Kristi Reynolds

Global burden of hypertension: analysis of worldwide data

BACKGROUND Reliable information about the prevalence of hypertension in different world regions is essential to the development of national and international health policies for prevention and control of this condition. We aimed to pool data from different regions of the world to estimate the overall prevalence and absolute burden of hypertension in 2000, and to estimate the global burden in 2025. METHODS We searched the published literature from Jan 1, 1980, to Dec 31, 2002, using MEDLINE, supplemented by a manual search of bibliographies of retrieved articles. We included studies that reported sex-specific and age-specific prevalence of hypertension in representative population samples. All data were obtained independently by two investigators with a standardised protocol and data-collection form. RESULTS Overall, 26.4% (95% CI 26.0-26.8%) of the adult population in 2000 had hypertension (26.6% of men [26.0-27.2%] and 26.1% of women [25.5-26.6%]), and 29.2% (28.8-29.7%) were projected to have this condition by 2025 (29.0% of men [28.6-29.4%] and 29.5% of women [29.1-29.9%]). The estimated total number of adults with hypertension in 2000 was 972 million (957-987 million); 333 million (329-336 million) in economically developed countries and 639 million (625-654 million) in economically developing countries. The number of adults with hypertension in 2025 was predicted to increase by about 60% to a total of 1.56 billion (1.54-1.58 billion). INTERPRETATION Hypertension is an important public-health challenge worldwide. Prevention, detection, treatment, and control of this condition should receive high priority.

Mortality Prediction with a Single General Self-Rated Health Question: A Meta-Analysis

AbstractOBJECTIVE: Health planners and policy makers are increasingly asking for a feasible method to identify vulnerable persons with the greatest health needs. We conducted a systematic review of the association between a single item assessing general self-rated health (GSRH) and mortality. DATA SOURCES: Systematic MEDLINE and EMBASE database searches for studies published from January 1966 to September 2003. REVIEW METHODS: Two investigators independently searched English language prospective, community-based cohort studies that reported (1) all-cause mortality, (2) a question assessing GSRH; and (3) an adjusted relative risk or equivalent. The investigators searched the citations to determine inclusion eligibility and abstracted data by following a standarized protocol. Of the 163 relevant studies identified, 22 cohorts met the inclusion criteria. Using a random effects model, compared with persons reporting “excellent” health status, the relative risk (95% confidence interval) for all-cause mortality was 1.23 [1.09, 1.39], 1.44 [1.21, 1.71], and 1.92 [1.64, 2.25] for those reporting “good,” “fair,” and “poor” health status, respectively. This relationship was robust in sensitivity analyses, limited to studies that adjusted for comorbid illness, functional status, cognitive status, and depression, and across subgroups defined by gender and country of origin. CONCLUSIONS: Persons with “poor” self-rated health had a 2-fold higher mortality risk compared with persons with “excellent” self-rated health. Subjects’ responses to a simple, single-item GSRH question maintained a strong association with mortality even after adjustment for key covariates such as functional status, depression, and co-morbidity.

The Obese Without Cardiometabolic Risk Factor Clustering and the Normal Weight With Cardiometabolic Risk Factor Clustering Prevalence and Correlates of 2 Phenotypes Among the US Population (NHANES 1999-2004)

BACKGROUND The prevalence and correlates of obese individuals who are resistant to the development of the adiposity-associated cardiometabolic abnormalities and normal-weight individuals who display cardiometabolic risk factor clustering are not well known. METHODS The prevalence and correlates of combined body mass index (normal weight, < 25.0; overweight, 25.0-29.9; and obese, > or = 30.0 [calculated as weight in kilograms divided by height in meters squared]) and cardiometabolic groups (metabolically healthy, 0 or 1 cardiometabolic abnormalities; and metabolically abnormal, > or = 2 cardiometabolic abnormalities) were assessed in a cross-sectional sample of 5440 participants of the National Health and Nutrition Examination Surveys 1999-2004. Cardiometabolic abnormalities included elevated blood pressure; elevated levels of triglycerides, fasting plasma glucose, and C-reactive protein; elevated homeostasis model assessment of insulin resistance value; and low high-density lipoprotein cholesterol level. RESULTS Among US adults 20 years and older, 23.5% (approximately 16.3 million adults) of normal-weight adults were metabolically abnormal, whereas 51.3% (approximately 35.9 million adults) of overweight adults and 31.7% (approximately 19.5 million adults) of obese adults were metabolically healthy. The independent correlates of clustering of cardiometabolic abnormalities among normal-weight individuals were older age, lower physical activity levels, and larger waist circumference. The independent correlates of 0 or 1 cardiometabolic abnormalities among overweight and obese individuals were younger age, non-Hispanic black race/ethnicity, higher physical activity levels, and smaller waist circumference. CONCLUSIONS Among US adults, there is a high prevalence of clustering of cardiometabolic abnormalities among normal-weight individuals and a high prevalence of overweight and obese individuals who are metabolically healthy. Further study into the physiologic mechanisms underlying these different phenotypes and their impact on health is needed.

