Biomedical subjects

H T Vu

Publications and source records attributed to H T Vu.

At least 19 recordsLinked to original sources

PubMed2006

Randomised controlled trial of topical ciclosporin A in steroid dependent allergic conjunctivitis.

AIM: To evaluate the efficacy, safety, and therapeutic effect of topical ciclosporin A 0.05% as a steroid sparing agent in steroid dependent allergic conjunctivitis. METHODS: Prospective, randomised, double masked, placebo controlled trial comparing signs, symptoms, and the ability to reduce or stop concurrent steroid in steroid dependent atopic keratoconjunctivitis and vernal keratoconjunctivitis using 0.05% topical ciclosporin A compared to placebo. Steroid drop usage per week (drug score), symptoms, and clinical signs scores were the main outcome measures. RESULTS: The study included an enrolment of 40 patients, 18 with atopic keratoconjunctivitis and 22 with vernal keratoconjunctivitis. There was no statistical significant difference in drug score, symptoms, or clinical signs scores between the placebo and ciclosporin group at the end of the treatment period. No adverse reactions to any of the study formulations were encountered. CONCLUSIONS: Topical ciclosporin A 0.05% was not shown to be of any benefit over placebo as a steroid sparing agent in steroid dependent allergic eye disease.

Adult↗

PubMed2001

How important is intrinsic spirituality in depression care? A comparison of white and African-American primary care patients.

We used a cross-sectional survey to compare the views of African-American and white adult primary care patients (N = 76) regarding the importance of various aspects of depression care. Patients were asked to rate the importance of 126 aspects of depression care (derived from attitudinal domains identified in focus groups) on a 5-point Likert scale. The 30 most important items came from 9 domains: 1) health professionals' interpersonal skills, 2) primary care provider recognition of depression, 3) treatment effectiveness, 4) treatment problems, 5) patient understanding about treatment, 6) intrinsic spirituality, 7) financial access, 8) life experiences, and 9) social support. African-American and white patients rated most aspects of depression care as similarly important, except that the odds of rating spirituality as extremely important for depression care were 3 times higher for African Americans than the odds for whites.

Adolescent↗

PubMed2001

Screening the public for depression through the Internet.

OBJECTIVE: Despite increased public screening, many individuals with depression remain undetected or untreated. This study explored the performance of an Internet-based program in screening for depression. METHODS: The Centers for Epidemiological Studies Depression (CES-D) scale was adapted as an online screening test. The program advised persons whose score indicated a high probability of depression to seek treatment and asked them to complete a survey of attitudes and preferences that could be printed and taken to a health professional. Responses were collected anonymously for epidemiologic research. Demographic characteristics of participants were compared with those of the U.S. population and participants in previous community screenings. The costs of the program were calculated. RESULTS: The CES-D scale was completed 24,479 times during the eight-month study period. The respondents' median age category was 30 to 45 years, and almost 30 percent were male; 58 percent (N=14,185) screened positive for depression, and fewer than half of those had never been treated for depression. The proportion of younger individuals was larger than in previous public screenings, but was still lower than that in the U.S. population. Our sample contained a lower proportion of minorities than the U.S. population (16.6 percent versus 28.3 percent). Sunk costs totaled $9,000, and additional marginal costs to maintain the system totaled $3,750. CONCLUSIONS: The Internet provides a continuously available, inexpensive, easily maintained platform to anonymously screen a large number of individuals from a broad geographic area. However, older adults and minorities may visit screening sites less frequently than other populations.

Adolescent↗

PubMed2000

Mental health versus substance abuse treatment programs for dually diagnosed patients.

