Demographic differences in the treatment and control of glucose in type 2 diabetic patients: implications for health care practice

OBJECTIVE

Identifying modifiable covariables that reduce demographic disparities in controlling type 2 diabetes could inform efforts to improve health equity.

RESEARCH DESIGN AND METHODS

This retrospective study utilized electronic health record data on 22,285 adults with type 2 diabetes seen at 110 outpatient clinics in the Southeast U.S. from 2004-2008. Demographic differences in diabetes control and modifiable covariables which reduce those disparities were quantified using descriptive and logistic regression analysis.

RESULTS

Patients were 55.8 +/- 14.6 (SD) years old, 57.5% women, 61.0% white: 39.0% black and had baseline body mass index 34. +/- .3 kg/ m2 and HbA1c 7.61 +/- 1.9%. The percentage with HbAlc <7% was higher in Whites than blacks (55.6% vs. 44.7%, P < .0001) and rose with age in all patients from 45.3% at <50, to 50.0% at 50-64, and 59.6% at > or =65 years, P < .001. white vs. black race (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.51-1.68) and age/ 10 years (OR 1.20/10 years, 95% CI 1.17-1.22) were predictors of HbAlc <7% in univariable logistic regression. In multivariable analysis, three modifiable covariables (initial HbAlc, therapeutic inertia, visit frequency) accounted for 47.9% of variance in diabetes control. When accounting for these modifiable covariables, the independent impact of race/ethnicity (OR 1.21, 95% CI 1.13-1.30) and age (OR 1.13, 95% Cl 1.11-1.16) on HbA1c control declined.

CONCLUSIONS

Race and age-related difference in diabetes control declined significantly when modifiable covariates were considered. Greater attention to early diagnosis and treatment, ensuring regular healthcare visits and overcoming therapeutic inertia could improve diabetes control and health equity.

Training providers in hypertension guidelines: cost-effectiveness evaluation of a continuing medical education program in South Carolina

BACKGROUND

Translation of published guidelines to clinical practice through continuing medical education (CME) can be effective at changing provider practice patterns and patient outcomes. Yet, cost-effectiveness analyses of CME interventions are rare. This study analyzed the cost-effectiveness of a CME program for improving patient hypertension outcomes relative to usual care.

METHODS

A CME, conducted by the Carolinas and Georgia chapter of the American Society of Hypertension, the Medical University of South Carolina, and the Heart Disease and Stroke Prevention Division of the South Carolina Department of Health and Environmental Control, trained primary care providers in evidence-based guidelines for hypertension prevention and control. A cost-effectiveness simulation model was created with inputs from primary data collection of program costs and secondary data analysis of the Hypertension Initiative Database for years 2000 through 2008. The data analysis consisted of a convenience sample of 8,183 patients in the Hypertension Initiative Database who saw a CME-trained provider at least once before and after the provider's training. Control patients saw providers who did not attend a CME program and were matched to CME patients using propensity score matching.

RESULTS

Incremental life-years gained (LYG) for CME compared with no intervention were 0.003 per patient. The incremental cost-effectiveness ratio was $39,494 ($19,184-$73,864) per LYG under optimistic assumptions and $54,755 ($32,423-$95,728) per LYG under pessimistic assumptions. These results were most sensitive to changes in the effectiveness of the intervention on systolic blood pressure.

CONCLUSIONS

The intervention is likely a cost-effective strategy to address hypertension in a real-world setting and can serve as a model for future innovations in hypertension prevention.

Progression is accelerated from prehypertension to hypertension in blacks

Prehypertension is a major risk factor for hypertension. Blacks have more prevalent and severe hypertension than whites, but it is unknown whether progression from prehypertension is accelerated in blacks. We examined this question in a prospective cohort study of 18 865 nonhypertensive persons (5733 black [30.4%] and 13 132 white [69.6%]) aged 18 to 85 years. Electronic health record data were obtained from 197 community-based outpatient clinics in the Southeast United States. Days elapsing from study entry to hypertension diagnosis, mainly blood pressure ≥140 mm Hg systolic and/or ≥90 mm Hg diastolic on 2 consecutive visits established conversion time within a maximum observation period of 2550 days. Cox regression modeling was used to examine conversion to hypertension as a function of race, while controlling for age, sex, baseline systolic and diastolic blood pressures, body mass index, diabetes mellitus, and chronic kidney disease. The covariable adjusted median conversion time when 50% became hypertensive was 365 days earlier for blacks than whites (626 versus 991 days; P<0.001). Among covariables, baseline systolic blood pressure 130 to 139 mm Hg (hazard ratio: 1.77 [95% CI: 1.69 to 1.86]) and 120 to 129 mm Hg (hazard ratio: 1.52 [95% CI: 1.44 to 1.60]), as well as age ≥75 years (hazard ratio: 1.40 [95% CI: 1.29 to 1.51]) and 55 to 74 years (hazard ratio: 1.29 [95% CI: 1.23 to 1.35]) were the strongest predictors of hypertension. Additional predictors included age 35 to 54 years, diastolic blood pressure 80 to 89 mm Hg, overweight and obesity, and diabetes mellitus (all P<0.001). Conversion from prehypertension to hypertension is accelerated in blacks, which suggests that effective interventions in prehypertension could reduce racial disparities in prevalent hypertension.

