Table 1 –

Study eligibility criteria

Criteria	Rationale
Inclusion criteria
1. Male	The study disease only affects men
2. Aged 30–80 yr inclusive	Most men with ED will be within this age group
3. Be able to provide written informed consent	Requirement for research in human subjects
4. Diagnosis of mild to moderate (12–21) or mild (22–25) ED according to the IIEF-EF score	Preliminary data show better SWT efficacy in ED classed as mild or mild to moderate; ~65% of men with ED fit this definition
5. In a stable heterosexual relationship with a minimum of 2 sexual attempts per month for at least 1 mo before enrolment	The primary outcome is assessed using the IIEF score; the IIEF instrument is not validated in the MSM population
6. Agreement to comply with all study-related tests and procedures	Protocol compliance
Exclusion criteria
1. Previous penile surgery of any kind (except circumcision and condyloma removal), such as penile lengthening, penile cancer surgery, penile plication, grafting	Penile surgery can change the hemodynamic parameters of the penis and potentially affect transduction of shockwaves
2. History of priapism, penile fracture, Peyronie’s disease, or penile curvature that negatively influences sexual activity	These conditions suggest severe pathologic penile vasculature and corporal dysfunction
3. Abnormal morning serum testosterone, defined as <300 ng/dl (±5%)	Normal serum testosterone levels are necessary for adequate erectile function
4. Psychogenic ED as determined by the study investigator	Men with psychogenic ED may respond differently to men with ED of other etiologies
5. ICI for management of ED	ICI can lead to penile fibrosis, which could be a confounding factor for erectile function recovery
6. Generalized polyneuropathy, neurological conditions, or psychiatric disease (such as bipolar disorder or depression)	Could be a confounding factor for erectile function recovery.
7. Serious comorbid illness or condition that, in the opinion of the investigator, may compromise the safety or compliance of the subject or preclude successful completion of the study	Protocol compliance and minimization of attrition
8. History of consistent treatment failure with PDE5i for ED therapy	Could be a confounding factor for erectile function recovery.
9. Poorly controlled diabetes mellitus as indicated by hemoglobin A1c >9%	Poorly controlled diabetes is a risk factor for neurogenic and vascular ED and could be a confounding factor for erectile function recovery
10. Use of antiplatelet medication	Antiplatelet medication may affect platelet degranulation and release of cytokines

ED = erectile dysfunction; IIEF = International Index of Erectile Function questionnaire; ICI = intracavernous injection; MSM = men who have sex with men; PDE5i = phosphodiesterase type 5 inhibitor.