The aim of this study was to assess the similarities and differences of patients with co-existing psychiatric and substance use disorders attending treatment in either a mental health setting or a substance abuse treatment setting. A total of 129 patients were assessed, including 65 individuals from the substance abuse treatment center and 64 individuals from the mental health program. Treatment records were reviewed for diagnoses and sociodemographic data. While the two groups were highly similar with regard to age and ethnicity, there were significant differences in psychiatric profile, with the substance abuse treatment group having less severe diagnoses and no patients with schizophrenia, while the mental health treatment group had a majority of patients with schizophrenia. Other differences in the two groups, such as marital and parental status, disability status, and medical problems appeared to be directly linked with the aforementioned diagnostic profile. These data suggest important differences in characteristics of patients with comorbid disorders that appear to be dependent on the type of treatment program they attend. For the most effective management, integrated treatment programs should be aware of these differences and tailor service provision accordingly.

Adult↗

PubMed2000

A description of precipitants of drug use among dually diagnosed patients with chronic mental illness.

In this report, we describe patients' perceptions of the chronological occurrence of their mental illness and substance abuse. The patients were enrolled in a community mental health center and received dual diagnosis treatment from an affiliated psychiatric rehabilitation program. Using a questionnaire designed to address this issue, we assessed patients' perceptions of support currently being received at the treatment program and how beneficial they perceived this support to be. In addition, we assessed why substance use was a coping strategy in times of perceived stress early in life and whether this behavior has changed to date. Assessing the perception of the sequence of co-occurring disorders among patients enables us to better understand the factors that precipitate substance use and exacerbate mental illness. This knowledge may aid in the design of effective treatment strategies for this population of patients.

Adaptation, Psychological↗

PubMed2000

Severely mentally ill patients with and without substance use disorders: characteristics associated with treatment attrition.

We aimed to describe characteristics associated with attrition for patients in community mental health treatment with chronic mental illness with and without substance use disorders. Baseline assessments included symptom severity, treatment satisfaction, social support, and a structured diagnostic interview. Treatment attrition was assessed at six months. At six months, 36% of the dual diagnosis group (n = 25), and 61% of the mental illness alone group (n = 23) were lost to follow-up. Attrition in the dually diagnosed group tended to be associated with less satisfaction with treatment, and higher mean symptom scores. There were no characteristics associated with attrition in the group of patients with mental illness alone. However, client satisfaction tended to increase among the mental illness alone patients that were successfully followed. The dually diagnosed group that remained in treatment had a significantly lower mean treatment satisfaction score than the mental illness alone group at six months. This type of investigation should aid in patient care and evaluation of treatment programs for persons with severe mental illness and co-occurring substance use disorders.

Adult↗

PubMed2000

The trypsin inhibitor content of 61 wild edible plant foods of Niger.

In the western Sahel and many other regions of sub-Saharan Africa, wild edible plants contribute significantly to human diets, not only during periods when cereal staples are scarce, but also when they are readily available. Although there have been published reports regarding the nutrient contents of these plant foods, little attention has been devoted to their content of antinutrients such as calcium chelators and inhibitors of the pancreas-derived proteases, trypsin and chymotrypsin, which are required for the efficient digestion and absorption of dietary proteins. In this study, aqueous extracts of 61 different leaves, seeds, fruits and flowers of edible plants gathered in the Republic of Niger were analyzed for their content of trypsin inhibitory substances using alpha-N-benzoyl-DL-arginine-p-nitroanilide as the substrate and bovine trypsin as the enzyme source. Twelve of these plant foods contained more antitrypsin activity than soybeans (1.34-8.18 vs. 1.32 microg trypsin inhibited/mg dry weight). Boiling for 3 min did not inactivate the antitrypsin activity in most of the plant extracts. These data confirm that more than half of the wild edible plant foods widely consumed by various populations who inhabit the western Sahel contain significant quantities of heat-stable trypsin inhibitor that could possibly compromise the bioavailability of proteins present in the diets of these populations.

Biological Availability↗

PubMed2000

Body mass index and alternative indices of obesity in relation to height, triceps skinfold and subsequent mortality: the Busselton health study.

