Biomedical subjects

A Oberman

Publications and source records attributed to A Oberman.

At least 73 records · Page 4Linked to original sources

PubMed1991

The Hypertension Prevention Trial: assessment of the quality of blood pressure measurements.

Blood pressure variability is an important consideration in hypertension trials for determining required sample size and consequently making accurate outcome statements. The Hypertension Prevention Trial was a randomized controlled trial carried out in 1983-1986 in four US clinics on men and women with high normal diastolic blood pressure. This trial provided an opportunity to assess conditions affecting blood pressure measurement variability. Trained blood pressure observers measured systolic and diastolic blood pressures twice, 30 seconds apart, using a random-zero sphygmomanometer. The quality of blood pressure measurements was assessed by computing the variability of the two readings per participant-visit for each blood pressure observer at each study clinic. Other sources of variability investigated included observer digit preference, time of day, and ambient temperature. On the basis of data from this population, it is estimated that the standard deviation of blood pressure values can be reduced by 5% by taking two measurements per participant-visit. An additional reduction of variability can be effected by having the duplicate blood pressure measurements made by different blood pressure observers. In special instances where the range of blood pressure values is very restricted, use of the random-zero sphygmomanometer can increase or decrease the among-participant variability in blood pressure values, depending upon where the distribution of blood pressure values is centered.

Adult↗

PubMed1991

Comparison of two methods of assessing physical activity in the Coronary Artery Risk Development in Young Adults (CARDIA) Study.

Physical activity was assessed by questionnaire among 4,956 young blacks and whites aged 18-30 years at the baseline examination (1985-1986) of the Coronary Artery Risk Development in Young Adults (CARDIA) study, a longitudinal study of cardiovascular risk factors. The Physical Activity Recall questionnaire categorized all activity during the previous week, while the Physical Activity History questionnaire quantified participation in 13 specific activities during the previous year. This report compares the two questionnaires with regard to their characterization of the activity levels of the sociodemographic subgroups of the study population and their associations with known physiologic correlates of physical activity. Both questionnaires resulted in the same physical activity patterns for sex (men greater than women) and age (younger greater than older) strata. However, the mean Physical Activity History score was higher in white women than in black women, while the Physical Activity Recall scores were nearly equal. The Physical Activity History score was directly related to educational status, and the Physical Activity Recall score was inversely related to educational status. The Physical Activity History score was generally more strongly associated with physiologic variables known to be related to physical activity (e.g., treadmill test duration). Based upon these findings, which may only be appropriate in this age group, it was concluded that the Physical Activity History score was the more valid measure of habitual physical activity in this study group of young adults.

Adolescent↗

PubMed1991

Effect of antihypertensives on sexual function and quality of life: the TAIM Study.

OBJECTIVE: To evaluate treatment of mild hypertension using combinations of diet and low-dose pharmacologic therapies. DESIGN: Multicenter, randomized, placebo-controlled clinical trial. SETTING: Three university-based tertiary care centers. PATIENTS: Patients (697) 21 to 65 years of age with diastolic blood pressure between 90 and 100 mm Hg as well as weight between 110% and 160% of ideal weight. INTERVENTION: Patients were stratified by clinical center and race and were randomly assigned to one of three diets (usual, low-sodium and high-potassium, weight loss) and one of three agents (placebo, chlorthalidone, and atenolol). MEASUREMENTS: Changes in measures of sexual problems, distress, and well-being after 6 months of therapy were analyzed. MAIN RESULTS: Low-dose chlorthalidone and atenolol produced few side effects, except in men. Erection-related problems worsened in 28% (95% CI, 15% to 41%) of men receiving chlorthalidone and usual diet compared with 3% (CI, 0% to 9%) of those receiving placebo and usual diet (P = 0.009) and 11% (CI, 2% to 20%) of those receiving atenolol and usual diet (P greater than 0.05). The weight loss diet ameliorated this effect. The low-sodium diet with placebo was associated with greater fatigue (34%; CI, 23% to 45%) than was either usual diet (18%; CI, 10% to 27%; P = 0.04) or weight reduction (15%; CI, 7% to 23%; P = 0.009). The low-sodium diet with chlorthalidone increased problems with sleep (32%; CI, 22% to 42%) compared with chlorthalidone and usual diet (16%; CI, 8% to 24%; P = 0.04). The weight loss diet benefited quality of life most, reducing total physical complaints (P less than 0.001) and increasing satisfaction with health (P less than 0.001). Total physical complaints decreased in 57% to 76% of patients depending on drug and diet group, and were markedly decreased by weight loss. CONCLUSION: In general, low-dose antihypertensive drug therapy (with chlorthalidone or atenolol) improves rather than impairs the quality of life; however, chlorthalidone with usual diet increases sexual problems in men.