Worldwide prevalence of hypertension: a systematic review.

Purpose To examine the prevalence and the level of awareness, treatment and control of hypertension in different world regions. Study selection A literature search of the MEDLINE database, using the Medical Subject Headings prevalence, hypertension, blood pressure and cross-sectional studies, was conducted. Published studies, which reported the prevalence of hypertension and were conducted in representative population samples, were included in the review. The search was restricted to studies published from January 1980 through July 2003. Data extraction All data were extracted independently by two investigators using a standardized protocol and data collection form. Results The reported prevalence of hypertension varied around the world, with the lowest prevalence in rural India (3.4% in men and 6.8% in women) and the highest prevalence in Poland (68.9% in men and 72.5% in women). Awareness of hypertension was reported for 46% of the studies and varied from 25.2% in Korea to 75% in Barbados; treatment varied from 10.7% in Mexico to 66% in Barbados and control (blood pressure < 140/90 mmHg while on antihypertensive medication) varied from 5.4% in Korea to 58% in Barbados. Conclusion Hypertension is an important public health challenge in both economically developing and developed countries. Significant numbers of individuals with hypertension are unaware of their condition and, among those with diagnosed hypertension, treatment is frequently inadequate. Measures are required at a population level to prevent the development of hypertension and to improve awareness, treatment and control of hypertension in the community.

Prevalence of the metabolic syndrome and overweight among adults in China.

BACKGROUND The metabolic syndrome and obesity are major risk factors for cardiovascular disease. Little information exists on the prevalence of the metabolic syndrome in China. We aimed to provide up-to-date estimates of the prevalence of the metabolic syndrome and overweight in the general adult population in China. METHODS We did a cross-sectional survey in a nationally representative sample of 15,540 Chinese adults aged 35-74 years in 2000-01. Metabolic syndrome was defined according to guidelines from the US National Cholesterol Education Program. Overweight was defined as body-mass index of 25.0 kg/m2 or greater. FINDINGS The age-standardised prevalence of metabolic syndrome was 9.8% (95% CI 9.0-10.6) in men and 17.8% (16.6-19.0) in women. The age-standardised prevalence of overweight was 26.9% (25.7-28.1) in men and 31.1% (29.7-32.5) in women. The prevalence of the metabolic syndrome and overweight was higher in northern than in southern China, and higher in urban than rural residents. INTERPRETATION Our results indicate that a large proportion of Chinese adults have the metabolic syndrome and that overweight has become an important public health problem in China. These findings emphasise the urgent need to develop national strategies for the prevention, detection, and treatment of overweight and the metabolic syndrome, to reduce the societal burden of cardiovascular disease in China.

Prevalence, Awareness, Treatment, and Control of Hypertension in China

Abstract—The objective of this study was to estimate the prevalence and distribution of hypertension and to determine the status of hypertension awareness, treatment, and control in the general adult population in China. The International Collaborative Study of Cardiovascular Disease in ASIA (InterASIA), conducted in 2000–2001, used a multistage cluster sampling method to select a nationally representative sample. A total of 15 540 adults, age 35 to 74 years, were examined. Three blood pressure measurements were obtained by trained observers by use of a standardized mercury sphygmomanometer after a 5-minute sitting rest. Information on history of hypertension and use of antihypertensive medications was obtained by use of a standard questionnaire. Hypertension was defined as a mean systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, and/or use of antihypertensive medications. Overall, 27.2% of the Chinese adult population age 35 to 74 years, representing 129 824 000 persons, had hypertension. The age-specific prevalence of hypertension was 17.4%, 28.2%, 40.7%, and 47.3% in men and 10.7%, 26.8%, 38.9%, and 50.2% in women age 35 to 44 years, 45 to 54 years, 55 to 64 years, and 65 to 74 years, respectively. Among hypertensive patients, only 44.7% were aware of their high blood pressure, 28.2% were taking antihypertensive medication, and 8.1% achieved blood pressure control (<140/90 mm Hg). Our results indicate that hypertension is highly prevalent in China. The percentages of those with hypertension who are aware, treated, and controlled are unacceptably low. These results underscore the urgent need to develop national strategies to improve prevention, detection, and treatment of hypertension in China.