OBJECTIVES: The ideal index for leanness and obesity in epidemiological studies should correlate strongly with body weight and with a direct measure of fat while minimizing the influence of height. The preferred index is expected to show meaningful associations with subsequent mortality. Our aims were to compare weight/height, weight/height(2) (body mass index or BMI), and weight/height(3) as candidates for this index. DESIGN: We analysed cross-sectional data from surveys of 6948 adults (3334 men (mean age 43 y, mean BMI 24.8 kg/m2), and 3614 women (mean age 42 y, mean BMI 24.3 kg/m2)) in Busselton, Australia whose weight, height, triceps skinfold, and cardiovascular risk factors were measured from 1966 through to 1978. In these same subjects we studied the mortality risks of indices of obesity using Cox regression analysis for survival time from first survey to death, or to follow up at the end of December 1995, after adjustment for age. Subjects dying within 5 y of the baseline survey were excluded from the analysis to avoid the bias of concurrent illness. We also studied subgroups including never smokers, subjects with no heart disease, and subjects <60 years of age at first survey. RESULTS: In men, weight/height2 met the criteria for a satisfactory index in that there was a very strong correlation with triceps skinfold, and a negligible correlation with height. For women, weight/height was as good a measure as weight/height2, with both having strong correlations with triceps skinfold, and minimal correlations with height. Weight/height2 as a predictor of mortality in men of all ages showed the typical U-shaped associations that were similar and consistent and of variable statistical significance. The significances of the hazard ratio curves were the strongest for cardiovascular disease deaths (all men P=0.001; men without heart disease at baseline P<0.001; never smoking men P=0.007). In never smoking men there was a near linear positive relationship with all-cause mortality (P=0.018). In women weight/height2 showed no consistent associations with mortality. There was a shallow U-shaped relationship with all-cause mortality (P=0.087), also seen in never smoking women (P=0.075). In assessing 'ideal' weight for height in this population, a weight/height2 of 25 kg/m2 (range 22.5-27.5 kg/m2) is appropriate. Weight/height and mortality showed very similar patterns in men to weight/height2 with quite similar levels of statistical significance. In women much more pronounced U-shaped curves were apparent in all groups and subgroups, with a significant all-cause mortality trend for all women (P=0.029) and never smoking women (P=0.034). In assessing 'ideal' weight for height a weight/height of 42.5 kg/m (range 35-50 kg/m) appears appropriate for men and women. CONCLUSIONS: Weight/height2 is an appropriate index of leanness and obesity in males at all ages, whereas weight/height is at least as good an index for females. In mortality studies weight/height2 and weight/height predict mortality similarly in males, but weight/height is a better discriminant of mortality in females. International Journal of Obesity (2000)24, 108-115

Adult↗

PubMed2000

Multicenter study of whole-blood creatinine, total carbon dioxide content, and chemistry profiling for laboratory and point-of-care testing in critical care in the United States.

OBJECTIVES: To introduce a creatinine biosensor and a total carbon dioxide content (TCO2) method for whole-blood measurements, to evaluate the clinical performance of a new transportable analyzer that simultaneously performs these two and six other tests (Na+, K+, Cl-, glucose, urea nitrogen, and hematocrit), and to assess the potential of the new analyzer for point-of-care testing in critical care by comparing results obtained by nonlaboratory personnel and by medical technologists. DESIGN: Multicenter sites compared whole-blood measurements with the transportable analyzer to plasma measurements from the same specimens with local reference instruments. One site compared whole-blood results produced by nonlaboratory personnel vs. medical technologists and evaluated day-to-day and within-day precision at the point of care. SETTINGS AND PATIENTS: Four medical centers in the United States. Venous and arterial specimens from 710 critically ill patients with a variety of diagnoses. Point-of-care testing in the emergency room and operating room. RESULTS: The linear regression analyses at the four medical centers showed the following: creatinine (a) slope, 0.91 to 1.22, (b) y intercept, -0.07 to 0.15 mg/dL, and (c) r2, 0.77 to 1.00; and TCO2: (a) slope, 0.64 to 1.00, (b) y intercept, 1.36 to 9.6 mmol/L, and (c) r2, 0.52 to 0.72 (yi, whole-blood analyses; xi, plasma reference measurements). Bland-Altman plots also were used to assess multicenter creatinine and TCO2 results. Of the other analytes, K+, glucose, and urea nitrogen had the highest r2-values. For the eight chemistry profile tests performed at the point of care (yi, nonlaboratory personnel results; xi, medical technologist results), the average value of r2 was 0.96 (SD 0.08) in the operating room and 0.96 (SD 0.06) in the emergency room, and mean paired differences (yi - xi) were not statistically or clinically significant. Precision was acceptable. CONCLUSIONS: The performance of the creatinine biosensor and the TCO2 method was acceptable for whole-blood samples. Comparisons of whole-blood results from the transportable analyzer and plasma results from the local reference instruments revealed analyte biases that may be attributed to differences between direct whole-blood analyses and indirect-diluted plasma measurements and other factors. Performance of nonlaboratory personnel and medical technologists was equivalent for point-of-care testing in critical care settings. The whole-blood analyzer should be useful when patient care demands immediate results.

