OR-17: Obstructive sleep apnea and sleep efficiency in patients with and without refractory hypertension

While obstructive sleep apnea (OSA) is associated with severe hypertension, its prevalence in patients with refractory hypertension (RH) has not been directly compared to those whose blood pressure (BP) is easily controlled with antihypertensive medications (AHM). The purpose of this study is to compare the frequency of OSA in patients with and without RH and to determine the relationship between OSA and sleep efficiency. Study subjects were recruited from a university hospital hypertension clinic. RH was defined as a clinic BP ≥140/90, while taking a sensible combination of ≥ 3 AHM, titrated to maximally recommended doses. Therapy included a diuretic and low sodium diet. Hypertensive patients without RH received ≥ 1 AHM, had clinic BP <140/90 and were matched to those with RH on age, sex and body mass index (BMI). Patients with known OSA were excluded. All subjects underwent overnight polysomnography to determine apnea-hypopnea index (AHI) and those with an AHI ≥10 events/h were classified as having OSA. In the Table results are expressed as mean ± SE and significance testing, as p-value. Non-significance (p > 0.05) is designated as n.s. Our findings show that OSA is significantly more common among patients with RH and is associated with sleep deprivation and decreased sleep efficiency that may contribute to making BP more difficult to control.CharacteristicRH (n = 40)Controls (n = 26)p-valueAge (yr)56.8 ± 1.658.8 ± 1.8n.s.Sex (% male)6058n.s.BMI (kg/m2)33.9 ± 1.033.1 ± 0.9n.s.Clinic BP (mmHg)167/94126/770.000AHM (# of drugs)3.6 ± 0.11.9 ± 0.20.000AHI (events/h)25 ± 3.316 ± 2.30.032OSA prevalence (%)83580.027Total time asleep (min)280 ± 14.7316 ± 9.10.040Sleep efficiency (%)69 ± 3.178 ± 1.50.012