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Biomedical subjects

R D Langer

Publications and source records attributed to R D Langer.

At least 37 records · Page 2Linked to original sources
PubMed1995

The epidemiology of hypertension control in populations.

Despite an aging population, prevalence rates for hypertension in the U.S. remain stable due to a decrease in rates in women but a corresponding increase in rates for men. Epidemiological factors which may contribute to these rates are discussed. The lack of a threshold for the association between blood pressure and disease events means that the majority of events occur in the larger number of people with mild disease. Because the efficacy and cost-effectiveness of medical therapy to lower mildly elevated blood pressure remains controversial, population-based strategies to effect behavior change are the most prudent course for this, the largest group at risk. Targeted, resource-intensive medical intervention for those at high risk combined with hygienic measures for the population with mildly elevated blood pressure from the basis for an effective public health strategy.

Blood Pressure↗
PubMed1994

Screening for peripheral arterial disease: the sensitivity, specificity, and predictive value of noninvasive tests in a defined population.

Large vessel peripheral arterial disease (LV-PAD) is a common condition that causes significant morbidity and disability. The authors evaluated the individual components of a comprehensive noninvasive vascular examination to identify the most sensitive and specific measurements for diagnosing LV-PAD. This cohort, initially screened between 1979 and 1981 in Rancho Bernardo, California, included 421 normal subjects and 63 subjects with LV-PAD. Segmental blood pressure ratios and flow velocities by Doppler ultrasound were used to define cases of LV-PAD. The sensitivity, specificity, positive predictive value, and negative predictive value of each individual component of the diagnostic algorithm were determined. Overall, measurements of posterior tibial flow showed the highest sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy. In addition, an absent or non-recordable posterior tibial peak forward flow, occurring in 96% of all limbs with isolated posterior tibial disease, or an ankle ratio < or = 0.8 considered in parallel yielded a test with sensitivity of 89%, specificity of 99%, positive predictive value of 90%, negative predictive value of 99%, and overall accuracy of 98%. These results indicate that the vast majority of LV-PAD cases can be detected with a single measurement using a handheld Doppler flowmeter employed at the ankle.

Adult↗
PubMed1994

Extended hormone replacement: who should get it, and for how long?

Hormone replacement therapy (HRT) after menopause may prevent cardiovascular disease and osteoporosis, chronic diseases that become increasingly important with age. For cardiovascular disease, this protection may be greatest in women with more risk factors, including age. Data suggest that HRT may mitigate bone loss in women 15 years or more past menopause, but reports are inconclusive regarding how HRT initiated after substantial bone is lost affects fracture incidence. The most troubling question is the possible association between HRT and breast cancer. Both clinician and patient must be aware of the potential for hormone-related symptoms following the initiation of HRT. Most symptoms fade in the first few months, but older women may be less willing to accept these problems unless they are provided a clear rationale for therapy.

Adult↗
PubMed1993

Effects of a preventive cardiology curriculum on behavioral cardiovascular risk factors and knowledge of medical students.

We evaluated a Preventive Cardiology Academic Award (PCAA) program designed to integrate preventive cardiology concepts into the medical school curriculum. Diet, preventive cardiology knowledge, preventive cardiology attitudes, exercise behavior, and body mass index were compared at entrance to medical school and during the graduation year. Complete data were available on 94 students (65 men and 29 women). Similar data from students who graduated in 1987, prior to the introduction of the PCAA curriculum, served as a control. Women showed a significant enhancement in attitude towards cardiovascular disease (CVD) prevention, while both men and women significantly increased their knowledge about CVD prevention. The frequency of planned physical activity decreased significantly in both sexes and men showed a significant increase in body mass index. Men significantly reduced total calories, percent of calories from fat and saturated fat and dietary cholesterol and increased fiber intake. In women, the only significant reduction was in total calories. In comparison to the control class that did not have the program, men receiving the PCAA curriculum reduced dietary cholesterol, dietary fat, saturated fat and monounsaturated fat. Changes in these dietary parameters were nonsignificant for women in comparison to the control class women. Additional analyses showed no systematic secular trends in dietary or other variables in classes entering from 1986 to 1990. We conclude that the PCAA curriculum changes have favorably affected the preventive cardiology knowledge, attitudes and diet of medical students.

Adult↗
PubMed1993

Blood pressure change and survival after age 75.