Prevalence and management of hypertension in the inpatient setting: a systematic review

BACKGROUND

Hypertension (HTN) is a major cardiovascular risk factor yet control rates remain suboptimal. Thus, improving recognition, treatment, and control of HTN by focusing on novel populations such as hospitalized patients is warranted. Current consensus guidelines do not address inpatient HTN, and little is known about HTN prevalence or patterns of care in this setting.

METHODS

We conducted a systematic review of English-language studies published in 1976 or later that reported on HTN prevalence and care patterns among adult inpatients. We included MEDLINE-indexed randomized-controlled trials, meta-analyses, and observational studies that: (1) reported estimates of the prevalence of HTN in the inpatient setting, and (2) used HTN diagnosis or treatment as a primary focus. We excluded randomized, controlled trials that recorded measures of inpatient blood pressure but whose focus was not HTN.

RESULTS

We identified 9 studies meeting inclusion criteria, and in those studies, HTN was highly prevalent among inpatients, ranging from 50.5% to 72%. Intensification of antihypertensive treatment was inconsistent, and 37% to 77% of hypertensive patients remained hypertensive at the time of discharge. Most patients with inpatient HTN continued to have elevated blood pressures at outpatient follow-up.

CONCLUSIONS

Inpatient HTN is prevalent and a large percentage of those with this condition remain hypertensive at the time of discharge and at follow-up. The potential exists for improved recognition and treatment of newly diagnosed and known, but uncontrolled, HTN observed in the inpatient setting.

Uncontrolled and apparent treatment resistant hypertension in the United States, 1988 to 2008

BACKGROUND

Despite progress, many hypertensive patients remain uncontrolled. Defining characteristics of uncontrolled hypertensives may facilitate efforts to improve blood pressure control.

METHODS AND RESULTS

Subjects included 13,375 hypertensive adults from National Health and Nutrition Examination Surveys (NHANESs) subdivided into 1988 to 1994, 1999 to 2004, and 2005 to 2008. Uncontrolled hypertension was defined as blood pressure ≥140/≥90 mm Hg and apparent treatment-resistant hypertension (aTRH) when subjects reported taking ≥3 antihypertensive medications. Framingham 10-year coronary risk was calculated. Multivariable logistic regression was used to identify clinical characteristics associated with untreated, treated uncontrolled on 1 to 2 blood pressure medications, and aTRH across all 3 survey periods. More than half of uncontrolled hypertensives were untreated across surveys, including 52.2% in 2005 to 2008. Clinical factors linked with untreated hypertension included male sex, infrequent healthcare visits (0 to 1 per year), body mass index <25 kg/m2, absence of chronic kidney disease, and Framingham 10-year coronary risk <10% (P<0.01). Most treated uncontrolled patients reported taking 1 to 2 blood pressure medications, a proxy for therapeutic inertia. This group was older, had higher Framingham 10-year coronary risk than patients controlled on 1 to 2 medications (P<0.01), and comprised 34.4% of all uncontrolled and 72.0% of treated uncontrolled patients in 2005 to 2008. We found that aTRH increased from 15.9% (1998-2004) to 28.0% (2005-2008) of treated patients (P<0.001). Clinical characteristics associated with aTRH included ≥4 visits per year, obesity, chronic kidney disease, and Framingham 10-year coronary risk >20% (P<0.01).

CONCLUSION

Untreated, undertreated, and aTRH patients have consistent characteristics that could inform strategies to improve blood pressure control by decreasing untreated hypertension, reducing therapeutic inertia in undertreated patients, and enhancing therapeutic efficiency in aTRH.

