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

Overview

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.

Conditions