Adult↗

PubMed1991

Niacin revisited: clinical observations on an important but underutilized drug.

STUDY OBJECTIVE: To evaluate the efficacy and side effects of niacin therapy in dyslipidemic individuals. DESIGN: A retrospective analysis of patients' charts. SETTING: An outpatient referral-based clinic specializing in the treatment of lipid disorders. PATIENTS: All patients with dyslipidemia treated by niacin (n = 82) at the Atherosclerosis Detection and Prevention Clinic during 1987 to 1990, including a subgroup of 17 dyslipidemic heart transplant recipients. RESULTS: Niacin was well tolerated in 83% of the nontransplant group (n = 65) at an average dose of 2.5 +/- 0.9 g/day. Similar beneficial lipoprotein effects were found in the transplant and nontransplant patients. The high-density lipoprotein cholesterol (HDL-C) response to niacin therapy was independent of the baseline (HDL-C level. In the transplant group, 11 patients (65%) discontinued treatment, primarily because of hyperglycemia; this was especially prominent in those patients with pretreatment diabetes mellitus. Of the 15 patients using sustained-release niacin, eight cases of hepatitis were recorded, some during therapy with relatively low niacin doses. Several different sustained-release preparations were responsible for this phenomenon, suggesting that the cause was not a contaminant in the preparation. No cases of hepatitis were documented in the 67 patients using regular niacin. One case of hepatitis was recently observed in a patient who switched from one type to regular niacin to another; however, we have data to suggest that the substituted preparation was not an immediate-release niacin. A familial predisposition to hepatitis is suggested by the occurrence of this side effect in identical twin brothers and two sisters. A pharmacy survey disclosed that most pharmacists are unaware of the relationship of sustained-release niacin to hepatitis, have a negative impression of regular niacin, and do not stock this formulation. Finally, we found that in this small sample of patients, niacin used with lovastatin is a particularly effective drug combination and appears to have few side effects beyond those seen with niacin alone. CONCLUSIONS: Our experience supports the fact that regular niacin is a useful lipid-modifying drug. When used appropriately, patients can usually tolerate adequate doses for prolonged periods and achieve meaningful results. However, this requires a certain amount of physician skill and patient motivation. The use of sustained-release preparations to overcome this problem can lead to harmful consequences and should only be done under strict medical supervision. In our opinion, the availability of sustained-release niacin as a nonprescription drug is unjustified and should be reexamined. Finally, we have observed that reduction of very-low-density lipoprotein cholesterol (VLDL-C) with niacin alone leads to an elevation in low-density lipoprotein cholesterol in many patients; this indicates to us that the mechanism whereby niacin lowers VLDL-C and total cholesterol is not solely the result of a decreased synthesis of VLDL-C.

Adult↗

PubMed1991

Correlates of fasting insulin levels in young adults: the CARDIA study.

