Table 2 Exposure rates for montelukast and other anti-asthmatic drugs during the 15 months preceding the onset of Churg-Strauss syndrome (CSS): total and individual 3-month effect periods and stratified for the year of CSS onset

	Montelukast		LABA		Inhaled CS		Oral CS
	N/total (%)	p_trend	N/total (%)	p_trend	N/total (%)	p_trend	N/total (%)	p_trend
Total	20/78 (26)		51/78 (65)		57/78 (73)		43/78 (55)
Control 4 (−12/−15 months before onset)	6/78 (8)		37/72 (51)		46/74 (62)		28/73 (38)
Control 3 (−9/−12 months before onset)	8/78 (10)		40/71 (56)		46/74 (62)		29/72 (40)
Control 2 (−6/−9 months before onset)	9/78 (12)	0.13	42/71 (59)	0.09	48/74 (65)	0.45	31/72 (43)	0.33
Control 1 (−3/−6 months before onset)	12/78 (15)		47/72 (65)		50/74 (68)		33/72 (46)
Index (0/−3 months before onset)	15/78 (19)		45/71 (63)		49/73 (67)		35/70 (50)
Control exposure according to year of CSS onset
1999/2000	1/112 (1)		60/105 (57)		65/112 (58)		48/108 (44)
2001	10/88 (11)	<0.0001	45/81 (56)	0.58	54/80 (68)	0.11	39/84 (46)	0.18
2002/3	24/112 (21)		61/100 (61)		71/104 (68)		34/97 (35)

CS, corticosteroids; LABA, inhaled long-acting β₂ agonists.
N/total, numbers of periods exposed/total periods.