Kessler 2014

Methods	Study design: parallel group randomised trial. Study dates: November 2009 to July 2012. Setting: outpatient. Country: Switzerland.
Participants	Inclusion criteria: CPPS III, duration of symptoms > 3 months, NIH‐CPSI total score > 15, NIH‐CPSI pain score > 8. Participants had been treated with a tetracycline for 4 weeks, alpha‐blocker treatment for ≥ 6 weeks and NSAID. All participants had written informed consent. Exclusion criteria: inclusion criteria not fulfilled. Postvoid residual > 100 mL, nitrite‐positive urine sample, positive urine culture (Meares‐Stamey 3‐glass test and postprostatic massage urine). Urethral stricture, prostate cancer, aged < 18 years, claustrophobia, cardiac pacemaker, implanted nerve‐stimulator, insulin or pain pump. Sample size: 60. Age (years): Group 1: mean 49 (SD 14.2); Group 2: mean 44.9 (SD 15.9). Baseline NIH‐CPSI score: Group 1: 25.8; Group 2: 25.2. Sex: men.
Interventions	Group 1 (n = 30): sono‐electromagnetic therapy at home, using the portable Sonodyn device (Sonodyn Corporation AG, Solothurn, Switzerland), with gel applied to perineum twice daily and for 10 min (ultrasound intensity 100 mW/cm2, ultrasonic power 12 mW and frequency 1.9 MHz, electric field force 0.3 V/m and magnetic field force of 0.4 A/m). Participants could not see settings and could not perceive the device. Duration of treatment 12 weeks. Group 2 (n = 30): placebo device with the same characteristics: quote: 'They looked identical, were packed identically, and the placebo device lit the same buttons when charged and when switched on as the verum device, but did not provide stimulation'. Cointerventions: not defined.
Outcomes	Prostatitis symptoms How measured: NIH‐CPSI score. Time points measured: baseline, and 6, 12 and 16 weeks. Time points reported: baseline, and 6, 12 and 16 weeks. Subgroups: age (cut‐off point 50 years), symptom severity (cut‐off point 25 points of NIH‐CPSI score). Adverse events How measured: National Cancer Institute Common Terminology for Adverse Events version 4.
Funding sources	'This research was supported by the Sonodyn Corporation AG (Solothurn, Switzerland) and the University Hospital Inselspital (Bern, Switzerland). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.'
Declarations of interest	'The authors declare that Sonodyn Corporation AG (Solothurn, Switzerland) provided all stimulation devices.'
Notes	ClinicalTrials.gov NCT00688506.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: 'Computer‐generated random numbers with a randomization ratio of 1:1 and a block size of 60.'
Allocation concealment (selection bias)	Low risk	Quote: 'The manufacturer pre‐packed and sequentially numbered the active and placebo devices according to the concealed randomization schedule.'
Blinding of participants and personnel (performance bias) Subjective outcomes	Low risk	Quote: 'Patients, recruiting investigators, study nurses and physicians performing follow‐up assessments were all unaware of the allocated treatment.'
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: 'Patients, recruiting investigators, study nurses and physicians performing follow‐up assessments were all unaware of the allocated treatment.'
Incomplete outcome data (attrition bias) All outcomes	Low risk	All outcomes: 'All patients completed 12 weeks of follow‐up.'
Selective reporting (reporting bias)	Low risk	Outcome reporting matched protocol.
Other bias	Low risk	No other sources of bias identified.