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Biomedical subjects

J D Curb

Publications and source records attributed to J D Curb.

At least 145 records · Page 8Linked to original sources

Is thiazide-produced uric acid elevation harmful? Analysis of data from the Hypertension Detection and Follow-up Program.

Interaction of thiazide diuretics and the serum uric acid and creatinine levels was studied in 3693 stepped care participants in the Hypertension Detection and Follow-up Program not receiving treatment at baseline. Among men grouped into quartiles by their level of uric acid at baseline, the upper quartile (average uric acid, 7.7 mg/dL [458 mumol/L]) had an average serum creatinine level of 1.2 mg/dL (106 mumol/L) and the lowest quartile (uric acid, 4.9 mg/dL [291 mumol/L]) had an average serum creatinine level of 1.1 mg/dL (97 mumol/L). Similar findings were present in women. Therapy with chlorthalidone or other thiazide-type diuretics tended to increase levels of uric acid and creatinine, but the increase in both was less in the upper quartile than in the lower quartile. Among individuals who were prescribed uric acid-lowering drugs, the level of serum creatinine increased just as much as in those whose uric acid level was not pharmacologically lowered. Baseline uric acid level was a weak predictor of mortality in men; the introduction of an interaction term for creatinine suggested that this effect was primarily restricted to those with elevated levels of both uric acid and creatinine at baseline. Change in uric acid level at one year after therapy was inversely correlated with mortality in men. There were few episodes of gout (only 15 recorded in five years among 3693 participants at risk). These results suggest that neither the baseline uric acid level nor the change in uric acid level produced by therapy injures the kidney. These results suggest no reason to lower uric acid levels pharmacologically in the treated hypertensive patient who is not gouty. They leave unanswered whether there is a predictive value to baseline uric acid level not explainable by other correlated cardiovascular risk factors.

Adult↗

Standardized physician preparation of death certificates.

One method for determining cause of death in a clinical trial is to use standard nosological coding of death certificates. In order to look at an alternative approach, the Hypertension Detection and Follow-up Program (HDFP) assessed underlying causes of death through the use of three physicians. These physicians were trained and standardized in the proper recording of cause of death on death certificates. Each physician completed a death certificate for each of the 768 deaths in the HDFP, utilizing all available information, including HDFP records, plus any additional hospital and autopsy records. The new standardized death certificates were then transmitted to a panel of three nosologists who coded the cause of death. The physician preparation procedure was compared with a procedure wherein a panel of three nosologists coded the original death certificate for the underlying cause of death. The procedures agreed on the three-digit International Classification of Disease, Adapted code in 60.1% of the cases. The agreement rate improved to 72.5% when disease codes were collapsed into broad disease categories utilized in the HDFP.

Adult↗

The association of postural changes in systolic blood pressure and mortality in persons with hypertension: the Hypertension Detection and Follow-up Program experience.

Participants in the Hypertension Detection and Follow-up Program (HDFP) were classified on the basis of baseline standing minus sitting systolic blood pressure into four groups (less than or equal to -20 [group 1], -19 to 0 [group 2], 1 to 20 [group 3], and greater than 20 mm Hg [group 4]) to study 5 year mortality. Group 1, 3.3% of the total, contained those participants who had postural hypotension. The 5 year total and age-adjusted mortality rates for these groups were significantly different (p less than .04), with group 1 having the highest rates. To account for the possible confounding effects of certain baseline risk factors--age, sex, race, prior antihypertensive treatment, randomization group, diabetes, end-organ damage, sitting diastolic and systolic blood pressures, pulse, hematocrit, smoking status, and relative weight (percent of ideal weight)--in assessing group differences in mortality rates, a multiple logistic model was used. Relative weight proved to be a confounding factor for the association of drop in postural systolic blood pressure with mortality. However, there is an interaction between history of diabetes and postural change in systolic blood pressure. Thus, postural hypotension may indicate a poor prognosis in diabetic hypertensive patients.

