Artemisia Annua (Sweet Wormwood) and Artemisinin

Our assessments of evidence for each medical benefit fall into one of these categories:

• Strong evidence: consistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analysesa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results
• Good evidence: significant effects in one large or several mid-sized and well-designed clinical studies ( randomized controlled trialsa study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects with an appropriate placebo or other strong comparison control or observational studies that control for confounds)
• Modest evidence: significant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods studies), or several small studies aggregated into a meta-analysis
• Preliminary evidence: significant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect
• Weak evidence: one or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects
• Insufficient evidence: preclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example)

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• Lower measures of pain, higher withdrawal rate of corticosteroids within 12 weeks and lower incidence rate of adverse effects among people with active rheumatoid arthritis medicated with leflunomide and methotrexate and treated with extract of Artemisia annua L. compared to leflunomide and methotrexate alone in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects³Yang M, Guo MY et al. Effect of Artemisia annua extract on treating active rheumatoid arthritis: a randomized controlled trial. Chinese Journal of Integrative Medicine. 2017 Jul;23(7):496-503.
• Lower measures of stiffness, physical function, and pain among people with osteoarthritis of the hip or knee treated with 150 mg Artemisia annua extract twice a day for 12 weeks compared to baseline, but only a weak trendan apparent change due to a therapy, close to but not achieving full statistical significance (this is the CancerChoices definition; other researchers and studies may define this differently among people treated with placebo and no evidence of an effect among people treated with 300 mg Artemisia annua extract in a small RCT;⁴Stebbings S, Beattie E, McNamara D, Hunt S. A pilot randomized, placebo-controlled clinical trial to investigate the efficacy and safety of an extract of Artemisia annua administered over 12 weeks, for managing pain, stiffness, and functional limitation associated with osteoarthritis of the hip and knee. Clinical Rheumatology. 2016 Jul;35(7):1829-36. these improvements in osteoarthritis symptoms were maintained among people continuing treatment for 6 months⁵Hunt S, Stebbings S, McNamara D. An open-label six-month extension study to investigate the safety and efficacy of an extract of Artemisia annua for managing pain, stiffness and functional limitation associated with osteoarthritis of the hip and knee. New Zealand Medical Journal. 2016 Oct 28;129(1444):97-102.