Elevated fasting insulin is an independent risk factor for hyperlipidemia, hypertension, and cardiovascular disease, but determinants of insulin other than age and body mass remain poorly described. Potentially modifiable factors associated with insulin were identified by correlating anthropometric, dietary and physical activity data in the CARDIA cohort of 2643 black and 2472 white men and women aged 18-30 years. Insulin was positively correlated with serum glucose, body mass index (BMI), skinfold thickness, waist/hip ratio and sucrose intake, and negatively correlated with heavy physical activity score, treadmill exercise duration, and magnesium intake (each p less than 0.01). After adjustment for other covariates, the positive association of insulin with waist/hip ratio, skinfold thickness, and sucrose intake remained in the group as a whole, as did the negative associations with magnesium and treadmill duration. These relationships provide insight into potentially modifiable factors affecting insulin levels, and should be considered in interpreting associations between insulin levels and cardiovascular disease.

Adolescent↗

PubMed1991

Trials of hypertension prevention. Phase I design.

Phase I of the Trials of Hypertension Prevention (TOHP) was a National Heart, Lung, and Blood Institute-sponsored, 3-year, national, multicenter, randomized, controlled trial designed to test the feasibility and efficacy of three life-style (weight loss, sodium restriction, and stress management) and four nutrition supplement (calcium, magnesium, fish oil, and potassium) interventions aimed at lowering diastolic blood pressure in those whose blood pressure was initially in the high normal range (80 to 89 mm Hg). A total of 2182 volunteers were recruited and allocated to the various treatment arms, such that each hypothesis was tested with a power of 85% or higher to detect a diastolic blood pressure treatment effect of 2 mm Hg. The four nutrition supplement interventions were delivered in a double-blinded fashion and the three life-style interventions, single (observed) -blinded. Phase I was designed to provide a rigorous test of short-term lowering of blood pressure for each of the seven treatments chosen and provides the basis for planning of a subsequent long-term trial of hypertension prevention.

Adult↗

PubMed1991

Effect of drug and diet treatment of mild hypertension on diastolic blood pressure. The TAIM Research Group.

The Trial of Antihypertensive Interventions and Management is a multicenter randomized trial designed to examine the diastolic blood pressure response of various combinations of pharmacological and dietary interventions in the treatment of mild hypertension (diastolic blood pressure 90-100 mm Hg). Eight hundred and seventy-eight participants at 110-160% of ideal weight were randomly allocated to nine drug/diet treatment groups receiving either a placebo, chlorthalidone (25 mg), or atenolol (50 mg), combined with a usual, a weight loss, or a low sodium/high potassium diet. The primary outcome was diastolic blood pressure change from baseline to 6 months. Seven hundred and eighty-seven participants had follow-up data. The mean baseline diastolic blood pressure was 93.8 mm Hg; 55.9% of the participants were male, and the weight loss diet group lost an average of 4.7 kg. Multiple comparisons were accounted for in the analysis. A significantly greater lowering of diastolic blood pressure (12.4 mm Hg) was achieved in the atenolol group compared with either the low sodium/high potassium diet group (7.9 mm Hg, p = 0.001) or weight loss group (8.8 mm Hg, p = 0.006). Adding weight loss to chlorthalidone significantly enhanced blood pressure lowering (15.1 mm Hg) when compared with the diuretic alone (10.8 mm Hg, p = 0.002), but adding a low sodium/high potassium diet (12.2 mm Hg, p = 0.029) did not. In the short-term treatment of mild hypertension where diastolic blood pressure is the sole consideration, drugs outperform diet, and weight loss is beneficial, especially with diuretics.

Adrenergic beta-Antagonists↗

PubMed1991

Risk factors and the natural history of coronary heart disease in blacks.

Contrary to early impressions of blacks' relative immunity to CHD, it is now clear that African Americans experience greater mortality from CHD than whites. The natural history of CHD differs between blacks and whites in three important respects: First, greater prevalence of established risk factors among blacks suggests that they may be at greater risk for heart disease than their white counterparts. Second, health care seeking differences are evident between blacks and whites, leading to lower rates of identification of early disease and slower seeking of services for acute events. However, risk factor differences and health care seeking behaviors do not appear to account for all of the differences in the natural history of heart disease between the ethnic groups, such as survival rate differences during treatment. Economic factors appear to account for only a portion of these differences in risk factors and health care seeking. Beyond differences in risk factors and health care seeking, other, as yet undetermined, factors seem to be involved. These unknown influences could include physiologic, behavioral, and/or psychologic differences.