Actuarial Analysis↗

Coffee, caffeine, and serum cholesterol in Japanese men in Hawaii.

The relationship between coffee consumption and serum cholesterol was investigated in a cohort of 5,858 Japanese males born in 1900-1919 and living in Hawaii in 1965 who are currently followed by the Honolulu Heart Program. Data on coffee consumption, other dietary variables from a 24-hour dietary recall, and other potentially confounding variables collected in 1965 were correlated with serum cholesterol at that examination and at examination six years later. The mean coffee and tea consumption was 3.4 and 1.8 cups/day, respectively. Those consuming no coffee had a mean serum cholesterol of 210 mg/dl, while that of those drinking 9+ cups/day was 220 mg/dl (no such relationship was apparent with tea or cola). The relationship of coffee consumption and serum cholesterol with potentially confounding variables including body mass index, cigarette smoking, diastolic blood pressure, alcohol consumption, physical activity index, serum glucose, serum uric acid, education, age, and fat consumption was examined. When these variables were entered into a multiple regression equation with coffee consumption, a significant relationship between coffee consumption and serum cholesterol (p less than 0.001) persisted, as did that between baseline coffee consumption and serum cholesterol six years later (p less than 0.001). There was no significant relationship between tea or cola, the other major caffeine contributors to the diet, and baseline serum cholesterol. Thus, this analysis indicates a significant positive relationship between coffee consumption and serum cholesterol which is not present with other sources of caffeine.

Aged↗

Plasma lipids and lipoproteins in elderly Japanese-American men.

Knowledge about blood lipids in older individuals is limited. In the Lipoprotein Study of the Honolulu Heart Program, plasma cholesterol, triglyceride, and high-density lipoprotein (HDL) were measured during 1980 and 1981 in Japanese-American men over 60 years of age. In addition, low-density lipoprotein cholesterol (LDL-C) was estimated via a regression model. Age-related differences in mean lipid levels between the youngest (60 to 64 years) and the oldest (75 years and older) groups included a decrease in total cholesterol from 214 to 207 mg/dL and plasma triglyceride from 188 to 144 mg/dL. High density lipoprotein cholesterol rose from 47 to 49 mg/dL and LDL was relatively stable (137 and 135 mg/dL, respectively). Age-adjusted total cholesterol tended to significantly increase with increasing body mass index and hematocrit but was not significantly related with systolic blood pressure, physical activity index, cigarettes per day, or alcohol intake. Among those variables HDL-C decreased significantly with increasing body mass index and hematocrit and increased significantly with increasing alcohol intake. Compared with elderly white men in the Lipid Research Clinic Program, total cholesterol values tended to be slightly higher and triglyceride values were substantially higher, whereas HDL and LDL values were appreciably lower. Both cholesterol and triglyceride values were substantially higher than values reported from Japan from men in these age groups.

Aged↗

Effect of propranolol after acute myocardial infarction in patients with congestive heart failure.

The incidence of congestive heart failure was studied in the Beta Blocker Heart Attack Trial in which postmyocardial infarction patients between the ages of 30 and 69 years, with no contraindication to propranolol, were randomly assigned to receive placebo (n = 1921) or propranolol 180 or 240 mg daily (n = 1916) 5 to 21 days after admission to the hospital for the event. Survivors of acute myocardial infarction with compensated or mild congestive heart failure, including those on digitalis and diuretics, were included in the study. A history of congestive heart failure before randomization characterized 710 (18.5%) patients: 345 (18.0%) in the propranolol group and 365 (19.0%) in the placebo group. The incidence of definite congestive heart failure after randomization and during the study was 6.7% in both groups. In patients with a history of congestive heart failure before randomization, 51 of 345 (14.8%) in the propranolol group and 46 of 365 (12.6%) in the placebo group developed congestive heart failure during an average 25 month follow-up. In the patients with no history of congestive heart failure, 5% in the propranolol group developed congestive heart failure and 5.3% in the placebo group developed congestive heart failure. Baseline characteristics predictive of the occurrence of congestive heart failure by multivariate analyses included an increased cardiothoracic ratio, diabetes, increased heart rate, low baseline weight, prior myocardial infarction, age, and more than 10 ventricular premature beats per hour.(ABSTRACT TRUNCATED AT 250 WORDS)

Heart Failure↗

Long-term surveillance for adverse effects of antihypertensive drugs.

