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Biomedical subjects

S L Hui

Publications and source records attributed to S L Hui.

At least 55 records · Page 3Linked to original sources
PubMed1996

Association of the epsilon 4 allele of apolipoprotein E with poor performance on a dementia screen in African Americans.

In a community-based study of Alzheimer's disease in African Americans age 65 and over, subjects were classified into three levels of performance based on their scores as measured by the Community Screening Instrument for Dementia (CSI"D"), consisting of cognitive and functioning components. In a subset of 268 subjects with apolipoprotein E (APOE) genotype data, we found that the epsilon 4 allele of APOE was associated with intermediate/poor performance (single copy epsilon 4 odds ratio 1.51, 95% CI 1.18 to 1.92; double copy epsilon 4 odds ratio 3.42, 95% CI 2.18 to 5.43). From these data, we believe it would be possible to conduct population screening for the effects of possession of the APOE-epsilon 4 allele using information derived from the CSI"D".

Aged↗
PubMed1995

Choosing between predictors of fractures.

The identification of those at highest risk of osteoporotic fractures is a clinical goal that requires appropriate statistical comparisons of potential predictors of fractures. This article provides a formal approach of comparing individual predictors (e.g., bone mass at one site vs bone mass at another), or sets of predictors (e.g., bone mass vs other risk factors), and contrasts newer methods, such as bootstrapping, to receiver-operating-characteristics (ROC) curves, which have been previously used. The advantages of the bootstrapping approach are illustrated using time-to-fracture data from a published study demonstrating the use of baseline bone mass measurements in the prediction of fractures in 521 subjects with variable lengths of follow-up, extending to 12.5 years. Bone mineral density (BMD) was shown to be significantly better than bone mineral content (BMD) in predicting fractures in free-living subjects, but not in retirement-community subjects. Bone mineral apparent density (BMAD) was also compared with BMC and BMD and shown not to improve fracture prediction in these subjects.

Bone Density↗
PubMed1995

Prevalence of Alzheimer's disease and dementia in two communities: Nigerian Africans and African Americans.

OBJECTIVE: This article reports on a prevalence study of dementia and Alzheimer's disease among two groups of subjects with the same ethnic background but widely differing environments. METHOD: The study was conducted among residents aged 65 years and older in two communities: Yorubas (N = 2,494) living in Ibadan, Nigeria, and African Americans (N = 2,212 in the community and N = 106 in nursing homes) living in Indianapolis, Indiana. The study design consisted of a screening stage followed by a clinical assessment stage for selected subjects on the basis of their performance on the screening tests. RESULTS: The age-adjusted prevalence rates of dementia (2.29%) and Alzheimer's disease (1.41%) in the Ibadan sample were significantly lower than those in the Indianapolis sample, both in the community-dwelling subjects alone (4.82% and 3.69%, respectively) and in the combined nursing home and community samples (8.24% and 6.24%, respectively). The prevalence rates of dementia and Alzheimer's disease increased consistently with advancing age in both study groups. CONCLUSIONS: To the authors' knowledge, this is the first study, using the same research method at the two sites, to report significant differences in rates of dementia and Alzheimer's disease in two different communities with similar ethnic origins.

Black or African American↗
PubMed1994

Influences on skeletal mineralization in children and adolescents: evidence for varying effects of sexual maturation and physical activity.

