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Biomedical subjects

N R Poulter

Publications and source records attributed to N R Poulter.

At least 19 recordsLinked to original sources

Lipid levels and the use of lipid-lowering agents in England and Scotland.

OBJECTIVE: Preventing cardiovascular events with lipid-lowering drugs has been established in several trials reported since 1994. Consequently national guidelines recommend statins for those with established cardiovascular disease (CVD) and those at high risk of developing CVD. We evaluated blood lipid levels, and compare treatment and control of dyslipidaemia in English and Scottish adults with national recommendations for lipid lowering. DESIGN AND METHODS: In 1998 the nationally-representative Health Survey for England and the Scottish Health Survey included valid cholesterol results for 9631 (England) and 6065 (Scotland) adults aged 16-74. Mean blood levels of total, high-density lipoproteins (HDL-), and total:HDL-cholesterol ratio; prevalence of elevated total cholesterol levels, and total:HDL-cholesterol ratios; prevalence of use of lipid-lowering agents in high risk subgroups; and lipid levels of those on treatment were calculated. RESULTS: Levels of dyslipidaemia, treatment and control were not significantly different between Scotland and England. Combining these data, mean total cholesterol levels were 5.43 and 5.48 mmol/l in men and women respectively; and mean HDL-cholesterol levels were 1.29 and 1.56 mmol/l. Overall 64.6% of adults had a total cholesterol > or =5 mmol/l, 24.6% had a total:HDL ratio > or =5 and 2.3% reported taking lipid-lowering drugs. Treatment rates among those with a total cholesterol >5 mmol/l and a history of coronary heart disease or stroke, hypertension, or diabetes, were 27.3%, 15.4% and 17.8% respectively, and control rates (total cholesterol <5 mmol/l) among those treated were 45.3%, 38.5% and 32.7%. CONCLUSIONS: Low treatment rates with lipid-lowering drugs existed overall, among high-risk patients suitable for primary prevention, and among those with established cardiovascular disease.

Adolescent↗

Better blood pressure control: how to combine drugs.

Prospective comparisons of different drug classes have shown that differences in blood pressure control, rather than differences between drug classes, have the over-riding influence on overall outcome. The same studies have also reinforced the need, in the majority of patients, to use combinations of drugs in order to achieve the target of <140/85 mmHg. By contrast, most patients in routine practice receive single agents and consequently fail to achieve target blood pressure. This failure reflects in part the emphasis in individual studies and subsequent guidelines on comparison of individual drugs. In this article we show how the consistency of both theory and a broad range of evidence permits a didactic approach to combination therapy. Our advice is based on the growing recognition that essential hypertension and its treatment fall into two main categories. Younger Caucasians usually have renin-dependent hypertension that responds well to angiotensin-converting-enzyme inhibition or angiotensin receptor blockade (A) or ss blockade (B). Most other patients have low-renin hypertension that responds better to calcium channel blockade (C) or diuretics (D). These latter drugs activate the renin system rendering patients responsive to the addition of renin suppressive therapy. Coincidence of the initials of these main drug classes with the first four letters of the alphabet permits an AB/CD rule, according to which recommended combinations are one drug from each of the "AB" and "CD" categories of drugs. However, the diabetogenic potential of the older "B" and "D" classes leads us to advise against combining "B" and "D" in older patients, and to recommend "A" + "C" + "D" as standard triple therapy for resistant hypertension.

Antihypertensive Agents↗

QT intervals and QT dispersion as measures of left ventricular hypertrophy in an unselected hypertensive population.

Electrocardiographic (ECG) QT intervals and dispersion correlate with echocardiographic left ventricular mass index (LVMI) in groups of selected essential hypertensives. We tested the strength of this relationship in a large group of unselected hypertensives to assess whether QT measurements may be a simple screening test for LVH in clinical practice. In a cross-sectional study of 386 unselected hypertensive subjects, maximal QT intervals (QTmax), QT dispersion (QTdisp), and ECG voltages (Sokolow-Lyon and Cornell sex-specific voltages) were measured from 12-lead ECG. The LVMI correlated most strongly with Cornell voltage (linear regression r = 0.44, P < .001). The strongest relationship between LVMI and QT parameters was with QTmax, (r = 0.25, P < .001). This relationship weakened using heart rate-corrected QTmax. Correlations between LVMI and QTdisp were weak, whether or not they were corrected for heart rate. Sokolow-Lyon voltages, Cornell voltage and QTmax, but not QTdisp, were independently predictive of LVMI after adjustment for age, sex, race, and the other ECG parameters. Receiver operating characteristic (ROC) curve analyses demonstrated that no QT parameter performed better than simple ECG voltage criteria in the detection of LVH. In conclusion, QTmax, the QT parameter most strongly associated with LVMI, was independently associated with LVMI after adjustment for standard ECG voltage criteria. However, as an isolated measure it was no better than simple ECG voltage criteria as a screening test for LVH in clinical practice.

