Richard P. Koopmans

Prevalence, awareness, treatment, and control of hypertension among Black Surinamese, South Asian Surinamese and White Dutch in Amsterdam, The Netherlands: the SUNSET study

Objective To assess ethnic differences in prevalence, levels of awareness, treatment and control of hypertension among Dutch ethnic groups and to determine whether these differences are consistent with the UK findings. Design Cross-sectional survey. Setting South-east Amsterdam, The Netherlands. Participants A random sample of 1383 non-institutional adults aged 35–60 years. Of these, 36.7% were White, 42% were Black and 21.3% were South Asian people. Main outcome measures Prevalence of hypertension, rates of awareness, treatment, and control of hypertension. Results The Black and South Asian subjects had a higher prevalence of hypertension compared with White people. After adjustments for age, the odds ratios (95% confidence interval) for being hypertensive were 2.2 (1.4–3.4; P < 0.0001) and 3.8 (2.6–5.7; P < 0.0001) for Black men and women, respectively, and 1.7 (1.0–2.6; P = 0.039) and 2.8 (1.8–4.5; P < 0.0001) for South Asian men and women, compared with White people. There were no differences in awareness and pharmacological treatment of hypertension between the groups. However, Black hypertensive men 0.3 (0.1–0.7; P < 0.01) and women 0.5 (0.3–0.9; P < 0.05) were less likely to have their blood pressure adequately controlled compared with White people. Conclusion The higher prevalence of hypertension found among Black and South Asian people in The Netherlands is consistent with the UK studies. However, the lower control rates and the similar levels of awareness and treatment of hypertension in Black Surinamese contrast with the higher rates reported in African Caribbeans in the UK. The rates for the South Asians in The Netherlands were relatively favourable compared to similar South Asian groups in the UK. These findings underscore the urgent need to develop strategies aimed at improving the prevention and control of hypertension, especially among Black people, in The Netherlands.

The M235T polymorphism in the angiotensinogen gene is associated with the risk of malignant hypertension in white patients.

Background Malignant hypertension can be considered an extreme phenotype of renin-mediated hypertension. Therefore, we compared the allelic frequencies of the angiotensinogen (AGT) M235T, angiotensin-converting enzyme insertion/deletion (ACE I/D) and angiotensin II-type I receptor (AT1R) A1166C polymorphisms in malignant hypertensive patients with hypertensive and normotensive controls. Methods A total of 101 consecutive patients between 1995 and 2005 admitted to a large university hospital fulfilled the criteria for malignant hypertension. Seventy-five patients (74%) were compared with 150 hypertensive and 150 normotensive controls, randomly selected from a population study and individually matched on age, sex and ethnicity. Results The odds of malignant hypertension in white subjects with the TT genotype of the AGT M235T polymorphism was 14.3 (5.5–37) compared to hypertensive controls, and 9.4 (3.8–23.2) compared to normotensive controls. Adjustment for age, sex, smoking and antihypertensive therapy did not affect this association. The association of AGT M235T with malignant hypertension was not significant in blacks. In patients with malignant hypertension, the TT genotype was associated with more severe renal dysfunction and microangiopathic haemolysis. No differences were found in allele frequencies of the ACE I/D or the AT1R A1166C polymorphisms between study groups. Conclusions The TT genotype of AGT M235T is associated with malignant hypertension in whites, carriers having an odds of approximately 10 to 1 compared to hypertensive and normotensive controls. These observations may provide a better understanding of the pathophysiology of malignant hypertension and offer possibilities for identifying patients at risk. Larger association or linkage studies are needed for a more detailed risk assessment.

Genetic factors are relevant and independent determinants of antihypertensive drug effects in a multiracial population.

BACKGROUNDnThe success of antihypertensive drugs may be improved by better prediction of their efficacy in individual patients. The objective of our study was to determine whether genetic variation predicts the individual systolic blood pressure (SBP) response to antihypertensive drugs and to assess to what extent the individual treatment response could be explained by the combined effects of known demographic, environmental, and genetic factors.nnnMETHODSnA population-based, crossover, open-label randomized treatment study stratified for ethnicity in 102 mildly hypertensive patients aged 35-60 years in an outpatient hypertension clinic (the ROTATE study). Patients underwent five successive 6-week treatment episodes of single-drug treatment in a randomized order with representatives of the major antihypertensive drug classes. The primary outcome measure was the DeltaSBP after 6-week drug therapy.nnnRESULTSnParticipants (n = 97) completed 407 treatment episodes. The estimated unpredictable natural variation of SBP within individuals was 65% of the total study variance. The primary analysis model that considered the effects of environmental, demographic, and genetic factors and their interactions to SBP response to antihypertensive drugs, explained 23% of the total variance accounting for 66% of the predictable variance. Ethnicity, low sodium intake, and ADD1 614G-->T polymorphism were the only drug-related predictors. A number of genetic variants (ADD1 614G-->T, ADRB1 145A-->G, ADRB2 79C-->G, CYP11B2 -344C-->T, and SLC12A3 78G-->A) contributed significantly (9%) to the total variance of the SBP response. The contribution of each individual single-nucleotide polymorphism (SNP) ranged from 1.1 to 2.4%.nnnCONCLUSIONSnGenetic factors are relevant and independent determinants of antihypertensive drug effects in a multiracial population.