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My 2 Cents On Study: Screening For Spinal Muscular Atrophy (SMA)
February 09, 2010 by Bill StrongThe results of a study has apparently "concluded" that pre-screening for Spinal Muscular Atrophy (SMA) is not cost-effective and its "findings" were presented Friday at the annual meeting of the Society for Maternal-Fetal Medicine in Chicago. The study, based on its statistical assumptions, estimates 11,000 women would have to be screened to prevent one case of SMA, at a cost of $4.7 million per case averted. That is definitely a staggering financial burden to only save one baby -- one human life -- from the cruel grasp of a terminal and preventable disease.
This study really irks me, at my core. Statistics are funny little things. They can be extremely useful. They can definitely be extremely helpful. They are no doubt extremely subjective. And, in my opinion, as in cases such as this...they can be extremely dangerous.
As with any study and statistical model, the researchers made many assumptions and I'd challenge almost ALL of those used in this study. A few issues with the study's assumptions:
- Prevalence --> They assume 1 in 10,000. Estimates are widely quoted between 1 in 6,000-10,000. They used the high end. That's up to a 40% difference.
- Carrier rate --> They assume 1 in 50. A Genzyme study published in July 2009, put the carrier rate range between 1 in 25 and 1 in 50. They used the high end. That's up to a 50% difference.
- Carrier screening sensitivity rate --> They assume 90%. Tests are as high as 98%.
- Carrier screening cost --> They use $400. The actual cost of performing the test in the lab is $30. That's a 93% difference.
- Lifetime cost of a child with severe disease --> They use $260,000. I don't even know where to begin on this one. Let's just say that it's low, WAY low. And that cost is only increasing as SMA children live longer as a result of better access to information and care options. A more accurate number based on 2 years of living with SMA -- $750,000 to $1.5 Million. And that doesn't include a penny of non-insurance out-of-pocket costs to care for SMA children which can run between $20,000-$50,000 per year.
- Maternal quality-adjusted-life-years --> They used 22% for Type I and 8% for fetal loss. The mere suggestion that quality of life could be deduced down to a single number or percentage with any semblance of remote accuracy for any study is unfathomable and disgusting. I would suggest they actually spend a day in the shoes of a family battling SMA Type I and see if they still think a percentage can adequately encompass quality of life adjustments for the diagnosed, family, friends, and community.
SMA may not be a treatable disease, but it IS preventable. There is a simple blood test, similar to the test routinely performed for cystic fibrosis, that can be given to prospective parents to test for the SMA gene -- and it can be done BEFORE pregnancy. It's extremely simple and very accurate. The problem is the price tag. The retail price for this SMA carrier test is currently between $250-$800. Why so high? Well, that's a long, complicated saga with roots in patent law and ownership rights of the SMA gene and we're not going to go down that path this time (click here to read a previous post about that topic). A very interesting tidbit though -- the actual cost of performing the SMA carrier test in the lab is approximately $30. Yes, $30! Stay with me here...
If we assume the SMA pre-screening test was $30 -- the actual cost of performing the test in the lab -- instead of $400, as the study estimates, the "cost per case averted" goes from $4.7 million to $352,500 -- pretty darn close to the arguably-much-too-low-based-on-my-own-personal-experience $260,000 lifetime cost of a child with SMA estimate the study used -- it would alter the study entirely!!!
See, statistics can be funny things. But the truly tragic and unfortunate part of studies like these is that we, as a society, have deduced human life down to averages, assumptions, and cost-effectiveness. I understand that, at some level, we have to. But, in my opinion this is downright immoral as their results are blindly relied upon in making sweeping policy decisions that have material and drastic impacts on real people's lives.
Perhaps my statistical-funny-math is a much too simplistic way to look at things, but I'd pose a simple non-statistical question to those involved in studies such as these: Question --> Rather than being so diligent about deriving complex, overly subjective statistical analyses to prove why we SHOULDN'T be SAVING LIVES, why don't we spend that energy focusing on why we SHOULD and how we COULD -- especially when these diseases CAN be easily prevented?
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