| Study characteristics |
| Methods |
|
| Participants |
Country: Israel Setting: single centre; workplace at a research centre with an on‐site medical clinic Inclusion criteria: adults aged 45 to 65 years with BMI ≥ 27 kg/m² or type 2 diabetes or coronary heart disease -
Number: 99/318 of study participants met inclusion criteria
Mean age ± SD (years): not available for subgroups Sex (M/F): not available for subgroups -
Baseline characteristics
Nationality: not reported Ethnicity: not reported Mean baseline BMI ± SD (kg/m²): low fat diet group (30.6 ± 3.2); Mediterranean diet group (31.2 ± 4.1); low carbohydrate diet group (30.8 ± 3.5) Stage of CKD: subgroup participants with an eGFR 30 to 60 mL/min/1.73 m²were included in this review Mean baseline eGFR ± SD (mL/min/1.73 m²): not available for subgroups Mean baseline energy intake ± SD (kcal/day): not available for sub‐groups Mean baseline SBP ± SD (mmHg): low fat diet group (130.2 ± 12.7); Mediterranean diet group (131.4 ± 14.7); low carbohydrate diet group (133.4 ± 15.0) Mean baseline DBP ± SD (mmHg): low fat diet group (76.8 ± 9.8); Mediterranean diet group (80.2 ± 8.2); low carbohydrate diet group (80.2 ± 6.9) Mean baseline energy intake (kcal/kg/day): not reported Comorbid conditions: type 2 diabetes; coronary heart disease; hypertension
Exclusion criteria: pregnant or lactating women; a SCr > 176 µmol/L (2 mg/dL); liver dysfunction (twofold or higher of the upper limit of normal in ALT or AST); intestinal problems that would prevent adherence to any of the diets; active cancer |
| Interventions |
Intervention group 1 (low fat, restricted energy)
Based on American Heart Association guidelines. Daily energy intake of 1500 kcal for women and 1800 kcal for men, 30% from fat, 10% from saturated fat and an intake of 200 mg of cholesterol per day. Participants were educated at group sessions to consume low fat grains, vegetable, fruits, and legumes and limit their intake of additional fats, sweets, and high fat snacks. Dietitians led groups of 17 to 19 patients for dietary sessions. Group education sessions were held at week 1, 3, 5, 7 and thereafter every 6 weeks for a total of 18 group sessions A further 6 individual phone calls 10 to 15 minutes were made by a different dietitian to assist struggling individuals with motivation. A group of spouses also received education to strengthen their support to participants
Intervention group 2: (Mediterranean restricted energy)
Moderate fat, Mediterranean restricted energy daily to 1500 kcal for women and 1800 kcal for men, goal no more than 35% of energy from fat, main sources of fat were 30 g to 45g of olive oil and a handful of nuts per day Dietitians led groups of 17 to 19 patients for dietary sessions. Week 1, 3, 5, 7 and thereafter every 6 weeks a total of 18 group sessions ‐ were educated to eat diet rich in vegetables, low in red meat, fish, and poultry to replace beef and lamb A further 6 individual phone calls 10 to 15 minutes were made by a different dietitian to assist struggling individuals with motivation. A group of spouses also received education to strengthen their support to participants
Intervention group 3 (low carbohydrate, non‐restricted energy)
Advised to consume 20 g of carbohydrate per day for the 2‐month induction phase gradual increase to a max of 120 g/day ‐ the intake of total energy, protein, and fat were not limited. The patients were counselled to choose vegetarian sources of fat and protein, and to avoid trans‐fat. Diet was based on the Atkins diet Dietitians led groups of 17 to 19 patients for dietary sessions. Week 1, 3, 5, 7 and thereafter every 6 weeks a total of 18 group sessions A further 6 individual phone calls 10 to 15 minutes were made by a different dietitian to assist struggling individuals with motivation. A group of spouses also received education to strengthen their support to participants
Co‐interventions
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| Outcomes |
Body weight (kg) BMI (kg/m²) Waist circumference (cm) Albuminuria (mg/L) (data not available for subgroup) SBP (mmHg) DBP (mmHg) Anti‐hypertensive medication changes (data not available for subgroup) Hypoglycaemic medication changes (data not available for subgroup) Fasting blood glucose (mmol/L) Total cholesterol (mmol/L) LDL cholesterol (mmol/L) HDL cholesterol (mmol/L) Triglycerides (mmol/L) Lipid lowering medication changes (data not available for sub‐study) Inflammation: C‐reactive protein (data not available for sub‐study) Adherence to treatment (data not available for sub‐study) |
| Notes |
Founding source: Israeli Ministry of Health, Chief Scientist Office (Project No. 300000‐4850) and The Dr. Robert C. and Veronica Atkins Research Foundation Trial registration: ClinicalTrials.gov No. NCT00160108 Additional data: requested ‐ See Appendix 3 Possible conflicts of interest for study author: none declared |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Participants were randomised by strata of sex, age, BMI, history of coronary heart disease, type 2 diabetes, and current use of statins |
| Allocation concealment (selection bias) |
Unclear risk |
Insufficient information about the sequence generation process to permit judgment |
| Blinding of participants and personnel (performance bias)
All outcomes |
High risk |
Masking of patients or study personnel not reported in the study report. Participants were randomised to either one of three different dietary groups. Therefore, participants and investigators (dietitians) were unlikely to be blinded to treatment allocation |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Quote: "The clinic and laboratory staff members were unaware of the treatment assignments and the study coordinators were unaware of all outcome data until the end of the intervention" |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Low and balanced attrition rates across each groups with similar reasons for withdrawal |
| Selective reporting (reporting bias) |
Low risk |
Authors appear to report on what they intended to report on as described in the study aims |
| Other bias |
High risk |
Post hoc reporting of sub‐groups with CKD stages 3 to 4 |
