Schmidt 2002.

Methods	Randomized allocation Double‐blind Outcome assessment blind: unclear Parallel design Duration: 26 weeks Sample size at the entry: 70 SSZ: 34 Placebo: 36 Clear description of withdrawal and drop out Intention‐to‐treat analysis: unclear
Participants	Participants fulfilling the modified New York criteria for AS Other inclusion criteria: 1. rheumatoid factor negative 2. morning stiffness >= 20 min 3. pain in the field of the axial skeleton >= 25 mm (100 mm visual analogue scale) Exclusion criteria: 1. known allergic to sulfonamide, salicylates and tartrazin 2. hematological diseases including thrombocytopenia (PLT < 140 G/L) and leukocytopenia (WBC < 4.0 G/L) 3. Severe liver diseases including GOT or GPT values > double of the upper norm limits 4. known renal diseases or increased creatinine 5. known G6PD deficiency, acute porphyria, asthma bronchial, pregnancy or urgent desire of an own baby, chronic inflammatory intestine diseases, RA, psoriasis, reactive arthritis, SLE, gout 6. corticosteroid treatment within the last month 7. severe diseases which were dangerous to participate in the trial Age: 27.5 +/‐ 8.3 SSZ group: 26.9 +/‐ 7.8 Placebo group: 28.0 +/‐ 8.8 Male: 87% Duration of disease: 16.7 +/‐ 7.2 SSZ group: 16.3 +/‐ 7.8 Placebo group: 17.1 +/‐ 6.6 With peripheral arthritis: 36%
Interventions	SSZ 1.0 g orally, 3 times a day Placebo: the same as SSZ
Outcomes	1. Back pain (100 mm visual analogue scale) 2. Nocturnal awakening (event) 3. Enthesopathy index (0 to 90) 4. Duration of morning stiffness (hr) 5. Number of painful joints 6. Number of swollen joints 7. Spondylitis function index (0 to 44) 8. Effectiveness in patient assessment (event) 9. Effectiveness in physician assessment (event) 10. Schober's test 11. Fingers‐to‐floor test (cm) 12. Occiput‐to‐wall test (cm) 13. Chin sternum distance (cm) 14. Chest expansion (cm) 15. ESR (mm/hr) 16. CRP (ug/mL) 17. Withdrawal due to side effect 18. Withdrawal due to ineffectiveness 19. Drop out for any reason
Notes	There was no financial interest to report All continuous outcomes were presented as change from baseline We changed 'effectiveness in patient assessment' to 'improvement in patient global assessment' We changed 'effectiveness in physician assessment' to 'improvement in physician global assessment' Those dropping out were counted as not improved We changed 'nocturnal awakening' to 'night pain ('no bother' participants who dropped out were counted as night pain (bother) For 'number of painful joints' and 'number of swollen joints', no SD was given For 'fingers‐to‐floor test' (cm), SD of SSZ group was missed German full‐text was translated into English
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information about the sequence generation process to permit judgment of Yes or No
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgment of Yes or No
Blinding (performance bias and detection bias) All outcomes	Unclear risk	"It treat of a prospective, randomized, double blind, placebo‐controlled study with intention‐to‐treat analyse of the results". But no information about which two were blinded
Incomplete outcome data (attrition bias) All outcomes	High risk	There were 16/34 and 7/36 participants withdrew from the trial in SZZ and placebo, respectively. No information about the missing data
Selective reporting (reporting bias)	Low risk	They reported the expected outcomes
Other bias	Low risk	The study appears to be free of other sources of bias