OBJECTIVE: To establish rates of skeletal mineralization in children and adolescents, and to identify factors that influence these rates. DESIGN: Three-year observational study. SETTING: University hospital. SUBJECTS: Ninety white children, aged 6 to 14 years. MEASUREMENTS: Bone mineral density of the radius, spine, and hip was measured at baseline and 3 years later. Physical activity was assessed by questionnaires at 6-month intervals and dietary calcium intake by diet diary 1 day per month for 36 months. Sexual maturation (Tanner stage) was determined by an endocrinologist at 6-month intervals, as necessary to classify children as prepubertal, peripubertal, or postpubertal. RESULTS: Skeletal mineralization accelerated markedly at puberty in the spine (0.077 vs 0.027 gm/cm2 per year, peripubertal vs prepubertal) and greater trochanter (0.050 vs 0.027 gm/cm2 per year), less markedly in the femoral neck (0.047 vs 0.030 gm/cm2 per year), and only slightly in the radius. Nearly one third (15 gm) of the total skeletal mineral in the lumbar spine of adult women (approximately 52 gm) was accumulated in the 3 years around the onset of puberty. Increases in height and weight were the strongest correlates of skeletal mineralization: weight changes were more strongly correlated with trabecular bone sites and changes in height with cortical bone sites. Increases in calf muscle area were strongly associated with mineralization, particularly in peripubertal children, and physical activity was associated with more rapid mineralization in prepubertal children. CONCLUSIONS: Puberty has varying effects on skeletal mineralization depending on skeletal site; trabecular bone is apparently more sensitive to changing hormone concentrations. Physical activity and normal growth are also positively associated with skeletal mineralization, also depending on skeletal site and sexual maturation.

Adolescent↗
PubMed1994

Depression in late life: the use of clinical characteristics to focus screening efforts.

BACKGROUND: The objective of the study was to identify clinical characteristics associated with depressive symptoms in late life so that screening could focus on elderly patients most likely to benefit from further evaluation. METHODS: We used cross-sectional screening for significant symptoms of depression using the Center for Epidemiologic Studies Depression scale and identification of patients' clinical characteristics from patient interviews and a computerized medical record. The setting was an academic primary care group practice at an urban ambulatory care center. Participants were 1,633 consecutively consenting patients aged 60 and older who visited the center between January and August 1991. Mean age was 70 years; 72% were women, 32% were White, 47% had less than 8 years of education, and 7% had no health insurance. RESULTS: There were 251 (15%) patients with significant symptoms of depression. Antidepressants were prescribed to 1 in 7 patients with such symptoms, with amitriptyline being the most commonly prescribed. Bivariate analyses indicated that patients with significant symptoms of depression were more likely to be White, female, without health insurance, and were more likely to have probable alcoholism, mild cognitive loss, and to receive narcotics, histamine H2 antagonists, and/or benzodiazepines. Depressive symptoms were not significantly correlated with age, education, income, or chronic medical conditions. CONCLUSIONS: Significant symptoms of depression were common and correlated with several readily available clinical variables. However, these variables lack sufficient discriminatory power to allow for the selective screening of elderly patients most likely to suffer from symptoms of depression. Thus, formal screening for depression among all elderly patients in primary care may be necessary to improve the recognition of this morbid illness.

Adrenergic beta-Antagonists↗
PubMed1994

Longitudinal study of depression and health services use among elderly primary care patients.

OBJECTIVE: To describe the prevalence and 9-month incidence of depressive symptoms among a cohort of elderly primary care patients and to determine whether different patterns of depression are associated with different patterns of health services use. DESIGN: Prospective study of depressive symptoms as measured by the Center for Epidemiologic Studies Depression (CES-D) scale and identification of patients' outpatient health services use through an electronic medical record system. SETTING: An academic primary care group practice at an urban ambulatory care clinic. PATIENTS/PARTICIPANTS: 1711 patients aged 60 and older who completed the CES-D at baseline and 9 months later; 935 of these patients also completed the CES-D at 6 months. MEASUREMENT AND MAIN RESULTS: The prevalence of significant symptoms of depression (CES-D > or = 16) was 17.1% at baseline and 18.8% at 9 months; 26.8% of patients exceeded the threshold on the CES-D either at baseline or 9 months, and the 9-month incidence was 11.7%. Among the patients re-interviewed at both 6 and 9 months, the 6-month incidence was 12%, and the incidence between the 6- and 9-month assessments was 10%. Of the 292 patients with depression at baseline, 140 (47.6%) remained depressed at the 9-month follow-up. Baseline and 6-month CES-D score, in addition to perceived health at 6 months, explained 45% of the variance in the 9-month CES-D score. Patients above the threshold on the CES-D at any time were more likely to rate their health as fair or poor (69.8% vs 43.7%) and more likely to have an emergency room visit (40.4% vs 29.4%). These patients also had 38% more outpatient visits (7.7 vs 5.6) and 61% higher total outpatient charges ($1209 vs $751) than patients who never exceeded the CES-D threshold over the 9-month window (all P values < 0.01). CONCLUSIONS: Depressive symptoms were frequent and often persistent in this patient population. We identified patterns of oscillating severity of symptoms within individuals but relatively stable incidence and prevalence rates over a 9-month period. Patients who exceeded the threshold on the CES-D at any time during the study had significantly greater health services use and poorer perceived health.

