Showing papers by "Ralph B. D'Agostino published in 1991"

Probability of stroke: a risk profile from the Framingham Study.

Abstract: A health risk appraisal function has been developed for the prediction of stroke using the Framingham Study cohort. The stroke risk factors included in the profile are age, systolic blood pressure, the use of antihypertensive therapy, diabetes mellitus, cigarette smoking, prior cardiovascular disease (coronary heart disease, cardiac failure, or intermittent claudication), atrial fibrillation, and left ventricular hypertrophy by electrocardiogram. Based on 472 stroke events occurring during 10 years' follow-up from biennial examinations 9 and 14, stroke probabilities were computed using the Cox proportional hazards model for each sex based on a point system. On the basis of the risk factors in the profile, which can be readily determined on routine physical examination in a physician's office, stroke risk can be estimated. An individual's risk can be related to the average risk of stroke for persons of the same age and sex. The information that one's risk of stroke is several times higher than average may provide the impetus for risk factor modification. It may also help to identify persons at substantially increased stroke risk resulting from borderline levels of multiple risk factors such as those with mild or borderline hypertension and facilitate multifactorial risk factor modification.

Variability of Body Weight and Health Outcomes in the Framingham Population

Abstract: Background. Fluctuation in body weight is a common phenomenon, due in part to the high prevalence of dieting. In this study we examined the associations between variability in body weight and health end points in subjects participating in the Framingham Heart Study, which involves follow-up examinations every two years after entry. Methods. The degree of variability of body weight was expressed as the coefficient of variation of each subject's measured body-mass-index values at the first eight biennial examinations during the study and on their recalled weight at 25 years of age. Using the 32-year follow-up data, we analyzed total mortality, mortality from coronary heart disease, and morbidity due to coronary heart disease and cancer in relation to intraindividual variation in body weight, including only end points that occurred after the 10th biennial examination. We used age-adjusted proportional-hazards regression for the data analysis. Results. Subjects with highly variable body weights had i...

Relation of low diastolic blood pressure to coronary heart disease death in presence of myocardial infarction: the Framingham Study.

Abstract: OBJECTIVE--To examine the hypothesis that a J curve relation between blood pressure and death from coronary heart disease is confined to high risk subjects with myocardial infarction. DESIGN--Cohort longitudinal epidemiological study with biennial examinations since 1950. SETTING--Framingham, Massachusetts, USA. SUBJECTS--5209 subjects in the Framingham study cohort followed up by a person examination approach. MAIN OUTCOME MEASURES--Coronary heart disease deaths and non-cardiovascular disease deaths in men and women with or without myocardial infarction relative to blood pressure. RESULTS--Among subjects without myocardial infarction non-cardiovascular disease deaths were twice to three times as common as coronary heart disease deaths. Furthermore, there was no significant relation between non-cardiovascular disease death and diastolic or systolic blood pressure. Also coronary heart disease deaths were linearly related to diastolic and systolic blood pressures. Among high risk patients (that is, people with myocardial infarction but free of congestive heart failure) death from coronary heart disease was more common than non-cardiovascular disease death. There was a significant U shaped relation between coronary heart disease death and diastolic blood pressure. Although there was an apparent U shaped relation between coronary heart disease death and systolic blood pressure, it did not attain statistical significance when controlling for age and change in systolic blood pressure from the pre-myocardial infarction level. None of the above conclusions changed when adjustments were made for risk factors such as serum cholesterol concentration, antihypertensive treatment, and left ventricular function. The U shaped relation between diastolic blood pressure and high risk subjects existed for both those given antihypertensive treatment and those not. CONCLUSIONS--These data suggest that an age and sex independent U curve relation exists for diastolic blood pressure and coronary heart disease deaths in patients with myocardial infarction but not for low risk subjects without myocardial infarction. The relation seems to be independent of left ventricular function and antihypertensive treatment.

Dietary Lipid Predictors of Coronary Heart Disease in Men: The Framingham Study

Abstract: The relationship between dietary lipids and the 16-year incidence of coronary heart disease (CHD) morbidity and mortality was examined in two male cohorts, aged 45 to 55 years (n = 420) and 56 to 65 years (n = 393) from the Framingham Study. Dietary lipids were assessed through a single 24-hour recall at the initiation of follow-up in 1966 to 1969. In the younger cohort, there were significant positive associations between the incidence of CHD and the proportion of dietary energy intake from total fat and monounsaturated fatty acids. The proportion of energy intake from saturated fatty acids had a marginally significant positive association with CHD. The associations remained even after adjustment for cardiovascular disease risk factors, including serum cholesterol level, suggesting that their effects are at least partially independent of other established risk factors. In contrast to the younger cohort, none of the dietary lipids were associated with CHD in the older cohort. Dietary intervention for the prevention of CHD in younger men is supported by these findings. ( Arch Intern Med . 1991;151:1181-1187)

A tool for judging coronary care unit admission appropriateness, valid for both real-time and retrospective use. A time-insensitive predictive instrument (TIPI) for acute cardiac ischemia: a multicenter study.