Effect of Nocturnal Nasal Continuous Positive Airway Pressure on Blood Pressure in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a very common risk factor for hypertension, and continuous positive airway pressure (CPAP) has been widely used to treat OSA. We conducted a meta-analysis of randomized, controlled trials to evaluate the effects of CPAP on blood pressure, reported as either a primary or secondary end point, among patients with OSA. Studies were retrieved by searching Medline (January 1980 to July 2006), the Cochrane Database of Systematic Reviews, conference abstracts, and bibliographies of review and original articles. From 255 relevant reports, 16 randomized clinical trials were selected that compared CPAP to control among participants with OSA, had a minimum treatment duration of 2 weeks, and reported blood pressure changes during the intervention or control period. Data on sample size, participant characteristics, study design, intervention methods, duration, and treatment results were independently abstracted by 2 investigators using a standardized protocol. Data from 16 trials representing 818 participants were examined using a random-effects model. Mean net change in systolic blood pressure for those treated with CPAP compared with control was −2.46 mm Hg (95% CI: −4.31 to −0.62); mean net change in diastolic blood pressure was −1.83 mm Hg (95% CI: −3.05 to −0.61); and mean net change in mean arterial pressure was −2.22 mm Hg (95% CI: −4.38 to −0.05). Net reductions in blood pressure were not statistically different between daytime and nighttime. These results indicate that CPAP decreases blood pressure among those with OSA and may help prevent hypertension.

The Relationship Between Visit-to-Visit Variability in Systolic Blood Pressure and All-Cause Mortality in the General Population Findings From NHANES III, 1988 to 1994

Recent data suggest that visit-to-visit variability of blood pressure is associated with stroke incidence. Correlates of increased visit-to-visit variability in blood pressure and the relationship between variability and all-cause mortality were examined using data on US adults ≥20 years of age from the Third National Health and Nutrition Examination Survey (n=956). Three consecutive blood pressure readings were taken during 3 separate study visits from 1988 to 1994. Based on the mean of the second and third measurements from each visit, visit-to-visit blood pressure variability for each participant was defined using the standard deviation and coefficient of variation across visits. Mortality was assessed through December 31, 2006 (median follow-up=14 years; n=240 deaths). The mean of the standard deviation for systolic blood pressure across visits was 7.7 mm Hg. After multivariable adjustment, older age, female gender, history of myocardial infarction, higher mean systolic blood pressure and pulse pressure, and use of angiotensin converting enzyme inhibitors were associated with higher standard deviation in systolic blood pressure. The multivariable adjusted hazard ratios for all-cause mortality associated with a standard deviation of systolic blood pressure of 4.80 to 8.34 mm Hg and ≥8.35 mm Hg, versus <4.80 mm Hg, were 1.57 (95% CI, 1.07 to 2.18) and 1.50 (95% CI, 1.03 to 2.18), respectively. Results were similar when coefficient of variation for systolic blood pressure was evaluated. Visit-to-visit variability for diastolic blood pressure was not associated with mortality. In this population-based study of US adults, higher levels of short-term visit-to-visit variability in systolic blood pressure were associated with increased all-cause mortality.

Systematic review: glucose control and cardiovascular disease in type 2 diabetes.

