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Biomedical subjects

B M Psaty

Publications and source records attributed to B M Psaty.

At least 145 records · Page 8Linked to original sources
PubMed1995

Optimal survey design for community intervention evaluations: cohort or cross-sectional?

Community intervention evaluations that measure changes over time may conduct repeated cross-sectional surveys, follow a cohort of residents over time, or (often) use both designs. Each survey design has implications for precision and cost. To explore these issues, we assume that two waves of surveys are conducted, and that the goal is to estimate change in behavior for people who reside in the community at both times. Cohort designs are shown to provide more accurate estimates (in the sense of lower mean squared error) than cross-sectional estimates if (1) there is strong correlation over time in an individual's behavior at time 0 and time 1, (2) relatively few subjects are lost to followup, (3) the bias is relatively small, and (4) the available sample size is not too large. Otherwise, a repeated cross-sectional design is more efficient. We developed methods for choosing between the two designs, and applied them to actual survey data. Owing to drop-outs and losses to followup, the cohort estimates were usually more biased than the cross-sectional estimates. The correlations over time for most of the variables studied were also high. In many instances the cohort estimate, although biased, is preferred to the relatively unbiased cross-sectional estimate because the mean squared error was smaller for the cohort than for the cross-sectional estimate. If these results are replicated in other data, they may result in guidelines for choosing a more efficient study design.

Cohort Studies↗
PubMed1995

Methods of assessing prevalent cardiovascular disease in the Cardiovascular Health Study.

The objective of this article is to describe the methods of assessing cardiovascular conditions among older adults recruited to the Cardiovascular Health Study (CHS), a cohort study of risk factors for coronary disease and stroke. Medicare eligibility lists from four US communities were used to obtain a representative sample of 5201 community-dwelling elderly, who answered standardized questionnaires and underwent an extensive clinic examination at baseline. For each cardiovascular condition, self-reports were confirmed by components of the baseline examination or, if necessary, by a validation protocol that included either the review of medical records or surveys of treating physicians. Potential underreporting of a condition was detected either by the review of medical records at baseline for other self-reported conditions or, during prospective follow-up, by the investigation of potential incident events. For myocardial infarction, 75.5% of the self-reports in men and 60.6% in women were confirmed. Self-reported congestive heart failure was confirmed in 73.3% of men and 76.6% of women; stroke, in 59.6% of men and 53.8% of women; and transient ischemic attack, in 41.5% of men and 37.0% of women. Underreporting was also common. During prospective follow-up of an average of about 3 years per person, approximately 50% of men and 38% of women were hospitalized or investigated for at least one potential incident event; for each cardiovascular condition, about 1 to 4% of those investigated during prospective follow-up were found to have had the cardiovascular condition prior to entry into the cohort.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Surveillance and ascertainment of cardiovascular events. The Cardiovascular Health Study.

While previous prospective multicenter studies have conducted cardiovascular disease surveillance, few have detailed the techniques relating to the ascertainment of and data collection for events. The Cardiovascular Health Study (CHS) is a population-based study of coronary heart disease and stroke in older adults. This article summarizes the CHS events protocol and describes the methods of surveillance and ascertainment of hospitalized and nonhospitalized events, the use of medical records and other support documents, organizational issues at the field center level, and the classification of events through an adjudication process. We present data on incidence and mortality, the classification of adjudicated events, and the agreement between classification by the Events Subcommittee and the medical records diagnostic codes. The CHS techniques are a successful model for complete ascertainment, investigation, and documentation of events in an older cohort.

Aged↗
PubMed1995

Fibrinogen and factor VIII, but not factor VII, are associated with measures of subclinical cardiovascular disease in the elderly. Results from The Cardiovascular Health Study.

No studies have examined the associations of coagulation factor levels with measures of subclinical cardiovascular disease (CVD) in the elderly. The Cardiovascular Health Study (CHS) is a prospective, population-based cohort study of CVD in persons older than 65 years. At the baseline examination, we measured fibrinogen, factor VII, and factor VIII levels in 5024 of the 5201 participants of the CHS and examined the associations of these coagulation factors with measures of subclinical CVD in a cross-sectional analysis. Subclinical CVD measures were based on electrocardiography, carotid ultrasonography, echocardiography, and ankle-arm blood pressure measurements (AAI). For analyses, we used the full cohort as well as two mutually exclusive subgroups: those with prevalent clinical CVD at baseline and those without. Fibrinogen and to a lesser extent factor VIII showed positive associations with a variety of subclinical CVD measures. In age-adjusted analyses, fibrinogen and factor VIII were significantly associated with 8 of 10 measures. In multivariate analyses, fibrinogen was significantly associated with carotid artery stenosis, internal (but not common) carotid artery wall thickness, and AAI. Factor VIII was associated with abnormal wall motion and AAI in the full cohort only. Factor VII was not consistently associated with subclinical disease measures. In bivariate analyses that included data from all three groups, there were 5 positive subclinical disease associations and 5 negative associations for factor VII. In multivariate analyses, there were no significant associations between factor VII and subclinical CVD in the full cohort or in either subgroup. We conclude that in these cross-sectional analyses, fibrinogen and to a lesser extent factor VIII are associated with subclinical CVD in the elderly, even in those without symptoms or a history of clinical CVD. Factor VII, however, was not associated with subclinical CVD in the elderly.

