Drug Retention Rates and Treatment Discontinuation among Anti-TNF-α Agents in Psoriatic Arthritis and Ankylosing Spondylitis in Clinical Practice

Table 2

Mean duration of anti-TNF-α therapy treatment courses and presence or absence of concomitant DMARDs therapy among patients remaining on therapy and those requiring a therapy change.

		Therapy courses discontinued			Therapy courses ongoing		Total
	𝑛 (%)	Mean duration, months (SD)	Concomitant DMARDs, 𝑛 (%)	𝑛 (%)	Mean duration, months (SD)	Concomitant DMARDs, 𝑛 (%)	𝑛 (%)	Mean duration, months (SD)	Concomitant DMARDs, 𝑛 (%)
Anti-TNF-α therapy
ADA	28 (28.6)	10.0 (9.0)	4 (44.4)	69 (27.1)	16.5 (15.4)	16 (26.2)	97 (27.5)	14.6 (14.2)	20 (28.6)
ETA	41 (41.8)	22.5 (20.4)	3 (33.3)	139 (54.5)	30.2 (24.7)	24 (39.3)	180 (51.0)	28.5 (23.9)	27 (38.6)
INF	29 (29.6)	16.3 (15.5)	2 (22.2)	47 (18.4)	43.7 (25.6)	21 (34.4)	76 (21.5)	33.3 (25.9)	23 (32.8)
𝑃 value		0.0149^b	0.5414^c		<0.0001^b	0.0007^c	0.0062^a	<0.0001^b	0.0194^c
Disease
AS	14 (14.3)	21.21 (22.2)	1 (11.1)	54 (21.2)	35.9 (24.8)	15 (24.6)	68 (19.3)	32.9 (24.9)	16 (22.9)
PsA	84 (85.7)	16.5 (16.1)	8 (88.9)	201 (78.8)	27.1 (24.0)	46 (75.4)	285 (80.7)	24.0 (22.5)	54 (77.1)
𝑃 value		0.4037^b	0.7752^c		0.0976^b	0.4544^c		0.0073^b	0.3945^c
Axial involvement
Ax-SpA	25 (25.5)	18.1 (19.5)	5 (55.6)	76 (29.8)	31.5 (23.7)	18 (29.5)	101 (28.6)	28.2 (23.4)	23 (32.8)
PsA	73 (74.5)	16.8 (16.2)	4 (44.4)	179 (70.2)	27.9 (24.7)	43 (70.5)	252 (71.4)	24.7 (23.1)	47 (67.2)
𝑃 value		0.9023^b	0.0300^c		0.1937^b	0.9538^c		0.0467^b	0.3801^c
Total	98 (27.8)	17.1 (17.0)	9 (9.2)	255 (72.2)	29.0 (24.4)	61 (23.9)	353	25.7 (23.2)	70 (19.8)

SD: standard deviation; ADA: adalimumab; ETA: etanercept; INF: infliximab; AS: ankylosing spondylitis; PsA: psoriatic arthritis; Ax-SpA: axial spondyloarthritis; ^a𝑃 values were calculated with the use of a stepwise logistic regression adjusted for gender, concomitant DMARDs, and anti-TNF-α therapy. Variables disease and axial involvement were excluded by a stepwise approach (variables being included for 𝑃<0.05 and excluded for 𝑃>0.1).
^b𝑃 values were calculated by an ANOVA model adjusted for gender, concomitant DMARDs, anti-TNF-α therapy, type of disease, and axial involvement.
^c𝑃 value from chi-square test.