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

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.

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.

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.

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.