Pycnogenol for the treatment of chronic disorders : a systematic review

Schoonees, Anel (2011-03)

Thesis (MNutr)-- Stellenbosch University, 2011.

Thesis

ENGLISH ABSTRACT: Background: Oxidative stress has been implicated in the development of a number of conditions including amongst others cancer, arthritic disorders and cardiovascular disease. Pycnogenol is a herbal dietary supplement derived from French maritime pine bark extract. Pycnogenol is standardised to contain 70 ± 5% procyanidin which is a powerful antioxidant. Pycnogenol is marketed as a supplement for preventing or treating a wide range of chronic conditions. Although several randomised controlled trials of Pycnogenol have been conducted to date, this evidence has not yet been systematically reviewed. Objectives: The aim was to carry out a systematic review in order to assess the efficacy and safety of Pycnogenol for the treatment of chronic disorders. Search methods The electronic databases CENTRAL (until 18 September 2010), MEDLINE (until 18 September 2010) and EMBASE (until 13 October 2010) were searched, as well as three trial registries. Furthermore the manufacturer of Pycnogenol was contacted and bibliographies of included studies were hand-searched. Selection criteria: Randomised controlled trials (RCTs) evaluating the effectiveness of Pycnogenol in adults or children with any chronic disorder were included. The primary outcomes were any clinical outcomes directly related to the disorder (stratified as participant- and investigator-reported) as well as all-cause mortality. Adverse events and biomarkers of oxidative stress were also assessed. Data collection and analysis: Two authors independently assessed trial eligibility, extracted all data and judged methodological quality. A third author additionally extracted information on outcomes and results. With two exceptions, results for outcomes across studies could not be pooled mainly due to poor quality reporting. Study authors were contacted for additional information. Results: This review includes 15 RCTs with a total of 791 participants that have evaluated Pycnogenol for the treatment of seven different chronic disorders. The disorders included asthma (2 studies; N = 86), attention deficit hyperactivity disorder (1 study; N = 61), chronic venous insufficiency (2 studies; N = 60), diabetes mellitus (4 studies; N = 201), erectile dysfunction (1 study; N = 21), hypertension (2 studies; N = 69) and osteoarthritis of the knee (3 studies; N = 293). Two of the studies were conducted exclusively in children; the others involved adults. Due to small sample size, limited numbers of trials per condition, variation in selected outcomes and outcomes measures and the risk of bias no definitive conclusions regarding the efficacy or safety of Pycnogenol are possible. Authors’ conclusions: Current evidence is insufficient to support Pycnogenol use for the treatment of any chronic disorder. Well designed, adequately powered trials are recommended to establish the value of this treatment.

AFRIKAANSE OPSOMMING: Inleiding: Oksidatiewe stres blyk ’n rol te speel in die ontwikkeling van ’n verskeidenheid siektes onder andere kanker, artritis en kardiovaskulêre siektes. Pycnogenol, ‘n kruie-bevattende dieetaanvulling wat uit Franse denneboombas vervaardig word, is gestandaardiseer om 70 ± 5% prosianidien – ’n kragtige anti-oksidant – te bevat. Die produk word bemark om ‘n wye reeks chroniese siektes te voorkom of te behandel. Alhoewel daar tot op hede verskeie kliniese proewe op Pycnogenol uitgevoer is, is die uitkomstes nog nie met behulp van ‘n stelselmatiese oorsig geëvalueer nie. Doelwitte: Die doel van hierdie studie was om met behulp van ‘n stelselmatiese oorsig die doeltreffendheid en veiligheid van Pycnogenol ten opsigte van die behandeling van chroniese siektes te evalueer. Soektogstrategie: Die elektroniese databasisse CENTRAL (tot 18 September 2010), MEDLINE (tot 18 September 2010) en EMBASE (tot 13 Oktober 2010) is deursoek, asook drie registers met kliniese proewe. Verder is die vervaardiger van Pycnogenol gekontak en is daar met die hand deur bibliografieë van ingeslote studies gesif. Keuringskriteria: Ewekansige gekontroleerde proewe (RCT’s) is ingesluit waarin die effektiwiteit van Pycnogenol in volwassenes of kinders met enige chroniese siekte geëvalueer is. Enige kliniese uitkomste wat direk aan die chroniese siekte verwant is (gesorteer as deelnemer- of ondersoeker-gerapporteerde uitkomstes) asook mortaliteit (enige oorsake) is as die primêre uitkomstes ondersoek. Dataversameling en -ontleding: Twee navorsers het onafhanklik van mekaar proewe gekeur, alle relevante data onttrek en gehalte van die metodiek beoordeel. ‘n Derde navorser het die resultate van die uitkomstes bykomend onttrek. Met twee uitsonderings, kon resultate van uitkomstes van die verskillende ingeslote studies kon nie statisties saamgevoeg word nie, hoofsaaklik as gevolg van swak rapportering. Skrywers van die ingeslote studies is in verband met die verlangde inligting gekontak. Resultate: Vyftien RCT’s met ‘n totaal van 791 deelnemers is ingesluit. In hierdie studies is Pycnogenol vir die behandeling van sewe verskillende chroniese siektes geëvalueer: asma (2 studies; N = 86), aandagafleibaarheid-hiperaktiwiteitsgebreksindroom (1 studie; N = 61), chroniese veneuse ontoereikendheid (2 studies; N = 60), diabetes mellitus (4 studies; N = 201), erektiele disfunksie (1 studie; N = 21), hipertensie (2 studies; N = 69) en osteo-artritis van die knie (3 studies; N = 293). Twee van hierdie studies is uitsluitlik met kinders gedoen; die res was volwassenes. As gevolg van klein steekproewe, ‘n beperkte aantal studies per siekte, wisseling in uitkomstes en die risiko vir sydigheid kan geen definitiewe gevolgtrekking oor die doeltreffendheid en veiligheid van Pycnogenol gemaak word nie. Skrywers se gevolgtrekking: Tans is daar nie voldoende wetenskaplike bewyse om Pycnogenol-gebruik vir die behandeling van enige chroniese siekte aan te beveel nie. Goed ontwerpte proewe met ‘n voldoende aantal deelnemers word aanbeveel om die waarde van hierdie behandeling onomwonde vas te stel.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/6882
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