Association of the FIB-4 Index With Obstructive Sleep Apnea Severity and Nocturnal Hypoxemia: A Retrospective Polysomnographic Study
Association of the FIB-4 Index With Obstructive Sleep Apnea Severity and Nocturnal Hypoxemia: A Retrospective Polysomnographic Study
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.
This is a single-center, retrospective observational study of adults aged 18-65 years who underwent diagnostic full-night polysomnography. Participants were classified according to the apnea-hypopnea index (AHI) as AHI <5 events/h, mild OSA (5-14.9 events/h), moderate OSA (15-29.9 events/h), or severe OSA (≥30 events/h).
Demographic, polysomnographic, hematologic, and biochemical data were obtained retrospectively from hospital records. Laboratory measurements closest to the polysomnography date within ±30 days were used. The FIB-4 index was calculated from age, aspartate aminotransferase, alanine aminotransferase, and platelet count.
FIB-4 was evaluated as a continuous variable and using clinically established risk thresholds. Associations between FIB-4 and polysomnographic measures, including AHI, oxygen desaturation index (ODI), and minimum peripheral oxygen saturation (SpO₂), were examined. The study also explored the relationship between FIB-4 and the neutrophil-to-lymphocyte ratio (NLR). No study-related intervention was administered.
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 <18 or >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.