Aged↗
PubMed1995

The role of physicians' personal knowledge of the patient in clinical practice.

BACKGROUND: Primary care physicians' personal knowledge of their established patients has not been investigated systematically, and its role in clinical practice has not been characterized empirically. METHODS: A qualitative study used an iterative, grounded theory method for thematic analysis of transcribed, semistructured long interviews. Subjects were family physicians in stable employment and in continuous clinical practice for at least 2 years at a staff-model health maintenance organization. RESULTS: Personal knowledge of the patient clearly influenced the use of time in the examination room, the recognition of changes in baseline status, and the ability to verbalize medical information in terms that have unique meaning for particular patients. Personal knowledge fostered a sense of predictability in personal interactions; facilitated the creation of trust; served as an organizing scheme for data collection, recall, and interpretation; counterbalanced impersonal professional principles such as compulsiveness, duty, and responsibility; shaped ability to communicate effectively about issues related to quality of life and functional status; influenced choices of consultants; but also had the potential to interfere with diagnosis or with patient presentation of new information. CONCLUSIONS: Personal knowledge of patients was an important influence on physicians' daily clinical practice in this setting.

Adult↗
PubMed1995

Should calcium antagonists be first line drugs in hypertension?

The goal of the treatment of hypertension is to reduce the risk of the cardiovascular complications--stroke, acute myocardial infarction, congestive heart failure and renal dysfunction--not just to lower an elevated blood pressure. There are no completed large long-term clinical trials of calcium antagonists--short-acting or long-acting--designed to assess their efficacy and safety in patients with hypertension. Two smaller trials of dihydropyridines have suggested that despite blood pressure control, there may be a paradoxical increase in cardiovascular complications. These adverse effects are similar to those reported from clinical trials of short-acting calcium antagonists in coronary patients. Due to concerns about their long-term safety, inadequate documentation of their long-term efficacy and their high cost, calcium antagonists should be reserved as third-line agents. If prescribed, they should be given in low doses, possibly in combination with another antihypertensive agent. Their use should be limited to patients who cannot tolerate the other proven agents such as diuretics and beta-blockers, and to those who are not controlled on these agents or those with relative or absolute contraindication to them.

Antihypertensive Agents↗
PubMed1994

Use of diuretics and other antihypertensive medications in relation to the risk of renal cell cancer.

In a population-based case-control study of the association between use of diuretics and renal cell cancer, 120 white men whose cancer was diagnosed during the years 1980-1991 and 86 white women diagnosed in 1960-1991 were identified among members of the Kaiser Permanente Northwest health plan. Controls were plan members who had been individually matched to cases on sex, race, age, and time period in the plan. Data on diuretic use and other selected variables were abstracted from outpatient and inpatient medical records. In an analysis confined to exposures present at least 2 years before case diagnosis, the odds ratios associated with any use of a diuretic drug were 2.2 (95% confidence interval 1.2-3.9) for men and 1.8 (95% confidence interval 1.01-3.2) for women. Increased duration of diuretic use was associated with an increased risk of renal cell cancer. This association was not restricted to one class of diuretic and was not confounded by cigarette smoking or body mass. Both hypertension and use of nondiuretic antihypertensive drugs were closely associated with diuretic use, and it was impossible to disentangle fully the effects of these three separate exposures. These results, together with those of prior studies, are generally compatible with the view that there is an association between diuretic use and the incidence of renal cell cancer, but the interpretation of that association remains in question.

Aged↗
PubMed1994

Prevalence of atrial fibrillation in elderly subjects (the Cardiovascular Health Study).

