Stephen B. Harrap

Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes.

BACKGROUND In patients with type 2 diabetes, the effects of intensive glucose control on vascular outcomes remain uncertain. METHODS We randomly assigned 11,140 patients with type 2 diabetes to undergo either standard glucose control or intensive glucose control, defined as the use of gliclazide (modified release) plus other drugs as required to achieve a glycated hemoglobin value of 6.5% or less. Primary end points were composites of major macrovascular events (death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke) and major microvascular events (new or worsening nephropathy or retinopathy), assessed both jointly and separately. RESULTS After a median of 5 years of follow-up, the mean glycated hemoglobin level was lower in the intensive-control group (6.5%) than in the standard-control group (7.3%). Intensive control reduced the incidence of combined major macrovascular and microvascular events (18.1%, vs. 20.0% with standard control; hazard ratio, 0.90; 95% confidence interval [CI], 0.82 to 0.98; P=0.01), as well as that of major microvascular events (9.4% vs. 10.9%; hazard ratio, 0.86; 95% CI, 0.77 to 0.97; P=0.01), primarily because of a reduction in the incidence of nephropathy (4.1% vs. 5.2%; hazard ratio, 0.79; 95% CI, 0.66 to 0.93; P=0.006), with no significant effect on retinopathy (P=0.50). There were no significant effects of the type of glucose control on major macrovascular events (hazard ratio with intensive control, 0.94; 95% CI, 0.84 to 1.06; P=0.32), death from cardiovascular causes (hazard ratio with intensive control, 0.88; 95% CI, 0.74 to 1.04; P=0.12), or death from any cause (hazard ratio with intensive control, 0.93; 95% CI, 0.83 to 1.06; P=0.28). Severe hypoglycemia, although uncommon, was more common in the intensive-control group (2.7%, vs. 1.5% in the standard-control group; hazard ratio, 1.86; 95% CI, 1.42 to 2.40; P<0.001). CONCLUSIONS A strategy of intensive glucose control, involving gliclazide (modified release) and other drugs as required, that lowered the glycated hemoglobin value to 6.5% yielded a 10% relative reduction in the combined outcome of major macrovascular and microvascular events, primarily as a consequence of a 21% relative reduction in nephropathy. (ClinicalTrials.gov number, NCT00145925.)

Risks of cardiovascular events and effects of routine blood pressure lowering among patients with type 2 diabetes and atrial fibrillation: results of the ADVANCE study.

AIMS The aim of this study was to investigate serious clinical outcomes associated with atrial fibrillation (AF) and the effects of routine blood pressure lowering on such outcomes in the presence or absence of AF, among individuals with type 2 diabetes. METHODS AND RESULTS About 11 140 patients with type 2 diabetes (7.6% of whom had AF at baseline) were randomized to a fixed combination of perindopril and indapamide or placebo in the Action in Diabetes and Vascular Disease: preterAx and diamicroN-MR Controlled Evaluation (ADVANCE) study. We compared total mortality and cardiovascular disease outcomes and effects of randomized treatment for 4.3 years on such outcomes between patients with and without AF at baseline. After multiple adjustments, AF was associated with a 61% (95% confidence interval 31-96, P < 0.0001) greater risk of all-cause mortality and comparable higher risks of cardiovascular death, stroke, and heart failure (all P < 0.001). Routine treatment with a fixed combination of perindopril and indapamide produced similar relative, but greater absolute, risk reductions for all-cause and cardiovascular mortalities in patients with AF, compared with those without AF. The number of patients needed to be treated with perindopril-indapamide for 5 years to prevent one cardiovascular death was 42 for patients with AF and 120 for patients without AF at baseline. CONCLUSION Atrial fibrillation is relatively common in type 2 diabetes and is associated with substantially increased risks of death and cardiovascular events in patients with type 2 diabetes. This arrhythmia identifies individuals who are likely to obtain greater absolute benefits from blood pressure-lowering treatment. Atrial fibrillation in diabetic patients should be regarded as a marker of particularly adverse outcome and prompt aggressive management of all risk factors.

Clinical practice guidelines for the management of hypertension in the community a statement by the American Society of Hypertension and the International Society of Hypertension.

Clinical Practice Guidelines for the Management of Hypertension in the Community A Statement by the American Society of Hypertension and the International Society of Hypertension

Genetic loci for retinal arteriolar microcirculation

Narrow arterioles in the retina have been shown to predict hypertension as well as other vascular diseases, likely through an increase in the peripheral resistance of the microcirculatory flow. In this study, we performed a genome-wide association study in 18,722 unrelated individuals of European ancestry from the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium and the Blue Mountain Eye Study, to identify genetic determinants associated with variations in retinal arteriolar caliber. Retinal vascular calibers were measured on digitized retinal photographs using a standardized protocol. One variant (rs2194025 on chromosome 5q14 near the myocyte enhancer factor 2C MEF2C gene) was associated with retinal arteriolar caliber in the meta-analysis of the discovery cohorts at genome-wide significance of P-value <5×10−8. This variant was replicated in an additional 3,939 individuals of European ancestry from the Australian Twins Study and Multi-Ethnic Study of Atherosclerosis (rs2194025, P-value = 2.11×10−12 in combined meta-analysis of discovery and replication cohorts). In independent studies of modest sample sizes, no significant association was found between this variant and clinical outcomes including coronary artery disease, stroke, myocardial infarction or hypertension. In conclusion, we found one novel loci which underlie genetic variation in microvasculature which may be relevant to vascular disease. The relevance of these findings to clinical outcomes remains to be determined.