Aged↗
PubMed1994

Improving treatment of late life depression in primary care: a randomized clinical trial.

OBJECTIVE: Facilitate primary care physicians' compliance with recommended standards of care for late life depression by reducing barriers to recognition and treatment. DESIGN: Randomized controlled clinical trial of physician-targeted interventions. SETTING: Academic primary care group practice caring for an urban, medically indigent patient population. PATIENTS/PARTICIPANTS: Patients aged 60 and older who exceeded the threshold on the Centers for Epidemiologic Studies Depression Scale (CES-D) and the Hamilton Depression Rating Scale (HAM-D) and their primary care physicians. INTERVENTION: Physicians of intervention patients were provided with patient-specific treatment recommendations during 3 special visits scheduled specifically to address the patient's symptoms of depression. In general, physicians were encouraged to establish a diagnosis of depression and educate their patient about the diagnosis, discontinue medications that can cause or exacerbate depressive symptoms, initiate antidepressants when appropriate, and consider referral to psychiatry. Guidelines for prescribing antidepressants were provided. Control physicians received no intervention, and control patients received usual care. MAIN OUTCOME MEASURES: Frequency of recording a depression diagnosis, stopping medications associated with depression, initiating antidepressant medication, and psychiatry referral; mean changes in HAM-D and Sickness Impact Profile (SIP) scores. RESULTS: One hundred three physicians and 175 patients were involved in the clinical trial. Physicians of intervention patients were more likely to diagnose depression and prescribe antidepressants (P < 0.01). There were no differences between the groups in the frequency of stopping medications associated with depression or referrals to psychiatry. Medications with the strongest cause and effect relationship to depression were infrequently used in this cohort of patients. Although both groups showed improvement in HAM-D and SIP scores, we were unable to demonstrate significant differences in HAM-D or SIP scores between the 2 groups. CONCLUSIONS: Intensive screening and feedback of patient-specific treatment recommendations increased the recognition and treatment of late life depression by primary care physicians. However, we were unable to demonstrate significant improvement in depression or disability severity among intervention patients despite the informational support provided to their physicians. Efforts to improve the functional status of these patients may require more integrated interventions and more aggressive attempts to target psychosocial stressors traditionally outside the purview of primary care.

Aged↗
PubMed1993

Longitudinal study of bone mass in end-stage renal disease patients: effects of parathyroidectomy for renal osteodystrophy.

The effectiveness of parathyroidectomy (PTHX) for the control of secondary hyperparathyroidism was assessed in 46 adult end-stage renal disease (ESRD) patients whose bone mineral content at the midshaft and distal radius was measured using single-photon absorptiometry (SPA) every 6 months before and after the surgery. They were compared to 46 age-, race-, and sex-matched ESRD patient controls who had not undergone surgery but who had had at least five SPA studies at similar intervals. Presurgery midradius bone mass was significantly lower for PTHX patients compared to controls. Comparing changes in bone mass of PTHX patients across surgery to controls in comparable time periods showed that PTHX patients lost significantly less bone mass after surgery. Similar results were obtained when rates of change in bone mass were evaluated. When patient characteristics were examined, the effect of surgery was found to be diminished in elderly patients and in oophorectomized patients. It is concluded that PTHX can have a salutary effect on renal osteodystrophy in the appendicular skeleton, but factors other than bone mass also need to be considered in identifying those patients who will benefit from surgery.

