D-dimer relates positively with increased blood pressure in black South Africans: the SABPA study.
BACKGROUND
Hypertension is highly prevalent in black South Africans in which morbidity and mortality from stroke are on the increase. Elevated blood pressure and haemostatic markers can induce changes in blood rheology and endothelial function which could result in a procoagulant state that increases the risk for cerebrovascular disease. Information about the coagulation and fibrinolytic systems of people from African descent are limited. We therefore, investigated the haemostatic profile and its relationships with blood pressure in black South Africans.


METHODS
We measured ambulatory blood pressure and haemostatic markers of 201 black and 208 white school teachers. The haemostatic markers included measurements representing coagulation and fibrinolysis (von Willebrand factor, fibrinogen, plasminogen activator inhibitor-1, fibrin D-dimer and clot lysis time).


RESULTS
Black participants displayed significantly higher blood pressure, von Willebrand factor, fibrinogen, plasminogen activator inhibitor-1 and D-dimer levels and longer clot lysis times (p≤0.001). Single, partial and multiple regression analyses showed that systolic (p≤0.011) and diastolic blood pressure (p=0.010) correlated positively with D-dimer in black participants, while systolic (p≤0.001) and daytime diastolic blood pressure (p=0.011) correlated negatively with clot lysis time in white participants.


CONCLUSIONS
The black population had a more prothrombotic profile, with higher levels of coagulation markers and inhibited fibrinolysis, than the white study participants. The positive association between blood pressure and elevated D-dimer in the blacks may contribute to the high prevalence of hypertension and related increased cardiovascular and cerebrovascular risk in this group.
Hypertension in Africa Research Team (HART), North-West University (Potchefstroom Campus), Potchefstroom, South Africa.
Leandi
L
Lammertyn
Hypertension in Africa Research Team (HART), North-West University (Potchefstroom Campus), Potchefstroom, South Africa.
Aletta E
AE
Schutte
Centre of Excellence for Nutrition (CEN), North-West University (Potchefstroom Campus), Potchefstroom, South Africa.
Marlien
M
Pieters
Hypertension in Africa Research Team (HART), North-West University (Potchefstroom Campus), Potchefstroom, South Africa. Electronic address: rudolph.schutte@nwu.ac.za.
Rudolph
R
Schutte
D000328:Adult; D044383:Black People / Q000706:statistics & numerical data; D001794:Blood Pressure / Q000502:physiology; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000453:epidemiology / Q000208:ethnology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D013019:South Africa / Q000453:epidemiology
D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D
Clot lysis time; Ethnicity; Fibrin D-dimer; Fibrinogen; Plasminogen activator inhibitor-1; von Willebrand factor