Higher diastolic pressure predicted better survival in men 75 years or older in two prior analyses in the Rancho Bernardo population. Diastolic change was implicated as a possible explanation. We studied this by assessing survival according to blood pressure change in 795 men and women aged 75 years and older at the time of a second measurement taken an average of 11 years after the first, who were then followed for 5 years. Sex-specific analyses compared participants with a diastolic decrease of 5 mm Hg or greater and participants with a systolic decrease of 10 mm Hg or greater with those whose blood pressure levels did not change or increased. In men, after adjustment for baseline pressure, a decrease in diastolic pressure of 5 mm Hg or greater was associated with higher all-cause mortality (relative risk, 2.33; 95% confidence interval, 1.39 to 3.91) and cardiovascular mortality (3.13, 1.47 to 6.66). The mortality risk was strongest in men who took antihypertensive medication and had a fall in diastolic pressure (12.33, 2.73 to 55.72) compared with treated men whose pressures did not decrease. Among men with isolated systolic hypertension, those treated whose diastolic pressure remained stable had the best survival. A systolic fall in men and a decrease in either diastolic or systolic in women was not associated with poorer survival after adjustment for baseline pressure. We conclude that a fall in diastolic pressure of 5 mm Hg was associated with poor survival in men after age 75. This risk was strongest in men who took antihypertensive medication.

Age Factors↗
PubMed1992

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 $19,502 (95% CI, $13,030 to $25,974) for medical treatments in the last month of life compared with $19,700 (95% CI, $13,704 to $25,696) for controls. CONCLUSIONS: Despite claims that public demand for longer life accounts for rising medical costs, most surveys suggest that patients are calling for less, not more, of the expensive, high-technology treatment often used in terminal phases of illness. Executing the California Durable Power of Attorney for Health Care and having a summary copy placed in the patient's medical record had no significant positive or negative effect on a patient's well-being, health status, medical treatments, or medical treatment charges.

Advance Directives↗
PubMed1992

Mortality over a period of 10 years in patients with peripheral arterial disease.

BACKGROUND: Previous investigators have observed a doubling of the mortality rate among patients with intermittent claudication, and we have reported a fourfold increase in the overall mortality rate among subjects with large-vessel peripheral arterial disease, as diagnosed by noninvasive testing. In this study, we investigated the association of large-vessel peripheral arterial disease with rates of mortality from all cardiovascular diseases and from coronary heart disease. METHODS: We examined 565 men and women (average age, 66 years) for the presence of large-vessel peripheral arterial disease by means of two noninvasive techniques--measurement of segmental blood pressure and determination of flow velocity by Doppler ultrasound. We identified 67 subjects with the disease (11.9 percent), whom we followed prospectively for 10 years. RESULTS: Twenty-one of the 34 men (61.8 percent) and 11 of the 33 women (33.3 percent) with large-vessel peripheral arterial disease died during follow-up, as compared with 31 of the 183 men (16.9 percent) and 26 of the 225 women (11.6 percent) without evidence of peripheral arterial disease. After multivariate adjustment for age, sex, and other risk factors for cardiovascular disease, the relative risk of dying among subjects with large-vessel peripheral arterial disease as compared with those with no evidence of such disease was 3.1 (95 percent confidence interval, 1.9 to 4.9) for deaths from all causes, 5.9 (95 percent confidence interval, 3.0 to 11.4) for all deaths from cardiovascular disease, and 6.6 (95 percent confidence interval, 2.9 to 14.9) for deaths from coronary heart disease. The relative risk of death from causes other than cardiovascular disease was not significantly increased among the subjects with large-vessel peripheral arterial disease. After the exclusion of subjects who had a history of cardiovascular disease at base line, the relative risks among those with large-vessel peripheral arterial disease remained significantly elevated. Additional analyses revealed a 15-fold increase in rates of mortality due to cardiovascular disease and coronary heart disease among subjects with large-vessel peripheral arterial disease that was both severe and symptomatic. CONCLUSIONS: Patients with large-vessel peripheral arterial disease have a high risk of death from cardiovascular causes.

Adult↗
PubMed1992

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

BACKGROUND: Several 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 RESULTS: Major 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 50% 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. CONCLUSIONS: The 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.

Alcohol Drinking↗
PubMed1991

Factors associated with paradoxical survival at higher blood pressures in the very old.

Paradoxically greater survival for persons aged 85 years and older with higher blood pressures has been reported in a Finnish population study (Br Med J 1988;296:887-9). In a previous report, the authors demonstrated improved 10-year survival with increasing diastolic blood pressure in men (but not in women) aged 75 years and older in the Rancho Bernardo Chronic Disease Study (Br Med J 1989;298:1356-7). However, few of the covariates which could potentially explain this effect were obtained at the visit used in that analysis. In an effort to confirm these reports of paradoxical survival and to explore possible reasons for them, the authors analyzed all-cause and cardiovascular mortality in 795 men and women aged 75-96 years (mean, 80.6), evaluated in 1984-1987 and followed prospectively for an average of 3 years after that comprehensive examination. Of 63 deaths, 48 (76%) were in men; 43 (68%) of all deaths were cardiovascular. Kaplan-Meier survival analyses showed a significant trend for improved survival with increasing diastolic pressure in men aged 80 years and older versus all-cause mortality (chi 2 p less than or equal to 0.01), and cardiovascular mortality (chi 2 p less than or equal to 0.00). These trends were not evident in men aged less than 80 years or in women in either age group. Results were not explained by differences in the use of antihypertensive medication, pulse pressure, history of hypertension, history of coronary heart disease, isolated systolic hypertension, interval change in diastolic pressure (over an average of 12 years), or by cholesterol, triglycerides, fasting plasma glucose, smoking, or body mass index. Thus, the paradoxical relation of improved all-cause and cardiovascular survival in men aged 80 years or older with higher diastolic pressure is not explained by a wide range of biologic and historical factors.