The large number of participants (5,485 patients) in the Hypertension Detection and Follow-Up Program, Stepped Care, form the largest group to date on which detailed surveillance of long-term antihypertensive therapy and drug side effects has been reported. Over a five-year period, among all hypertensive persons (mild, moderate, and severe combined) who were not taking antihypertensive medications at the beginning of the study and who attended the clinic at least once during the five-year trial, a total of 9.3% had definite or probable side effects severe enough to cause discontinuation of the drug treatment in question. An additional 23.4% had drug treatment discontinued due to possible side effects. Within the mild, moderate, and severe hypertension categories, 8.6%, 11%, and 12%, respectively, had definite or probable side effects. The incidence of side effects declined over the five years in all race-sex groups. Five-year incidence of total side effects was 29.8% in those aged 60 to 69 years at entry and 38.0%, 36.8%, and 34.1%, respectively, in those aged 50 to 59, 40 to 49, and 30 to 39 years. Sexually related side effects required discontinuation of treatment in 8.3% of male participants. However, less than 1% of active participants required hospitalization for side effects. No death that could be attributed to side effects was detected. Thus, the Hypertension Detection and Follow-up Program data, which have previously demonstrated the beneficial effects of antihypertensive therapy, confirm the relative safety of such therapy.

Adult↗

Dietary therapy slows the return of hypertension after stopping prolonged medication.

This study asks whether prolonged antihypertensive therapy will "cure" a substantial percent of rigorously treated hypertensive patients and whether nutritional change will add an antihypertensive effect and reduce the relapse rate. Of 584 eligible patients normotensive while receiving therapy, 496 were randomized into control and discontinued-medication groups with and without dietary intervention. At 56 weeks, 50% of those who were no longer receiving medication remained normotensive by study criteria. Randomization either to weight-loss group (mean loss of 4.5 kg [10 lb]) or to sodium-restriction group (mean reduction of 40 mEq/day) increased the likelihood of remaining without drug therapy, with an adjusted odds ratio of 2.17 for the sodium group and 3.43 for the weight group. Highest success rates were in the nonoverweight mild hypertensives with sodium restriction (78%) and the overweight mild hypertensives who were reducing their weight (72%). These data demonstrate that weight loss or sodium restriction, in hypertensives controlled for five years, more than doubles success in withdrawal of drug therapy.

Clinical Trials as Topic↗

Enhancement of visit adherence in the national beta-blocker heart attack trial.

Efforts were made in the Beta Blocker Heart Trial (BHAT), a double-blind study of 3837 post-MI patients, to enhance visit adherence, a measure of compliance that is not subjective and can be easily monitored. Of the required visits, 93.9% were completed in the window, 3.9% of the patients were classified as dropouts and 12 persons were lost to follow-up. Methods used to enhance compliance varied with circumstances but included appointment reminders, assistance with transportation, minimal waiting times, newsletters, continuity of care, involvement of family members, and close contact with private physicians. Comparisons of the BHAT visit adherence rates to those from other clinical trials are difficult to make because there are few reports in the literature regarding follow-up in large multicenter clinical trials. However, data obtained through personal communications, as well as published reports, indicate that adherence in primary prevention trials was generally less than that of secondary prevention trials. Adherence rates in the BHAT tended to be slightly higher than those of comparable trials.

Adult↗

Termination of clinical trials: the beta-blocker heart attack trial and the hypertension detection and follow-up program experience.

