D.G. Beevers

Ethnic differences in blood pressure and the prevalence of hypertension in England

The objective of this study was to examine the prevalence of hypertension and mean blood pressures among Afro-Caribbeans and South-Asians in England compared with Caucasians. Data from the Birmingham Factory Screen, Birmingham INTERSALT volunteers, and four West Midlands churches were combined into a single database (nu2009=u20092853), since all three studies employed identical methods. The cohort comprised 2169 (76%) Caucasians (71% men); 453 (16%) Afro-Caribbean (60% men); and 231 (8%) South-Asian men. The results were that overall prevalence of hypertension (⩾160/95 mmu2009Hg or taking antihypertensives) was greater in both Afro-Caribbean men (31%) and women (34%) (both Pu2009<u20090.001), compared with Caucasians (19% and 13% respectively), while South-Asian men had a similar overall prevalence to Caucasians (16%). Compared with Caucasians, Afro-Caribbeans had significantly higher mean systolic blood pressure, with higher mean diastolic blood pressures evident among Afro-Caribbean women. After adjustment for age, body mass index, smoking, and weekly alcohol intake, the odds ratios (95% CI) for being hypertensive were 1.56 (1.14 to 2.13; Pu2009=u20090.005) and 2.40 (1.51 to 3.81; Pu2009=u20090.0002) for Afro-Caribbean men and women, respectively and 1.31 (0.88 to 1.97; Pu2009=u20090.19) for South-Asian men, compared with Caucasians. In conclusion the prevalence of hypertension and mean blood pressures are higher among Afro-Caribbeans compared with Caucasians. South-Asian men had similar rates of hypertension and mean blood pressures to Caucasians.

Improving Survival of Malignant Hypertension Patients Over 40 Years

BACKGROUNDnTo examine changing demography and survival of patients with malignant phase hypertension (MHT) over 40 years.nnnMETHODSnPatients from our MHT registry whose survival status on 31 December 2006 was known were included, with analyses conducted based on decade of MHT diagnosis.nnnRESULTSnFour-hundred and forty-six patients with MHT (overall mean (s.d.) age 48.2 (12.9), years; 65.5% male; 64.7% white-European; 20.4% African Caribbean, and 14.8% South-Asian) were included. No significant demographic differences at diagnosis were evident over the 40 years, with the exception of a significant increase (P = 0.001) in the proportion of MHT among ethnic minorities (South-Asian and Afro-Caribbeans). There were no significant differences in mean systolic blood pressure (SBP) at presentation but baseline diastolic BP (DBP) was significantly lower after 1976 (P < 0.0001). The total number of person-years of observation was 5,725.5 years, with a median (interquartile range (IQR)) length of follow-up of 103.8 (31.3-251.2) months. Overall 203 patients (55.6%) died, 125 (32.0%) within 5 years of diagnosis. There was a significant improvement in 5-year survival from 32.0% prior to 1977 to 91.0% for patients diagnosed between 1997 and 2006. SBP and DBP improved significantly during follow-up (P < 0.0001). Multivariate analyses revealed that age, decade of MHT diagnosis, baseline creatinine, and follow-up SBP were independent predictors of survival (all P < 0.0001).nnnCONCLUSIONSnDemography and number of new cases of MHT have not changed dramatically over the past 40 years. Five-year post-MHT survival has improved significantly, possibly related to lower BP targets, tighter BP control, and availability of new classes of antihypertensive drugs.

ANTI-HYPERTENSIVE DRUGS IN PREGNANCY AND FETAL GROWTH: EVIDENCE FOR “PHARMACOLOGICAL PROGRAMMING” IN THE FIRST TRIMESTER?

Objectives: To determine the timing and exact nature of the effect of the drug atenolol upon fetal growth. Also to discover if the reduction in fetal growth is due to superimposed pre-eclampsia or any other confounding variable. Design: A retrospective cohort study of prospectively collected data in a hypertensive pregnancy database. Setting: Two district general hospitals in the midlands of England. Both hospitals have specialised medical antenatal clinics for pregnant women with chronic hypertension. Participants: 491 pregnancies in 380 women with essential or secondary hypertension. Outcome measures: The outcome measures used were the infant birth weight, birth weight standardized for gestational age, and the ponderal index at birth, a surrogate measure for in utero growth restriction. Results: The babies of women taking atenolol at conception or during the first trimester had significantly lower birth weights (by 139–512 g, p<0.01) than women on calcium channel blockers or no medication. Likewise the ponderal index was also significantly reduced, p<0.01. In addition most of these babies were small for gestational age (SGA) with 70% on or below the 10th centile and 40% below the third centile. No such independent association was seen with anti-hypertensives taken in the second trimester. Conclusions: Atenolol taken at the time of conception and/or during the first trimester of pregnancy was associated with low birth weight. This finding was independent of the development of superimposed pre-eclampsia. Other anti-hypertensives were not found to be associated with low birth weight. Use of atenolol in the second trimester of pregnancy did not produce the same effect and was not materially different in its effects from the other anti-hypertensive drugs. In the second trimester, the development of superimposed pre-eclampsia is the over-riding effect in the reduction of infant birth weight. Atenolol used in the first trimester could be pharmacologically programming these infants to restricted growth patterns.