Impacting population cardiovascular health through a community-based practice network: update on an ASH-supported collaborative

The Hypertension Initiative began in 1999 to help transition South Carolina from a leader in cardiovascular disease (CVD) to a model of heart and vascular health. Goals were to reduce heart disease and stroke by 50% by promoting healthy lifestyles and access to effective care and medications. Continuing medical education was used to train providers, encourage physicians to become American Society of Hypertension (ASH)-certified hypertension specialists and recruit practices into the community-based practice network (CBPN). Practice data audit with provider specific feedback is a key quality improvement tool. With ASH support, the CBPN has grown to 197 practices with approximately 1.6 million patients (approximately 700,000 hypertensives). Clinical data are obtained from electronic health records and quarterly provider feedback reports are generated. Hypertension, hypercholesterolemia, and diabetes control rose and South Carolina's ranking improved from 51st to 35th in CVD mortality from 1995 to 2006. The Hypertension Initiative expanded to the Outpatient Quality Improvement Network (O'QUIN) to encompass comparative effectiveness research and other chronic diseases. Lessons learned include: trust enables success, addressing practice priorities powers participation, infrastructure support must be multilateral, and strategic planning identifies opportunities and pitfalls. A collaborative practice network is attainable that produces positive, sustainable, and growing impacts on cardiovascular and other chronic diseases.

Office and ambulatory blood pressure-lowering effects of combination valsartan/hydrochlorothiazide vs. hydrochlorothiazide-based therapy in obese, hypertensive patients

The authors evaluated the blood pressure (BP)-lowering effects of combination valsartan/hydrochlorothiazide (HCTZ) vs. amlodipine/HCTZ in a 16-week, double-blind, randomized, forced-titration study and ambulatory BP monitoring (ABPM) substudy involving centrally obese hypertensive patients 40 years and older. Patients were started on valsartan/HCTZ 160/12.5 mg or HCTZ 12.5 mg monotherapy, force-titrated at week 4 to valsartan/HCTZ 320/25 mg and HCTZ 25 mg, respectively. The HCTZ group initiated amlodipine 5 mg at week 8 and 10 mg at week 12. A subset of patients had 24-hour ABPM at baseline and weeks 8 and 16. At week 16 in the intent-to-treat population (n=401), valsartan/HCTZ and amlodipine/HCTZ lowered office systolic BP (-30.6 vs. -28.3 mm Hg; P=.14). In the ABPM subgroup (n=111), valsartan/HCTZ was more effective than amlodipine/HCTZ in reducing 24-hour systolic BP (-20.6 vs. -14.5 mm Hg; P=.011). In obese hypertensive patients, valsartan/HCTZ reduced office BP similar to amlodipine/HCTZ but lowered 24-hour systolic BP more.

Prehypertension: an opportunity for a new public health paradigm

From 2005 to 2006, approximately 3 of 8 adults in the United States had blood pressure (BP) in the prehypertensive range of 120 to 139/80 to 89 mm Hg and roughly 1 in 8 adults had BP in the range of 130 to 139/85 to 89 mm Hg, which is referred to as high normal BP or stage 2 prehypertension. Adults with stage 2 prehypertension are also roughly twice as likely as adults with normotension to suffer cardiovascular disease. The Seventh Report of the Joint National Committee on Hypertension recommended only lifestyle changes for most prehypertensive patients. BP in the range of 120 to 129/80 to 84 mm Hg is also associated with increased risk but roughly half of that of stage 2 prehypertension.

A cluster-randomized effectiveness trial of a physician-pharmacist collaborative model to improve blood pressure control

Numerous studies have demonstrated the value of team-based care to improve blood pressure (BP) control, but there is limited information on whether these models would be adopted in diverse populations. The purpose of this study was to evaluate whether a collaborative model between physicians and pharmacists can improve BP control in multiple primary care medical offices with diverse geographic and patient characteristics and whether long-term BP control can be sustained. This study is a randomized prospective trial in 27 primary care offices first stratified by the percentage of underrepresented minorities and the level of clinical pharmacy services within the office. Each office is then randomized to either a 9- or 24-month intervention or a control group. Patients will be enrolled in this study until 2012. The results of this study should provide information on whether this model can be implemented in large numbers of diverse offices, if it is effective in diverse populations, and whether BP control can be sustained long term.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00935077.

Cardiovascular disease risk factor clustering among African American adults

OBJECTIVES

Although the co-occurrence of multiple risk factors increases the risk of cardiovascular disease (CVD) morbidity/mortality, few studies have examined the prevalence of risk factor clustering among African Americans in community-based faith settings. This study examined the prevalence and clustering of CVD risk factors in a sample of church members from South Carolina.