Biosensing Techniques↗

PubMed2000

Striated muscle-specific beta(1D)-integrin and FAK are involved in cardiac myocyte hypertrophic response pathway.

Alterations in the extracellular matrix occur during the cardiac hypertrophic process. Because integrins mediate cell-matrix adhesion and beta(1D)-integrin (beta1D) is expressed exclusively in cardiac and skeletal muscle, we hypothesized that beta1D and focal adhesion kinase (FAK), a proximal integrin-signaling molecule, are involved in cardiac growth. With the use of cultured ventricular myocytes and myocardial tissue, we found the following: 1) beta1D protein expression was upregulated perinatally; 2) alpha(1)-adrenergic stimulation of cardiac myocytes increased beta1D protein levels 350% and altered its cellular distribution; 3) adenovirally mediated overexpression of beta1D stimulated cellular reorganization, increased cell size by 250%, and induced molecular markers of the hypertrophic response; and 4) overexpression of free beta1D cytoplasmic domains inhibited alpha(1)-adrenergic cellular organization and atrial natriuretic factor (ANF) expression. Additionally, FAK was linked to the hypertrophic response as follows: 1) coimmunoprecipitation of beta1D and FAK was detected; 2) FAK overexpression induced ANF-luciferase; 3) rapid and sustained phosphorylation of FAK was induced by alpha(1)-adrenergic stimulation; and 4) blunting of the alpha(1)-adrenergically modulated hypertrophic response was caused by FAK mutants, which alter Grb2 or Src binding, as well as by FAK-related nonkinase, a dominant interfering FAK mutant. We conclude that beta1D and FAK are both components of the hypertrophic response pathway of cardiac myocytes.

Amino Acid Sequence↗

PubMed2000

BAX and PKCalpha modulate the prognostic impact of BCL2 expression in acute myelogenous leukemia.

