The clinical effectiveness of Ginger (Zingiber officinale) in adults with osteoarthritis

Background  Osteoarthritis (OA) is a degenerative joint disease, which is associated with increased pain and disability, and a simultaneous decline in the quality of life of sufferers. While there is no cure for OA, there are numerous treatments that aim to reduce sufferers' symptoms and disability, and improve their quality of life. Medications, which have long been integral interventions for the management of OA, have recently been found to cause harm in some patients. Simultaneously, the increasing recognition of complementary and alternative therapies as part of mainstream health care, has seen many sufferers of OA use these therapies. Ginger has been commonly prescribed by herbalists for sufferers of OA due to its anti-inflammatory and circulatory stimulant effects. However, to date there has been no systematic review of the literature to evaluate the clinical effectiveness of Ginger for OA. Objective  The objective of this systematic review was to evaluate the safety and effectiveness of Ginger in adults with OA. Data sources  A comprehensive search was undertaken on 18 electronic databases from their inception to January 2007, including AARP Ageline, AMED, AMI, BioMed central gateway, CAM on PubMed, CENTRAL, CINAHL, Cochrane library, Current controlled trials, Current contents connect, DARE, Dissertations Abstract International, EMBASE, Health Source Nursing/Academic edition, International Pharmaceutical Abstract, MEDLINE, Natural medicines comprehensive database and TRIP. Review methods  Randomised controlled trials or clinical controlled trials were sought, which evaluated the effectiveness of mono-preparations of ginger in adults with OA of the knee or hip. Critical appraisal of study quality was undertaken using Joanna Briggs Institute critical appraisal instruments. Data extraction was via the Joanna Briggs Institute standard data extraction form for evidence of effectiveness. Results  Five randomised controlled trials were identified from the search, of which three met the inclusion criteria. The methodological quality of the included studies was good. However, given that studies were clinically and methodologically heterogeneous, meta-analysis could not be conducted. Instead, evidence was summarised in narrative form. For changes in pain severity, studies comparing ginger extract (n = 110) to placebo (n = 111) reported mixed findings in support of the use of Ginger. Studies comparing ginger to an active control found participants who received Ibuprofen (n = 96) had a greater change in median pain intensity compared with participants who received Ginger (n = 110), and while findings were statistically significant for only one of the two studies, the results had limited clinical significance. Similarly, while two placebo-controlled studies reported differences between ginger (n = 70) and placebo (n = 71) for changes in disability and functional capacity, the difference was statistically and clinically significant for only one study. In one study comparing ginger to an active control, participants receiving Ibuprofen (n = 56) reported a statistically significant improvement in disability and functional capacity over time when compared with participants receiving Ginger (n = 56). In terms of safety, Ginger was well tolerated when compared with Ibuprofen, with infrequent reports of mild, and predominantly gastrointestinal, adverse effects. Conclusion  Current evidence is weak for the use of Ginger in adults with OA of the knee and/or hip. Much of this can be attributed to significant heterogeneity between studies. Improvements in research design, instrumentation and ginger dosage, which more closely reflect current clinical practice, may help to demonstrate the safe and effective use of Ginger in OA sufferers.