Clinically, patients with SpA and obesity have been reported to demonstrate heightened disease activity (BASDAI, ASDAS), impaired function (BASFI), accelerated radiographic progression (syndesmophytes, enthesophytes), and diminished biologic response rates, potentially attributable to pharmacokinetic alterations (e.g., subtherapeutic TNF inhibitor levels) and pharmacodynamic resistance. This evidence concerns the gene TNF and obesity disorder.