Previously, we demonstrated that the level of BCL2 expression is prognostic in acute myelogenous leukemia (AML). High levels of BCL2 correlate with an adverse outcome when associated with favorable and intermediate prognosis cytogenetics (FIPC), whereas low levels portend an adverse outcome when associated with unfavorable cytogenetics (UC). Because BCL2 function can be modulated by dimerization with family members, like BAX, or by phosphorylation by protein kinase C alpha (PKCalpha), we hypothesize that the relative expression of these proteins in primary leukemic cells might alter the prognostic impact of BCL2 expression. We therefore measured BAX and PKCalpha protein levels in peripheral blood mononuclear cell lysates from 165 newly diagnosed AML patients and correlated the expression of these proteins with BCL2 expression, patient survival, and remission induction success. Expression levels of BAX and PKCalpha were normalized against a control cell line, K562. BAX and PKCalpha expression levels were heterogeneous and did not correlate with the percentage of blasts in the sample (R2 = 0.01 and <0.01). The median expression of both was similar across FAB groups but the range was greater for M4. A similar distribution of expression was observed in all cytogenetic groups, except that patients with inversion 16 demonstrated lower levels of BAX. Individually, neither PKCalpha nor BAX expression was prognostic of response to induction therapy or survival. A similar outcome was obtained when patients were stratified by cytogenetics into FIPC and UC groups. However, the ratio of either BCL2:BAX (B2:BX) or PKCalpha*B2:BX (PK*B2:BX) was highly prognostic. Patients with FIPC and a lower ratio (less than median) of either B2:BX or PK*B2:BX had a significantly higher remission induction rate (88 versus 69%, P = 0.04) and longer survival (median: 141 versus 80.5 weeks, P = 0.007) compared with those with ratios more than median. For patients with UC, values of either B2:BX or PK*B2:BX below the median had an inferior response rate to induction therapy (35 versus 78%, P = 0.0006) and inferior survival outcomes (median survival: 11 versus 53 weeks, P = 0.00002). Interestingly, FIPC and UC patients with antiapoptotic ratios (defined as B2:BX or PK*B2:BX more than median) had identical response rates and survival outcomes. In multivariate analyses, the compound variables of cytogenetics and B2:BX, or PK*B2:BX were independent predictors of survival. These results suggest that expression levels of proteins that affect the functional status of BCL2 modify the prognostic impact of BCL2 and suggest that the role of apoptosis in different cases of AML varies independently in the different cytogenetic subgroups.

Adolescent↗

PubMed1999

Race, gender, and partnership in the patient-physician relationship.

CONTEXT: Many studies have documented race and gender differences in health care received by patients. However, few studies have related differences in the quality of interpersonal care to patient and physician race and gender. OBJECTIVE: To describe how the race/ethnicity and gender of patients and physicians are associated with physicians' participatory decision-making (PDM) styles. DESIGN, SETTING, AND PARTICIPANTS: Telephone survey conducted between November 1996 and June 1998 of 1816 adults aged 18 to 65 years (mean age, 41 years) who had recently attended 1 of 32 primary care practices associated with a large mixed-model managed care organization in an urban setting. Sixty-six percent of patients surveyed were female, 43% were white, and 45% were African American. The physician sample (n = 64) was 63% male, with 56% white, and 25% African American. MAIN OUTCOME MEASURE: Patients' ratings of their physicians' PDM style on a 100-point scale. RESULTS: African American patients rated their visits as significantly less participatory than whites in models adjusting for patient age, gender, education, marital status, health status, and length of the patient-physician relationship (mean [SE] PDM score, 58.0 [1.2] vs 60.6 [3.3]; P = .03). Ratings of minority and white physicians did not differ with respect to PDM style (adjusted mean [SE] PDM score for African Americans, 59.2 [1.7] vs whites, 61.7 [3.1]; P = .13). Patients in race-concordant relationships with their physicians rated their visits as significantly more participatory than patients in race-discordant relationships (difference [SE], 2.6 [1.1]; P = .02). Patients of female physicians had more participatory visits (adjusted mean [SE] PDM score for female, 62.4 [1.3] vs male, 59.5 [3.1]; P = .03), but gender concordance between physicians and patients was not significantly related to PDM score (unadjusted mean [SE] PDM score, 76.0 [1.0] for concordant vs 74.5 [0.9] for discordant; P = .12). Patient satisfaction was highly associated with PDM score within all race/ethnicity groups. CONCLUSIONS: Our data suggest that African American patients rate their visits with physicians as less participatory than whites. However, patients seeing physicians of their own race rate their physicians' decision-making styles as more participatory. Improving cross-cultural communication between primary care physicians and patients and providing patients with access to a diverse group of physicians may lead to more patient involvement in care, higher levels of patient satisfaction, and better health outcomes.

Adult↗

PubMed1998

Multicenter study of oxygen-insensitive handheld glucose point-of-care testing in critical care/hospital/ambulatory patients in the United States and Canada.

