Relationship between T90 and systemic hypertension in patients with obstructive sleep apnea: Data from the European sleep apnea database.

Abstract

Background: Hypertension (HTN) is one of the most prevalent cardiovascular comorbidities in patients with obstructive sleep apnoea (OSA). Although OSA severity measured by the apnoea-hypopnoea index (AHI) is a known risk factor, the role of hypoxic load in HTN remains less well established.

Methods: We analysed data from 12,141 patients with OSA enrolled in the European Sleep Apnea Database (ESADA). Clinical and sleep study parameters were assessed to identify factors associated with HTN.

Results: The cohort included 2650 patients with mild OSA, 3339 with moderate OSA, and 6152 with severe OSA. The mean age was 53.1 ± 12.5 years, the mean body mass index (BMI) 31.7 ± 6.2 kg/m², and 73.1% were male. HTN was present in 41.8% of the patients. In univariate analyses, older age, female sex, obesity, larger neck circumference, greater OSA severity as measured by AHI or oxygen desaturation index (ODI), minimum oxygen saturation (SpO₂), and increased hypoxic load (T90% ≥ 5%) were significantly associated with HTN. After adjustment for age, sex and BMI, increased neck circumference, higher AHI and T90% ≥ 5% remained independently associated with HTN. Notably, HTN prevalence was higher in mild-to-moderate OSA patients with T90% ≥ 5 than in severe OSA patients with T90% < 5 (51.5% vs. 42.8%, p < 0.001). Following propensity score matching, only minimum SpO₂ (p = 0.022) and T90% ≥ 5% (p = 0.044) remained significantly associated with HTN.

Conclusions: Hypoxic load as reflected by T90% and minimum SpO₂, rather than AHI alone, is independently associated with hypertension in patients with OSA, underscoring the importance of oxygenation metrics in cardiovascular risk assessment.