The rapid eye movement (REM) apnea hypopnea index (AHI) is significantly and positively associated with hypertension in patients with obstructive sleep apnea (OSA), with a stronger effect occurring in female patients, researchers reported in Nature and Science of Sleep.
The cross-sectional study assessed the clinical and polysomnographic characteristics of patients with OSA and hypertension, as well as sex differences in the relationship between REM OSA and hypertension.
The study authors reviewed the medical records of patients diagnosed with OSA at a sleep center in Tianjin, the People’s Republic of China, from January 1, 2017, to December 31, 2020. A total of 416 patients with OSA and hypertension (mean age, 50.35±13.04 years; 74% men) and 392 patients with OSA and without hypertension (mean age, 43.90±2.30 years; 79% men) were included. Patients with hypertension were older and had more obesity (body mass index, 30.84 vs 29.07 kg/m2). Patients with hypertension also had a greater neck circumference (42.40 vs 41.15 cm); waist circumference (107.63 vs 101.70 cm); waist-to-height ratio (0.63 vs 0.59); body shape index score (0.084 vs 0.083 m11/6kg−2/3); and a higher proportion of family history of hypertension (73.3% vs 49.0%) (P <.001 for all), compared with patients with OSA without hypertension.
After adjustment for potential confounders, the overall risk of hypertension increased with an increasing level of REM AHI (odds ratio [OR]=1.61 for tertile 3 vs tertile 1; 95% CI, 1.07-2.42; P =.022 for trend). Each standard deviation increment of REM AHI was significantly associated with the increased risk of hypertension in patients with OSA (OR=1.007; 95% CI, 1.001-1.014; P <.05).
REM AHI also had a positive relationship with the risk of hypertension in women as a categorical or continuous variable (all P <.05). Among men with OSA, no significant relationships were observed between increasing levels of REM AHI and the risk of hypertension (all P >.05).
Higher REM AHI categories were significantly associated with an increased risk of prevalent hypertension among all participants (P =.022). Among the female participants, the association between higher REM AHI categories and higher odds of prevalent hypertension was highly significant (P =.022). Among the male participants, greater REM AHI categories were associated with higher odds of hypertension, although it did not reach statistical significance (P =.181).
The percentages of hypertension among all participants significantly increased in line with increasing tertiles of REM AHI (42.91% in tertile 1, 52.35% in tertile 2, and 59.92% in tertile 3; P =.001).
The researchers noted that they could not identify causality and that other potential confounding factors, such as dietary habits, labor intensity, economic status, and psychological conditions, were not included in the analysis. Another study limitation is the single-center design that included only patients with OSA.
“Our findings may have important clinical implications for the duration of continuous positive airway pressure use that is needed to reduce the risk of hypertension and control blood pressure,” the investigators commented.
Wang L, Wei D, Zhang J, Cao J, Zhang X. High rapid eye movement sleep apnea hypopnea index is associated with hypertension in patients with obstructive sleep apnea. Nat Sci Sleep. Published online July 6, 2022. doi:10.2147/NSS.S369614