Sutton‐Tyrrell 1994.
| Study characteristics | ||
| Methods |
Study design: randomised, double‐blind, placebo‐controlled, stepped‐care treatment programme Total duration of study: 2 years Details of any 'run‐in' period: "participants were monitored at multiple drug evaluation visits during a 2‐ to 8‐week period to determine blood pressure eligibility off medication" Number of study centres and location: 1 centre, University of Pittsburgh Centre Study setting and date of study: outpatients; June 1984 to October 1996 |
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| Participants |
Number randomised: 129 participants Number lost to follow‐up/withdrawn: no details given Number analysed: 129 participants Number of interest: 129 participants Mean age: 75 years old Age range: 60 to 100 years old Gender: 49 men and 80 women Severity of condition: isolated systolic hypertension Diagnostic criteria: SBP 160 to 219 mmHg and DBP < 90 mmHg Smoking history: 48 smokers Inclusion criteria
Exclusion criteria: "persons were excluded on the basis of history and/or signs of specified major cardiovascular diseases. Other major diseases (e.g. cancer, alcoholic liver disease, established renal dysfunction), with competing risk for the SHEP (Systolic Hypertension in the Elderly Program) primary end point or the presence of medical management problems, were also exclusions" |
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| Interventions |
Intervention: chlorthalidone 12.5 mg daily Comparison: placebo Concomitant medications: "drug dosage was doubled (including matching placebo) for participants failing to achieve the SBP goal at follow‐up visits. If the SBP goal was not reached at the maximal dose of step 1 medication, atenolol, 25 mg/d, or matching placebo was added as the usual step 2 drug. When atenolol was contraindicated, reserpine, 0.05 mg/d, or matching placebo could be substituted. When required to reach the blood pressure goal, the dosage of the step 2 drug could be doubled. Potassium supplements were given to all participants who had serum potassium concentrations below 3.5 mmol/L at two consecutive visits" Excluded medications: no details given |
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| Outcomes |
Primary outcome: total stroke Secondary outcomes: sudden cardiac death, rapid cardiac death, nonfatal MI, fatal MI, left ventricular failure, other cardiovascular death—presumed myocardial infarction that did not meet diagnostic criteria, or other cardiovascular causes, TIA, coronary artery therapeutic procedures, renal dysfunction Ancillary study outcomes: "determine progression of carotid artery stenosis" Time points reported: "2 serial duplex scans of the carotid arteries separated by 2 years were obtained" |
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| Notes |
Funding for trial: "SHEP trial was supported by contracts with the National Heart, Lung, and Blood Institute and the National Institute on Aging. Drugs were supplied by the Lemmon Co, Sellersville, Pa; Wyeth Laboratories/Ayerst Laboratories, AH Robins Co, Richmond, Va; and Stuart Pharmaceuticals, Wilmington, Del" "This ancillary study was supported by National Institutes of Health grant HL‐39871" Notable conflicts of interest of trial authors: no details given Protocol: NCT00000514 |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "screeners were randomly allocated by the coordinating centre to one of two treatment groups. Randomization was stratified by clinical centre and by anti hypertensive medication status at initial contact." |
| Allocation concealment (selection bias) | Low risk | Quote: "screeners were randomly allocated by the coordinating centre to one of two treatment groups. Randomization was stratified by clinical centre and by anti hypertensive medication status at initial contact." |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Quote: "Participants were to be randomized at each centre to either chlorthalidone or matching placebo in a double‐blind manner." |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Quote: "Scans were recorded on videotape for later scoring. A reader assigned a grade from 0 to 3 to each of seven segments in the carotid system based on the number and size of lesions present." |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | All participants apparently completed the study. No treatment withdrawals, no losses to follow‐up, no trial group changes and no major adverse events were reported |
| Selective reporting (reporting bias) | High risk | One weakness of this study is that the duplex scans were not obtained earlier in the study, before treatment. Unfortunately, the SHEP trial ended before all participants had completed their follow‐up scans. At the beginning of the study, a decision was made that progression of disease would include all areas of the carotid system, not just the ICA. Before analysis of the data, changes in the blood flow velocity and velocity ratios were used to ascertain progression |
| Other bias | Low risk | No other source of bias detected |