Meta-Analysis of Horse Chestnut Studies for CVI
Conservative therapy of chronic venous insufficiency (CVI) consists largely of compression treatment. However, this often causes discomfort and has been associated with poor compliance. Therefore, oral drug treatment is an attractive option.
To review the efficacy and safety of oral horse chestnut seed extract (HCSE) versus placebo, or reference therapy, for the treatment of CVI.
We searched the Cochrane Peripheral Vascular Diseases Review Group's Specialised Register (last searched February 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library Issue 1, 2007, MEDLINE (January 1966 to February 2007), EMBASE (January 1980 to February 2007), Allied and Complementary Medicine (AMED) (inception to July 2005) and Phytobase (inception to January 2001) for randomised controlled trials (RCTs) of HCSE for chronic venous insufficiency. Manufacturers of HCSE preparations and experts on the subject were contacted for published and unpublished material. There were no restrictions on language.
RCTs were included if they compared oral HCSE mono-preparations with placebo, or reference therapy, in people with CVI. Trials assessing HCSE as one of several active components in a combination preparation, or as a part of a combination treatment, were excluded.
Data collection and analysis
Both authors independently selected the studies and, using a standard scoring system, assessed methodological quality and extracted data. Disagreements concerning evaluation of individual trials were resolved through discussion.
Overall, there appeared to be an improvement in CVI related signs and symptoms with HCSE compared with placebo. Leg pain was assessed in seven placebo-controlled trials. Six reported a significant reduction of leg pain in the HCSE groups compared with the placebo groups, while another reported a statistically significant improvement compared with baseline. One trial suggested a weighted mean difference (WMD) of 42.4 mm (95% confidence interval (CI) 34.9 to 49.9) measured on a 100 mm visual analogue scale. Leg volume was assessed in seven placebo-controlled trials. Meta-analysis of six trials (n = 502) suggested a WMD of 32.1ml (95% CI 13.49 to 50.72) in favour of HCSE compared with placebo. One trial indicated that HCSE may be as effective as treatment with compression stockings. Adverse events were usually mild and infrequent.
The evidence presented implies that HCSE is an efficacious and safe short-term treatment for CVI. However, several caveats exist and more rigorous RCTs are required to confirm the efficacy of this treatment option.
Plain language summary
Horse chestnut seed extract for long-term or chronic venous insufficiency
Poor blood flow in the veins of the legs, known as chronic venous insufficiency, is a common health problem, particularly with ageing. It can cause leg pain, swelling (oedema), itchiness (pruritus) and tenseness as well as hardening of the skin (dermatosclerosis) and fatigue. Wearing compression stockings or socks helps but people may find them uncomfortable and do not always wear them. A seed extract of horse chestnut (Aesculus hippocastanum L.) is an herbal remedy used for venous insufficiency. Seventeen randomized controlled trials were included in the review. In all trials the extract was standardised to escin, which is the main active constituent of horse chestnut seed extract.
Overall, the trials suggested an improvement in the symptoms of leg pain, oedema and pruritus with horse chestnut seed extract when taken as capsules over 2 to 16 weeks. Six placebo-controlled studies (543 participants) reported a clear reduction of leg pain when the herbal extract was compared with placebo. Similar results were reported for oedema, leg volume, leg circumference and pruritis. The other studies which compared the extract with rutosides (four trials), pycnogenol (one trial) or compression stockings (two trials) reported no significant differences between the therapies for leg pain or a symptom score that included leg pain. The herbal extract was equivalent to rutosides, pycnogenol and compression on the other symptoms with the exception that it was inferior to pycnogenol on oedema.
Pittler MH, Ernst E.
Horse chestnut seed extract for chronic venous insufficiency.
Cochrane Database Syst Rev.
Peninsula Medical School, Universities of Exeter and Plymouth, Complementary Medicine, 25 Victoria Park Road, Exeter, Devon, UK, EX2 4NT.