Evidence of platelet activation in hypertension

To test the hypothesis that platelet activation is present in hypertension, we measured plasma markers beta thromboglobulin and soluble P-selectin in hypertensive patients and normotensive controls. Both markers were raised in the patients (Pu2009<u20090.05), and in a subgroup of patients, beta thromboglobulin was reduced with successful treatment of hypertension with the ace inhibitor quinapril. we suggest that reversible platelet activation is present in hypertension. this may be a contributing factor to the link between this risk factor and the development of thrombotic disease such as stroke.

STRATEGIES FOR IMPROVEMENT OF AWARENESS, TREATMENT AND CONTROL OF HYPERTENSION: RESULTS OF A PANEL DISCUSSION

High blood pressure (BP) is a major risk factor for coronary heart disease, heart failure, stroke, chronic kidney disease, end stage renal disease, and a variety of other clinically important outcomes.1, 2, 3, 4 Results from the surveys described in this issue and elsewhere5 underscore a common finding that hypertension is both highly prevalent and insufficiently treated and controlled. Recognizing the differences in sampling and survey measurement techniques, the reported prevalence of hypertension (SBP/DBP ≥140/90u2009mmHg or treatment with antihypertensive medication) in adults exceeded 25% in all of the surveys reported in this issue. In Latvia, the prevalence of hypertension for 25–64-year-old adults in the general population was 46.1%.6 Control of hypertension with medication to an SBP/DBP <140/90u2009mmHg in the general population ranged from as low as 12% to a high of only 29%.7, 8, 9 Data from other parts of the world provide an equally distressing picture of what is (not) being accomplished in treatment and control of hypertension at the level of the general population.5, 10, 11 These data provide testimony to an urgent need for greater attention to the treatment and control of hypertension in populations around the world. This was the basis for a panel discussion at the International Society of Hypertension satellite conference The Epidemiology of Hypertension-Regional Differences in Treatment and Control. Panel participants included Drs P Whelton, S Sonkodi, DG Beevers, JG Fodor, H Elliot, R Cifkova, A Nissinen, A Javor, and there was active participation of other symposium attendees. The following summarizes key elements of the discussion and recommendations of the panel.

Matrix metalloproteinases and their tissue inhibitors in hypertension-related pregnancy complications

Matrix metalloproteinases (MMPs) are a family of endopeptidases that degrade the components of the extracellular matrix (ECM) such as collagen, and thus contribute to the remodelling and the physiological homeostasis of the ECM and its blood supply. The activities of these enzymes are regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and it has been suggested that a balance between MMPs and TIMPs plays an important role in vascular remodelling, angiogenesis and vasodilatation in a number of physiological situations. It follows that, regarding a relationship between MMPs and TIMPs, an imbalance between these molecules may lead to pathology in a wide range of conditions, including hypertension, cancer and pulmonary disease, and in the pathophysiology of reproduction. Indeed, regarding the latter, abnormalities in the maternal peripheral vasculature have been proposed as being (partly) responsible for the effects of hypertension on pregnancy and the development of complications including pre-eclampsia and eclampsia. However, the associations between MMPs, TIMPs and disease may be simply of association, not of pathology. This brief review explores current literature on the role of abnormalities of the ECM in general, focusing on the pathogenesis of hypertension and its complications during pregnancy as a model of disordered angiogenesis and remodelling.

