ANBP2 2003.

Study characteristics
Methods	Randomized, open‐label trial
Participants	6083 patients in Australia aged 65 to 84 years with hypertension (SBP ≥ 160 mmHg or DBP ≥ 90 mmHg) Mean age 72 years 3102 F:2981 M
Interventions	Enalapril Hydrochlorothiazide (recommended agents, although other ACE inhibitors and diuretics were permitted; doses not provided)
Outcomes	Combined endpoint of all cardiovascular events (coronary and cerebrovascular events, both fatal and nonfatal) or death from any cause Individually reported events: all‐cause mortality, coronary event, MI, HF, cerebrovascular event, stroke BP at 1 year Duration: median follow‐up 4 years
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study indicates that patients were randomly allocated to treatment groups, but no further information provided regarding the method of randomization.
Allocation concealment (selection bias)	Unclear risk	No description of allocation concealment was provided.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Study used an open‐label design.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "An end‐point committee whose members were unaware of the treatment group assignments adjudicated all potential end points."
Incomplete outcome data (attrition bias) All outcomes	Low risk	An intention‐to‐treat analysis was used. Quote: "All subjects who underwent randomisation were included in the final analysis. For subjects who were lost to follow‐up monitoring, we used the last available data; vital status was ascertained for all but two subjects." A total of 2.2% of patients in the ACE inhibitor group and 3.3% of patients in the diuretic group were lost to follow‐up.
Selective reporting (reporting bias)	Unclear risk	Without a protocol, cannot fully determine if all prespecified outcomes have been reported.
Use of supplemental drugs	High risk	Add‐on therapy was permitted at physician's discretion with no clear algorithm. Since this was an open‐label trial this could lead to bias. Quote: "To achieve the blood‐pressure goals, the addition of beta‐blockers, calcium‐channel blockers, and alpha‐blockers was recommended in both groups"
Industry sponsorship	High risk	Quote: "Supported by the Australian Commonwealth Department of Health and Aging; the National Health and Medical Research Council of Australia; and Merck Sharp & Dohme, Australia."