Annals of Internal Medicine Annals of Internal Medicine is published by the American College of Physicians. These highlights are not intended to substitute for articles as sources of information. For an embargoed copy of an article, call 1-800-523-1546, ext. 2656, or 215-351-2656.
(NOTE: This article and accompanying editorial appear early online at the Web site of Annals of Internal Medicine, www/annals.org on Monday, June 18 after 5 p.m. ET. They will appear in the August 21 print edition of the journal. The article is the subject of a video news release. Call for coordinates. A separate news release will be issued.)
In a randomized placebo-controlled trial involving 389 women with osteopenia, those who took 54 mg/d of genistein, a phytoestrogen derived from soy products, had greater bone mineral density and improved markers of bone metabolism after two years than women who took a pill containing only calcium and vitamin D (Article, p.839). Osteopenia (diminished amount of bone but not as severe as osteoporosis) is common among women after menopause. The most serious consequences of low bone density are bone fractures. Those who took the genistein pills did not have increased endometrial thickness, a problem with some hormone treatments for low bone density. The genistein group had more gastrointestinal side effects than the control group.
(Review, p. 868)
(Article, p. 848; Editorial, p. 891)
The authors of one article on this subject say that stopping randomized trials early because of apparent benefit raises “serious ethical problems” because truncated trials systematically overestimate treatment effects. This problem is especially severe when the number of outcome events is small, the writers say (Perspective, p. 878). The author of the other article disagrees, saying that the primary purpose of a clinical trial is not to get an accurate assessment of the risk and benefits associated with a given treatment. It is “to decide which treatment is more efficacious, with statistical control over how often false-positives and false-negatives are made” (Review, p. 882). This writer says that randomized controlled trials and data monitoring committees “must balance many competing and worthwhile medical, statistical, ethical and social goals.”