Context The relative benefits and harms of intensive versus conventional glucose control for type 2 diabetes are controversial. Contribution This review of 5 large trials found that, compared with conventional control, intensive glucose control reduced the risk for cardiovascular disease (mostly nonfatal myocardial infarction) but not for cardiovascular death or all-cause mortality, and increased risk for severe hypoglycemia. Trial design, achieved control, and findings were heterogeneous: Early trials suggested possible decreased risk for death with intensive control, whereas some more recent trials suggested possible increased risk for death with more stringent control. Caution The investigators did not evaluate costs. They pooled summary findings from trials rather than individual data from patients. The Editors The prevalence of type 2 diabetes is increasing globally (13). Epidemiologic evidence indicates that diabetes is a major risk factor for cardiovascular disease (CVD), and recent data suggest that the CVD burden attributable to diabetes is on the rise (47). Clinical trials have shown that intensive glucose control reduces the risk for microvascular complications among patients with type 2 diabetes, but its effect on CVD, including coronary heart disease (CHD), stroke, and peripheral arterial disease, is uncertain (810). Early data from the UKPDS (United Kingdom Prospective Diabetes Study) 34 suggested a protective effect of improved glucose control on CVD, CVD deaths, and all-cause mortality (11). However, within the past year, 3 large randomized, controlled trials have reported conflicting results (1214). Although ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation) and VADT (Veterans Affairs Diabetes Trial) found no effect of intensive glucose control on major cardiovascular events (13, 14), ACCORD (Action to Control Cardiovascular Disease in Diabetes) identified an increased risk for death from cardiovascular causes and total mortality associated with intensive glucose control (12). On the basis of these results, a recent article by Montori and colleagues suggested that additional research is needed to confirm or refute the importance of tight glucose control (15). Thus, recommendations for health care providers regarding optimal hemoglobin A1c (HbA1c) levels in patients with type 2 diabetes remain unclear. Because of the early termination of ACCORD and fewer events than anticipated in ADVANCE and VADT, there is real concern that these studies were underpowered to capture the true effects of intensive glucose control on CVD risk (1214). Therefore, we conducted a meta-analysis of randomized, controlled trials to examine the effects of intensive glucose control on CVD among patients with type 2 diabetes. Furthermore, we examined the separate effects of intensive glucose control on all-cause mortality, CVD mortality, CHD, congestive heart failure (CHF), stroke, and peripheral artery disease. In an effort to explain incongruities among trial results, we conducted subgroup analyses and examined the occurrence of severe hypoglycemia. Methods Data Sources and Searches We developed and followed a standard protocol for all steps of the review. Investigators searched the MEDLINE database (January 1950 through April 2009) using the Medical Subject Headings cardiovascular diseases; coronary disease; stroke; peripheral vascular diseases; hypoglycemic agents; and diabetes mellitus, type 2, as well as the keywords coronary heart disease, glucose control, and glycemic control. We restricted the search to randomized, controlled trials conducted among human adults (age 19 years), with no language restrictions. We also manually searched references cited in the published original reports and contacted experts in the field. Study Selection Two investigators independently reviewed the contents of 341 abstracts or full-text manuscripts identified through the literature search to determine whether they met the eligibility criteria. Studies were eligible for inclusion if 1) the study was a randomized, controlled trial; 2) the study compared intensive glucose control with conventional treatment, with a priori specification of glycemic goals for the intensive and conventional glucose control groups; 3) clinical CVD was the primary end point; 4) the study sample size was 500 patients or more; and 5) the study participants had type 2 diabetes mellitus. Reviewers resolved disagreements about study inclusion or exclusion by consensus and by referring to the original reports. Data Extraction and Quality Assessment Study investigators independently abstracted data in duplicate using a standardized data collection form. Reviewers did not contact authors to request additional information. Reviewers abstracted characteristics of each trial and its participants. Reviewers critically appraised methodological characteristics of trials, such as randomization procedures, blinded assessment of outcomes, adjudication procedures for outcomes, and follow-up rates, but did not use a scoring system to formally rate study quality of the individual trials (Appendix Table 1). Appendix Table 1. Assessment of Methodological Characteristics Reviewers recorded the following as the main outcomes of interest: number of clinical CVD, CHD, stroke, and CHF events, along with cardiovascular deaths and all-cause mortality, for the intensive and conventional glucose control groups. Reviewers also recorded single end points, including nonfatal myocardial infarction, fatal myocardial infarction, nonfatal stroke, fatal stroke, and peripheral artery disease. In addition, reviewers recorded the number of severe hypoglycemic events for each trial