Prevalence of obstructive sleep apnea syndrome in patients with pulmonary embolism: a prospective observational study

BACKGROUND: The relationship between obstructive sleep apnea syndrome (OSAS) and pulmonary embolism (PE) remains inadequately characterized, and prospective data obtained with objective sleep testing in confirmed PE patients are scarce. We aimed to determine the prevalence of OSAS in patients with radiologically confirmed PE and to compare clinical, laboratory, and polysomnographic features according to OSAS status. METHODS: ) within two weeks of diagnosis. OSAS was defined as an apnea-hypopnea index (AHI) ≥ 5 events/hour. Group comparisons used the Mann-Whitney U test and chi-square or Fisher's exact test; associations with AHI were assessed by Spearman's rank correlation. RESULTS: OSAS was identified in 31 patients (68.9%): 11 mild, 12 moderate, and 8 severe. Body mass index (BMI) was significantly higher in OSAS-positive patients [median 31.2 (IQR 26.5-34.6) vs. 27.3 (24.2-30.4) kg/m²; p = 0.037]. Blood urea nitrogen was also elevated in the OSAS group [36.0 (25.1-52.0) vs. 19.5 (16.2-43.5) mg/dL; p = 0.026]. Minimum nocturnal oxygen saturation was markedly lower in OSAS patients [83.0% (79.0-86.5) vs. 91.0% (88.5-92.0); p < 0.001], as were the oxygen desaturation index and time with SpO₂ <90% (both p < 0.001). AHI correlated positively with age (r = 0.363; p = 0.014) and negatively with minimum nocturnal SpO₂ (r =- 0.753; p < 0.001). Classical Wells criteria did not differ between groups; 38.7% of OSAS-positive patients had no identifiable Wells risk factor for PE. CONCLUSIONS: OSAS was present in nearly 70% of PE patients and was associated with greater nocturnal hypoxemic burden, higher BMI, and elevated blood urea nitrogen. The absence of classical precipitating factors in a substantial proportion of OSAS-positive patients is consistent with the hypothesis that sleep-disordered breathing may be associated with an increased thrombotic risk. Further prospective studies are needed to evaluate the clinical utility and cost-effectiveness of targeted OSAS screening strategies in PE patients, particularly those without conventional risk factors.