Grant: Project Grant

The number of medications available to treat various health problems increases steadily. Most new drugs help improve patients' health, their quality of life and life expectancy, but some may have important unintended side effects while other may be less effective than existing, often less expensive, 'older' medications. Thus, an accurate assessment and comparison of the safety and effectiveness of alternative medications has become one of the primary objectives for both public health agencies and patients' organizations. Accordingly, considerable resources are invested in research attempting to link data on the use of specific medications with both intended and unintended health outcomes. In Canada, such research endeavors are largely facilitated by the existence, in several provinces, of large, administrative databases that contain complete information on both health outcomes and prescriptions received by individual subjects. However, to draw scientifically valid and rigorous conclusions from the analyses of population-based studies of drug safety or effectiveness, we have to address several methodological challenges. For example, patients prescribed a new drug may be more likely to have a more advanced disease and additional risk factors than those not given any drug or prescribed a less expensive older drug. If not accounted for, such differences in the characteristics of drug users may lead to biased results and incorrect conclusions. In addition, differences in the treatment duration and dose of drugs used by different patients, possibly due to treatment non-adherence, may also affect the accuracy of the results. We propose several new statistical methods that will address the above challenges and will permit more accurate assessments of the safety and effectiveness of different drugs used by Canadians. Our new methods may also help designing more rational treatment regimens, to maximize health benefits while reducing the risks of serious adverse events.