Table 1

Studies investigating adherence to MTX treatment

Study	Place	N	Study design	RA definition	Age (years)	Percentage of females	Disease severity	Disease duration (years)	First time or established MTX user	Follow-up	Average MTX dose mg/week
Harley et al21	USA	2662	Retro	ICD9	53.3±14.7	73	NP	NP	First time	365 days	10±NP
de Klerk et al22	NED	127	Prosp cohort	Rheum	60±14*	66*	NP	NP	First time	210 days	NP
Grijalva et al23	USA	14 932	Retro cohort	ICD9	54 (44–63)	78	NP	NP	First time	NP	NP
Contreras-Yanez et al24	MEX	93	Prosp cohort	Rheum	40.8±13.9†	80†	DAS28: 2.1±1.1†	<1†	Established	6 months	NP
Grijalva et al25	USA	14 586	Retro cohort	ICD9	55 (45–64)†	76†	NP	NP	First time	NP	NP
de Thurah et al26	DEN	941	Retro cohort	ICD10	60.5	69	Erosions 71%	52.9%<5	First time	384 (233–931) days	15
de Thurah et al27	DEN	103	Prosp cohort	ICD10	63 (32–80)	64	Erosions 60%	6.3 (0–27)	First time	9 months	13.8 (12.5–15.1)
Cannon et al28	USA	455	Retro cohort	ACR 1987	64±11	8	DAS: 3.9±1.6	NP	First time	42.7±3 1.2 months	16±4
Salt and Frazier29	USA	108	Cross-sectional	ACR 1987	52±13†	76†	NP	10±10†	Established	NA	NP
Waimann et al30	USA	111	Prosp cohort	ACR 1987	NP	87†	DAS28: 4.7±1.6†	8±6†	Both	24 months	NP

Median (IQR), mean (95%CI) otherwise mean±SD.
†Values represent total RA sample and not specific to MTX users.
ACR1987, American College of Rheumatology Classification 1987 Criteria; DAS, Disease Activity Score; DEN, Denmark; ICD, International Statistical Classification of Diseases; MEX, Mexico; MTX, methotrexate; NED, Netherlands; NP, information not presented; Prosp, prospective; RA, rheumatoid arthritis; Retro, retrospective; Rheum, RA diagnosed by a rheumatologist.