Clinical practice guidelines for the management of hypertension in the community: a statement by the American Society of Hypertension and the International Society of Hypertension.

Michael A. Weber, MD; Ernesto L. Schiffrin, MD; William B. White, MD; Samuel Mann, MD; Lars H. Lindholm, MD; John G. Kenerson, MD; John M. Flack, MD; Barry L. Carter, Pharm D; Barry J. Materson, MD; C. Venkata S. Ram, MD; Debbie L. Cohen, MD; Jean-Claude Cadet, MD; Roger R. Jean-Charles, MD; Sandra Taler, MD; David Kountz, MD; Raymond R. Townsend, MD; John Chalmers, MD; Agustin J. Ramirez, MD; George L. Bakris, MD; Jiguang Wang, MD; Aletta E. Schutte, MD; John D. Bisognano, MD; Rhian M. Touyz, MD; Dominic Sica, MD; Stephen B. Harrap, MD

Brief angiotensin converting enzyme inhibitor treatment in young spontaneously hypertensive rats reduces blood pressure long-term.

Our study examines the long-term cardiovascular effects after a brief period of angiotensin converting enzyme (ACE) inhibitor treatment in young spontaneously hypertensive rats (SHR). SHR were treated with perindopril (3 mg/kg/day) by gavage from 2 to 6, from 6 to 10, or from 2 to 10 weeks of age. Systolic blood pressure was measured in the tail weekly until 25 weeks of age. Corresponding control groups received distilled water for the same periods. In each treatment group blood pressure was reduced significantly during treatment, rose when treatment stopped, but plateaued significantly below control SHR thereafter. This difference in blood pressure at 25 weeks of age was due to reduced total peripheral resistance as determined by microsphere methods, but plasma renin activity and angiotensin II concentrations were not different Cardiac hypertrophy was also reduced in treated SHR. In a separate experiment, perindopril treatment from 6 to 10 weeks of age resulted in a significant reduction in the media/ lumen ratios of mesenteric resistance vessels at 32 weeks of age. Concomitant administration of angiotensin II with perindopril from 6 to 10 weeks of age not only prevented the long-term effects on blood pressure seen with perindopril treatment alone but was associated with cardiovascular hypertrophy in excess of untreated control SHR. Finally, perindopril given for a shorter period (6 to 7 weeks) or later in life (20 to 24 weeks) had no significant long-term effects on blood pressure. These results demonstrate that a 4-week period of ACE inhibitor treatment in young SHR is sufficient to prevent the full expression of genetic hypertension and cardiovascular hypertrophy and that angiotensin II might be important in the development of hypertension in this model, its role in later life being less important.

Abnormalities of glucocorticoid metabolism and the renin-angiotensin system: a four-corners approach to the identification of genetic determinants of blood pressure.

AIM To assess the feasibility and utility of a new method to identify factors associated with increased predisposition to high blood pressure in young people. SUBJECTS Eight hundred and sixty-four people aged 16-24 years and their parents. SETTING Ladywell Medical Centre, Edinburgh, Scotland, UK. METHOD Blood pressure was measured in 864 young adults and in both of their parents. Four groups of approximately 50 offspring were selected from the corners of a scatter diagram, with offspring blood pressure scores on one axis and combined parental blood pressure scores on the other. Blood and urine samples were taken for biochemical and genetic analyses. RESULTS Two groups of offspring had parents with high blood pressure and two groups had parents with low blood pressure. When parental blood pressure was low, comparison of offspring with high and low blood pressure revealed significantly higher mean body mass index in offspring with high blood pressure, but no significant elevation of biochemical or hormonal variables. When parental blood pressure was high, comparison of offspring with high and low blood pressure also revealed a significant difference in body mass index, but in addition, offspring with high blood pressure and high parental blood pressure had higher levels of angiotensinogen, cortisol and 18-OH corticosterone. Restriction fragment length polymorphism analysis revealed that 27% of offspring at the greatest genetic risk (high personal and parental blood pressure) were homozygous for the larger allele of the glucocorticoid receptor gene compared with only 9% of those at lowest genetic risk (low personal and parental blood pressure). CONCLUSION The combined biochemical and genetic findings suggest that abnormalities of glucocorticoid metabolism and the renin-angiotensin system may help to explain genetic predisposition to high blood pressure. The new sampling method is practicable and could be applied to the investigation of other continuously distributed variables which show familial aggregation.