Atrial fibrillation (AF) is a common arrhythmia in elderly persons and a common cause of embolic stroke. Most studies of the prevalence and correlates of AF have used selected, hospital-based populations. The Cardiovascular Health Study is a population-based, longitudinal study of risk factors for coronary artery disease and stroke in 5,201 men and women aged > or = 65 years. AF was diagnosed in 4.8% of women and in 6.2% of men at the baseline examination, and prevalence was strongly associated with advanced age in women. Prevalence of AF was 9.1% in men and women with clinical cardiovascular disease, 4.6% in patients with evidence of subclinical but no clinical cardiovascular disease, and only 1.6% in subjects with neither clinical nor subclinical cardiovascular disease. A history of congestive heart failure, valvular heart disease and stroke, echocardiographic evidence of enlarged left atrial dimension, abnormal mitral or aortic valve function, treated systemic hypertension, and advanced age were independently associated with the prevalence of AF. The low prevalence of AF in the absence of clinical and subclinical cardiovascular disease calls into question the existence and clinical usefulness of the concept of so-called "lone atrial fibrillation" in the elderly.

Aged↗
PubMed1994

Race- and ethnicity-specific characteristics of participants lost to follow-up in a telephone cohort.

The purpose of this study was to describe race- and ethnicity-specific characteristics of subjects lost to follow-up. For a study of community-based health interventions, adult subjects from 11 US communities were initially recruited by random digit dialing and interviewed by telephone in 1988; 2 years later, they were recontacted, and the same survey was administered a second time. Associations with loss to follow-up were assessed in separate models for whites, African Americans, Hispanic Americans, and Asian Americans. After 2 years, 40.8% of the 5,851 participants were lost to follow-up; cohort attrition was highest among African Americans (51.3%) and lowest among whites (37.5%). Age, aspects of employment, education, marital status, and income were significant independent predictors of loss to follow-up for one or more of the four racial and ethnic groups. Characteristics of subjects lost to follow-up in this telephone cohort differed among various racial and ethnic groups. After adjustment for demographic, socioeconomic, and health status variables, the important behavioral predictors of loss to follow-up were current smoking for whites (p < 0.05), having a high fat diet for African Americans (p < 0.10), consuming one or more alcoholic drinks per day for Hispanic Americans (p < 0.10), and high levels of physical activity for Asian Americans (p < 0.05).

Adolescent↗
PubMed1994

Diuretic therapy for hypertension and the risk of primary cardiac arrest.

BACKGROUND: The results of trials of the primary prevention of coronary heart disease have suggested that treating hypertension with high doses of thiazide diuretic drugs might increase the risk of sudden death from cardiac causes. In contrast, treatment with low doses of thiazide reduces the risk of coronary heart disease. METHODS: To examine the association between thiazide treatment for hypertension and the occurrence of primary cardiac arrest, we conducted a population-based case-control study among enrollees of a health maintenance organization. The case patients were 114 persons with hypertension who had a primary cardiac arrest from 1977 through 1990. The control patients were a stratified random sample of 535 persons with hypertension. The patients' treatment was assessed with the use of a computerized pharmacy data base. Records of their ambulatory care were reviewed to determine other clinical characteristics. RESULTS: The risk of primary cardiac arrest among patients receiving combined thiazide and potassium-sparing diuretic therapy was lower than that among patients treated with a thiazide without potassium-sparing therapy (odds ratio, 0.3; 95 percent confidence interval, 0.1 to 0.7). As compared with low-dose thiazide therapy (25 mg daily), moderate-dose therapy (50 mg daily) was associated with a moderate increase in risk (odds ratio, 1.7; 95 percent confidence interval, 0.7 to 4.5), and high-dose therapy (100 mg daily) was associated with a larger increase in risk (odds ratio, 3.6; 95 percent confidence interval, 1.2 to 10.8) (P value for trend, 0.02). The addition of a potassium-sparing drug to low-dose thiazide therapy was associated with a reduced risk of cardiac arrest (odds ratio, 0.4; 95 percent confidence interval, 0.1 to 1.5). CONCLUSIONS: Both the dose of thiazide drugs and the addition of potassium-sparing drugs influence the risk of primary cardiac arrest. These results may explain the differences in the effect of antihypertensive therapy on mortality from coronary heart disease in previous clinical trials.

Aged↗
PubMed1994

The risk of myocardial infarction associated with the combined use of estrogens and progestins in postmenopausal women.

