Table 7:

Summary of Subgroup Analyses for Pain-Related Outcomes, nVNS vs. Control, Acute Treatment, Episodic Cluster Headache

Pain outcome	Author, year (study)	Measurement, time	Participants, nVNS/control, n	Mean or proportion		Summary effect (95% CI or SE)	P a
				nVNS	Control
Response	Silberstein et al, 201651 (ACT1)	Proportion after first attack, 15 min	38/47	34.2	10.6	RR 3.22 (1.26 to 8.22)b	.01b
	Goadsby et al, 201852 (ACT 2)	Mean proportion of treated attacks per person, 30 min	14/13	57.5	25.5	Absolute difference: 32 (15)	.07
Response in ≥ 50% of attacks	Silberstein et al, 201651 (ACT1)	Proportion, 15 min	38/47	34.2	14.9	RR 2.30 (1.02 to 5.18)b	.05b
	Goadsby et al, 201852 (ACT 2)	Proportion, 15 min	14/13	64.3	15.4	RR 4.18 (1.10 to 15.85)b	.04b
Sustained response	Silberstein et al, 201651 (ACT1)	Proportion, 15 min sustained to 60 min	38/47	34.2	10.6	RR 3.22 (1.26 to 8.22)b	.01b
Pain freedom	Goadsby et al, 201852 (ACT 2)	Proportion, 30 min	14/13	43	19.1	Absolute difference: 23.9 (14.4)	.08
Pain freedom in ≥ 50% of attacks	Silberstein et al, 201651 (ACT1)	Proportion, 15 min	38/47	15.8	2.1	RR 7.42 (0.93 to 59.01)b	.06b
	Goadsby et al, 201852 (ACT 2)	Proportion, 15 min	14/13	35.7	7.7	RR 4.64 (0.62 to 34.65)b	.13b
Headache intensity	Silberstein et al, 201651 (ACT1)	Mean for all treated attacks, 15 min	38/47	2.0	2.0	Mean difference: 0 (-0.34 to 0.34)b	.0b
	Goadsby et al, 201852 (ACT 2)	Mean change from attack onset to follow-up, 15 min	11/8	-1.7	-0.6	Mean difference: -1.10 (-1.98 to -0.22)	.01
		Mean change from attack onset to follow-up, 30 min	11/8	-1.9	-0.8	Mean difference: -1.10 (NR)	.03

Abbreviations: CI, confidence interval; nVNS, noninvasive vagus nerve stimulation, RR, relative risk; SE, standard error.

^aCalculated P values may differ from those in the published analyses due to varying statistical techniques and rounding.

^bCalculated using data provided.