Mechanistically informed non-invasive peripheral nerve stimulation for peripheral neuropathic pain: a randomised double-blind sham-controlled trial

Table 1 Patient demographics and baseline characteristics of Intention to treat analysis population

	Category	Active (n = 38)	Sham (n = 38)	All patients (n = 76)	Mechanistic study (n = 19)^#
Age		47.3 ± 15.9	53.6 ± 11.2	50.4 ± 14.0	61.8 ± 14.9
Gender	Female	22 (58%)	18 (47%)	40 (53%)	9
	Male	16 (42%)	20 (53%)	36 (47%)	10
Duration Pain (months)		44 [27, 96]	48 [26, 72]	47 [27, 87]	61 [23,63]
Mechanism of Injury	Nerve entrapment	1 (3%)	2 (5%)	3 (4%)	2 (11%)
	Nerve injury
	Surgery	29 (76%)	25 (66%)	54 (71%)	8 (42%)
	Other mech. Trauma	6 (16%)	7 (18%)	13 (17%)	6 (32%)
	Radiotherapy	2 (5%)	0 (0%)	2 (3%)	0 (0%)
	Medication	0 (0%)	1 (3%)	1 (1%)	0 (0%)
	Post-herpetic neuralgia	0 (0%)	3 (8%)	3 (4%)	2 (11%)
Number pain meds		1.6 ± 1.5	1.7 ± 1.4	1.7 ± 1.4	1.8 ± 1.1
Pain medications⁺	General pain meds	18 (58%)	24 (69%)	42 (64%)	3 (16%)
	NSAIDs	9 (29%)	13 (37%)	22 (33%)	2 (11%)
	Opioids	9 (29%)	7 (20%)	16 (24%)	7 (37%)
	Anti-Epileptics	15 (48%)	20 (57%)	35 (53%)	10 (53%)
	Anti-Depressants	16 (52%)	11 (31%)	27 (41%)	6 (32%)
	Muscle relaxants	1 (3%)	2 (6%)	3 (5%)	0 (0%)
Baseline assessments
Primary	Pain in last 7 days	7.2 ± 1.2	7.5 ± 1.4	7.3 ± 1.3	7.42 ± 1.3
Variability pain*		0.85 ± 0.51	0.84 ± 0.44	0.85 ± 0.47	0.65 ± 0.55
Secondary	EQ VAS	51 ± 18	57 ± 25	54 ± 22	48 ± 27
	EQ-5D index	0.35 ± 0.23	0.34 ± 0.29	0.35 ± 0.26	0.27 ± 0.29
	BPI I	6.2 ± 1.9	6.4 ± 2.0	6.3 ± 1.9	6.3 ± 2.9
Exploratory	BPI W	8.4 ± 1.1	8.2 ± 1.4	8.3 ± 1.2	8.5 ± 0.9
	HADS anxiety	10.7 ± 4.3	10.4 ± 5.2	10.5 ± 4.8	9.8 ± 5.6
	HADS depression	9.3 ± 4.6	9.0 ± 4.5	9.1 ± 4.5	9.5 ± 5.7
	PESQ	24 ± 14	23 ± 14	24 ± 14	19.7 ± 13
	DMA mapped area	207 ± 192	175 ± 141	191 ± 168	204 ± 166
	NPSI total score	63 ± 15	61 ± 19	62 ± 15	53 ± 19

Summary statistics are mean ± standard deviation, median [inter-quartile range] or number (percentage). There were no significant differences in any baseline measures between active and sham groups
EQ VAS = EuroQol visual analogue score, EQ-5D Index = EQ-5D-5L index score (utility), BPI I = Brief pain inventory interference subscale, BPI W = Brief pain inventory worst pain intensity, HADS anxiety = Hospital anxiety scale anxiety subscale, HADS depression = Hospital anxiety scale depression subscale, PSEQ = Pain self-efficacy questionnaire, DMA mapped area = Dynamic allodynia mapped area, NPSI total = Neuropathic pain symptom inventory subscale total score
*Measured by the standard deviation of the baseline daily pain scores in the week prior to randomisation
⁺Patients could be on more than one type of pain medication. Percentage values may not add up to 100%
^# For mechanistic study the variables age, gender, duration of pain, mechanism of injury and information relating to medications were available for all 19 patients, but for all other outcomes, the numbers represent n = 15/19 available data sets

ISSN: 1479-5876