Adult↗

PubMed1990

Pharmacologic and nutritional treatment of mild hypertension: changes in cardiovascular risk status.

OBJECTIVE: To evaluate the 6-month change in cardiovascular (coronary heart disease) risk as a function of diet and drug therapy for mild hypertension. DESIGN: Collaborative randomized, controlled clinical trial to assess the efficacy of alternative regimens in treating mild hypertension. SETTING: Three university-based tertiary care centers-the Trial of Antihypertensive Interventions and Management (TAIM). PATIENTS: Six hundred and ninety-two men and women ages 21 to 65 years with diastolic blood pressure between 90 and 100 mm Hg and weight between 110% and 160% of ideal weight. MEASUREMENTS AND MAIN RESULTS: Patients stratified by clinical center and race were randomized into diet (usual, low sodium-high potassium, weight loss) and drug (placebo, chlorthalidone, and atenolol) groups resulting in nine diet plus drug combinations. The cardiovascular risk at 6-month follow-up was estimated relative to baseline in 692 participants using the Framingham Study model. Due to the blood pressure reduction, cardiovascular risk declined from baseline for all treatment groups (except the usual diet plus chlorthalidone group because of increased cholesterol levels). The relative cardiovascular risk at 6 months compared to baseline ranged from 0.83 in the weight loss plus atenolol subgroup to 1.03 in the usual diet plus chlorthalidone subgroup. The active drug plus weight loss groups showed the lowest relative cardiovascular risk at 6 months. CONCLUSIONS: Mild hypertension was generally reduced to desirable levels within 6 months by monotherapy. Evaluating blood pressure changes together with the risk factors indicated a differential effect on overall cardiovascular risk depending on the diet and drug used. Dietary therapy, particularly weight reduction, was important adjunctive treatment in reducing overall cardiovascular risk.

Adrenergic beta-Antagonists↗

PubMed1990

The utility of indirect measures of obesity in racial comparisons of blood pressure. CARDIA Study Group.

The associations between estimates of obesity derived from anthropometric measurements (body mass index, the sum of three skin folds, and the computed percent body fat) and blood pressures were examined by multiple regression analysis in 4508 young black and white adults. The three estimates of obesity yielded similar results in regression analyses. The strength of associations between these three estimates of obesity and systolic and diastolic blood pressures did not differ in black and white subjects of either sex. All three estimates lead to the same interpretation of the relationship between obesity and systolic or diastolic blood pressure. Estimated percent body fat offered no advantage over the other indices in this context.

Adult↗

PubMed1990

A comparison of two automated monitors in the measurement of blood pressure reactivity. Trials of Hypertension Prevention Collaborative Research Group.

Cardiovascular reactivity is the change in blood pressure, pulse, and other parameters of cardiovascular function in response to a challenging task. During the conduct of cardiovascular reactivity protocols, researchers frequently use automated blood pressure devices to measure blood pressure reactivity. However, the accuracy of automated devices in measuring blood pressure reactivity is unknown. To investigate the accuracy and precision of the Dinamap 1846 SXP and the VitaStat 2600B in the measurement of blood pressure reactivity, we compared blood pressure reactivity recorded by the VitaStat and Dinamap with that obtained by observers using a conventional mercury sphygmomanometer. At three sites, 159 normotensive subjects performed the same task twice, once with blood pressure reactivity measured by the manual observers and once by the VitaStat (n = 79) or Dinamap (n = 80), with the order determined at random. Ratios (VitaStat/Dinamap) of aggregate within-person variance for baseline and task, systolic and diastolic blood pressures ranged from 1.53 to 4.93 (all P < 0.01), suggesting that the Dinamap has better precision than the VitaStat. For both diastolic and systolic blood pressure reactivity and for both types of automated devices, the mean differences in blood pressure reactivity between manual and automated measurements were small (range, -1.8 to 0.8 mm Hg). However, the VitaStat versus manual scatter plot of diastolic blood pressure reactivity showed greater dispersion (correlation coefficient r = 0.16, P = 0.15) than the Dinamap versus manual scatter plot (r = 0.36, P = 0.001). For systolic blood pressure reactivity, the VitaStat versus manual and Dinamap versus manual scatter plots were similar. Our data indicate that the Dinamap is superior to the VitaStat in the measurement of blood pressure reactivity. The substantial performance differences between the VitaStat and Dinamap suggest that other automated blood pressure monitors must be evaluated prior to use in cardiovascular reactivity studies.

