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Biomedical subjects

D G Kleinbaum

Publications and source records attributed to D G Kleinbaum.

35 records · Page 2Linked to original sources
PubMed1985

The Edgecombe County High Blood Pressure Control Program: III. Social support, social stressors, and treatment dropout.

In a hypertension prevalence survey of a stratified random sample of 1,000 households, 2,030 adults (aged 18 years and over) were interviewed and information on psychosocial variables collected. Among 359 hypertensives, there was a consistent relationship between indicators of difficulty in the social environment and dropout from treatment in women. Compared to those who remained in treatment, women who dropped out can be characterized as having less social support on the job, having less perceived spouse approval (if married), having a lower level of perceived access to supportive resources, and being more likely to report feeling pushed most or all of the time if they are homemakers. Relationships between indicators of social support and dropout from treatment in men were found only with support on the job, and for White men, with perceived friend approval.

Adult↗
PubMed1984

John Henryism and blood pressure differences among black men. II. The role of occupational stressors.

In this study, the effects of psychosocial job stressors on the resting blood pressure (BP) of 112 black male workers were examined. The subjects resided in a rural, poor, predominantly black community in eastern North Carolina. The job stressors included unemployment, lack of job security, lack of job success, the perception that wages earned were too low for the work performed (and inhibited anger about unfair wages), and the perception that being black had hindered chances for achieving job success. The effect-modifying influence of on-the-job social support, and John Henryism, on several of these relationships was also examined. For systolic blood pressure, a main effect was observed for job security, and an interaction effect was observed for employment status and time of day of interview. For diastolic blood pressure, significant interactions were observed for job success and John Henryism, and for job success and the perception that being black had hindered chances for achieving job success. These findings further clarify under what conditions John Henryism may be associated with higher BPs in this sample of black men. These findings also shed light on the emotional pathways through which selected job stressors may influence resting BPs in these men.

Adaptation, Psychological↗
PubMed1984

The Edgecombe County High Blood Pressure Control Program: I. Correlates of uncontrolled hypertension at baseline.

To guide the planning of a multifacetted hypertension control program in Edgecombe County, North Carolina, a baseline survey of a stratified (by township) random sample of 1,000 households was conducted. All adults (greater than or equal to 18 years) were interviewed and had their blood pressures (BP) measured. Five hundred thirty-nine individuals, 27 per cent of the survey population, had diastolic BP greater than or equal to 90 mm Hg or were receiving anti-hypertensive drug therapy. The 539 hypertensives were divided into seven subgroups reflecting successive stages in the control of hypertension based on the awareness, treatment, and control of their hypertension. Unaware hypertensives were further subdivided into three groups according to the recency of their last BP check, and those aware but untreated were subdivided by whether they had previously received treatment. The seven subgroups of hypertensives were compared, separately for women and men, with respect to sociodemographic characteristics, health behaviors, and health status. In general, the progression from undetected hypertension to treatment and control appeared to be associated with being older, female, and White. This progression was further associated with greater educational levels and higher family incomes among women and increasing self-reported morbidity among men. The implications for intervention of these and other described associations are discussed.

Adolescent↗
PubMed1984

The Edgecombe County (NC) High Blood Pressure Control Program: II. Barriers to the use of medical care among hypertensives.

As the initial step in a five-year project to improve control of high blood pressure in Edgecombe County, North Carolina, a survey was conducted in 1980 to determine the prevalence of hypertension and to identify factors which might constitute barriers to the use of medical care by hypertensives. This report summarizes the findings for the 539 hypertensives identified through the baseline survey. In general, Black hypertensives reported more access problems than Whites. Within race, however, males and females differed very little on selected measures of potential access to medical care. Among women, lower scores on potential access were strongly associated with being untreated, whereas for men, concerns about the safety of anti-hypertensive drug therapy were associated with being unaware. On a summary measure of the actual use of medical care in response to symptoms, both male and female treated hypertensives scored higher than their untreated counterparts. The implications of these and other findings for community-based blood pressure control activities are discussed.

Black or African American↗
PubMed1983

Correcting for misclassification in two-way tables and matched-pair studies.

Barron has presented a matrix formula that allows correction for nondifferential misclassification in two-by-two tables. We show how extensions of his result can be applied to situations involving differential misclassification, matched data, and arbitrary two-way tables. We also discuss some important limitations in the application of algebraic corrections for misclassification. In particular, we show that study misclassification rates need not reflect population misclassification rates if the distribution of the misclassified variable is determined by aspects of the study design.

Classification↗
PubMed1981

Selection bias in epidemiologic studies.

Consideration of factors involved in the selection of subjects is essential for evaluating the validity of a putative etiologic association. The purpose of this paper is to provide a quantitative conceptual framework for understanding selection bias; this framework integrates both epidemiologic and statistical considerations. Emphasis is given to specifying the conditions under which such bias is likely to occur, identifying the direction and magnitude of the bias, and illustrating how these features differ by type of study design.

Cross-Sectional Studies↗
PubMed1981

Matching in epidemiologic studies: validity and efficiency considerations.

