The research was designed to predict the relationship between the apnea-hypopnea index (AHI) as the main indicator of severity of obstructive sleep apnea syndrome (OSAS), and lipid panel test results. A cross-sectional observational study was done on 90 patients with suspected sleep-related breathing disorders as assumed by polysomnography. Patients were categorized into three equal groups depending on AHI: mild degree (5-15 events/hour), moderate degree (15-30 events/hour), and severe degree (>
30 events/hour). All patients underwent a comprehensive medical history, PSG, and lipid panel tests, which included measurements of total cholesterol level, low-density lipoprotein (LDL) level, very low-density lipoprotein (VLDL) level, high-density lipoprotein (HDL) level, and triglycerides (TGs) level. Aclose relation was noted between degree of severity of OSA and lipid panel tests that in third group (Severe degree) exhibited significantly higher levels of triglycerides (212 ± 36 mg/dL), total cholesterol (180 ± 54 mg/dL), and LDL (178.1 ± 39.8 mg/dL) compared to those with moderate (TGs: 158 ± 57 mg/dL, total cholesterol: 151 ± 65 mg/dL, LDL: 153.2 ± 31.5 mg/dL) and mild OSA (TGs: 106 ± 37 mg/dL, total cholesterol: 85 ± 12 mg/dL, LDL: 87 ± 9.3 mg/dL), with P-values <
0.001. Conversely, significantly lower level of HDLin the severe OSA group (25.8 ± 3.6 mg/dL) compared to moderate (32.7 ± 4.2 mg/dL) and mild OSA groups (45.8 ± 9.2 mg/dL), with a