In the context of OSA, hypoxia-driven inflammatory activation and impaired albumin synthesis provide a biologically plausible explanation for the strong discriminatory performance observed with PNI (AUC = 0.994; optimal cut-off ≤ 48.1), highlighting nutritional–immune imbalance as a previously underrecognized dimension of severe disease [31,33]. This evidence concerns the gene ALB and obstructive sleep apnea syndrome.