DESIGN

Cross-sectional analysis of baseline data from a faith-based intervention, Faith, Activity, and Nutrition (FAN).

SETTING

African Methodist Episcopal churches in four geographically-defined districts in South Carolina.

PARTICIPANTS

1119 church members.

MAIN OUTCOME MEASURES

Self-reported presence or absence of healthcare provider diagnosed diabetes, high cholesterol, and hypertension. Objectively measured blood pressure, height, and weight (body mass index) were also taken. The prevalence of single, multiple, and clustering of risk factors was computed.

RESULTS

62% of participants were obese, 64% had hypertension, 23% had diabetes, and 39% had high cholesterol; 15% had no risk factors, 24% had 1 risk factor, 30% had 2 risk factors, 22% had 3 risk factors, and 10% had 4 risk factors. The most common clusters of risk factors were: obese and hypertensive (18%), obese, hypertensive and hypercholesterolemic (13%), and obese, hypertensive, hypercholesterolemic, and diabetic (10%).

CONCLUSIONS

The prevalence of risk factors and risk factor clustering in church members in South Carolina is exceedingly high. Culturally-relevant behavioral interventions targeting risk factor reduction in this population should be a public health goal.

Angiotensin receptor blocker/diuretic combination preserves insulin responses in obese hypertensives

BACKGROUND

Thiazide diuretics can impair glucose metabolism and increase new-onset diabetes. Adding an angiotensin receptor blocker to diuretics may protect against these metabolic effects; however, the mechanism of this protection is unclear.

METHOD

To explore potential mechanisms, a 16-week multicenter trial was conducted to ascertain the relative glucose metabolism effects of combined hydrochlorothiazide and angiotensin receptor blocker (valsartan) therapy compared with hydrochlorothiazide and calcium channel blocker (amlodipine) treatment in 412 centrally obese hypertensive individuals (BMI = 35 +/- 7 kg/m, seated BP = 159 +/- 8/94 +/- 8 mmHg, and mean age 56 years). Individuals were randomized to valsartan/hydrochlorothiazide, with force-titration to 320/25 mg or hydrochlorothiazide, with titration to hydrochlorothiazide 25 mg and amlodipine 10 mg, respectively. Changes from baseline to week 16 in fasting and 2-h postprandial glucose and insulin levels after an oral glucose load were measured.

RESULTS

At week 16, clinic blood pressure reductions were similar (P > 0.05) in both groups. Fasting and 2-h glucose levels increased (P < 0.05) with the amlodipine combination but not with the valsartan combination. In concert with these glucose responses, postprandial insulin increases from baseline were substantially greater with valsartan than with amlodipine plus hydrochlorothiazide group (P = 0.001). The glucose responses were inversely related to insulin responses at the study conclusion.

CONCLUSION

The novel observation of this investigation was that the combination of valsartan and hydrochlorothiazide was associated with greater glucose-stimulated insulin secretory and lesser glycemic excursion responses than the amlodipine combination group. Thus, this data suggests that adding an angiotensin receptor blocker attenuates the negative effects of thiazides on pancreatic beta-cell glucose-induced insulin secretion.

Antihypertensive medication prescribing patterns in a university teaching hospital

Treatment of hypertension among hospitalized patients represents an opportunity to improve blood pressure recognition and treatment. To address this issue, the authors examined patterns of antihypertensive medication prescribing among 5668 hypertensive inpatients. Outcomes were treatment with any antihypertensive medication and treatment with first-line therapy, defined as angiotensin-converting enzyme inhibitors, beta-blockers, thiazide diuretics, or calcium channel blockers. Logistic regression models adjusting for age, sex, race, length of stay, service line, and comorbidity were used for all comparisons. The multivariate-adjusted odds ratios for treatment were higher for men (1.4, P<.001), older patients (2.5 for age older than 80 vs 1.0 for age younger than 40; P<.001), non-white race (1.2 vs 1.0 for white race; P<.004), and generalist service line (1.4 vs 1.0 for all other services; P<.001). Multivariate-adjusted odds ratios for receiving first-line agents were higher for older patients and generalist service line. Among surgical patients, receipt of medical consultation was only marginally associated with higher odds of antihypertensive or first-line treatment after adjustment for relevant clinical variables. Demographic factors and service line appear to play a major role in determining the likelihood of inpatient hypertension treatment. Understanding and addressing these disparities has the potential to incrementally improve hypertension control rates in the population.