Adult↗

Rationale, design, methods and baseline demography of participants of the Anglo-Scandinavian Cardiac Outcomes Trial. ASCOT investigators.

OBJECTIVE: To test the primary hypothesis that a newer antihypertensive treatment regimen (calcium channel blocker +/- an angiotensin converting enzyme inhibitor) is more effective than an older regimen (beta-blocker +/- a diuretic) in the primary prevention of coronary heart disease (CHD). To test a second primary hypothesis that a statin compared with placebo will further protect against CHD endpoints in hypertensive subjects with a total cholesterol < or = 6.5 mmol/l. DESIGN: Prospective, randomized, open, blinded endpoint trial with a double-blinded 2 x 2 factorial component. SETTING: Patients were recruited mainly from general practices. PATIENTS: Men and women aged 40-79 were eligible if their blood pressure was > or = 160 mmHg systolic or > or = 100 mmHg diastolic (untreated) or > or = 140 mmHg systolic or > or = 90 mmHg diastolic (treated) at randomization. INTERVENTIONS: Patients received either amlodipine (5/ 10 mg) +/- perindopril (4/8 mg) or atenolol (50/ 100 mg) +/- bendroflumethiazide (1.25/2.5 mg) +K+ with further therapy as required to reach a blood pressure of < or = 140 mmHg systolic and 90 mmHg diastolic. Patients with a total cholesterol of < or = 6.5 mmol/l were further randomized to receive either atorvastatin 10 mg or placebo daily. MAIN OUTCOME MEASURE: Non-fatal myocardial infarction (MI) and fatal coronary heart disease (CHD). RESULTS: 19 342 men and women were initially randomized, of these 10297 were also randomized into the lipid-lowering limb. All patients had three or more additional cardiovascular risk factors. CONCLUSIONS: The study has 80% power (at the 5% level) to detect a relative difference of 20% in CHD endpoints between the calcium channel blocker-based regimen and the beta-blocker-based regimen. The lipid-lowering limb of the study has 90% power at the 1% level to detect a relative difference of 30% in CHD endpoints between groups.

Adrenergic beta-Antagonists↗

Association between smoking and blood pressure: evidence from the health survey for England.

Cigarette smoking causes acute blood pressure (BP) elevation, although some studies have found similar or lower BPs in smokers compared with nonsmokers. Cross-sectional data from 3 years (1994 to 1996) of the annual Health Survey for England were used to investigate any difference in BP between smokers and nonsmokers in a nationally representative sample of adults (>/=16 years old). Randomly selected adults (33 860; 47% men) with valid body mass index (BMI) and BP measurements provided data on smoking status (never, past, or current) and were stratified into younger (16 to 44 years old) and older (>/=45 years old) age groups. Analyses provided between 89% and 94% power to detect a difference of 2 mm Hg systolic BP between smokers and nonsmokers in the 4 age/gender strata (alpha=0.05). Older male smokers had higher systolic BP adjusted for age, BMI, social class, and alcohol intake than did nonsmoking men. No such differences were seen among younger men or for diastolic blood pressure in either age group. Among women, light smokers (1 to 9 cigarettes/d) tended to have lower BPs than heavier smokers and never smokers, significantly so for diastolic BP. Among men, a significant interaction between BMI and the BP-smoking association was observed. In women, BP differences between nonsmokers and light smokers were most marked in those who did not drink alcohol. These data show that any independent chronic effect of smoking on BP is small. Differences between men and women in this association are likely to be due to complex interrelations among smoking, alcohol intake, and BMI.

Adolescent↗

Improved hypertension management and control: results from the health survey for England 1998.

A survey in 1994 showed that among the 20% of the adult English population who were identified as hypertensive, approximately 30% had their blood pressures controlled to <160 mm Hg systolic and <95 mm Hg diastolic. The 1998 Health Survey for England data update the 1994 findings in light of new thresholds and targets for treatment outlined in recent national and international guidelines. This cross-sectional survey is analyzed to describe the prevalence, awareness, treatment, and control of hypertension in a random, nationally representative sample of 11 529 English adults (>/=16 years) living in noninstitutional households in 1998 and to compare these rates with those from 1994. In 1998, 20% and 37% of adults were hypertensive according to the old (systolic >/=160 mm Hg or diastolic >/=95 mm Hg) and new (systolic >/=140 mm Hg or diastolic >/=90 mm Hg) definitions, respectively. Corresponding values in 1994 were 20% and 38%. Treatment and control rates among hypertensive adults (new definition) improved from 26% to 32% and from 6% to 9%, respectively, although 60% of those on treatment received only 1 antihypertensive drug in both years. Among persons with controlled hypertension, 59% reported having received nonpharmacological advice from their physicians in 1998 compared with 30% in 1994. Rates of hypertension treatment and control have increased significantly (P=0.05 and P<0.01, respectively) since 1994 but remain low by international standards. The 1998 data suggest that improved detection, greater use of nonpharmacological measures, and increased use of >1 antihypertensive agent per patient would produce greater success in achieving target levels. This could lead to major reductions in fatal and nonfatal cardiovascular events.

