Supplementary Table 1.

Characteristics of Studies with Mixed Populations

TTNS
Welk, 2020	Canada	RCT	OAB+neurogenic bladder	50 (not mentioned)	10/40	62	Patient perception of bladder condition (PPBC)
Amarenco, 2004	France	Prospective, open-label trial	Neurologic+idiopathic	44 (13)	15/29	53.3	Urodynamic parameters including mean first involuntary detrusor contraction volume, maximum cystometric capacity
Seth, 2018	UK	Prospective, single centre, open label	Neurologic+idiopathic	48 (24)	10/38	46.4 and 46.9 in two arms	ICIQ-OAB,ICIQ-LUTSqol , 3-day bladder diary and a Global Response Assessment (GRA)
Valles-Antuna, 2017	Spain	prospective cohort	Urge urinary incontinence (UUI)	65 (9)	24/41	55.06	48-hour micturitional calendar
Tornic, 2019	Switzerland	RCT	Neurogenic LUTD	9 (2 )	7/2	52.8	feasibility, acceptability, safety of TTNS
PTNS
Tudor, 2018	UK	retrospective cohort	Neurologic+idiopathic	74 (19 )	22/52	56	ICIQ-OAB, ICIQ-LUTSqol, 3-day bladder diary parameters
Jung 2020, (A)	USA	retrospective cohort	OAB	141 (not mentioned)	All female	70	PGI-I, OABq-SF
Jung 2020, (B)	USA	retrospective cohort	OAB	334 (not mentioned)	All female	70.9	PGI-I, OABq-SF
Salatzki, 2019	UK	cross-sectional	OAB	79 (27)	20/59	58.9	bladder diary, PTNS Service Evaluation Questionnaire (PTNS-SEQ), ICIQ-OAB, ICIQ-LUTSqol
Arrabal-Polo, 2012	Spain	prospective cohort	OAB	14 (1)	All female	60.8	48-hour micturitional calendar

1. F/U: Follow-up; 2. MS: Multiple sclerosis; 3. M/F: Male/female; 4. TTNS: Transcutaneous tibial nerve stimulation; 5. RCT: Randomized controlled trial; 6. OAB: Overactive bladder; 7. Hz: Hertz; 8. ms: Millisecond; 9. ICIQ-OAB: International Consultation on Incontinence Questionnaire on OAB; 10. ICIQ-LUTSqol: International Consultation on Incontinence Questionnaire Lower Urinary Tract Symptoms Quality of Life Module; 11. LUTD: Lower urinary tract dysfunction; 12. μs: Microsecond; 12. PGI-I: Patient Global Impression- Improvement; 12. OABq-SF: Overactive Bladder Questionnaire-Short Form