Prevalence of hypertension by duration and age at exposure to the stroke belt

Geographic variation in hypertension is hypothesized as contributing to the stroke belt, an area in the southeastern United States with high stroke mortality. No study has examined hypertension by lifetime exposure to the stroke belt. This association was studied in 19,385 participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study, a national population-based cohort. Prevalent hypertension was defined as systolic blood pressure >/=140, diastolic blood pressure >/=90, or use of antihypertensive medications. Stroke belt exposure was assessed by residence at birth, currently, early childhood, adolescence, early adulthood, mid-adulthood, and recently. After adjustment for age, race, sex, physical activity level, body mass index, smoking, alcohol, education, and income, the prevalence of hypertension was significantly more strongly related (P < .0001) with lifetime exposure, adolescence, or early adulthood exposure than exposures at other times. Birthplace and current residence were independently associated with hypertension; however, lifetime, adolescence, or early adulthood exposures were more predictive than joint model with both birthplace and current residence. That adolescence and early adulthood periods are more predictive than residence in the stroke belt for most recent 20-year period suggests community and environmental strategies to prevent hypertension need to start earlier in life.

US trends in prevalence, awareness, treatment, and control of hypertension, 1988-2008

CONTEXT

Hypertension is a major risk factor for cardiovascular disease and treatment and control of hypertension reduces risk. The Healthy People 2010 goal was to achieve blood pressure (BP) control in 50% of the US population.

OBJECTIVE

To assess progress in treating and controlling hypertension in the United States from 1988-2008.

DESIGN, SETTING, AND PARTICIPANTS

The National Health and Nutrition Examination Survey (NHANES) 1988-1994 and 1999-2008 in five 2-year blocks included 42 856 adults aged older than 18 years, representing a probability sample of the US civilian population.

MAIN OUTCOME MEASURES

Hypertension was defined as systolic BP of at least 140 mm Hg and diastolic BP of at least 90 mm Hg, self-reported use of antihypertensive medications, or both. Hypertension control was defined as systolic BP values of less than 140 mm Hg and diastolic BP values of less than 90 mm Hg. All survey periods were age-adjusted to the year 2000 US population.

RESULTS

Rates of hypertension increased from 23.9% (95% confidence interval [CI], 22.7%-25.2%) in 1988-1994 to 28.5% (95% CI, 25.9%-31.3%; P < .001) in 1999-2000, but did not change between 1999-2000 and 2007-2008 (29.0%; 95% CI, 27.6%-30.5%; P = .24). Hypertension control increased from 27.3% (95% CI, 25.6%-29.1%) in 1988-1994 to 50.1% (95% CI, 46.8%-53.5%; P = .006) in 2007-2008, and BP among patients with hypertension decreased from 143.0/80.4 mm Hg (95% CI, 141.9-144.2/79.6-81.1 mm Hg) to 135.2/74.1 mm Hg (95% CI, 134.2-136.2/73.2-75.0 mm Hg; P = .02/P < .001). Blood pressure control improved significantly more in absolute percentages between 1999-2000 and 2007-2008 vs 1988-1994 and 1999-2000 (18.6%; 95% CI, 13.3%-23.9%; vs 4.1%; 95% CI, -0.5% to 8.8%; P < .001). Better BP control reflected improvements in awareness (69.1%; 95% CI, 67.1%-71.1%; vs 80.7%; 95% CI, 78.1%-83.0%; P for trend = .03), treatment (54.0%; 95% CI, 52.0%-56.1%; vs 72.5%; 95% CI, 70.1%-74.8%; P = .004), and proportion of patients who were treated and had controlled hypertension (50.6%; 95% CI, 48.0%-53.2%; vs 69.1%; 95% CI, 65.7%-72.3%; P = .006). Hypertension control improved significantly between 1988-1994 and 2007-2008, across age, race, and sex groups, but was lower among individuals aged 18 to 39 years vs 40 to 59 years (P < .001) and 60 years or older (P < .001), and in Hispanic vs white individuals (P = .004).

CONCLUSIONS

Blood pressure was controlled in an estimated 50.1% of all patients with hypertension in NHANES 2007-2008, with most of the improvement since 1988 occurring after 1999-2000. Hypertension control was significantly lower among younger than middle-aged individuals and older adults, and Hispanic vs white individuals.

