcomes in CHF patients.