BACKGROUND: While observational studies have suggested that unopposed estrogens reduce the incidence of coronary disease in postmenopausal women, there are few data on the effect of combined therapy with estrogens and progestins--a regimen adopted in recent years to minimize the risk of endometrial hyperplasia and cancer. In clinical trials, the addition of progestins has an adverse effect on serum lipid levels, and these lipid effects have raised the question of whether combined estrogen-progestin therapy increases the risk of coronary disease compared with the use of estrogen alone. METHODS: We conducted a population-based, case-control study among enrollees of Group Health Cooperative of Puget Sound. Cases were postmenopausal women who sustained an incident fatal or nonfatal myocardial infarction in 1986 through 1990. Controls were a stratified random sample of female Group Health Cooperative enrollees frequency matched to the cases by age and calendar year. We reviewed the medical records of the 502 cases and 1193 controls and conducted brief telephone interviews with consenting survivors. The health maintenance organization's computerized pharmacy database was used to ascertain the use of postmenopausal hormones. For the primary analysis of current use, we classified women into one of three groups: (1) nonusers of hormones; (2) users of estrogens alone; or (3) users of combined therapy including both estrogens and progestins. Each group of hormone users was compared with nonusers. RESULTS: After adjustment for potential confounding factors, the risk ratio of myocardial infarction associated with current use of estrogens alone was 0.69 (95% confidence interval, 0.47 to 1.02); and the risk ratio of myocardial infarction associated with current use of combined therapy was 0.68 (95% confidence interval, 0.38 to 1.22). Duration of combined-therapy use was relatively short, averaging less than 2 years in cases and controls. CONCLUSIONS: In this case-control study, the reduced risk of myocardial infarction associated with the use of estrogens alone was consistent with previous observational studies. Although the 95% confidence interval only excluded a risk above 1.22, the current use of combined therapy was not associated with an adverse effect on the incidence of myocardial infarction in postmenopausal women.

Aged↗
PubMed1994

The association between cholesterol and death from injury.

PURPOSE: To review the association between low serum cholesterol and death from injury. DATA SOURCES: Relevant English-language papers identified through MEDLINE and Current Contents searches and bibliographies of identified articles. STUDY SELECTION: More than 150 articles were reviewed to identify data, meta-analyses, or important reviews of the association between low cholesterol and injuries. DATA EXTRACTION: Estimates of the association between cholesterol and death from injury were extracted from published reports. DATA SYNTHESIS: Animal studies and descriptive studies have provided little information about serum cholesterol and injuries. The Conference on Low Blood Cholesterol pooled results from 14 cohort studies in men and found a relative risk of 1.4 for death from injury in men whose cholesterol levels were lower than 4.14 mmol/L (160 mg/dL) compared with men whose cholesterol levels were 4.14 to 5.15 mmol/L (P = 0.003). Most cohort studies support this finding. The strongest evidence that cholesterol and death from injury are related comes from a meta-analysis of six randomized cardiac primary prevention trials of cholesterol reduction; the relative risk for death from injury for treated men compared with controls was 1.42 (95% Cl, 0.94 to 2.15). CONCLUSIONS: In cohort studies, the strength of the association between low serum cholesterol levels and subsequent death from injury is weak and may be caused by confounding factors such as socioeconomic status. The modestly elevated risk ratio found in a meta-analysis of trials of cholesterol reduction in men is of borderline statistical significance. This association may be related to efforts to lower cholesterol rather than to low absolute levels of serum cholesterol. Until more data are available, the hypothesized relation between low cholesterol and injuries remains unsettled.

Animals↗
PubMed1994

Modifiable risk factors for incident heart failure in the coronary artery surgery study.

BACKGROUND: Even with aggressive treatment, heart failure is associated with a substantial morbidity and mortality. This poor prognosis has led to increasing interest in primary prevention, and the identification of modifiable risk factors. Our objective was to determine whether modifiable cardiovascular risk factors, including systolic and diastolic blood pressure, fasting glucose level, cholesterol level, weight, and smoking, were independent risk factors for heart failure in patients with anatomically confirmed coronary artery disease. METHODS: We studied all patients with documented coronary artery disease eligible for the multicenter, randomized-controlled Coronary Artery Surgery Study. After excluding 79 prevalent cases, we identified incident cases of heart failure using hospital discharge abstracts, mortality records, or self-reported follow-up questionnaires. Criteria for self-reported cases were treatment with digitalis and/or furosemide plus two or more heart failure symptoms, including dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, or edema. Cox regression analysis was used to estimate adjusted relative risks. RESULTS: At 12-year follow-up, the cumulative incidence of heart failure was 20.6%. Smoking (relative risk, 1.47) and weight (relative risk, 1.15/10 kg) were independently associated with incident heart failure. Myocardial infarction during follow-up, age, female sex, and baseline left ventricular dysfunction were also risk factors for heart failure. CONCLUSIONS: Patients with stable coronary artery disease are at high risk for developing heart failure, especially following myocardial infarction. However, interventions aimed at smoking cessation and weight reduction may prevent clinical heart failure in these patients.

Coronary Disease↗
PubMed1994

Characteristics of children selecting low-fat foods in an elementary school lunch program.

