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Lookup NU author(s): Dr Heather Dickinson, Donald Nicolson, Dr Fiona CampbellORCiD, Professor James Mason
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
Objective: To inform a national guideline development group about the effectiveness of nutritional supplements to reduce hypertension. Methods: RCTs of parallel and crossover design were included, comparing potassium, calcium or magnesium supplements with placebo or no treatment. Participants had blood pressure ≥140/85 mm Hg and ≥8 weeks follow-up. Relevant studies were identified from existing systematic reviews and by searching electronic databases from 1998 onwards. Meta-analyses estimated weighted mean differences using a random effects model. Results: We found 23 studies (12 parallel and 11 crossover) of 1,126 patients (769 and 357 respectively). Crossover trials rarely reported the variance of the crossover treatment effect. We investigated various solutions: stochastic and deterministic imputation of this variance, use only of first periods of crossover trials, or exclusion of such trials. Conclusions: Omission of crossover trials from meta-analyses is a poor use of available evidence. However, choice of method of inclusion did not materially affect the conclusions. There was no evidence that these nutritional supplements reduced blood pressure.
Author(s): Dickinson H, Nicolson DJ, Campbell F, Mason J
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: XI Cochrane Colloquium: Evidence, Health Care and Culture
Year of Conference: 2003
