Wilhelmsen 1986.
| Methods |
Design: RCT Setting: Participants selected from all men living in Gothenburg, Sweden, and born either between 1915 ‐ 1922 or 1924 ‐ 1925, age 47 ‐ 55 years at start of study Dates: Initial screening done 1970 ‐ 1973; 2nd screening (At 4 years) done 1974 ‐ 1977; final examination (10 year) done 1980 ‐ 1983 Follow‐up: 2nd examination after 4 years for all of intervention group (n = 7517) and 11% random sample of control group 1 (n = 826) Final assessment at 10 years, new 20% random samples of intervention were invited. Of these, 1473 in intervention group and 1404 in control group 1 participated. |
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| Participants | N randomised 30,022 Intervention n = 10,004 Control 1 n = 10,011 Control 2 n = 10,007 Healthy. No data given on the prevalence of underlying CVD. % on antihypertensive treatment (from those who were screened in intervention group and control group 1): 5.9% (total for both groups) Of those in the intervention group, those with risk factors were allotted to mutually exclusive intervention groups (even though risk factors may have coexisted): Hypertension 980 (13%) Hypercholesterolemia 694 (9.2%) Smoking ≥ 15 cigarettes a day 1086 (14.4%) Total 2760 (36.6%) % men: 100% |
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| Interventions |
Setting: 'Screening centre' Intervention: ‐ Postal questionnaire: family Hx of heart disease/stroke, participant’s cardiac symptoms, known hypertension, smoking, physical activity, stress ‐ Screening examination at baseline: weight, height, total serum cholesterol, BP, ECG, “some interview responses” ‐Treatment of the risk factors of elevated cholesterol, elevated BP and smoking where relevant ‐ BP intervention (for BP ≥ 175/115 mmHg): referred to specialist clinic (for borderline high BP (160 ‐ 174 SBP, 95 ‐ 114 DBP), participants had regular BP checks) ‐ Cholesterol intervention (> 7.8 mmol/l): diet information from dietician/physician, booklets. Clofibrate/nicotinic acid given if cholesterol remained elevated after 6 months. Men with cholesterol values at screening 6.8 ‐ 7.7 mmol/l invited to group meetings together with wives, same material used. Those with values < 6.8 mmol/l received written information but no other action ‐ Smoking interventions: for ≥ 15/day smokers, invited to anti‐smoking clinic and nicotine gum. Other smokers given written information on smoking cessation ‐ Rescreening at 4 years ‐ Final screening in subgroup (20%) at 10 years Control group 1: No intervention. 2% of control group 1 had postal questionnaire and screening examination with no follow‐up, 11% had 2nd screening at 4 years, and 20% had the final exam at 10 years Control group 2: none of the 2nd control group had the initial screening/2nd screening/final exam |
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| Outcomes | Total mortality, stroke, MI, BP, attendance rates, case‐finding rates | |
| Notes | "F/U complete for all subjects included" for the endpoints of the study (Fatal and non‐fatal CHD and stroke, cancer deaths, other deaths, and total mortality), but not all those who were invited for screening attended. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Not reported |
| Allocation concealment (selection bias) | Unclear risk | Not reported |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Not reported |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Not reported, but outcomes objective so low risk of bias |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Reported proportion invited for assessment at 4 and 20 years, but numbers declining invitation not clear |
| Selective reporting (reporting bias) | High risk | No measures of variance reported, baselines not reported for intervention group and control group 1 separately, Numbers unclear |
| Other bias | Unclear risk | Unclear |
BMI: body mass index CABG: coronary artery bypass graft CCF: congestive cardiac failure CHD: congenital heart disease CHF: congestive heart failure DBP: diastolic blood pressure DM: diabetes mellitus ECG: electrocardiograph HTN: hypertension Hx: history IHD: ischaemic heart disease MI: myocardial infarction SBP: systolic blood pressure SEM: standardised error of the mean