Table 2.

When to start treatment with TNF-α inhibitors.

Axial involvement	Persistently high disease activity (BASDAI >4)
	Failure at least two NSAIDs
Peripheral involvement	Failure of local or systemic steroids
	Failure of DMARDs
Enthesitis/dactylitis	In severe case or after failure of traditional therapy.
Poor prognostic factor risk	High CRP/ESR bone edema at MRI
Active inflammatory bowel disease	Moderate or severe form in case of fail to respond at least one DMARDs
Inflammatory bowel disease complicated by abdominal abscess or stricture	Abdominal surgery before starting TNF-α inhibitors

BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; DMARDs, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; MRI, magnetic resonance imaging; NSAIDS, nonsteroidal anti-inflammatory drug; TNF, tumour necrosis factor.