Abstract: This study developed and tested a tool to assess the likelihood of patients having acute cardiac ischemia and thus the appropriateness of admitting them to the coronary care unit (CCU). It is valid both for real-time clinical use and for retrospective review: a time-insensitive predictive instrument (TIPI). The authors' earlier acute ischemia predictive instrument, not designed specifically to support retrospective use, could not offer the advantage of a single tool usable by both clinicians and reviewers of care. Over a two-year period, the authors prospectively collected data on 5,773 emergency room patients seen in six New England hospitals for symptoms suggesting acute cardiac ischemia. In the Developmental Phase, based on 3,453 such patients seen during the first year, the authors developed a logistic regression-based TIPI for acute cardiac ischemia. Using seven clinical features reliably ascertainable both in the emergency room setting and by medical record review, the TIPI expressed a patient's probability of having acute ischemia as between 0-100%. In this phase, a risk category system based on the TIPI scale was also devised, which created four similar-sized groups, by cutting at 10%, 25%, and 55%. In the Test Phase, when prospectively tested on the 2,320 emergency room patients seen during the second year, the TIPI showed excellent diagnostic performance. Its receiver-operating characteristic (ROC) curve area of 0.88 was comparable to the original predictive instrument and the ROC curve path suggested performance comparable to physicians as well. Its slope of the relationship between predicted and observed probabilities of having acute ischemia was 1.11 (R2 = 0.97) with a correlation of 0.99 (P less than 0.0001), suggesting excellent calibration of predictions throughout the probability range. For patients who proved to have acute ischemia, the average TIPI probability was 59%, whereas for those without ischemia, the average TIPI value was 21% (P less than 0.0001). This differentiation was maintained even for those given different (including inappropriate) triage to the CCU, ward, or home (P less than 0.0001 for each disposition). When the performance of the four TIPI-based risk groups was prospectively tested on year-two patients, among the 552 patients in the low probability group, only 1.6% had acute cardiac ischemia, including only 0.7% with acute infarctions. Among the 484 patients in the high probability group, 81.6% had acute ischemia, and 53.3% acute myocardial infarctions, suggesting these to be clinically relevant groups for aiding or assessing emergency room triage.(ABSTRACT TRUNCATED AT 400 WORDS)

Predicting Reading Problems In At-Risk Children

Abstract: This study was designed to determine early predictors of reading problems in children at risk for such problems. Three groups of children participated in the study: those with a specific language i...

A time-insensitive predictive instrument for acute myocardial infarction mortality: a multicenter study.

Abstract: This study develops a “time-insensitive” predictive instrument for acute myocardial infarction mortality that would be useful both as a real-time clinical decision aid in the emergency medical setting and also for retrospective assessment and comparison of medical care based on risk-adjusted mortality predictions. This was done using prospectively-collected data on 5,773 patients with chief complaints of chest pain or other symptoms suggesting acute cardiac ischemia who came to six New England hospitals over a 2-year period. In phase one, based upon 4,099 patients, multivariate logistic regression was used to develop the predictive instrument. In phase two, its accuracy and diagnostic performance were tested on an independent sample of 1,387 patients presenting with symptoms compatible with acute cardiac ischemia. Discrimination between patients who lived and those who died was reflected by receiver-operating characteristic (ROC) curve areas of 0.85, 0.80, and 0.76, respectively, for all emergency department study subjects regardless of final diagnosis, subjects who proved to be having acute cardiac ischemia, and subjects who proved to be having acute infarction. Good calibration was shown by the fact that the predicted mortality was found to not vary significantly from actual mortality rates across deciles of predicted probabilities from 0% to 100%. In phase three, based on all 945 study subjects with acute myocardial infarction, each of the six hospitals' actual mortality rates were compared to their rates predicted by the predictive instrument. Actual hospital mortality rates ranged from 9.9% to 19.3%, with one hospital having a significantly higher rate (P = 0.005) and two hospitals having significantly lower rates than the remaining hospitals (P=0.003 for both). Predicted mortality rates ranged from 13.4% to 19.4%, with one hospital having a significantly higher predicted rate (P=0.005) and two hospitals having significantly lower predicted rates (P=0.04 and P=0.03). Individual hospitals' differences between actual and predicted mortality ranged from -3.4% to +3.1% (all NS). When grouped by hospital type, the actual mortality rates were 14.9%, 17.3%, and 13.0%, respectively, for urban teaching, smaller city teaching, and rural nonteaching hospitals (all NS). The predicted mortality rates were 16.5%, 17.1%, and 13.6%, respectively, with the rate for rural nonteaching hospitals being significantly lower (P=0.009). No hospital type had significant differences between their actual and predicted mortality rates (NS). The time-insensitive predictive instrument for acute infarction mortality shows potential for risk-adjusted studies of hospitals mortality for multihospital groups, hospital- to-hospital comparisons, and within-hospital assessment. Once further validated for retrospective and real-time use, it should be attractive to those who should be working together, i.e., clinicians, administrators, consumers, and health care payors.

