Introduction and objective:
Obstructive sleep apnea (OSA) is associated with cardiovascular risk and higher mortality. Assessment of subclinical organ lesions is significant for prevention of clinically manifested complications which might result in death. The aim of the study was to assess the prevalence of subclinical target organ damage in hypertensive patients with OSA, and to establish whether these lesions are dependent on the intensity of sleep-disordered breathing.

Material and methods:
The study covered 67 patients with OSA diagnosed on the basis of polygraphy. Depending on the apnea/hypopnea index (AHI), the patients were divided into two groups: G1 (n=32; AHI=5–30) and G2 (n=35; AHI>30). The control group C consisted of 31 hypertensive subjects with OSA risk estimated as low based on the Berlin Questionnaire (BQ). Each patient had the following parameters measured: intima-media thickness (IMT), ankle-brachial index (ABI), left ventricular mass index (LVMI), and estimated glomerular filtration rate (eGFR).

Results:
The patients with severe OSA had significantly higher LVMI compared to the control group (130.99±44.6 g/m² versus 106.61±27.86 g/m²; p=0.0332). The G2 group had higher eGFR than C (104.7±17.96 ml/min/1.73m², 88.85±17.68 ml/min/1.73m²; p=0.0058). Similar results of eGFR were observed between G1 and C (104.35±21.06 ml/min/1.73m², 88.85±17.68 ml/min/1.73m²; p=0.0081). G1 and G2 did not differ significantly in terms of eGFR. The other measured parameters, such as IMT and ABI, did not differ significantly between OSA and controls.

Conclusions:
Patients with severe OSA demonstrate signs of left ventricular hypertrophy, while early atherosclerotic lesions (ABI and IMT) were not more intense than in the control group. High eGFR levels may indicate hyperfiltration, which does not correlate with OSA intensity level.