Friday, September 7, 2012

Stephen Strasburg and the Limits of our Medical Knowledge

English: Stephen Strasburg
English: Stephen Strasburg (Photo credit: Wikipedia)
Tonight, Washington Nationals pitching phenom Stephen Strasburg will make his last start for the year in DC.  He’ll pitch one more game on the road and then become just another spectator as the Nationals make their run for the playoffs and, I hope, the World Series.
The Nationals early made the decision to limit Strasburg’s innings to protect him from a possible career threatening injury in the aftermath of his Tommy John surgery in 2011. (The procedure, named after the Dodgers pitcher who first had the surgery in 1974, repairs a damaged elbow ligament using a graft taken from somewhere else in the body. There’s a great article about it here.)  The Nationals are following the advice of Strasburg’s surgeon, Lewis Yocum, who had recommended the same course after pitcher Jordan Zimmerman’s surgery in 2010. Zimmerman has had a great year in 2012.
It’s impossible to argue with the Nats’ baseball decisions.  They’ve put together the best team in baseball through a methodical course of brilliant drafts and trades, excellent player development, strategic acquisitions, and a terrific manager (Davey Johnson).  I also don’t doubt Dr. Yocum’s proficiency as a surgeon.
But I do wonder whether the innings limit comes from careful research or simply the best guess of physicians like Dr. Yocum based on their own patients’ post-operative experiences and conventional wisdom among their peers.  The fact is that in many cases, doctors are just guessing about best practices.
The right way to test the conventional wisdom about Tommy John surgery would be to randomly assign pitchers who have undergone the surgery to two groups—one with an innings limit and one without. Watch them for many years, and see who tends to have the better outcome, presumably measured as quality games (or innings) pitched.  The relevant research question is whether pitchers can expect to gain at least as many games down the road as they sacrifice via the earnings limit.  It might well be that the innings limit will prolong careers, but it could also be that the innings forgone are simply lost forever.
As an economist, it is natural for me to think about this as a cost-benefit problem.  We know there is a cost:  the value of the starts the pitcher skips.  In the case of Jordan Zimmerman, pitching for a mediocre Nats team in 2011, the cost of his missing starts was pretty minimal.  In Strasburg’s case, the cost could be a World Series ring.  It would be nice to know the benefits as well.
Dr. Yocum has clearly convinced Mike Rizzo, the brilliant general manager of the Nats, that there are substantial benefits to shutting Strasburg down.  But the doctor might be misled by the evidence that he sees.  Even if there were no therapeutic benefit to an innings limit, pitchers who continue pitching for an entire season are obviously more likely to suffer an injury than those who pitch for part of a season since every start creates a small risk of injury.  This is true not only in the year after surgery, but every year that a pitcher plays.  So Dr. Yocum is more likely to see pitchers who exceed his recommended innings limit than those who don’t, which seems to confirm his supposition that the practice is ill-advised, but it might simply reflect the fact that pitchers can’t get hurt pitching if they’re not doing it.  The real question is whether Strasburg would be statistically more likely to suffer an injury pitching this September and October than he would be next year or the year after.
Washington Post columnist Tom Boswell thinks he knows the answer. He called continuing to pitch Strasburg a “high-risk high-reward gamble” and unethical to boot.  He cited anecdotes about pitchers who threw too much after Tommy John surgery and ultimately had short careers.  Chicago Cubs pitcher Kerry Wood is the poster child, but Wood himself has pointed out that he pitched well for several years after his surgery and doesn’t think that his recovery regime led to his ultimate injuries.  The problem, though, is that neither Boswell nor Wood nor anybody else really knows whether the risks are large or small.  We need to know what would have happened to Wood if he had limited his innings after surgery; for Strasburg, we’d like to know what would happen if he didn’t sit out the last month and a half.  We will never know.
Beyond baseball, this is a poignant example of what is wrong with our healthcare system.  In so many cases, docs are flying by the seat of their pants.  We need to know which courses of treatment are effective and which aren’t.  In too many cases, we don’t know.  There are lots of examples where the conventional wisdom was exactly wrong.  It used to be that physicians thought that bed rest was the right course of treatment for back pain. It sort of makes intuitive sense—just like resting Strasburg does. Now it appears that keeping active despite the pain results in quicker healing.  Prostate surgery used to be routinely recommended for older patients with prostate cancer or even just enlarged prostates.  Now it appears that in most cases the treatment does more harm than good.  And for decades, hysterectomies were routinely prescribed for a host of “female troubles.”  Talk about a “war on women!”
Fortunately, policy is moving in the right direction.  The stimulus bill includedfunding for effectiveness research and the Affordable Care Act continued that effort.  Regardless of your favorite health reform option, having more information about what works and what doesn’t would make the health system work better for patients and those who pay the bills.  Someday, it might even work for baseball players and fans.

Go Nats!
PS, I lived in the DC area for 25 years before coming to Syracuse and still attend more Nationals games every year than 95 percent of DC-area residents.  (I just made up that statistic, but am sure that it is true. :-)
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