Return to Main Page | Ragout: Vioxx: Excess Deaths, Excess Liability?
A Spicy Stew of Economics, Politics, Data, Food, Carpentry, etc.
Monday, August 29, 2005

Vioxx: Excess Deaths, Excess Liability?

In the reporting about Vioxx, I've seen a lot of citations of epidemiological estimates of the excess deaths and heart attacks, which range from 35,000 to 160,000. I've also seen a lot of estimates of Merck's potential liability, which are said to range from a few billion dollars up to $50 billion. But I haven't seen any estimates of the figures you'd actually need to estimate the potential liability. It seems to me that the relevant figures are simply deaths, not "excess" deaths.

"Excess" deaths are something of a statistician's fiction. It's not like there's any clear method to distinguish someone killed by a Vioxx-induced heart attack from a Vioxx user who would have had a heart attack anyway. To see what I mean, consider the estimates of David Graham, the FDA whistleblower-scientist.

Graham finds that about Vioxx users suffered heart attacks (fatal and not) at a rate of about 8 per 1000 person-years. Those using other anti-inflammatory drugs had a rate of 5 per 1000 person-years. The difference, 3 per 1000, is an estimate of excess heart attacks (it's not actually the estimate Graham uses, but it's close).

Since, Vioxx was used for about 10 million person-years, we get:
80,000 heart attacks among Vioxx users
50,000 heart attacks among similar patients using other drugs
which implies 30,000 excess heart attacks.

The final number (30,000) is what the epidemiologists focus on, and what gets reported in the newspapers. But the total number of heart attacks (80,000) is the relevant count of legitimate lawsuits. It's not like the coroner can examine the blood clot clogging somebody's arteries and look for Vioxx molecules. Although randomized trials have shown that Vioxx raises the likelihood of heart attacks, they don't tell us which particular Vioxx user died because of the drug, and which ones would have died anyway. So Merck's potential liability is awfully big (I'm shorting their stock).

From the point of view of economic efficiency, I think Merck is going to end up paying too much, even leaving aside any bogus lawsuits that are filed. Merck ought to be liable for the excess heart attacks and other diseases they caused, not the illness that would have occurred if Vioxx had never been invented. But even though only about a third of the heart attacks suffered by Vioxx users were actually caused by Vioxx, there's no way to tell which are which. So Merck will probably end up paying for all of them.

I don't see any way around this, except for dividing the court awards by three, which might not be such a bad idea.

Number 1 in Ragout Economics!

March 2004 / April 2004 / May 2004 / June 2004 / July 2004 / August 2004 / September 2004 / October 2004 / November 2004 / December 2004 / January 2005 / April 2005 / May 2005 / June 2005 / July 2005 / August 2005 / September 2005 / October 2005 /

First Team
Angry Bear
Crooked Timber
Brad DeLong
Economist's View
Mark Kleiman
Nathan Newman
Political Animal
Max Sawicky
Brian Setser
Sock Thief
Talking Points Memo
Matthew Yglesias

Second Opinion
Stephen Bainbridge
Marginal Revolution
Andrew Samwick
The Volokh Conspiracy

Third Way

Fourth Estate
Economic Reporting Review
New York Times
Washington Post

Fifth Republic
Le Figaro
Le Monde

Sixth Sense
The Intersection
In the Pipeline
What's New

Politics & Polls
Daily Kos
Donkey Rising
Electoral Vote Predictor
Rasmussen Tracking Polls

Art Sucks
Enzo Titolo
L’esprit d’escalier
A Level Gaze
Approximately Perfect

ragoutchef at yahoo dot com


Powered by Blogger