Moser 1991.
| Methods | Randomized, double‐blind, placebo‐controlled trial (parallel arms). Wash‐out period = 2 to 4 weeks. Multicenter, conducted in USA | |
| Participants | Sitting DBP 95 to 114 mmHg. Mean age 50 years. Males 66%. Baseline BP range was 151 to 154/101 to 102 mmHg | |
| Interventions | Benazepril 2 mg (N = 34), 5 mg (N = 38), 10 mg (N = 34) or 20 mg/d (N = 36), hydrochlorothiazide 25 mg/d (N = 33) or placebo (N = 31) Trial duration = 4 weeks (followed by a 2‐week open‐label HCTZ phase in non‐responders; not to be discussed here) |
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| Outcomes | Mean trough sitting, standing and supine DBP and SBP (at 1‐week intervals from weeks 1 to 4); response rate; pulse rate; ECG and on a periodic basis plasma renin activity, hematology, urinalysis and serum biochemistry | |
| Notes | A sample size calculation was not provided. Study authors stated that there were no statistically significant differences (P value = NS) in baseline patient demographics and characteristics across treatment groups. Mortalities and SAEs not given. Subgroup analysis in black versus non‐black patients | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | "...patients were randomised to placebo, 25 mg, hydrochlorothiazide, or 2, 5, 10, or 20 mg benazepril once daily for a 4‐week double‐blind treatment period." (line 5 from top of p.323). No further information was given. |
| Allocation concealment (selection bias) | Unclear risk | Not stated by study authors |
| Blinding (performance bias and detection bias) All outcomes | Unclear risk | "...patients were randomised to placebo, 25 mg, hydrochlorothiazide, or 2, 5, 10, or 20 mg benazepril once daily for a 4‐week double‐blind treatment period." (line 5 from top of p.323). No further information was given |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | The primary efficacy analysis was based on an intention‐to‐treat (ITT) technique Exclusions: 87/293 (30%) of patients were excluded from the study during the single‐blind placebo run‐in period prior to randomization Attrition: 2/33 (6%) versus 5/31 (16%) of patients from the HCTZ and placebo groups, respectively withdrew from the study due to 1 ‐ "lost to follow up" and 1 ‐ "protocol violation", versus 2 ‐ "lost to follow up", 2 ‐ "lack of efficacy" and 1 ‐ "adverse experience" WDAEs: 1 patient from the placebo group withdrew due to an "adverse experience" for "lymphoma" |
| Selective reporting (reporting bias) | Unclear risk | Standing and supine BP, ECG, serum chemistry and urinalysis were measured, but actual values were not reported on at the end of the study. Mortalities and SAEs were not given. Total AEs (referred to in the study as "adverse experiences") were reported in terms of percentages of patients: HCTZ, 55%; placebo, 45%. Only the most frequently occurring AE (i.e. headache) was listed |
| Industry sponsorship | High risk | Supported by a grant from Ciba‐Geigy Pharmaceuticals |