Adult↗

PubMed1990

Ten-year follow-up of quality of life in patients randomized to receive medical therapy or coronary artery bypass graft surgery. The Coronary Artery Surgery Study (CASS)

Quality of life indexes were assessed in 780 patients 10 years after randomization to medical therapy (n = 390) or coronary artery bypass graft surgery (n = 390) in the Coronary Artery Surgery Study. At 10 years, mortality was 21.8% in the medical group and 19.2% in the surgical group (p = NS), and 144 (37%) of the medical group had undergone surgery because of increasing chest pain. At study entry, 22% of medical and surgical patients were angina free; at 1 and 5 years after entry, the frequency of asymptomatic patients was 66% and 63% in the surgical group and 30% and 38% in the medical group. However, by 10 years after entry, the proportion of patients free of angina had fallen to 47% in the surgical group and to 42% in the medical group. Activity limitation and use of beta-blockers and long-acting nitrates were less in the surgical than the medical group at 1 and 5 years after entry but little different from the medical group at 10 years after entry. Throughout follow-up, recreational status, employment status, frequency of heart failure, use of other medications, and hospitalization frequency were similar between the two groups. Thus, indexes of quality of life such as angina relief, increased activity, and reduction in use of antianginal medications initially appear superior in patients with stable manifestations of ischemic heart disease assigned to surgery, but by 10 years after entry, these advantages are much less apparent. Although the observed similarities of the medically and surgically assigned groups at 10 years reflect return of symptoms in the surgical group to some extent, a more important explanation is the performance of late surgery in a large proportion of the medically assigned patients, rendering them asymptomatic.

Activities of Daily Living↗

PubMed1990

Estimation of protein intake: comparison of dietary assessment and urinary excretion.

Estimates of dietary intake of nutrients have many problems, and confirmation of these estimates by chemical measurements of excretory products helps to establish their validity. The correlation between urinary amino acid excretion and dietary history of protein intake are reported herein. Diet diaries were kept by and 24-h urine collected from participants in the Trial of Antihypertensive Therapy and Management, a multicenter cooperative trial comparing the effects of drugs and diet on blood pressure control, side effects, and quality of life. The nutritional information was coded and the data stored by the nutritional analyses facility at Albert Einstein College of Medicine. The chemical determinations were done in the laboratories of the Department of Pathology, Izumo, Japan. The correlation between total protein and 3-methylhistidine was r = 0.42 (n = 96). The correlation was similar for animal protein (r = 0.4). These correlations are of the same order of magnitude as those between dietary sodium and urine sodium, and dietary potassium and urine potassium. We conclude that measurement of urinary protein excretion products may be a useful way to estimate dietary protein intake.

Adult↗

PubMed1990

The effect of thiazide therapy on glucose, insulin and cholesterol metabolism and of glucose on potassium: results of a cross-sectional study in patients from the Hypertension Detection and Follow-up Program.

