McVeigh 1988.
| Methods | Randomized, double‐blind, placebo‐controlled trial (parallel arms). Wash‐out period = 4 weeks. Conducted in Belfast | |
| Participants | DBP 90 to 110 mmHg. Mean age 57 years. Males 41.5%. Baseline BP was 166.7/97 mmHg in the treatment group and 157/94 mmHg in the control group | |
| Interventions | Cyclopenthiazide 50 μg/d (N = 13), 125 μg/d (N = 15), 500 μg/d (N = 13) or placebo (N = 12) Trial duration = 8 weeks | |
| Outcomes | Sitting SBP and DBP (at weeks 2, 4, 6 and 8 intervals); ECG, serum biochemistry, plasma renin activity, urinalysis and body weight | |
| Notes | A sample size calculation based on 6 or more patients per treatment group to detect a 10 mmHg (± 5 mmHg) difference in DBP was provided at a power of 80%. There was a small sample size of 12 to 15 patients in each treatment group. The study authors stated that the baseline patient age and body weight were similar across treatment groups. Mortalities and SAEs not given | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "...patients were randomly allocated in a double‐blind fashion to one of four regimens of treatment incorporating 50μg, 125μg and 500μg cyclopenthiazide or a placebo that looked identical." (line 17 from bottom of p.96). "Randomisation was achieved with a balanced block design." (line 20 from bottom of p.96) |
| Allocation concealment (selection bias) | Unclear risk | Not stated by study authors |
| Blinding (performance bias and detection bias) All outcomes | Low risk | "...patients were randomly allocated in a double‐blind fashion to one of four regimens of treatment incorporating 50μg, 125μg and 500 μg cyclopenthiazide or a placebo that looked identical." (line 17 from bottom of p.96) |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | It was not shown whether the primary efficacy analysis was based on an intention‐to‐treat (ITT) or per‐protocol technique Exclusions: 30/83 (36%) patients were excluded from the study during the placebo run‐in period prior to randomization. 22 of these patients became normotensive (DBP < 90 mmHg), 3 were unable to tolerate the placebo, 2 were hospitalized for low back pain, 1 developed "unacceptable" ankle edema, 1 had a SBP exceeding 240 mmHg and 1 had DBP exceeding 110 mmHg Attrition: no patients withdrew from the study WDAEs: none |
| Selective reporting (reporting bias) | Unclear risk | Mean body weight was reported at baseline only. Serum levels of creatinine and magnesium were measured but actual values were not shown. BP data were presented as mean ± SD at both baseline and endpoint. Medical history was not included in the baseline patient characteristics. Mortalities and SAEs were not mentioned. Total AEs: cyclopenthiazide 50, 125 and 500 μg/d groups ‐ 13, 13 and 8 patients; placebo group ‐ 9 patients |
| Industry sponsorship | Unclear risk | Sponsor not reported |