Does dark chocolate have a role in the prevention and management of hypertension?: commentary on the evidence

The notion that eating chocolate would prevent or treat hypertension is appealing to many who produce and enjoy chocolate. Several studies have documented beneficial effects of dark chocolate on insulin action and endothelial function. However, the published studies on chocolate and blood pressure include a relatively small number of subjects, and results are conflicting. In addition, because of secrecy surrounding the production of chocolate and the unique sociocultural context of this popular food, research on efficacy and effectiveness is complex. This commentary summarizes 13 peer-reviewed studies on dark chocolate and blood pressure and raises questions relevant to its future as an evidence-based lifestyle intervention.

DASH lowers blood pressure in obese hypertensives beyond potassium, magnesium and fibre

The mechanism underlying blood pressure (BP) reduction in the high fruits and vegetables arm of the Dietary Approaches to Stop Hypertension (DASH) study is unknown but may include potassium, magnesium and fibre. This study was designed to separate minerals and fibre from other components of DASH on BP in abdominally obese individuals with metabolic syndrome with pre-hypertension to stage 1 hypertension (obese hypertensives). A total of 15 obese hypertensives and 15 lean normotensives were studied on a standardized usual diet, randomized to DASH or usual diet supplemented with potassium, magnesium and fibre to match DASH, then crossed over to the complementary diet. All diets were 3 weeks long, isocaloric and matched for sodium and calcium. In obese hypertensives, BP was lower after 3 weeks on DASH than usual diet (-7.6+/-1.4/-5.3+/-1.4 mm Hg, P<0.001/0.02) and usual diet supplemented (-6.2+/-1.4/-3.7+/-1.4 P<0.005/0.06), whereas BP was not significantly different on usual and supplemented diets. BP values were not different among the three diets in lean normotensives. Small artery elasticity was lower in obese hypertensives than in lean normotensives on the usual and supplemented diets (P<0.02). This index of endothelial function improved in obese hypertensives (P<0.02) but not lean normotensives on DASH, and was no longer different from values in lean normotensives (P>0.50). DASH is more effective than potassium, magnesium and fibre supplements for lowering BP in obese hypertensives, which suggest that high fruits and vegetables DASH lowers BP and improves endothelial function in this group by nutritional factors in addition to potassium, magnesium and fibre.

Low-Sodium DASH reduces oxidative stress and improves vascular function in salt-sensitive humans

Salt induces oxidative stress in salt-sensitive (SS) animals and man. It is not known whether in SS subjects the low-sodium dietary approaches to stop hypertension (LS-DASH) reduces oxidative stress more than DASH, which is high in antioxidants. To assess the effects of DASH and LS-DASH on oxidative stress, 19 volunteers were studied after 3 weeks of a standardized usual low fruits and vegetables diet (ULFV), followed by 3 weeks on DASH (both diets approximately 120 mmol Na(+) per day), then 3 weeks on LS-DASH (60 mmol Na(+) per day). SS was defined as systolic blood pressure >or=5 mm Hg lower on LS-DASH than DASH. In SS subjects (N=9), systolic blood pressure was lower on LS-DASH (111.0+/-2.0 mm Hg) than DASH (118.0+/-2.2, P<0.01) and ULFV (122.3+/-2.7, P=0.002). In salt-resistant (SR) volunteers (N=10), systolic blood pressure was lower on DASH (113.0+/-1.6) than ULFV (119.0+/-1.8, P<0.05) but not LS-DASH (115.7+/-1.8). Urine F2-isoprostanes, a marker of oxidative stress, were lower in SS subjects on LS-DASH (1.69+/-0.24) than ULFV (3.09+/-0.50, P<0.05) and marginally lower than DASH (2.46+/-0.44, P<0.20). F2-isoprostanes were not different among the three diets in SR volunteers (2.18+/-0.29, 2.06+/-0.29, 2.27+/-0.53, respectively). Aortic augmentation index, a measure of vascular stiffness, was lower in SS subjects on LS-DASH than either DASH or ULFV, and lower on DASH than ULFV in SR volunteers. In SS but not SR subjects, LS-DASH is associated with lower values for F2-isoprostanes and the aortic augmentation index. The results suggest that LS-DASH decreases oxidative stress, improves vascular function and lowers blood pressure in SS but not SR volunteers.

The role of sympathetic activation in cardiovascular disease

Activation of the sympathetic nervous system plays an important role in the development and maintenance of essential hypertension and the subsequent development of cardiac hypertrophy, heart failure, and sudden cardiac death. Current research suggests that pharmacologic treatment of hypertension should be aimed not only at lowering blood pressure, but also at inhibiting sympathetic drive.