Follow-up of Blood-Pressure Lowering and Glucose Control in Type 2 Diabetes

BACKGROUND In the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) factorial trial, the combination of perindopril and indapamide reduced mortality among patients with type 2 diabetes, but intensive glucose control, targeting a glycated hemoglobin level of less than 6.5%, did not. We now report results of the 6-year post-trial follow-up. METHODS We invited surviving participants, who had previously been assigned to perindopril-indapamide or placebo and to intensive or standard glucose control (with the glucose-control comparison extending for an additional 6 months), to participate in a post-trial follow-up evaluation. The primary end points were death from any cause and major macrovascular events. RESULTS The baseline characteristics were similar among the 11,140 patients who originally underwent randomization and the 8494 patients who participated in the post-trial follow-up for a median of 5.9 years (blood-pressure-lowering comparison) or 5.4 years (glucose-control comparison). Between-group differences in blood pressure and glycated hemoglobin levels during the trial were no longer evident by the first post-trial visit. The reductions in the risk of death from any cause and of death from cardiovascular causes that had been observed in the group receiving active blood-pressure-lowering treatment during the trial were attenuated but significant at the end of the post-trial follow-up; the hazard ratios were 0.91 (95% confidence interval [CI], 0.84 to 0.99; P=0.03) and 0.88 (95% CI, 0.77 to 0.99; P=0.04), respectively. No differences were observed during follow-up in the risk of death from any cause or major macrovascular events between the intensive-glucose-control group and the standard-glucose-control group; the hazard ratios were 1.00 (95% CI, 0.92 to 1.08) and 1.00 (95% CI, 0.92 to 1.08), respectively. CONCLUSIONS The benefits with respect to mortality that had been observed among patients originally assigned to blood-pressure-lowering therapy were attenuated but still evident at the end of follow-up. There was no evidence that intensive glucose control during the trial led to long-term benefits with respect to mortality or macrovascular events. (Funded by the National Health and Medical Research Council of Australia and others; ADVANCE-ON ClinicalTrials.gov number, NCT00949286.).

The angiotensin I converting enzyme gene and predisposition to high blood pressure.

Phenotypic abnormalities of the renin-angiotensin system have been associated with the predisposition to high blood pressure. The angiotensin I converting enzyme (ACE) gene has been implicated as a candidate gene. We examined the distribution of common alleles of the ACE gene and measured circulating components of the renin-angiotensin system and urinary sodium excretion in 170 young Caucasian adults with contrasting genetic predisposition to high blood pressure. Predisposition was defined on the basis of personal and parental blood pressure levels by using the four corners sampling method. Young adults with greatest predisposition who had high blood pressure and two parents with high blood pressure did not show any significant difference in the distribution of the markers of the ACE gene, either as genotype or allele frequencies, when compared with young adults with least predisposition who had low blood pressure and two parents with low blood pressure. Offspring with urinary sodium excretion above the median (143.4 mmol per day) also showed no significant differences in the distribution of ACE alleles or genotype between groups. Different genotypes were associated with different average serum ACE concentrations (p < 0.0001), but plasma angiotensin II and aldosterone showed no significant variation with ACE genotype. These results suggest that in a group of Caucasians selected from the general population, the ACE gene is not associated with genetic predisposition to high blood pressure. In this population common ACE gene allelic markers would not be useful indexes of susceptibility to hypertension.

Antihypertensive treatments obscure familial contributions to blood pressure variation.

Abstract—The linkage and association between inherent blood pressure and underlying genotype is potentially confounded by antihypertensive treatment. We estimated blood pressure variance components (genetic, shared environmental, individual-specific) in 767 adult volunteer families by using a variety of approaches to adjusting blood pressure of the 244 subjects (8.2%) receiving antihypertensive medications. The additive genetic component of variance for systolic pressure was 73.9 mm Hg2 (SE, 8.8) when measured pressures (adjusted for age by gender within each generation) were used but fell to 61.4 mm Hg2 (SE, 8.0) when treated subjects were excluded. When the relevant 95th percentile values were substituted for treated systolic pressures, the additive genetic component was 81.9 mm Hg2 (SE, 9.5), but individual adjustments in systolic pressure ranged from −53.5 mm Hg to +64.5 mm Hg (mean, +17.2 mm Hg). Instead, when 10 mm Hg was added to treated systolic pressure, the additive genetic component rose to 86.6 mm Hg2 (SE, 10.1). Similar changes were seen in the shared environment component of variance for systolic pressure and for the combined genetic and shared environmental (ie, familial) components of diastolic pressure. There was little change in the individual-specific variance component across any of the methods. Therefore, treated subjects contribute important information to the familial components of blood pressure variance. This information is lost if treated subjects are excluded and obscured by treatment effects if unadjusted measured pressures are used. Adding back an appropriate increment of pressure restores familial components, more closely reflects the pretreatment values, and should increase the power of genomic linkage and linkage disequilibrium analyses.