The close-out of clinical trials that end ahead of schedule often involves problems that differ from those of trials that end as planned. The Beta-Blocker Heart Attack Trial (BHAT), a double-blind study of 3837 post-myocardial infarction patients, was a multicenter clinical trial that ended early because therapeutic benefit had been demonstrated. The Hypertension Detection and Follow-up Program (HDFP), a randomized unblinded study of 10,940 hypertensive individuals, was a multicenter trial that ended as planned. Using these trials as illustrations, the issues arising in multicenter trials that end ahead of schedule are contrasted to those that arise in trials that end as scheduled. Close-out activities that are discussed include documentation of close-out procedures, release of trial information, preparation of trial participants and staff, ascertaining vital status, continuing patient care, data collection and coding, and publication of trial results. Because of the possibility a study might end early, advance planning for close-out is essential.

Adult↗

Participation in a clinical trial: the patients' point of view.

Little systematic information is available concerning the advantages and disadvantages of participation in a clinical trial from the patients' point of view. Surveys were undertaken among participants in the Beta-Blocker Heart Attack Trial (BHAT) and the Aspirin Myocardial Infarction Study (AMIS) to obtain data on these perceptions. In AMIS, an open-ended personal interview format was employed. For BHAT, a questionnaire partially based on hypotheses generated in AMIS, was mailed out. Results from the two studies suggested that patients in both trials felt that the additional medical monitoring, the opportunity for a "second opinion," and the reassurance received were more important benefits than actual physical improvement. Altruistic motivations were high in both studies. Frequency of perceived disadvantages was low, centering mainly around transportation problems and clinic waiting time. The large majority of patients indicated that they would volunteer for similar research in the future. The results are discussed in the context of the available literature and of the possibilities for extensions of this line of research.

Adult↗

Ascertainment of vital status through the National Death Index and the Social Security Administration.

Ascertainment of the vital status of individuals is of central importance to epidemiologic studies which monitor mortality as an end point. Utilizing identifying information collected in 1973-1974, the Hypertension Detection and Follow-up Program, a prospective, multicenter study, followed 25,362 individuals to determine eight-year mortality. In the most recent follow-up, there were 617 individuals whose vital status was not known. Available identifying information on these and on all 1,322 participants known to have died in 1979-1981 was submitted to the National Death Index (NDI) for possible confirmation of vital status. A subset of individuals who had Social Security numbers (490 lost to follow-up and 1,154 known deaths) was also submitted to the Social Security Administration (SSA). The NDI correctly identified 87.0% of the known deaths. Of the 1,154 known deaths (those with known Social Security numbers) submitted to both agencies, the NDI identified 93.1% and the SSA 83.6%. Significant variations by race and sex were noted in the identification rates, in part because of Social Security number discrepancies. False matches through the NDI matching process occurred for 10.4% of the known deaths. In the more restrictive SSA search, only 0.5% false matches resulted. For those lost to follow-up, vital status was ascertained in 57.1%. This paper describes the relative efficacy and attributes of the use of these systems to ascertain vital status.

Aged↗

Isolated systolic hypertension in 14 communities.