Absorptiometry, Photon↗
PubMed1993

Estimating physician costliness. An empirical Bayes approach.

Outpatient data obtained from the general medicine practice of an urban, health care facility are used to provide an application of empirical Bayes techniques in the estimation of physician "costliness." The results illustrate that application of the simplest empirical Bayes estimation procedure can provide more reasonable estimates of physician's utilization of resources than a standard estimation procedure. Empirical Bayes estimates are shown to adjust for potential instability in standard estimates that may arise from either a physician treating a small number of patients or an inappropriate case-mix adjustment. Using simulation, it is demonstrated that the empirical Bayes procedure can provide overall better estimates using fewer data than the standard procedure. This application, although somewhat limited in scope, should provide impetus for increased utilization of the numerous Bayesian and empirical Bayes techniques that currently exist in the statistical literature and pertain to small area estimation techniques.

Ambulatory Care↗
PubMed1991

Role of physical activity in the development of skeletal mass in children.

A group of 118 children, aged 5.3-14 years, were enrolled in a prospective study of calcium supplementation and bone mass. At entry to the study, questionnaires regarding the child's usual physical activity were administered to the children and their mothers. Repeated activity assessments at 6 month intervals indicated good within-person agreement for total activity and for most individual activities. Consistent positive associations were observed between bone mineral densities (BMD) in the radius, spine, and hip and most activities. A summary measure (total hours of weight-bearing activity) was significantly related to BMD in the radius and hip, independently of age or gender effects. Self-reported sports and play activities were associated with BMD, but neither time spent watching television nor hours of physical education classes were associated either positively or negatively with skeletal mass. These data suggest that important increments in skeletal mass may result from physical activity during childhood.

Adolescent↗
PubMed1991

Validation techniques for logistic regression models.

This paper presents a comprehensive approach to the validation of logistic prediction models. It reviews measures of overall goodness-of-fit, and indices of calibration and refinement. Using a model-based approach developed by Cox, we adapt logistic regression diagnostic techniques for use in model validation. This allows identification of problematic predictor variables in the prediction model as well as influential observations in the validation data that adversely affect the fit of the model. In appropriate situations, recommendations are made for correction of models that provide poor fit.

Benzothiadiazines↗
PubMed1991

Practice randomization and clinical research. The Indiana experience.

Thoughtful preparation of a research laboratory is an early step in designing a program for scientific investigation. The Division of General Internal Medicine at Indiana University has maintained a "laboratory" for outpatient clinical investigation for more than 15 years. In this report, we describe the structure and function of the General Medicine Practice in the Regenstrief Health Center on the campus of the Indiana University School of Medicine in Indianapolis. Specifically, we discuss the ongoing random allocation of subjects, the local resources for data management and tracking of patients' use of clinical services, and how combining this information system into a randomized primary care system has fostered successful ventures in clinical investigation.

Health Services Research↗
PubMed1990

Predictors of bone mass in perimenopausal women. A prospective study of clinical data using photon absorptiometry.

STUDY OBJECTIVE: To determine whether clinically available data on risk factors are adequate to identify perimenopausal women with either low or high bone mass. DESIGN: Cross-sectional observational study of a cohort of perimenopausal women (mean age, 50.8 years). SETTING: Community volunteers in a university hospital. SUBJECTS: One hundred twenty-four white volunteers established as perimenopausal by history and serum concentrations of estrogens and follicle-stimulating hormone. MEASUREMENTS AND MAIN RESULTS: Models were constructed to predict bone mass in the radius, lumbar spine, and hip using risk factors (age, height, weight, calcium and caffeine intake, alcohol and tobacco use, and urinary markers of bone turnover). Although highly significant predictive models were developed for all skeletal sites, none of the models correctly identified more than 70% of women with low bone mass at any site. However, for the radius, a model was constructed that never overestimated bone mass by more than 0.10 g/cm. A small subgroup (7%) with short stature, low body weight, low calcium intake, and who were heavy smokers always had low radial bone mass. Using these models, about 30% of our population could be assessed without bone mass measurements. Predictions for the spine and femur were less efficient, suggesting that direct measurements are required if therapy decisions are to be based on bone mass at these sites. CONCLUSIONS: Risk factors for osteoporosis are of limited use in identifying women with low bone mass around the time of menopause. Measurements of bone mass are probably necessary if the risk for osteoporosis is to be the basis for deciding on estrogen replacement therapy.

