Asset Details
Do you wish to reserve the book?
Evaluating Short-Term Drug Effects Using a Physician-Specific Prescribing Preference as an Instrumental Variable
Hey, we have placed the reservation for you!
By the way, why not check out events that you can attend while you pick your title.
Oops! Something went wrong.
Looks like we were not able to place the reservation. Kindly try again later.
Are you sure you want to remove the book from the shelf?
Evaluating Short-Term Drug Effects Using a Physician-Specific Prescribing Preference as an Instrumental Variable
Do you wish to request the book?
Evaluating Short-Term Drug Effects Using a Physician-Specific Prescribing Preference as an Instrumental Variable
Please be aware that the book you have requested cannot be checked out. If you would like to checkout this book, you can reserve another copy
We have requested the book for you!
Your request is successful and it will be processed during the Library working hours. Please check the status of your request in My Requests.
Oops! Something went wrong.
Looks like we were not able to place your request. Kindly try again later.
Journal Article
Evaluating Short-Term Drug Effects Using a Physician-Specific Prescribing Preference as an Instrumental Variable
2006
Overview
Background: Postmarketing observational studies of the safety and effectiveness of prescription medications are critically important but fraught with methodological problems. The data sources available for such research often lack information on indications and other important confounders for the drug exposure under study. Instrumental variable methods have been proposed as a potential approach to control confounding by indication in nonexperimental studies of treatment effects; however, good instruments are hard to find. Methods: We propose an instrument for use in pharmacoepidemiology that is based on a time-varying estimate of the prescribing physician's preference for one drug relative to a competing therapy. The use of this instrument is illustrated in a study comparing the effect of exposure to COX-2 inhibitors with nonselective, nonsteroidal anti-inflammatory medications on gastrointestinal complications. Results: Using conventional multivariable regression adjusting for 17 potential confounders, we found no protective effect due to COX-2 use within 120 days from the initial exposure (risk difference = -0.06 per 100 patients; 95% confidence interval = -0.26 to 0.14). However, the proposed instrumental variable method attributed a protective effect to COX-2 exposure (-1.31 per 100 patients; -2.42 to -0.20) compatible with randomized trial results (-0.65 per 100 patients; -1.08 to -0.22). Conclusions: The instrumental variable method that we have proposed appears to have substantially reduced the bias due to unobserved confounding. However, more work needs to be done to understand the sensitivity of this approach to possible violations of the instrumental variable assumptions.
Publisher
Lippincott Williams & Wilkins,Lippincott Williams & Wilkins, Inc
Subject
/ Anti-Inflammatory Agents, Non-Steroidal - therapeutic use
/ Biological and medical sciences
/ Cyclooxygenase 2 Inhibitors - therapeutic use
/ Female
/ Gastrointestinal Tract - drug effects
/ Humans
/ Instrumental variables estimation
/ Male
/ Pharmacoepidemiology - statistics & numerical data
/ Practice Patterns, Physicians
