The Spectrum of Hypercoagulable States in Minority Patients with Unexplained Thrombosis.

The association of genetic risk factors with hypercoagulable states in minority populations has not been well defined. With an estimated prevalence of anywhere between 2-15% in healthy individuals, activated protein C resistance (APCR/Factor V Leiden) is considered to be the most common risk factor for venous thromboembolism( VTE) in the white population. It has also been postulated that this mutation is extremely rare in non-white populations. The prevalence of the prothrombin gene mutation G20210A in the white population is estimated at 0.7–4%, protein C and S deficiencies at 2% each and antithrombin III deficiency at 0.1–0.5% but unknown in Blacks with VTE though case control studies have identified protein C and protein S deficiencies in this population. This study is a retrospective review of all patients with thrombophilia registered at the Hemophilia Treatment Center between 1999–2005. 45/164(27%) of patients with thrombophilia were identified to be from minority groups. Of these minority patients 23/45(51%) had an identifiable primary hypercoagulable state. This group included 7/23(30%) males and 16/23(70%) females. The mean age of the patients was 35 years (range 12–80 years ). 4/23( 17%) were smokers and only 4/23(17%) had a family history of thrombosis with no documented hypercoagulable states in any family members. The majority of the patients were of African American descent 16/23(69%), 5/23(22%) were Hispanic and 2/23(9%) were Asians. 16/23(69%) of the patients had documented deep venous thrombosis/pulmonary embolus, 1/23(4%) had arterial thrombosis, 3/23(13%) had fetal loss, and 2/23(9%) were asymptomatic. APCR was the most common diagnosis in 8/23(35%) of the patients, followed by antiphospholipid antibody syndrome in 7/23(30%) of the patients. Protein S deficiency was diagnosed in 5/23(22%), hyperhomocysteinemia in 4/23(17%), Protein C deficiency in 1/23(4%), antithrombin III in 1/23(4%), and prothrombin gene mutation in 1/23(4%) of the patients. 4/23(17%) of the patients were found to have two coexisting hypercoagulable diagnoses. Recurrent VTE occurred in 7/23(30%) of the patients.

Conclusion: Primary hypercoagulable states are not rare in minorities. In this study, APCR was found to be the most common identified abnormality, followed by antiphospholipid antibody and protein S deficiency. Similar to the white population, thrombophilia in minorities occurred more commonly in young female patients. Work up for primary hypercoagulable states should be considered in minority patients with unexplained thrombosis. Further studies are warranted to determine the true prevalence of hypercoagulable states in minority populations.