Absorptiometry, Photon↗
PubMed1990

The contribution of bone loss to postmenopausal osteoporosis.

We have addressed the relative importance of peak bone mass and subsequent rate of loss in determining postmenopausal women's bone mass in old age, by examining longitudinal measurements of radial mid-shaft bone mass on various samples of healthy white postmenopausal women. Using both the variance estimate of age-specific rates of bone loss and the population variance in bone mass, we determined that rates of loss could contribute importantly to future bone mass. However, since we found a small negative correlation between initial bone mass and rate of loss, it was necessary to estimate the effect of bone loss as the complement of the contribution of initial bone mass. We found that the influence of bone loss (relative to initial bone mass) increases as the women age, such that by about age 70, the contribution of initial bone mass and rate of loss approached equality. However, estimated rates of bone loss were not very stable over time, so it was difficult to identify long-term 'fast-losers'. We conclude that the rate of postmenopausal bone loss is an important contributor to osteoporosis at old age, but it is difficult to identify long-term fast-losers, thereby reducing the clinical value of assessments of rates of change in bone mass early in the postmenopause.

Aged↗
PubMed1990

Bone mass and anthropometric measurements in adult females.

Bone mass and anthropometrics were measured in 342 adult female twins, aged 25-79 (mean = 44.1 years) for the purpose of: (1) identifying which anthropometric measurements were most strongly associated with bone mass at various skeletal sites, and (2) determining the accuracy of combinations of these measurements in the prediction of bone mass. Among the eight skinfolds measured, the subscapular site was more strongly correlated with all bone mass measurements than any other skinfold. Similarly, calf circumference (among four sites) and biacromial width (among five frame size measurements) provided the strongest correlations within these groups of anthropometrics with all bone sites. The somewhat surprising consistency of these results was then tested in multivariable models for the prediction of bone mass. For the entire study group, each of the anthropometric measurements (subscapular skinfold, calf circumference and biacromial width) were independent, significant predictors of bone mass, even when height, weight and age were included in the models. These data suggest that frame size, muscularity and adiposity have independent effects on the skeleton, and that single measurements of each of these anthropometric characteristics are associated with all skeletal sites.

Adipose Tissue↗
PubMed1990

Ibuprofen-associated renal impairment in a large general internal medicine practice.

The authors determined the incidence of ibuprofen-associated renal impairment and risk factors for its development in 1908 patients treated with ibuprofen using data from a computerized medical records system. Renal impairment occurred in 343 patients (18%). Multivariable analysis revealed six independent predictors of renal impairment: age, prior renal insufficiency, coronary artery disease, male gender, elevated systolic blood pressure, and diuretic use. They then tested the degree to which ibuprofen contributed to the development of renal impairment by evaluating a control group of 3933 acetaminophen recipients. Neither ibuprofen nor acetaminophen was among the independent predictors of risk when all patients were considered (adjusted odds ratio, 1.05; 95% Cl, 0.88-1.26). However, two subsets of at risk patients had an ibuprofen effect: patients greater than or equal to 65 years of age who received ibuprofen were at greater risk of renal impairment as compared to acetaminophen recipients (adjusted odds ratio, 1.34; 95% Cl, 1.05 to 1.72) as were patients with coronary artery disease (adjusted odds ratio, 2.54; 95% Cl, 1.38 to 4.68). Their results suggest that elderly patients and patients with coronary artery disease are at risk for ibuprofen-associated renal impairment and therefore should have their renal function monitored when ibuprofen and possibly other nonsteroidal anti-inflammatory drugs are prescribed.

Acetaminophen↗