OBJECTIVE: To describe the demographic characteristics of children that were associated with the selection of low-fat entrees available in a school lunch program. DESIGN: For 5 consecutive months, we recorded student entree selections on the 46 days in which one of the two available lunch entrees was low fat (< or = 30% of calories from fat). Entree selections were tracked using a computerized meal-card system. The lunch menus did not indicate that one of the two entrees was low fat. Demographic and family characteristics were obtained from the school district's registration database and, in one school, from a household telephone survey. SETTING: A school lunch program in two public elementary schools in Bellevue, Wash. PARTICIPANTS: Students who regularly eat school lunches (N = 471). Sixty-five percent were from families with incomes less than 185% of the federal poverty level, and 49% were nonwhite. INTERVENTION: None. MAIN OUTCOME MEASURE: The proportion of days that each student selected the low-fat entree. RESULTS: Girls selected the low-fat entree more often than boys (33% of days vs 27% of days; P < .001), and the proportion of students selecting the low-fat entree increased with grade level (P = .003). Children were more likely to select low-fat entrees if a household member was known to have an elevated blood cholesterol level (P = .004). The proportion of students selecting the low-fat entree increased with maternal education level (P = .007), but children receiving free or reduced-price lunches (< 185% of the federal poverty level) chose the low-fat entree as often as those receiving full-price lunches (30% of days vs 29% of days; P = .14). There were no significant differences in entree selection among races. CONCLUSIONS: Given a choice of low-fat school lunch entrees, girls, older children, and those who had family members with elevated cholesterol levels were most likely to select these entrees. While parental education level was directly related to the selection of low-fat entrees, race and family income had little association with entree selection.

Age Factors↗
PubMed1994

Differences in sociodemographic, health status, and lifestyle characteristics among American Indians by telephone coverage.

BACKGROUND: Telephone interviews are often used to obtain population-based estimates of health-related behaviors but they have serious limitations if phone coverage is poor and people without telephones differ from those with telephones. In this article we examine differences in selected sociodemographic, health status, and lifestyle factors among a sample of American Indian adults with and without telephones. METHODS: In-person interviews were conducted with 410 adult residents of a Rocky Mountain state American Indian reservation. The interview included a question asking about telephone coverage. We compared respondents with and without telephones on demographics, health status, and lifestyle practices. The comparison was repeated for health status and lifestyle practices after adjusting for differences in demographic characteristics. RESULTS: Residents without phones generally were less educated, had lower income and were more likely to be unemployed. The prevalence of unhealthful lifestyle practices/factors was consistently higher for residents without telephones. Many of the differences were reduced by adjusting for demographic characteristics, but significant differences remained for alcohol and marijuana use. CONCLUSIONS: These results suggest that developing estimates of sociodemographic, health, and lifestyle characteristics on a Native American Indian reservation using a telephone survey method may result in significant noncoverage biases. Adjusting for demographic characteristics eliminated most of these differences. However, significant differences were still apparent with alcohol and marijuana use.

Adolescent↗
PubMed1994

Randomized intervention to increase children's selection of low-fat foods in school lunches.

OBJECTIVE: The purpose of this study was to determine whether children would increase their selection of low-fat foods in school lunches if these foods were labeled on the menu and parents were notified of their availability. METHODS: The 16 elementary schools in the Bellevue (Washington) School District were randomly assigned to intervention and control groups. Participants were the students eating the school lunch--an average of 2445 students per day, of whom one third received free or reduced-price lunches. In all schools, one of the two daily lunch entrees was low in fat (< or = 30% of calories from fat). After a 5-month baseline period, eight schools received a 4-month intervention. The monthly menus carried home by students began to indicate the low-fat entree and to compare the fat content of both entrees. In the first month, parents in the intervention schools (2329 households) received a mailing with a copy of the menu, an informational pamphlet on dietary fat, and a letter that described the menu changes and asked the parents to encourage their children to select low-fat entrees. A follow-up telephone survey was performed in one school 1 month after the intervention mailing to assess the recall and impact of the intervention. The main outcome, based on 249,861 student meal selections, was the proportion of students who selected the low-fat entree, and the unit of analysis was the school. RESULTS: At baseline, there was little difference between intervention and control schools in the percentage of children choosing the low-fat entree (31.5% vs 30.8%). During the intervention, there was an increase in low-fat entree selection in the intervention schools compared with the control schools (35.5% vs 32.2%; p = 0.03). Of 221 parents surveyed, 71% recalled the mailing, 53% remembered that there were now low-fat entrees on the menu, and 10% reported that, after the mailing, they asked their child to choose a low-fat entree.

Child↗