Table 2. Kaplan-Meier and multivariable Cox regression analysis of potential factors associated with time-to-discontinuation of all first-line DMTs and the initial DMT prescribed.

		All DMTs				Initial DMT
Covariate (at index)	n	Median Time to Discontinuation (y) (95% CI)	p value a	Hazard Ratio (95% CI)	p value b	Median Time to Discontinuation (y) (95% CI)	p value a	Hazard Ratio (95% CI)	p value b
Overall	1,471	11.1 (10.4–12.0)				8.6 (7.7–9.5)
Age (y)			<0.0001		<0.0001		<0.0001		<0.0001
18–30	274	7.8 (6.0–9.9)		1.00		5.0 (3.7–6.3)		1.00
30–73	1,197	11.8 (11.0–12.4)		0.61 (0.50–0.76)		9.4 (8.3–10.3)		0.63 (0.52–0.76)
Gender			0.50		0.69		0.56		0.06
Women	1,108	11.3 (10.6–12.1)		1.00		8.3 (7.4–9.7)		1.00
Men	363	10.6 (8.9–12.4)		0.96 (0.80–1.16)		9.1 (6.8–10.3)		0.85 (0.71–1.01)
EDSS			0.02		0.0006		0.003		0.0001
0–1.5	475	12.3 (10.8–13.6)		1.00		8.9 (7.0–10.9)		1.00
2–3.5	797	11.6 (10.3–12.3)	0.43	1.21 (1.00–1.46)	0.05	8.9 (7.9–10.0)	0.90	1.09 (0.92–1.30)	0.30
4–8	193	9.0 (6.9–10.8)	0.004	1.66 (1.28–2.14)	0.0001	5.6 (3.9–8.6)	0.003	1.64 (1.30–2.07)	<0.0001
MS Duration (y)	—	—	0.22	1.00 c (0.99–1.01)	0.96	—	0.08	1.00 c (0.98–1.01)	0.45
Initial DMT			0.01		0.07		0.0001		0.008
GA	906	12.1 (10.8–12.6)		1.00		9.2 (8.1–10.7)		1.00
IFN-β	565	10.4 (9.5–11.1)		1.11 (1.00–1.23)		7.3 (5.7–8.9)		1.29 (1.11–1.50)
Initiation Period			<0.0001		<0.0001		<0.0001		<0.0001
1996–2000	440	12.5 (11.4–13.3)		1.00		10.1 (8.9–11.3)		1.00
2001–2005	546	11.8 (10.9–12.4)	0.58	1.10 (0.89–1.35)	0.38	10.3 (9.3–11.8)	0.75	0.99 (0.82–1.19)	0.89
2006–2011	485	6.0 (5.5–6.6)	<0.0001	2.45 (1.95–3.09)	<0.0001	4.6 (4.0–5.5)	<0.0001	2.24 (1.83–2.75)	<0.0001
GOF test				χ2, 9 = 5.09, p = 0.83				χ2, 9 = 11.60, p = 0.24

DMT = disease modifying therapy; EDSS = Expanded Disability Status Scale; GA = glatiramer acetate; IFN-β = interferon-beta; y = years, GOF = goodness-of-fit; n = 1465 in multivariable models.

^aLog-rank test.

^bWald test from multivariable Cox regression model adjusted for all covariates.

^cPer one-unit increase in MS duration.