Fasting and one hour post-glucose load blood samples were obtained from 497 participants in the Hypertension Detection and Follow-up Program (HDFP), 79.8% of whom were on antihypertensive therapy at the time of their five-year examination. Major findings include a positive correlation between glucose/insulin ratio and serum potassium (P = 0.0014) and a weaker negative correlation between fasting insulin and serum potassium (P = 0.004). These data are compatible with a primary effect of hypokalaemia producing insulin 'resistance'. In addition, the glucose load was followed by a mean reduction in serum potassium of 0.135 +/- 0.525 meq/l (P less than 0.001). Twenty percent of participants experienced a drop of more than 0.5 meq/l. Cholesterol was associated with the fasting glucose/insulin ratio (P less than 0.032). The results are compatible with the hypothesis that prevention of hypokalaemia may prevent certain metabolic effects attributed to thiazide.

Adult↗

PubMed1990

Effect of weight loss on thiazide produced erectile problems in men.

Thiazide-type diuretics frequently produce erectile dysfunction in men on a regular diet. However, men on a weight-loss diet have much less erectile dysfunction. Thiazide-type diuretics also produce erectile dysfunction in rats and interfere with normal copulation. The mechanism of the dysfunction and the favorable response to weight loss is unknown.

Animals↗

PubMed1989

Trial of antihypertensive interventions and management. Design, methods, and selected baseline results.

The Trial of Antihypertensive Interventions and Management was a multicenter randomized, placebo-controlled trial designed to assess the effectiveness of various combinations of pharmacologic and dietary interventions in the treatment of mild hypertension (diastolic blood pressure 90-100 mmHg). The primary outcome was blood pressure change between baseline and 6 months. The study consisted of a 3 X 3 factorial design wherein participants were randomly allocated to nine drug-diet treatment groups. Drugs included placebo, diuretic, and beta-blocker. Diets were usual, weight loss, and low sodium/high potassium. The basic strategy was to address clinical questions of interest by comparing mean blood pressure changes of selected drug-diet combinations. This paper describes the study including experimental design, sample size considerations, statistical analysis, organizational structure, and baseline findings.

Adult↗

PubMed1989

Baseline characteristics in the Hypertension Prevention Trial. Hypertension Prevention Trial Research Group.

The Hypertension Prevention Trial (HPT) was a randomized, controlled, multicenter (four clinics, four resource centers) trial designed to test the feasibility of achieving and sustaining dietary changes in the intake of calories, sodium, and potassium and to assess the effect of those changes on blood pressure in a normotensive population. The trial involved 841 men and women (plus a test cohort of 78) who, at the first baseline (BL) examination were in the age range of 25-49 years and had diastolic pressure (DBP) greater than or equal to 76 but less than 100 mm Hg (average of two readings), and at the examination prior to randomization (BL 2), had DBP greater than or equal to 78 but less than 90 mm Hg (also averaged). Participants were randomly assigned to a control treatment group (no dietary counseling) or to one of four dietary treatment groups involving counseling designed to reduce calorie intake; reduce sodium intake, reduce sodium and calorie intake, and reduce sodium and increase potassium intake. This chapter presents HPT baseline characteristics by weight stratum, clinic, and treatment group for various demographic, medical history, and nutritional characteristics, for several physiologic variables used in monitoring treatment compliance, and for blood pressure. The degree of comparability observed among treatment groups was within the range expected for the randomization procedure used.

Adult↗

PubMed1989

Reproducibility of two-dimensional exercise echocardiography.

To determine the reproducibility of two-dimensional exercise echocardiography, duplicate studies were performed on the same patients a median of 14 days apart. Because measurements are operator-dependent, interobserver variability was calculated for two experienced readers who interpreted the findings independently in a blinded manner. A high degree of interobserver agreement was found in evaluation of both ejection fraction measurements and wall motion abnormalities. Readings for ejection fraction immediately after exercise taken on different days could be estimated within 4% of the values measured in the first test; similarly measured wall motion score index was within 6% of that in the first test. Ejection fractions and wall motion scores were highly correlated between tests 1 and 2. The correlation coefficients between tests 1 and 2 were 0.92 for both the pre- and postexercise ejection fractions and 0.98 for both the pre- and postexercise wall motion scores. Quantitative two-dimensional echocardiography immediately after exercise is highly reproducible, providing a valuable tool for assessing serial changes in left ventricular function.

Adult↗