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Health and medicine

Yes, that's good for you - except for when it turns out to be bad

CHICAGO - Here's some medical news you can trust: A new study confirms that what doctors once said was good for you often turns out to be bad - or at least not as great as initially thought.

The report is a review of major studies published in three influential medical journals between 1990 and 2003, including 45 highly publicized studies that initially claimed a drug or other treatment worked.

Subsequent research contradicted results of seven studies - 16 percent - and reported weaker results for seven others, an additional 16 percent. That means nearly one-third of the original results did not hold up, according to the study in today's Journal of the American Medical Association.

"Contradicted and potentially exaggerated findings are not uncommon in the most visible and most influential original clinical research," said the study author, Dr. John Ioannidis, a researcher at the University of Ioannina in Greece.

Experts say the study is a reminder to doctors and patients that they should be cautious about study results and understand that treatments often become obsolete with medical advances.

"A single study is not the final word, and that is an important message," editors at the New England Journal of Medicine said in a statement about the study.

The refuted studies dealt with a wide range of drugs and treatments. Hormone pills were once thought to protect menopausal women from heart disease but later were shown to do the opposite. Contrary to initial results, Vitamin E pills have not been shown to prevent heart attacks.

Contradictions also included a study that found nitric oxide does not improve survival in patients with respiratory failure, despite earlier claims. And a study suggested that an antibody treatment did not improve survival in certain sepsis patients; a smaller previous study found the opposite.

Ioannidis acknowledged an important but not very reassuring caveat: "There's no proof that the subsequent studies ... were necessarily correct." But he noted that in all 14 cases in which results were contradicted or softened, the subsequent studies were either larger or better designed. Also, none of the contradicted treatments is currently recommended by medical guidelines.

Ioannidis' study examined research in the New England Journal of Medicine, Lancet and JAMA - prominent journals whose weekly studies help feed a growing public appetite for medical news.

Not by accident, this week's JAMA also includes a study contradicting previous thinking that stomach-lying helped improve breathing in children hospitalized with acute lung injuries. The new study found they did no better than patients lying on their backs.

Ioannidis said scientists and editors should avoid "giving selective attention only to the most promising or exciting results" and should make the public more aware of the limitations of science.

"The general public should not panic" about refuted studies, he said. "We all need to start thinking more critically."

DeAngelis also said the media can complicate matters with misleading or exaggerated headlines about studies.

CHICAGO - A new survey suggests that hormone supplements might postpone menopausal symptoms, but they aren't able to prevent the symptoms entirely.

The survey, which appears in today's Journal of the American Medical Association, also found that menopause symptoms can last longer than many women thought. More than one-third of women who reported symptoms after stopping the study pills were in their 60s and 70s - at least 10 years older than the average age of menopause.

"You can't necessarily expect to just skip that stage" by taking hormones, said Dr. Judith Ockene of the University of Massachusetts Medical School, the survey's lead author.

Researchers conducting the Women's Health Initiative study said in July 2002 that estrogen-progestin pills sold as Prempro could increase risks for heart attacks, breast cancer and strokes.

Hormone supplements once were prescribed for millions of women for menopausal symptom relief and other aging ills. Use plummeted after the Women's Health Initiative released its results.

The rate of hepatitis A infections in the United States has dropped by 76 percent since the beginning of a vaccination program in 1999 targeting children in 17 high-risk states, federal researchers said Wednesday.

The program has driven the rate of infection down to 2.6 cases per 100,000 people, or 7,653 cases, in 2003, the latest year for which figures are available.

That is the lowest rate since monitoring of the disease began in the 1960s, according to the report published in the current issue of the Journal of the American Medical Association.

[Last modified July 13, 2005, 00:10:12]