Table 4. Findings on multiple episodes, number and duration of ENL episodes.

Study number	Country	Type of study	LE	Study design	Follow up/study period (years)	ENL cases	ENL cases with >2 episodes (%)	Average number of episodes	Average duration episode (weeks)
2	Thailand [44]	Field	2b	Observational cohort (prospective)	<2	16	7 (44)
4	Ethiopia [45]	Field	2b	Observational cohort (prospective)	mean 2.5, <4	4	2 (50)	(range 1–3)
5	Ethiopia [41]	Field	2b	Observational cohort (prospective)	<10	16	10 (63)	3 (range 1–8)***
8	India [47]	Field	2b	Observational cohort (retrospective)	5 after RFT	92	47 (51.1§)
9	China [48]	Field	4	Observational cohort (retrospective)	1	293		2.9
14	Thailand [50]	Hospital	1b	Observational cohort (prospective)	<3	44	34 (77.3)	“often >4 times”
16	India [55]	Hospital	2b	Controlled trial	mean 8.5- 8.4	50	26 (52)
16a						51	30 (58.8)
17	India [76]	Hospital	2b	Observational cohort (retrospective)	<4	164	164 (†)
19	India [60]	Hospital	2b	Observational cohort (retrospective)	>1	88**	81 (92††)	3.2 (CI 2.7–3.5)
20	Philippines [63]	Hospital	2b	Observational cohort (retrospective)	4	60		2.9	5.3
20a						36		2.4	17
21	Philippines [61]	Hospital	2b	Observational cohort (prospective)	2 after RFT	8			15
21a						10			26.1
22	Zaire [59]	Hospital	2b	Controlled trial	<3	34		1.8	8.5
26	Brazil [52]	Hospital	2b	Observational cohort (retrospective)	2	51	38 (74.5‡‡)	2.5
27	Uganda [56]	Hospital	4	Cross-sectional	5	18	7 (39)	1.4
30	India [58]	Hospital	4	Observational cohort (retrospective)	3–13	337	217 (64.3)	2.6
31	Nepal [57]	Hospital	4	Cross-sectional	8	107	52 (49‡)	2
39	India [18]	Hospital	3b	Controlled trial	<4	10	7 (70§§)	2.0
39a						12	9 (75§§)	2.4
40	India [19]	Hospital	4	Cross-sectional	<1	17			14.35 days (sd 3.53; range 8–20)
	Total					896	567 (63.3)	2.6

^†Only cases with multiple episodes of ENL reported, this accounted for 28.4% of MB cases. This study is excluded from the calculations.

^‡49 (45%)single, 27 (25%) two, 13 (12%) three, 6 (5%)four, 2 (2%) five, 5 (5%) >five episodes.

^§45(49%) single, 28 (30%)two, 14 (11%) three, 5 (5%) four or more episodes.

^**Of the original cohort of 116 patients, 28 were excluded because they had too short follow-up and could not be categorized.

^††37.5% having acute multiple ENL (i.e. more than one episode lasting less than six months, steady decrease in steroid tapering) and 62.5% chronic ENL (i.e. episode lasting for more than six months).

^‡‡13 (25%)single, 12 (24%)two, 14 (27%)three, 11(22%)four, 1(2%)five episodes.

^§§Vaccine versus control group; 3 vs 3 single, 4 vs 4 two, 3 vs 2 three, 0 vs 3 more than three episodes.

^***An episode of ENL was taken as a separate event if more than 3 months had elapsed since the last episode.