J Kleijnen1, D Mackerras. 1. NHS Centre for Reviews and Dissemination, University of York, Heslington, York, North Yorkshire, UK, YO10 5DD. jk13@york.ac.uk
Abstract
BACKGROUND: It is thought that vitamin E may improve tolerance to intermittent claudication (i.e. pain caused by ischaemia in the muscles of the leg during exercise), thereby relieving the pain, through a variety of mechanisms. OBJECTIVES: The objective of this review was to determine the effects of vitamin E on people with intermittent claudication. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group trials register, reference lists of relevant articles and a library specialising in literature on vitamins. SELECTION CRITERIA: Controlled trials comparing vitamin E with placebo, or other interventions, in patients with intermittent claudication. DATA COLLECTION AND ANALYSIS: Both reviewers extracted data and assessed study quality independently. MAIN RESULTS: Five eligible studies were found with a total of 265, predominantly male, participants. The average age was 57 years. The follow-up varied from 12 weeks to 18 months. The trials were small and generally of poor quality. The people studied were reasonably homogeneous but five different doses of vitamin E were used and four different physical outcomes were measured. No trials were identified that compared vitamin E with treatments other than placebo. All trials showed positive effects on one of their main outcomes. No serious adverse effects of vitamin E were reported. Two trials that lasted approximately eight months and used similar doses reported patients' subjective evaluation of the treatment. The relative risk for the combined results of these two trials using a random effects model was 0.57 with a 95% confidence interval of 0.28 to 1.15. REVIEWER'S CONCLUSIONS: While vitamin E - which is inexpensive and has had no serious side effects reported with its use - may have beneficial effects, there is insufficient evidence to determine whether it is an effective treatment for intermittent claudication.
BACKGROUND: It is thought that vitamin E may improve tolerance to intermittent claudication (i.e. pain caused by ischaemia in the muscles of the leg during exercise), thereby relieving the pain, through a variety of mechanisms. OBJECTIVES: The objective of this review was to determine the effects of vitamin E on people with intermittent claudication. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group trials register, reference lists of relevant articles and a library specialising in literature on vitamins. SELECTION CRITERIA: Controlled trials comparing vitamin E with placebo, or other interventions, in patients with intermittent claudication. DATA COLLECTION AND ANALYSIS: Both reviewers extracted data and assessed study quality independently. MAIN RESULTS: Five eligible studies were found with a total of 265, predominantly male, participants. The average age was 57 years. The follow-up varied from 12 weeks to 18 months. The trials were small and generally of poor quality. The people studied were reasonably homogeneous but five different doses of vitamin E were used and four different physical outcomes were measured. No trials were identified that compared vitamin E with treatments other than placebo. All trials showed positive effects on one of their main outcomes. No serious adverse effects of vitamin E were reported. Two trials that lasted approximately eight months and used similar doses reported patients' subjective evaluation of the treatment. The relative risk for the combined results of these two trials using a random effects model was 0.57 with a 95% confidence interval of 0.28 to 1.15. REVIEWER'S CONCLUSIONS: While vitamin E - which is inexpensive and has had no serious side effects reported with its use - may have beneficial effects, there is insufficient evidence to determine whether it is an effective treatment for intermittent claudication.
Authors: Aurelio Perez-Favila; Margarita L Martinez-Fierro; Jessica G Rodriguez-Lazalde; Miguel A Cid-Baez; Michelle de J Zamudio-Osuna; Ma Del Rosario Martinez-Blanco; Fabiana E Mollinedo-Montaño; Iram P Rodriguez-Sanchez; Rodrigo Castañeda-Miranda; Idalia Garza-Veloz Journal: Medicina (Kaunas) Date: 2019-10-25 Impact factor: 2.430