Four in ten seniors don't take all the prescription drugs prescribed for them, according to the results of a national survey published today in the journal Health Affairs. Respondents in the survey conducted in 2003, prior to the enactment of the Medicare Modernization Act, said they did not follow their prescription regimens either because the costs were too high, because they didn't think the drugs were helping them, or because they didn't think they needed them. The survey of nearly 18,000 seniors was conducted by the Kaiser Family Foundation, the Commonwealth Fund and Tufts-New England Medical Center. According to the survey, 25 percent of seniors skipped doses or stopped taking a drug because it made them feel worse or wasn't helping, and 26 percent said they did not fill a prescription, skipped doses or took smaller doses due to cost reasons. Drug coverage made a substantial difference in adherence rates, with 37 percent of seniors without drug coverage reporting cost-related non-adherence, compared with 22 percent of seniors with drug coverage. Low-income seniors without drug coverage generally took fewer drugs than those with drug coverage, the survey said. More information about the survey can be found at www.kff.org and www.cmwf.org.