Adolescent↗

Effects of blood pressure lowering with amlodipine or lisinopril on vascular structure of the common carotid artery.

Increased intima-media thickness of the common carotid artery predicts increased risk of myocardial infarction and stroke. Preliminary evidence suggests that a decrease in blood pressure (BP) is associated with diminished wall thickness. It is not known if all classes of anti-hypertensive agents have similar protective effects. In this double-blind parallel-group clinical trial, 69 previously untreated patients with hypertension were allocated randomly to 1 year of treatment with either amlodipine (5-10 mg daily) or lisinopril (5-20 mg daily). Doxazosin and bendrofluazide were added if required to achieve BP control. After 12 months of treatment, clinic BP, ambulatory BP and cardiac mass were reduced similarly by the two treatment regimens. Common carotid artery intima-media thickness decreased by 0.048 mm (95% confidence intervals -0.066, -0.031 mm) in the amlodipine-treated group, but decreased by only 0.027 mm (-0.046, -0.007 mm) in the lisinopril-treated group (P<0.05 for difference between treatments). Common carotid artery lumen diameter declined significantly only in patients treated with lisinopril [amlodipine, -0.02 mm (-0.14, 0.10 mm); lisinopril, -0.21 mm (-0.32, -0.11 mm); P<0.02], while intima-media area declined similarly in the two treatment groups [amlodipine -1.32 mm(2) (-1.91, -0.74 mm(2)), lisinopril -1.26 mm(2) (-1.80, -0.72 mm(2)); not significant]. The results confirm that a decrease in BP causes regression of structural changes in the carotid artery in hypertensive patients. The nature of the structural regression differed markedly between the two treatment regimens, in spite of similar decreases in BP. The calcium channel blocker induced greater regression of common carotid artery intima-media thickness than the angiotensin-converting enzyme inhibitor. However, carotid artery wall mass, as indicated by intima-media area, was reduced to a similar extent by the two treatments. It remains to be established whether such differences confer a prognostic advantage.

Adult↗

Cardiovascular risk: its assessment in clinical practice.

Cardiovascular disease is one of the major causes of mortality and morbidity in Western industrialised countries. Many factors impact on the likelihood of an individual suffering a stroke or heart attack. One of the greatest challenges facing clinicians today is how best to identify those individuals at increased risk, to prevent them becoming tomorrow's patients. Risk assessment tools can provide useful frameworks to support the identification of individuals who may benefit from therapeutic intervention; however, such tools should be used with care, as they do not include all the factors that contribute to future disease risk, and they are subject to an age bias. Nonetheless, they provide a systematic, evidence-based approach to the delivery of preventative healthcare services.

Cardiovascular Diseases↗

Lipid concentrations and the use of lipid lowering drugs: evidence from a national cross sectional survey.

OBJECTIVE: To evaluate the prevalence of the use of lipid lowering agents and its relation to blood lipid concentrations in English adults. DESIGN: Cross sectional survey. SETTING: England, 1998. PARTICIPANTS: Nationally representative sample of 13 586 adults (aged >/=16 years) living in non-institutional households. MAIN OUTCOME MEASURES: Mean blood concentrations of total cholesterol and high density lipoprotein (HDL) cholesterol, and the ratio of total cholesterol to HDL cholesterol, in participants classified by age and sex; prevalence of raised total cholesterol concentrations and increased ratio of total to HDL cholesterol; prevalence of use of lipid lowering agents and the lipid concentrations of people taking them. RESULTS: Mean total cholesterol concentrations were 5.47 (SE 0. 02) mmol/l in men and 5.59 (0.02) mmol/l in women. Mean HDL cholesterol concentrations were 1.28 (0.01) mmol/l in men and 1.55 (0.01) mmol/l in women. Overall, of 10 569 adults who had a valid cholesterol measurement taken 7133 (67.5%; 95% confidence interval 66.5% to 68.4%) had a total cholesterol concentration >/=5 mmol/l, 2804 (26.5%; 25.7% to 27.4%) had a ratio of total cholesterol to HDL cholesterol >/=5 mmol/l, and 237 (2.2%; 1.9% to 2.5%) reported taking lipid lowering drugs. Of 117 participants with no history of cardiovascular disease but whose estimated 10 year risk of coronary heart disease was >/=30% and whose total cholesterol concentration was >/=5 mmol/l, four (3%) were taking lipid lowering drugs. Of 385 adults aged 16-75 with a history of coronary heart disease and eligible for lipid lowering treatment, 114 (30%; 25% to 34%) were taking lipid lowering drugs, of whom only 50 (44%; 35% to 53%) had a total cholesterol concentration <5 mmol/l. CONCLUSIONS: Despite the high prevalence of dyslipidaemia in English adults, the proportion of adults taking lipid lowering drugs in 1998 was only 2.2%. Rates of treatment were low among high risk patients eligible for primary prevention with lipid lowering drugs, and less than one third of patients with established cardiovascular disease received such treatment.

Adolescent↗