Ferrara 1984.
| Methods | Randomized, double‐blind, placebo‐controlled trial (parallel arms). Wash‐out period = 2 weeks. Conducted in Italy | |
| Participants | Mild to moderate hypertension. Values not mentioned. Mean age 45.5 years. % of males not given. Mean baseline SBP/DBP was 161/107 mmHg in the treatment group and 151/104 in the placebo group. Pulse pressure 54/47 respectively | |
| Interventions | Slow‐release nifedipine 20 mg/d, chlorthalidone 25 mg/d or placebo (all combined, N = 30 patients randomized) Trial duration = 8 weeks | |
| Outcomes | Standing and supine SBP and DBP; heart rate; left ventricular mass and function; systolic time intervals | |
| Notes | A sample size calculation was not provided. Study authors did not state whether there were statistically significant differences between treatment groups in baseline patient demographics and characteristics. The majority of patients were overweight (average BMI = 27) at baseline. A separate group of 10 patients (group A) who did not enter a wash‐out period at the beginning of the study due to adequate BP control on other antihypertensives were not included in this review. Total withdrawals (TW), WDAEs, mortalities, SAEs and total AEs were not reported. Biochemical data not given | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | "...patients...were randomly allocated to chlorthalidone 25 mg/day (Group B), slow release nifedipine 20 mg/day (Group C) or placebo (Group D)." (line 9 under "Summary" p.525). No further information was given for how patients were randomized to treatment |
| Allocation concealment (selection bias) | Unclear risk | Not stated by study authors |
| Blinding (performance bias and detection bias) All outcomes | Unclear risk | "The study was performed according to a double blind model since echocardiograms were numerically coded and read by two blinded observers." (line 3 from bottom of p.526). As well as the statement by the study authors above, the title of study included the word "double‐blind"; no further information was given, however |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Whether primary efficacy analysis was based on an ITT or per‐protocol technique was not reported. Exclusions: the number of patients excluded from the study during the run‐in period prior to randomization was not given Attrition: total number of withdrawals and their reasons were not given WDAEs: information not given |
| Selective reporting (reporting bias) | High risk | Gender, weight and medical history of patients were not given at baseline. Biochemical data including hematology, serum chemistry, urinalysis and ECG were not reported. For BP data, statistical significance was calculated within groups but not between groups. Number of patients randomized to each treatment arm was not reported and it is not known how many were included in the efficacy and safety analysis. Mortalities, SAEs and total AEs were not reported |
| Industry sponsorship | Unclear risk | Sponsor not reported |