Validity and efficiency issues are considered with regard to the use of matching and random sampling as alternative methods of subject selection in follow-up and case-control studies. We discuss the simple situation involving dichotomous disease and exposure variables and a single dichotomous matching factor, and we consider the influence on efficiency of a possible loss of subjects due to matching constraints. The decision to match or not should be motivated by efficiency considerations. An efficiency criterion based on a comparison of confidence intervals under matching and random sampling for the effect measure of interest (the risk ratio and risk difference in follow-up studies, and the odds ratio in case-control studies) leads to the following conclusions when the sampling method does not influence the size of the comparison group. In follow-up studies, matching on a confounder is expected to lead to a gain in efficiency over random sampling, while matching on a nonconfounder is not expected to result in a loss of efficiency. In case-control studies, the same conclusions hold, except that matching is not as advantageous as in follow-up studies and can lead to a loss of efficiency in some situations (usually of little practical importance). When matching reduces the size of the comparison group, there is likely to be a meaningful gain in efficiency due to random sampling only when the matched comparison group is at most 40-50% the size of the randomly-sampled comparison group is a follow-up study, and at most 50-65% the size in a case-control study.

Follow-Up Studies↗
PubMed1980

Department of Epidemiology and Public Health, School of Medicine, Yale University, New Haven, CT.

This paper distinguishes between 2 concepts for measuring the incidence of disease: risk and rate. Alternative procedures for estimating these measures from epidemiologic data are reviewed and illustrated. An attempt is made to integrate statistical principles with epidemiologic methods while minimizing the use of higher mathematics. Several theoretical and practical criteria are discussed for choosing the appropriate incidence measure in the planning of a study and for selecting the best method of estimation in the analysis.

Epidemiologic Methods↗
PubMed1978

Physician opnions on the use of antibiotics in respiratory infections.

To investigate the feasibility of establishing standards of care based on a broad consensus, a questionnaire concerning the management of signs and symptoms of common respiratory infections in infants was given to a national sample of pediatric infectious disease specialists, general pediatricians, and family physicians. There was significant disagreement (p less than .01) among the three groups of physicians in 15 of the 18 clinical situations concerning the appropriateness of prescribing antibiotics. Whenever there was disagreement, the family physician group was most inclined and the infectious disease group least inclined to favor antibiotics therapy. More than 75% of each group favored antibiotics in the same situation in only three instances. These results suggest that it may be difficult to set widely accepted standards for the evaluation of medical care where there are such differences of opinion.

Age Factors↗
PubMedDate not supplied

What can go wrong when you assume that correlated data are independent: an illustration from the evaluation of a childhood health intervention in Brazil.

The key analytical challenge presented by longitudinal data is that observations from one individual tend to be correlated. Although longitudinal data commonly occur in medicine and public health, the issue of correlation is sometimes ignored or avoided in the analysis. If longitudinal data are modelled using regression techniques that ignore correlation, biased estimates of regression parameter variances can occur. This bias can lead to invalid inferences regarding measures of effect such as odds ratios (OR) or risk ratios (RR). Using the example of a childhood health intervention in Brazil, we illustrate how ignoring correlation leads to incorrect conclusions about the effectiveness of the intervention.

Age Factors↗
PubMedDate not supplied

A longitudinal analysis of predictors of quitting smoking among participants in a self-help intervention trial.

Predictors of 7-day abstinence from smoking were identified among participants in a randomized self-help smoking-cessation intervention trial conducted from 1985 to 1988 in Seattle, WA. Subjects were adult smokers belonging to a health maintenance organization who responded to an offer of free quitting assistance. Self-reported smoking status was assessed at 8, 16, and 24 months following enrollment. Predictors of abstinence were identified by longitudinal data analysis using Generalized Estimating Equations (GEEs), a modeling approach which handles repeated-measures data and accommodates time-dependent as well as time-independent covariates. Seventeen items emerged as significant (p < .05) predictors, with odds ratios ranging from 1.3 to 2.1. While much of the previous work in smoking-cessation research has focused on demographic and smoking history variables, results of this study indicate that emphasis should also be placed on psychosocial/motivational factors and quitting activities as important predictors of abstinence. Longitudinal data analysis represents a powerful technique for handling correlated (repeated measures) data, which may prove very useful for future studies of smoking cessation as well as other dynamic processes.

Adult↗
PubMedDate not supplied

Hypertension control in a rural southern community: medical care process and dropping out.

As part of the Edgecombe County High Blood Pressure Control Program, we conducted a medical record review within a private group practice to assess the interrelationships between patient characteristics, the process of medical care, and dropping out of care by hypertensive patients. Twenty-one percent of 641 randomly selected hypertensive patients did not have a clinic visit in the year before their record review date. Loss to follow-up varied from 31% for black men to 13% for white women. More intense prior contact with the medical care system was associated with remaining under medical care for all groups by race and sex. Black men were much less likely to have intense contact with the medical care system than the other groups. Physician aggressiveness in the use of drug therapy was associated with a nearly 40% reduction in the risk of being lost to follow-up. These findings suggest that patient characteristics and several factors that reflect the process of medical care are associated with dropping out of medical care by hypertensive patients.

Adult↗
PubMedDate not supplied

The Edgecombe County High Blood Pressure Control Program: the process of medical care and blood pressure control.

As part of the Edgecombe County High Blood Pressure Control Program, a medical record review was conducted within a multispecialty private group practice in the county. The purposes of the review were to assess the relationship between the process of medical care and blood pressure control and to explore the variation in level and impact of medical care by race and sex. At the end of a three-year period, 41 percent of 628 hypertensive patients from the practice had uncontrolled diastolic blood pressure (DBP), as defined by Hypertension Detection and Follow-up Program criteria. The percentage of uncontrolled hypertensives ranged from 53 percent for black men to 34 percent for white women. Hypertensive patients whose physicians were more aggressive in their use of antihypertensive drug therapy were more likely to be controlled. The effect of the level of physician drug aggressiveness tended to be more pronounced for blacks than for whites. Differences by race in exposure to and efficacy of aggressive drug treatment may influence racial variation in blood pressure control.

Age Factors↗