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Blood group O and black race are independent risk factors for thrombotic thrombocytopenic purpura associated with severe ADAMTS13 deficiency
Author(s) -
Terrell Deirdra R.,
Motto David G.,
Kremer Hovinga Johanna A.,
Lämmle Bernhard,
George James N.,
Vesely Sara K.
Publication year - 2011
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2011.03125.x
Subject(s) - adamts13 , medicine , abo blood group system , thrombotic thrombocytopenic purpura , von willebrand factor , gastroenterology , risk factor , logistic regression , immunology , platelet
BACKGROUND: It has been postulated that blood group O subjects may be partially protected against thrombotic thrombocytopenic purpura (TTP) because they have lower plasma levels of von Willebrand factor. STUDY DESIGN AND METHODS: The Oklahoma TTP Registry enrolled 301 consecutive patients from November 13, 1995 (when systematic ADAMTS13 measurements began), through 2009; 281 (93%) patients had ADAMTS13 measurements. Patients were designated as having severe ADAMTS13 deficiency when the activity measurement by either method was less than 10%. ABO blood group was determined in all 281 patients. The observed frequency of blood group O was compared to the expected frequency. The association between severe ADAMTS13 deficiency and blood group, race, sex, and age were analyzed by logistic regression. RESULTS: The frequency of blood group O was unexpectedly and significantly greater than the race‐ethnicity–adjusted expected frequency in 65 patients with severe ADAMTS13 deficiency (60.0% vs. 47.4%, p = 0.042) but not in 216 patients without severe ADAMTS13 deficiency (44.9% vs. 46.5%, p = 0.639). Blood group O and race‐ethnicity were independently associated with severe ADAMTS13 deficiency among patients with TTP. The probability for severe ADAMTS13 deficiency was 45.8% with O and 32.1% with non‐O blood groups for black patients and 24.1% with O and 15.1% with non‐O blood groups for white patients. CONCLUSION: Among patients with TTP and severe ADAMTS13 deficiency the relative frequency of patients with blood group O was greater than expected, suggesting that blood group O may be a risk factor for TTP associated with severe ADAMTS13 deficiency.