FIB-4 Index, Sleep Apnea Severity, and Nocturnal Hypoxemia

This retrospective study evaluates whether the Fibrosis-4 (FIB-4) index is associated with the severity of obstructive sleep apnea (OSA) and nighttime oxygen desaturation. Adults who underwent full-night polysomnography were grouped according to apnea-hypopnea index (AHI) as no OSA, mild OSA, moderate OSA, or severe OSA. Routine clinical, laboratory, and sleep-study data were reviewed. The main aim is to compare FIB-4 values across OSA severity groups and to examine whether FIB-4 is related to AHI, oxygen desaturation index (ODI), and minimum oxygen saturation during sleep. The study also evaluates the proportion of patients with FIB-4 values at or above 1.30, a commonly used threshold for identifying individuals who may need further liver fibrosis assessment. FIB-4 is used in this study as a noninvasive liver fibrosis risk marker and not as a diagnosis of liver fibrosis.

Inclusion Criteria: Adults aged 18-65 years. Underwent technically adequate diagnostic full-night polysomnography. Sufficient demographic and clinical data available for OSA classification. Exclusion Criteria: Age \65 years. Technically inadequate polysomnography. Split-night or positive airway pressure (PAP) titration studies. Known advanced chronic liver disease or cirrhosis. Hematologic malignancy. Active infection. Clinically significant systemic inflammatory or autoimmune disease. Chemotherapy, radiotherapy, or immunosuppressive therapy. Pregnancy. Clinically significant alcohol use or alcohol-related liver disease. Missing laboratory components required for the relevant FIB-4 or NLR analysis.