Parent Page: Thrombotic Microangiopathy id: 31868 Active Page: What is the Frequency of TTPid:31883

What is the Frequency of TTP?

We see all of the patients who are treated with PEX for a suspected diagnosis of TTP or a related disorder (disorders such as HUS or TMA – described in other sections of our website). We see all patients in Central and Western Oklahoma because the Oklahoma Blood Institute (OBI) does all of the PEX treatments for all hospitals in this region. From 1989, when the Oklahoma TTP-HUS Registry began, through 2014 (26 years), there were exactly 500 patients treated by the OBI for one of these disorders.  Since 1995 we have collected blood from 357 patients immediately before the first PEX to measure the ADAMTS13 level.  79 (22%) have had ADAMTS13 activity less than 10% - these are the 79 patients are the patients whom we have diagnosed as having TTP.

Because we see all patients who are diagnosed with TTP in a defined region of Oklahoma, we can estimate how often TTP occurs. Since we know this for our region of Oklahoma, we can use U.S. census data to compare our region to the U.S. population, so we can also estimate how often TTP occurs in the U.S. Our estimate for the U.S. is 3 people per 1,000,000 people per year will develop TTP.  It may be a little more common for this, because some people have relapses of their TTP, the recurrence of an acute episode. TTP is 30-times more common in adults than in children (less than 18 years old). TTP is 3-times more common in women than in men.  TTP is 7 times more common in black Americans than in non-black Americans.  

Click the following links for more details about TTP:


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