Inter99 2014.
| Methods |
Design: RCT Setting: Suburbs of Copenhagen, Denmark. People identified in the civil registration system, selecting all people born in 1939 ‐ 40, 1944 ‐ 45, 1949 ‐ 50, 1954 ‐ 55, 1959 ‐ 60, 1964 ‐ 65, 1969 ‐ 70 Dates: Participants identified December 1998; Baseline examination March 1999 to Jan 2001; Final follow‐up: January 2011 Follow‐up: 10 years |
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| Participants | N randomised: 59,993 337 excluded post‐randomisation (reasons given) Study population: 59,616 Intervention n = 11,629 Control n = 47,987 Mainly healthy. 1308 in total had IHD before study start (excluded from IHD/combined outcome) 676 had stroke before study start (excluded from stroke/combined outcome). Age 30 ‐ 60 years included % men: 49.9% intervention, 49.1% control High 10‐year risk of IHD: 60% |
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| Interventions |
Setting: The Research Centre for Prevention and Health (an independent research institute in Denmark) Intervention: Intervention: Screened with a comprehensive questionnaire (lifestyle, motivation to change lifestyle, symptoms, medical Hx, family Hx, psychosocial factors), physical measurements (ECG, BP, height, weight, waist/hip circumference, spirometry), bloods (total cholesterol, total lipid profile), oral glucose tolerance test. A 10‐year risk of IHD calculated using the PRECARD programme (now registered as HeartScore), with “at‐risk” people defined as being in the upper 5th quintile of risk; or if smokers, SBP > 160 mmHg, on anti‐hypertensive treatment, total cholesterol > 7.5 mmol/l, having lipid‐lowering drugs, BMI > 30, Hx DM or IHD, or impaired glucose intolerance/DM on oral glucose tolerance test. Each person was simulated in the computer programme as 60 years old to reach a substantial level of risk. Based on risk, each intervention pt had lifestyle counselling session (15 ‐ 45 minutes), written material (on physical activity, smoking, diet, alcohol as relevant). High‐risk participants offered 6 counselling sessions over 4 ‐ 6 months (e.g. smoking cessation, diet, physical activity). High‐risk participants were given a letter for their GP with results from the examinations, and re‐invited at 1 and 3 years for repeat screening, risk assessment ad lifestyle counselling as above. Low‐risk participants only got a questionnaire. At 5 years, all intervention group were re‐invited for final screening, counselling and plan for maintenance. Control group: Not invited for screening |
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| Outcomes | IHD, stroke, mortality (combined event (IHD, stroke or both), attendance rates, case‐finding rates | |
| Notes | Intervention: 6091 of intervention group examined at baseline (617 did not attend screening, 47.6% loss) 4028 participated at 5‐year screening (of 6091 who did baseline screening) = 2063 (34%) loss for this intervention |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Computer‐generated, different randomisation ratios in different age/sex groups |
| 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 | Used unique identifiers to extract data |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Numbers lost to follow‐up low |
| Selective reporting (reporting bias) | High risk | The numbers without IHD and/or stroke at baseline not reported. Limited data reported |
| Other bias | Unclear risk | Unclear |