January 23, 2005

Do Your Residents Use Plavix?

The New York Times published a piece about a study raising questions about its safety:

Patients taking Plavix, a popular and expensive antistroke drug, experience more than 12 times as many ulcers as patients who take aspirin plus a heartburn pill, a study to be published today in The New England Journal of Medicine found.

Up to half of those now taking Plavix do so because their doctors assume that Plavix is safer on the stomach than aspirin, said Dr. Francis K. L. Chan, the study's lead author. Both the American College of Cardiology and the American Heart Association recommend that heart and stroke patients at risk of developing ulcers be given Plavix instead of aspirin.

Here is a description of how Dr. Chan conducted his study:

Dr. Chan said he was surprised to find that almost no studies had been done to confirm whether this assumption was true. He found 320 patients whose ulcers had healed and gave half of them Plavix and half of them aspirin plus Nexium, a heartburn pill. He followed them for a year.

However, the physician blogger over at DB's Medical Rants puts this study in perspective:

Reports like this make the news, especially the financial news. The challenge that clinicians and clinician scientists must understand involves putting each new data piece into perspective. Several questions come to mind immediately, prior to reading the remainder of the article:

  • Would PPIs (proton pump inhibitors) also decrease ulcer rates in Plavix treated patients?
  • Which patients really benefit from Plavix?
  • What duration of therapy should we use?
  • How important were the ulcers (did they bleed, cause pain, or were they “incidental” findings)?
  • Thirteen of the patients taking Plavix, or 8.6 percent, experienced renewed ulcer bleeding during the year while just one, or 0.7 percent, of those taking aspirin and Nexium had an ulcer bleed.

    --Snip--

This is the wrong study. The results make Plavix look bad, but it does not answer the key questions:

  • Given a patient with NO ulcer history - does Plavix induce ulcers?
  • How would a combination of Plavix + a PPI compare with ASA + a PPI in patients with previous ulcer?

We clearly should understand the risks of Plavix, but this article does not really help. Most patients who receive Plavix, do so for clear indications. We need to understand side effects in patients who resemble our patient populations.