Croft 1986.

Methods	DESIGN: parallel, randomised, no information on blinding DURATION: 6 months NUMBER OF STUDY CENTRES: 1 COUNTRY OF PUBLICATION: UK SPONSOR: West Midlands Regional Research Committee; UK
Participants	WHO PARTICIPATED: newly diagnosed hypertensive and obese patients SETTING: outpatient clinic (1 urban group practice) MAIN INCLUSION CRITERIA: age between 35 and 60 years; BMI > 25 kg/m2; SBP > 140 mm Hg or DBP > 90 mm Hg, or both, in 3 measurements MAIN EXCLUSION CRITERIA: SBP > 200 mm Hg; DBP > 114 mm Hg; previous antihypertensive medication; myocardial infarction or stroke within the previous 3 months; concurrent serious disease, conditions requiring diets, or medication likely to influence weight or blood pressure NUMBER: 66 vs 64 were randomised, 66 vs 64 (last observation carried forward analysis)/47 vs 50 were analysed per protocol (dietary intervention vs no dietary intervention) GENERAL BASELINE CHARACTERISTICS (dietary intervention vs no dietary intervention): AGE [YEARS]: range 35 to 60 GENDER [% MALE]: 44 vs 61 NATIONALITY: ‐ ETHNICITY: ‐ WEIGHT [kg]: 87 vs 82 BODY MASS INDEX [kg/m2]: ‐ SYSTOLIC BLOOD PRESSURE [mm Hg]: 161 vs 161  DIASTOLIC BLOOD PRESSURE [mm Hg]: 98 vs 96  COMORBID CONDITIONS: obesity ANTIHYPERTENSIVE TREATMENT: ‐ DURATION OF HYPERTENSION: newly diagnosed patients SUBGROUP ANALYSES: ‐
Interventions	LENGTH OF FOLLOW‐UP: 6 months DIETARY INTERVENTION: active dietary advice for weight reduction by 2 experienced dietitians emphasising the importance of weight reduction for blood pressure control NO DIETARY INTERVENTION: visits at general practitioners, no active dietary advice; if participants indicated that they intended to lose weight, they were not discouraged but were given no specific advice or diet sheets ADDITIONAL TREATMENT: advice about modest restriction of salt use and reduction of excessive alcohol intake
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: body weight change from baseline to endpoint visit ADDITIONAL OUTCOMES MEASURED IN THE STUDY: 1. Start of antihypertensive medication
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: No details on generation sequence are provided
Allocation concealment (selection bias)	Unclear risk	Comment: Method of concealment is not described
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Quote: "... (using random number tables) ..." Comment: as described for normotensive participants only; no information on blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "... The data was submitted to an 'intention to treat' analysis which included all entrants and assumed that no further change in weight or blood pressure occurred for drop‐outs after the last occasion on which they attended." In addition an "outcome of continued attendance" analysis was used, which compared only those participants still attending after 6 months WITHDRAWALS (dietary intervention vs no dietary intervention): 17 vs 3 REASONS/DESCRIPTIONS (dietary intervention vs no dietary intervention): ‐
Selective reporting (reporting bias)	Unclear risk	Comment: No primary and secondary outcomes were defined
Other bias	High risk	Comments: 1. Lack of information on randomisation and concealment of allocation increases risk of bias even using the LOCF analysis 2. There was no information on reasons for and description of dropouts