Ethnic differences in left ventricular size and the prevalence of left ventricular hypertrophy among hypertensive patients vary with electrocardiographic criteria

The objective of this study was to investigate differences in electrocardiographic (ECG) parameters and the prevalence of left ventricular hypertrophy (LVH) by various ECG criteria between different ethnic groups in west Birmingham, United Kingdom. In all, 380 consecutive patients, mean age 63 (7.8) years, 75 (20%) female patients assessed for inclusion in hypertension trials in a city centre teaching hospital were studied: 303 (80%) were Caucasian, 43 (11.4%) Afro-Caribbean and 32 (8.5%) South Asian. LVH was assessed using seven different criteria, with adjustment for age and body mass index (BMI). The performance of the various criteria were compared between the three ethnic groups. There were significant differences in the R-wave voltage in lead aVL, the Sokolow–Lyon voltage and in criteria based on limb lead voltages alone between the three ethnic groups. Highest ECG voltages were seen in Afro-Caribbeans, and this translated into a significantly higher prevalence of LVH when assessed by the R-wave in aVL and the Sokolow–Lyon criteria. There were no significant differences between Caucasians and South Asians. These differences were abolished after adjustment for age and BMI. There was no difference in the Cornell voltage or its derivatives in men between the three ethnic groups. In conclusion, apparent differences in electrocardiographic voltage and the prevalence of LVH between ethnic groups are dependent upon the criteria chosen and may simply be secondary to differences in BMI. Unlike Afro-Caribbean patients, South Asians do not demonstrate significant differences in ECG voltage compared with Caucasians.

Echocardiographic changes in patients with malignant phase hypertension: The West Birmingham Malignant Hypertension Register

In order to study the echocardiographic abnormalities in consecutive patients with malignant phase hypertension (MHT), we reviewed echocardiograms of 31 patients (23 male; mean age 52±14 years) with MHT who were admitted to our unit. Trans-thoracic echocardiography was carried out in all patients, and echocardiographic measurements were compared with those of 39 patients (30 male; mean age 54±10 years) with controlled nonmalignant essential hypertension, and 32 (19 male; mean age 51±10 years) healthy normotensive volunteers. Patients with MHT had a significantly higher mean systolic and diastolic blood pressure (P<0.001) compared to the other two groups. MHT patients had significantly greater mean left atrial dimensions (P=0.002), as well as aortic root dimensions (P=0.01) and left ventricular (LV) dimensions (with the exception of the diastolic internal diameter) (P<0.001). MHT patients also had a mean larger LV mass and LV mass index (both P<0.001) when compared to the other two groups. The mean ejection fraction was also lower in the MHT group (P<0.001). In conclusion, patients with MHT have significant cardiac hypertrophy, in association with systolic dysfunction and dilated left atria, irrespective of the duration of known hypertension. These abnormalities may predispose MHT patients to cardiovascular complications including heart failure and cardiac arrhythmias, such as atrial fibrillation.

The measurement of blood pressure and the detection of hypertension in children and adolescents.

Despite the publication of several expert committee guidelines for the measurement of blood pressure (BP) and the diagnosis of hypertension in children and adolescents, it was our perception and clinical experience that there still appeared to be a general lack of standardisation of BP measurement techniques and little consensus on the criteria for diagnosing hypertension. To investigate this further, we have conducted a postal survey of consultant-grade paediatricians who were members of the British Paediatric Association (BPA). A total of 1500 questionnaires were sent out and 708 analysable replies were received (47.1%). This showed that 68.6% of paediatricians routinely measured BP, at least on one occasion, in children or adolescents attending their outpatient clinics, 17.7% started at or soon after birth, 12.3% started at the age of 1 year, 20.0% at 3 years, 12.0% from 7 years of age and 3.5% from the age of 13. Only 60.5% reported that they had a choice of four or more different cuff sizes in their clinic. Forty-one percent of respondents reported that the BP was always or sometimes measured by nurses. Fifty-one percent of respondents measured diastolic BP at the phase of muffling of sound (Korotkoff phase IV), 31.9% used the disappearance of sound (phase V) whilst 15.9% claimed that they measured both end-points. The criteria for diagnosing a child as being hypertensive varied greatly; 17.9% reported that they responded to the systolic BP alone, 13.5% to the diastolic BP alone, 65.9% relied on both pressures, and 2.7% responded to either the systolic or diastolic pressure if it was raised. Furthermore, 12.9% diagnosed hypertension if the BP exceeded the 90th percentile in relation to age and 41.8% used the 95th percentile. However 45.3% of respondents employed a higher dividing line. In hospitalised children, leg blood pressures were measured routinely by 30.3%, although a further 44.0% would do so if aortic coarctation or other vascular diseases were suspected. Despite considerable variation in clinical practice, techniques and criteria, only 11.4% of clinicians would manage the patients themselves, with the remainder referring the child on to the appropriate specialist. The survey suggests a general lack of standardisation of BP measurement techniques and little consensus on the criteria for diagnosing hypertension amongst paediatricians. Simplified, shortened and updated guidelines on hypertension in paediatric practice and research are needed.

Lipid lowering in hypertension and heart protection: observations from the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) and the Heart Protection Study

Lipid lowering in hypertension and heart protection: observations from the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) and the Heart Protection Study