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How the 'off-label' drugs series was done
Knight Ridder's investigative series is based on dozens of interviews with patients, doctors, researchers and drug companies, and the review of thousands of records from lawsuits, government hearings and regulatory actions, medical records and scientific studies.
To calculate how often drugs are prescribed off-label, Knight Ridder purchased and reviewed prescribing data routinely used by the pharmaceutical industry. Verispan of Yardley, Pa., collects the data from a monthly survey of 3,400 doctors with office-based practices.
Knight Ridder analyzed the three top-selling drugs in 15 classes of medications, comparing what doctors said they prescribed them for with the FDA's approval for each. The analysis looked at 900 million prescriptions written in 1998 and 2003 for more than 1,000 different ailments. Its estimate of the prevalence of off-label prescribing excluded cancer treatments or pediatric off-label uses, because they already are known to have a large percentage of off-label use. When calculating whether off-label prescribing had grown over the last five years, the study considered only the 31 drugs that had been on the market the entire time.
Prescribing data are for the 12 months ending July 31; sales figures are for the 12 months ending Aug. 31.
The analysis is perhaps the most comprehensive ever done of off-label prescribing.
While various reports have quoted the American Medical Association as estimating that 50 percent of drugs are prescribed off-label, an association representative said that figure was a misinterpretation of a remark an official made years ago and that it has no good estimate. Knight Ridder's analysis found that 21 percent of the prescriptions examined were for off-label uses, and that some of the drugs had off-label uses as high as 90 percent.
To estimate how often patients are harmed by this practice, Knight Ridder reviewed the FDA's database of adverse drug reactions. The FDA estimates that only 1 to 10 percent of reactions are reported. Knight Ridder identified more than 800 reports filed during 2002 of serious reactions involving off-label prescriptions for its sample of 45 drugs. Experts say that means anywhere from 8,000 to 80,000 people probably were affected.
http://161.188.204.190/krdigital/drug/
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