group. Because definitions of certain composite outcomes varied between trials, each outcome is defined for each trial in Appendix Table 2. Appendix Table 2. Definitions of Composite Outcomes for Each Trial Data Synthesis and Analysis We examined the relationship between intensive glucose control and risk for all study outcomes using relative risk and risk difference measures. We calculated the relative risks in each trial on the basis of the number of events in the intensive glucose control and conventional treatment groups and used these estimates for pooling analyses. To estimate the risk difference, we first calculated the annual absolute risk for an event in participants in each trial group by dividing the number of events in each trial group by the corresponding number of person-years (estimated as median treatment time number of participants in the trial group). We then multiplied the annual absolute risk by 5 to estimate the 5-year risk among participants in each trial group. We calculated the risk difference for each trial by subtracting the 5-year risk in the conventional glucose control group from the 5-year risk in the intensive glucose control group. We logarithmically transformed the relative risks and risk differences and their corresponding standard errors to stabilize the variance and normalize their distribution. We pooled relative risks and risk differences using both fixed-effects and DerSimonian and Laird random-effects models (16). We used inverse variance weighting to calculate fixed- and random-effects summary estimates. We assessed heterogeneity formally by using the Dersimonian and Laird Q test, considering any P value less than 0.100 as evidence of heterogeneity, and by examining the I 2 quantity. Although fixed- and random-effects models yielded similar findings, we detected between-study heterogeneity for several study outcomes (severe hypoglycemia, cardiovascular deaths, all-cause mortality, and fatal myocardial infarction). Because of this heterogeneity and trial differences in median diabetes duration of participants, achieved HbA1c levels, and therapeutic regimens, we present results from the random-effects models. We conducted a prestated subgroup analysis to examine the effects of intensive glucose control on all study outcomes. We then compared the relative risks for CVD, CHD, CHF, stroke, cardiovascular deaths, all-cause mortality, and severe hypoglycemia, as well as fatal and nonfatal myocardial infarction, fatal and nonfatal stroke, and peripheral artery disease between the early UKPDS trials (8, 11) and the 3 more recent ACCORD, ADVANCE, and VADT trials (1214). We conducted all analyses by using Stata software, version 9.2 (Stata Corp, College Station, Texas). Role of the Funding Source This study was funded in part by a career development award from the National Heart, Lung, and Blood Institute and by an award from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The funding sources played no role in the study design; collection, analysis, and interpretation of the data; writing of the report; or decision to submit the paper for publication. Results Figure 1 depicts the study selection process. We excluded 2 trials, the Kumamoto Study (n = 110) and the Veterans Affairs (VA) Diabetes Feasibility Trial (n = 153), because of small sample sizes (9, 17). The VA Diabetes Feasibility Trial was a pilot study that examined whether intensive glucose control could be effectively sustained in patients with type 2 diabetes and was a precursor to the subsequent VADT. The Kumamoto Study examined the effects of intensive glucose control on microvascular complications of diabetes. The current meta-analysis included a total of 5 trials conducted among 27 802 participants (8, 1114). Table 1 presents the characteristics of the 5 randomized, controlled trials and trial participants. The number of trial participants ranged from 753 to 11 140, while intervention duration ranged from 3.4 to 10.7 years. The UKPDS 33 and 34 recruited participants with newly diagnosed diabetes. Those inclusion criteria differed from those of ADVANCE, ACCORD and VADT, whose participants had an average duration of diabetes ranging

Epidemiology of the Metabolic Syndrome

The clustering of cardiovascular risk factors, known as the metabolic syndrome, greatly increases the risk of developing diabetes, kidney disease, and cardiovascular disease. Individuals with the metabolic syndrome are also at increased risk for premature death from cardiovascular disease or all-cause mortality. Cross-sectional and longitudinal epidemiologic studies provide prevalence data on the syndrome based on criteria proposed by the World Health Organization and the National Cholesterol Education Program Adult Treatment Panel III. Owing to differences in the criteria, estimates of the prevalence of the syndrome vary according to the criteria used. Generally, the syndrome is more common in older people and in the United States and it is more prevalent among Mexican Americans. Obesity and sedentary lifestyles are major contributing factors to the syndrome and provide opportunities for interventions. Recent data from a randomized controlled trial indicate that a weight loss and exercise intervention reduced the incidence of the metabolic syndrome by 41% among individuals with impaired glucose tolerance. Pharmacologic treatment of the individual components of the metabolic syndrome provides an alternate strategy for managing the syndrome. The rising global epidemics of overweight and obesity will likely lead to increases in the prevalence of the metabolic syndrome posing a serious burden for clinicians and public health officials.