ODES 1995.
| Methods | DESIGN: parallel, 2x2 factorial, randomised, open design DURATION: 12 months NUMBER OF STUDY CENTRES: unclear (probably 1, because all eligible participants were screened at the Ullevaal Hospital, Oslo) COUNTRY OF PUBLICATION: Norway SPONSOR: supported by grant from the Research Council of Norway, the Norwegian Council of Cardiovascular Diseases, and the insurance company Vital Friskvern | |
| Participants | WHO PARTICIPATED: men and women ≥ 40 years old from screening programme for cardiovascular risk factors in Oslo (Norway) since 1981;
participants were post‐hoc divided in tertiles according to DBP (tertile 1 DBP > 91 mm Hg, tertile 2 DBP 84 to 91 mm Hg, tertile 3 DBP < 84 mm Hg); only subgroups of tertile 1 (DBP > 91 mm Hg) will be reported here
SETTING: outpatient clinic MAIN INCLUSION CRITERIA: all criteria had to be fulfilled simultaneously (based on the screening performed 1 to 10 years before baseline examination): age 41 to 50 years + physical inactivity as measured by questionnaire (exercising at most once per week) + BMI > 24 kg/m2 + DBP 86 to 99 mm Hg + total serum cholesterol 5.20 to 7.74 mmol/l + HDL cholesterol < 1.20 mmol/l, fasting serum triglycerides > 1.4 mmol/l MAIN EXCLUSION CRITERIA: overt cardiovascular disease, diabetes, treatment with antihypertensive drugs or acetylsalicylic acid, lipid‐lowering diet No exercise subgroup (dietary intervention vs no dietary intervention) NUMBER: 55 vs 43 participants were randomised, 16 vs 12 participants with complete data were post‐hoc allocated to tertile 1 and analysed GENERAL BASELINE CHARACTERISTICS TERTILE 1 (dietary intervention vs no dietary intervention): MEAN AGE [YEARS]: ‐ GENDER [% MALE]: ‐ NATIONALITY: Norwegian ETHNICITY: ‐ WEIGHT [kg]: ‐ BODY MASS INDEX [kg/m2]: 30 vs 30 SITTING SYSTOLIC BLOOD PRESSURE [mm Hg]: 145 vs 138 SITTING DIASTOLIC BLOOD PRESSURE [mm Hg]: 97 vs 96 COMORBID CONDITIONS: ‐ ANTIHYPERTENSIVE TREATMENT: 0 vs 0 (exclusion criteria) DURATION OF HYPERTENSION: ‐ Exercise subgroup (exercise + dietary intervention vs exercise + no dietary intervention) NUMBER: 67 vs 54 participants were randomised, 24 vs 20 participants with complete data were post‐hoc allocated to tertile 1 and analysed GENERAL BASELINE CHARACTERISTICS TERTILE 1 (exercise + dietary intervention vs exercise + no dietary intervention): MEAN AGE [YEARS]: ‐ GENDER [% MALE]: ‐ NATIONALITY: Norwegian ETHNICITY: ‐ WEIGHT [kg]: ‐ BODY MASS INDEX [kg/m2]: 30 vs 30 SITTING SYSTOLIC BLOOD PRESSURE [mm Hg]: 143 vs 140 SITTING DIASTOLIC BLOOD PRESSURE [mm Hg]: 97 vs 96 COMORBID CONDITIONS: ‐ ANTIHYPERTENSIVE TREATMENT: 0 vs 0 (exclusion criteria) DURATION OF HYPERTENSION: ‐ SUBGROUP ANALYSES: ‐ |
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| Interventions | LENGTH OF FOLLOW‐UP: 12 months No exercise subgroup: DIETARY INTERVENTION: individual dietary counselling for each participant together with participant's spouse; main emphasis was a low‐calorie diet and a substantial increase in the intake of fish and fish products, an increase in the consumption of vegetables and fibre‐rich products of complex carbohydrates, and a reduction in intake of sugar and saturated fat; target body weight reduction was agreed upon, usually 0.5 to 1 kg monthly according to Anderssen 1995 and 0.5 to 2 kg according to the design paper Urdal 1993; hypertensive participants were also advised to reduce salt intake Follow‐up of dietary habits took place at months 3 and 9 NO DIETARY INTERVENTION: no dietary counselling, no change in lifestyle Exercise subgroup: DIETARY INTERVENTION + EXERCISE: individual counselling as mentioned above as well as additional supervised aerobic exercise program consisting of circuit training and jogging for 1 hour 3 times a week NO DIETARY INTERVENTION + EXERCISE: no dietary counselling but same exercise program as mentioned above ADDITIONAL TREATMENT: all participants were advised against smoking |
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| Outcomes |
PRIMARY OUTCOMES:
1. MORTALITY: ‐
2. CARDIOVASCULAR MORBIDITY: ‐
3. ADVERSE EVENTS: ‐ SECONDARY OUTCOMES: 1. CHANGES IN SYSTOLIC BLOOD PRESSURE [mm Hg]: Definition: SBP change from baseline to endpoint visit 2. CHANGES IN DIASTOLIC BLOOD PRESSURE [mm Hg]: Definition: DBP change from baseline to endpoint visit 3. BODY WEIGHT [kg]: Definition: changes in BMI from baseline to endpoint visit ADDITIONAL OUTCOMES MEASURED IN THE STUDY: 1. Effect on haemostatic variables (primary study endpoint) |
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| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "Each participant has a 25% chance of being allocated to each of the four treatment groups. The list is not blocked in any way, but randomization is stratified by sex." |
| Allocation concealment (selection bias) | Unclear risk | Quote: "A sealed envelope is opened, revealing the randomization number and the name of the group to which the participant has been allocated." No information about numbered or opaque envelopes |
| Blinding (performance bias and detection bias) All outcomes | High risk | Quote: "Unmasked, but blinded objective blood analyses" |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Not reported for the hypertensive subgroup (tertile 1) WITHDRAWALS (only for the whole study population of normo‐ and hypertensives): No exercise subgroup (dietary intervention vs no dietary intervention): 3 vs 0 Exercise subgroup (dietary intervention vs no dietary intervention): 2 vs 5 REASONS/DESCRIPTIONS: 10 total dropouts in 3 groups (diet, exercise, and combined)
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| Selective reporting (reporting bias) | High risk | Comment: Post‐hoc analyses of blood pressure; not all predefined outcomes are reported for each tertile (e.g. quality of life) |
| Other bias | High risk | Comment: 1. Final analysis NOT done according to the intention‐to‐treat‐principle, also it was initially planned 2. Multiple testing was done without adjustment (e.g. Bonferroni correction) 3. Hypertensive participants in dietary‐intervention group advised to reduce salt intake (intervention bias) 4. Tertile 3 was defined as DBP < 84 mm Hg, whereas inclusion criteria was DBP > 86 mm Hg. In total, 68 participants (31%) were analysed in tertile 3! |