Age Factors↗
PubMed1991

Coronary disease and stroke in patients with large-vessel peripheral arterial disease.

Previous reports have indicated an excess of mortality from coronary heart disease (CHD), cardiovascular disease (CVD), and all causes in subjects with large-vessel peripheral arterial disease (LV-PAD). However, there is little information available concerning the risk of nonfatal events (morbidity) in this patient group. In a population-based study of 67 patients with LV-PAD and 408 control subjects without this condition, nonfatal CHD and stroke, and total CVD events, morbidity and mortality were evaluated in both men and women. Those with LV-PAD had a 3-fold excess of CVD morbidity at baseline compared with control subjects of the same sex. However, the absolute CVD rates were greater in men than women. During the 10 years of follow-up, women with LV-PAD had more nonfatal CVD events than men, resulting in comparable overall morbidity rates. In logistic regression models adjusted for other CVD risk factors, total CVD morbidity and mortality combined with 2.5 times as great in men and 5 times as great in women with LV-PAD as in those without peripheral arterial disease. These results suggest that the total morbidity and mortality burden are dramatically increased in both men and women with LV-PAD.

Adult↗
PubMed1990

A program for health behavior change in a preventive cardiology center.

The Preventive Cardiology Center at the University of California, San Diego, was designed to conduct training, service activities, and research related to behavioral modification of cardiovascular disease (CVD) risk. A primary aim is to train medical students and other health care professionals in the application of scientifically established methods of behavior change. This training takes place in the context of a behavior-change program for patients with CVD risk factors. Participants at increased risk for CVD and their families are recruited to the Preventive Cardiology Center. A comprehensive assessment of physiological and behavioral risk factors leads to the development of dietary and/or exercise behavior-change targets. A five-session group intervention instructs participants how to change health behaviors. Behavioral techniques included in the program include self-monitoring, goal-setting, social support, self-reward, self-talk, and problem solving. Students and others are trained through readings, videotapes, and coleading of intervention groups.

Academic Medical Centers↗
PubMed1989

Dietary alcohol, calcium, and potassium. Independent and combined effects on blood pressure.

To determine whether or not the previously reported association between alcohol intake and high blood pressure is influenced by differential intake of calcium and potassium in drinkers compared with nondrinkers and to assess the magnitude of the independent contributions of alcohol, calcium, and potassium to blood pressure, these associations were evaluated in 7,011 men of Japanese descent. Categorical analyses and multiple linear regression techniques were used to test the hypotheses that alcohol, calcium, and potassium were independent predictors of blood pressure. Alcohol consumption above a threshold of approximately 20 ml/day was found to be positively, strongly, and independently correlated with systolic and diastolic pressures, and this effect was completely independent of the effects of calcium and potassium. Calcium and potassium intake were highly correlated (r = 0.59) and were inversely related to blood pressure, and their combined effect was greater than the effect of either alone. However, in the subgroup of moderate and heavier drinkers, only potassium was inversely related to blood pressure. This finding is compatible with previous reports of malabsorption and increased excretion of calcium at higher levels of alcohol intake, and it indicates that a small portion of the alcohol-induced blood pressure elevation may be mediated through calcium depletion. In the range of dietary intake in this cohort, the effect of alcohol on blood pressure was stronger than was either the separate or combined effects of calcium and potassium.

Alcohol Drinking↗
PubMedDate not supplied

A research-oriented medical cost accounting system.

Prospective research into factors affecting health care costs for individual patients requires a hybrid information management system with some features usually associated with a medical billing package and other features common to research databases. Furthermore, data collection for such a project must often be done in the field where a portable computer is most convenient. A software program is described which has been developed to address these disparate needs. It allows classification by study protocol assignment and provides multiple summary formats for the assessment of costs. For example, charges can be stratified by specialty, by category of service (pharmacy, room, surgery, respiratory therapy, etc.), by magnitude of expense ('big' vs 'little' ticket items) and so forth. The system design described may prove useful to other investigators studying variation in health care costs.

Accounting↗