Robert D. Langer

Ankle brachial index combined with Framingham risk score to predict cardiovascular events and mortality - A meta-analysis

CONTEXT Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction. OBJECTIVE To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction. DATA SOURCES Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies. STUDY SELECTION Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality. DATA EXTRACTION Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease. RESULTS Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women. CONCLUSION Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS.

The epidemiology of peripheral arterial disease: importance of identifying the population at risk

Data from the Framingham Study and other population studies indicate that intermittent claudication (IC) sharply increases in late middle age and is somewhat higher among men than women. Noninvasive testing in populations indicates that the true prevalence of peripheral arterial disease (PAD) is at least five times higher than would be expected based on the reported prevalence of IC. Peripheral arterial disease correlates most strongly with cigarette smoking and either diabetes or impaired glucose tolerance. Other risk factors for PAD include hypertension; low levels of high-density lipoprotein cholesterol; and high levels of triglycerides, apolipoprotein B, lipoprotein(a), homocysteine, fibrinogen and blood viscosity. Individuals with PAD are more likely to have coronary heart disease and cerebrovascular disease than those without PAD. Because of the high risk of both nonfatal and fatal cardiovascular disease (CVD) events in PAD patients, individuals with evidence of PAD should undergo both a careful examination of the entire cardiovascular system and aggressive modification of CVD risk factors.

Lipoproteins and blood pressure as biological pathways for effect of moderate alcohol consumption on coronary heart disease.

BackgroundSeveral epidemiological studies have shown light-to-moderate alcohol consumption to have a net protective effect on the incidence of coronary heart disease (CHD). Methods and ResultsMajor components of this effect, both positive and negative, may be explored using models that include both alcohol and variables expected to mediate the observed alcohol effect. Such modeling in a cohort of men of Japanese descent followed in the Honolulu Heart Program indicates that about half of the observed protection against CHD afforded by moderate alcohol consumption is mediated by an increase in high density lipoprotein cholesterol. An additional 18% of this protection is attributable to a decrease in low density lipoprotein cholesterol, but it is counterbalanced by a 17% increase in risk due to increased systolic blood pressure. The explanation for the residual 59% benefit attributable to alcohol is unknown but may include interference with thrombosis. The results in this population replicate those in the Lipid Research Clinics cohort studied earlier with the same analytic technique. ConclusionsThe consistency of these findings across populations, along with the demonstration of reasonable biological pathways for this effect of alcohol, provides strong support for the hypothesis that light-to-moderate alcohol intake is protective against heart disease in men.

Ethnicity and peripheral arterial disease: the San Diego Population Study.

Background— Previous studies have indicated higher rates of peripheral arterial disease (PAD) in blacks than in non-Hispanic whites (NHWs), with limited information available for Hispanics and Asians. The reason for the PAD excess in blacks is unclear. Methods and Results— Ethnic-specific PAD prevalence rates were determined in a randomly selected defined population that included 4 ethnic groups; NHWs, blacks, Hispanics, and Asians. A total of 2343 participants aged 29 to 91 years were evaluated. There were 104 cases of PAD (4.4%). In weighted logistic models with NHWs as the reference group and containing demographic factors only, blacks had a higher PAD prevalence than NHWs (OR=2.30, P<0.024), whereas PAD rates in Hispanics and Asians, although somewhat lower, were not significantly different from NHWs. Blacks had significantly more diabetes and hypertension than NHWs and a significantly higher body mass index. Inclusion of these variables and other PAD risk factors in the model did not change the effect size for black ethnicity (OR=2.34, P=0.048). A model containing interaction terms for black ethnicity and each of the other risk factors revealed no significant interaction terms, which indicates no evidence that blacks were more “susceptible” than NHWs to cardiovascular disease risk factors. Conclusions— Black ethnicity was a strong and independent risk factor for PAD, which was not explained by higher levels of diabetes, hypertension, and body mass index. There was no evidence of a greater susceptibility of blacks to cardiovascular disease risk factors as a reason for their higher PAD prevalence. Thus, the excess risk of PAD in blacks remains unexplained and requires further study.

Effects of Offering Advance Directives on Medical Treatments and Costs

OBJECTIVE To examine the effects of advance directives on medical treatments and on patient satisfaction and well-being and to determine whether the enhancement of patient autonomy through advance directives provides a more ethically feasible approach to cost control than does the imposition of limits through rationing. DESIGN Randomized, controlled trial. SETTING University and Veterans Affairs medical center. PATIENTS Two hundred and four patients with life-threatening illnesses, 100 of whom died after enrollment in the study. INTERVENTION Patients randomly assigned to the experimental group were offered the California Durable Power of Attorney (a typical proxy-instruction directive), and patients assigned to the control group were not offered the advance directive. Hospital admissions were monitored to assure that a summary of the document was present in the active medical record at each hospitalization. MEASUREMENTS Cognitive function, patient satisfaction, psychological well-being, health locus of control, sense of coherence, health-related quality of life, receipt of medical treatments, and medical treatment charges. RESULTS No significant differences were found between advance-directive and control groups regarding psychosocial variables, health outcome variables, and medical treatments or charges. Patients offered an advance directive had an average hospital stay of 40.8 days (95% CI, 32.2 to 49.4 days), compared with an average of 33.1 days (95% CI, 26.0 to 40.2 days) for controls. Patients offered an advance directive were charged an average of

Measurement and predictors of resilience among community-dwelling older women

19,502 (95% CI,

Sleep detection with an accelerometer actigraph: comparisons with polysomnography

13,030 to

Mitral and Aortic Annular Calcification Are Highly Associated With Systemic Calcified Atherosclerosis

25,974) for medical treatments in the last month of life compared with

Benefits and Risks of Postmenopausal Hormone Therapy When It Is Initiated Soon After Menopause

19,700 (95% CI,

Risk of Cardiovascular Disease by Hysterectomy Status, With and Without Oophorectomy The Women’s Health Initiative Observational Study

13,704 to