Multiple comparisons in over-the-counter drug clinical trials with both positive and placebo controls.

Abstract: Evaluations of the efficacy of over-the-counter drugs using ANOVA techniques often misuse multiple comparison procedures. Studies that involve both a placebo control and established drugs as positive controls are especially prone to these problems. The most common mistake involves using a procedure which does not control the experimentwise type I error rate, usually the Duncan procedure or some version of multiple t tests. These procedures control comparisonwise type I error rate, but lack the important experimentwise error control. The purpose of this paper is to clarify the issues involved in performing ANOVA followed by a multiple comparison procedure for over-the-counter drug studies involving both placebo and positive controls.

Is coronary-care-unit admission restricted for elderly patients? A multicenter study.

Abstract: BACKGROUND. To investigate whether elderly patients are more likely to experience restricted access to high technology medical care, we examined the impact of age on the likelihood of coronary care unit (CCU) admission for patients with acute myocardial infarction. METHODS. As part of a prospective investigation of emergency room triage for patients with suspected cardiac ischemia, we studied 4223 patients presenting to six hospitals. Because CCU admission is the accepted standard of care for acute infarction, we defined nonadmission to the CCU as a restriction of access to care. We used a logistic regression model to control for gender, hospital, and CCU occupancy at the time of admission and examined the relationship between age and CCU nonadmission. RESULTS. Patients 75 years or older with acute myocardial infarction were 2.5 times more likely not to be admitted to the CCU than younger patients (RR 2.5, 95% CI 1.64, 3.85). Coronary unit admission was restricted even when the physician's admitting diagn...

Anticalculus effect of a dentifrice containing 0.5% zinc citrate trihydrate.

Abstract: A doubleblind 3-month anticalculus clinical study was conducted to determine the magnitude of the antitartar effect to be derived from use of a 0.5% zinc citrate dentifrice. From a population of 1600 subjects exhibiting calculus, 1210 subjects (age 18 and over) were selected and received a dental prophylaxis. The subjects were initially stratified on the basis of calculus score, age, and sex, then allocated randomly to a 3-month usage period of one of two treatment groups. These were a dentifrice containing 0.5% zinc citrate or a control dentifrice without zinc citrate. Calculus was assessed using the Volpe-Manhold Index. Oral soft tissue status was assessed throughout the course of the study. At the conclusion of the study 964 subjects had completed the trial: 486 using the zinc citrate dentifrice and 478 using the control. The results showed that the mean calculus scores in the group using the dentifrice containing zinc citrate were 13.7% lower than those of the group using the control dentifrice. This finding was statistically significant (P less than 0.05). No adverse effects related to the use of either dentifrice were observed.

Technology assessment in the Framingham Heart Study.

Abstract: To assess the role of observational data bases in technology assessment, we examined 26 articles from the Framingham Heart Study that evaluated a technology, therapy, or predictive instrument. These assessments were grouped into four categories: (a) the study of a technology voluntarily in use by the cohort, (b) the application of an external technology to members of the cohort, (c) the use of the Framingham results to evaluate an unrelated assessment, and (d) the use of the results to validate predictive instruments from other studies. Factors that contribute to the ability of the study to assess voluntary and external technologies include long-term follow-up, a stable cohort, and storage of such nonnumeric data as cardiograms and blood samples. Framingham results have been used to determine outcome measures in later studies. Although the Framingham Study was not designed to assess a technology, we found that large-scale, observational data bases can and do contribute to technology assessment.