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On the Trail of Drug Risks

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Getting more people to report drug issues to the FDA could certainly help detect post-approval problems. But many patients, for various reasons, aren’t likely to make those reports, no matter how painless the process becomes, says Shawndra Hill, an assistant professor of operations and information management at the University of Pennsylvania Wharton School. Often people prefer informal networks such as message boards and social media for discussing drug side effects, and in several recent and ongoing studies, researchers have been looking for ways to mine those communications.

A study that Hill and others published in 2011 in the Journal of Biomedical Informatics focused on information about the side effects of four hormonal breast cancer treatment drugs that researchers extracted from 1.1 million messages on popular breast cancer Internet message boards. They found that about one in four side effects mentioned in message board comments hadn’t been listed in labeling information for the drugs. Most of those problems, however, weren’t serious. “That could mean one of two things,” says Hill. “If the side effect is really adverse, people may be too sick to talk about it. Or the FDA trials are doing a good job at uncovering the things that are really problematic.” The research also couldn’t determine whether the side effects were the direct result of taking one of the four drugs.

Brownstein and his team, meanwhile, are six months into a three-year project to explore what they can glean by monitor- ing online patient discussions. A similar study at the University of Virginia and West Virginia University is using many of the same tools Brownstein’s group is applying—computer algorithms, natural language processing, data parsing—in trying to extract information about adverse drug events from social media chatter. That research, in turn, builds on a study analyzing online posts from 2000 to early 2012 to find mentions of 20 drugs. The retrospective survey identified known adverse drug reactions 80% of the time—and its methods would have detected problems much earlier than FDA warnings were issued.

A related approach is to monitor Web searches, as the information patients are seeking may suggest what problems they’re having. For a study published this year in the Journal of the American Medical Informatics Association, researchers from Stanford and other institutions partnered with Microsoft to analyze the search logs of 6 million Web users who agreed to take part in the project. Scientists analyzed 82 million queries about drugs, symptoms and conditions in 2010. They paid particular attention to pairings of paroxetine, an antidepressant, and pravastatin, a cholesterol-lowering drug—because in 2011, the combination of the two drugs was reported to cause hyperglycemia (high blood sugar).

Researchers found that about 5% of people who searched for paroxetine or its brand names also searched for a hyperglycemia-related term; for pravastatin and its brand names, the rate was below 4%. But for those who searched for both drugs, suggesting they might be taking both, the search rate for hyperglycemia doubled to 10%—offering further, but far from conclusive, evidence. “The challenge now is to figure out what application this has in continuous monitoring for such side effects,” says Stanford’s Shah. To be more effective, he says, search histories will need to be compared with data from other sources—social media, patient support forums, electronic health records and FAERS. “If a warning signal shows up in one and can be confirmed in another,” he says, “there’s a high probability that it’s true and worth investigating in more detail.”

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1. “Novel Data-Mining Methodologies for Adverse Drug Event Discovery and Analysis,” by Rave Harpaz et al. Clinical Pharmacology & Therapeutics, June 2012. A leading researcher in biomedical informatics and colleagues discuss the potential and challenges of developing data mining tools and using diverse data sources.

2. “The U.S. Food and Drug Administration’s Mini-Sentinel Program: Status and Direction,” by Richard Platt et al. Pharmacoepidemiology and Drug Safety, January 2012. A report on the FDA’s drug surveillance pilot, using electronic health records of 100 million people, by the lead investigator at the Harvard Pilgrim Health Care Institute.

3. “Serious Adverse Drug Events Reported to the Food and Drug Administration, 1998–2005”, by Thomas Moore et al., JAMA Internal Medicine, Sept. 10, 2007. The first analysis using the FDA’s adverse event reporting database uncovered a number of disturbing trends during the time period, including a nearly threefold increase in reported serious injuries, disability and death associated with drug therapy, suggesting inadequacies in the existing surveillance system.

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