Tiong 2009.

Methods	Prospectively, randomised trial single centre study
Participants	67 patients (35 alfuzosin, 32 placebo)
Interventions	A (35): Alfuzosin XL 10 mg once daily B (32): Placebo '...TWOC at least 2h after taking the second dose of trial medication.'
Outcomes	TWOC success rates: A (21/35), B (11/32)
Notes	Both patient groups offered alpha blocker treatment after successful TWOC
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised '...using a centrally established computer‐assigned randomization list'.
Allocation concealment (selection bias)	Low risk	'The allocation and administration of treatment were double‐blinded'.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete data
Selective reporting (reporting bias)	Unclear risk	All the outcomes as detailed in the method section of the trial were reported in the result section. Some outcomes which are considered important from patients’ perspective were not reported. Without the protocol it was difficult to judge whether or not these outcomes were included in the protocol and not reported in the report.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	'The allocation and administration of treatment were double‐blinded'.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not specified
Other bias	Low risk	Groups comparable at baseline for all characteristics measured (except mean retention urine volume at initial catheterisation; borderline non‐significance [P = 0.06]) Ethical approval and informed consent obtained Low withdrawal rate

AUR = acute urinary retention
 BPH = benign prostatic hyperplasia
 IPSS = International Prostate Symptom Score
 PVR = post‐void residual
 TURP = transurethral resection of the prostate
 TWOC = trial without catheter
 SD = standard deviation
 SR = sustained release
 XL = extended release