In the Hypertension Detection and Follow-up Program, 158,906 individuals from 14 communities around the United States had their blood pressure measured in their homes in 1972-1973. Of the total population screened, 2.4% had isolated systolic hypertension (systolic blood pressure greater than or equal to 160 mmHg and diastolic blood pressure less than 90 mmHg). Isolated systolic hypertension was present for 0.5% of those aged 30-39 years and 6.8% among those aged 60-69 years. The prevalence in blacks and women was greater than the prevalences in both whites and men. The prevalence among those taking antihypertensive medications at the time of screening was 6.1%, and 1.9% among those not on antihypertensive medications. From the individuals with "normal" diastolic blood pressure on the single home measurement (less than 90 mmHg), a random sample of 5,032 individuals were followed for mortality for eight years. Prevalence of isolated systolic hypertension was similar in this sample to that in the total. Among those not on antihypertensive medications, 8-year life table all-cause mortality rates adjusted for age, race, and sex were 17.6% for those with systolic blood pressure greater than or equal to 160 mmHg and 7.7% for those with systolic blood pressure greater than 160 mmHg. Among this population, all of whom had a diastolic blood pressure less than 90 mmHg, a multiple logistic analysis adjusting for baseline treatment status, age, race, sex, education, smoking, weight, pulse, physical activity, and systolic blood pressure revealed that each millimeter increase in systolic blood pressure was associated with approximately a 1% increase in mortality over the eight years of follow-up (p less than 0.05). Isolated systolic hypertension is both relatively common and a significant risk factor for subsequent mortality.

Actuarial Analysis↗

Detection and treatment of hypertension in older individuals.

The Hypertension Detection and Follow-up Program screened 34,012 individuals aged 60-69 years old in their homes in 14 communities around the United States during 1972 and 1973. The prevalence of hypertension, defined as diastolic blood pressure greater than or equal to 90 mmHg or on antihypertensive medication, was 42.1%. After a second clinic screen, 2,376 hypertensives were identified and randomized into Stepped Care, a special intensive treatment group, or Referred Care, a group referred to their usual medical care sources. These individuals were followed for five years (until they reached the ages of 65-74 years). Over the five years, 79.4% of older individuals remained under active care and 81.4% of those were at their goal diastolic blood pressure. Side-effects tended to be less frequent in older individuals than in younger ones. Older Stepped Care participants with mild hypertension (diastolic blood pressure 90-104 mmHg) had a 17.2% reduction in all-cause mortality over five years compared to Referred Care, which was primarily due to a reduction in deaths attributed to cardiovascular causes. Thus, antihypertensive treatment can be safely and beneficially administered to individuals in this age range with diastolic hypertension, including those with mild hypertension.

Adult↗

Return of hypertension after withdrawal of prolonged antihypertensive therapy, effect of weight loss, sodium reduction, and baseline factors.

The effect of dietary modification on continued blood pressure control after discontinuation of antihypertensive therapy has been studied. Participants who had been treated for 5 years in the Hypertension Detection and Follow-up Program were enrolled and randomly assigned to continue medication, discontinue medication with no dietary intervention, discontinue medication and reduce weight, discontinue medication and reduce sodium groups. Relapse of hypertension was slow, even without dietary modification. Both weight loss and sodium restriction slowed relapse. The severity of the hypertension and the number of drugs required for hypertension control had a marked effect on the rate of relapse. Relapse was slowest in the participants who had attained the lowest blood pressure on therapy.

Adult↗

A coordinating center in a clinical trial: the Hypertension Detection and Followup Program.

Multicenter clinical trials are often larger and more complex than other methods of clinical inquiry. They tend to involve a number of research or clinical centers and several formal committees. In many of these trials a coordinating center is one of the participating organizational units. This article describes one such coordinating center, that of the Hypertension Detection and Follow-up Program (HDFP). In 1971 the HDFP Coordinating Center was established to assist in planning and implementing this National Heart, Lung, and Blood Institute (NHLBI)-sponsored, multicenter, community-based, randomized, controlled clinical trial. The HDFP Coordinating Center is a large, intricate organization comprised of personnel who perform a wide variety of functions. From 1972 to 1979 it supervised the adherence to a common protocol among the cooperating centers and reported the Program's progress to the various monitoring and review committees, the Steering Committee, and the NHLBI Program Office. The Program screened approximately 159,000 persons ages 30 to 69 years, identifying and following 10,940 hypertensive participants. It has been the responsibility of this Coordinating Center to institute, coordinate, and monitor the data-gathering activities of the study as a whole and to process, store, and analyze the large, multifaceted set of data that were collected.

Clinical Trials as Topic↗