OBJECTIVES: Existing handheld glucose meters are glucose oxidase (GO)-based. Oxygen side reactions can introduce oxygen dependency, increase potential error, and limit clinical use. Our primary objectives were to: a) introduce a new glucose dehydrogenase (GD)-based electrochemical biosensor for point-of-care testing; b) determine the oxygen-sensitivity of GO- and GD-based electrochemical biosensor test strips; and c) evaluate the clinical performance of the new GD-based glucose meter system in critical care/hospital/ambulatory patients. DESIGN: Multicenter study sites compared glucose levels determined with GD-based biosensors to glucose levels determined in whole blood with a perchloric acid deproteinization hexokinase reference method. One site also studied GO-based biosensors and venous plasma glucose measured with a chemistry analyzer. Biosensor test strips were used with a handheld glucose monitoring system. Bench and clinical oxygen sensitivity, hematocrit effect, and precision were evaluated. SETTING: The study was performed at eight U.S. medical centers and one Canadian medical center. PATIENTS: There were 1,248 patients. RESULTS: The GO-based biosensor was oxygen-sensitive. The new GD-based biosensor was oxygen-insensitive. GD-based biosensor performance was acceptable: 2,104 (96.1%) of 2,189 glucose meter measurements were within +/-15 mg/dL (+/-0.83 mmol/L) for glucose levels of < or = 100 mg/dL (< or = 5.55 mmol/L) or within +/-15% for glucose levels of > 100 mg/dL, compared with the whole-blood reference method results. With the GD-based biosensor, the percentages of glucose measurements that were not within the error tolerance were comparable for different specimen types and clinical groups. Bracket predictive values were acceptable for glucose levels used in therapeutic management. CONCLUSIONS: The performance of GD-based, oxygen-insensitive, handheld glucose testing was technically suitable for arterial specimens in critical care patients, cord blood and heelstick specimens in neonates, and capillary and venous specimens in other patients. Multicenter findings benchmark the performance of bedside glucose testing devices. With the new +/-15 mg/dL --> 100 mg/dL --> +/-15% accuracy criterion, point-of-care systems for handheld glucose testing should score 95% (or better), as compared with the recommended reference method. Physiologic changes, preanalytical factors, confounding variables, and treatment goals must be taken into consideration when interpreting glucose results, especially in critically ill patients, for whom arterial blood glucose measurements will reflect systemic glucose levels.

Adult↗

PubMed1998

Prognostic factors in elective aortic reconstructive surgery.

BACKGROUND: The present study was carried out to determine the risk factors associated with peri-operative mortality and long-term survival in patients undergoing abdominal aortic reconstructive surgery (ARS). METHODS: A retrospective review was performed of the case notes of all patients having ARS at a university teaching hospital during a 5.5-year period, and their details entered onto a pro forma. RESULTS: A total of 252 patients underwent ARS between July 1989 and December 1994. The peri-operative mortality was 7.5%. The most frequent adverse events were cardiac events, accounting for 8 (42%) of the peri-operative deaths. The risk of a peri-operative cerebrovascular accident was low (n = 3, 1.2%) as was the risk of peri-operative renal failure requiring dialysis (n = 3, 1.2%). Factors independently linked to increased peri-operative mortality included moderate-to-severe hypertension (P = 0.05, odds ratio = 3.54), those with renal impairment (P = 0.05, odds ratio = 2.69), and blood transfusion requirements (P < 0.001, odds ratio = 1.26). Long-term survival was independently shortened by occlusive disease (P = 0.004, hazard ratio = 2.78) and ischaemic heart disease (P < 0.001, hazard ratio = 3.58). CONCLUSIONS: The risks of ARS were significantly increased in patients with severe hypertension, those with renal impairment and those requiring blood transfusion. Long-term survival was shortened for those patients with occlusive aortic disease and ischaemic heart disease. These risk factors should be carefully assessed in each patient before performing elective ARS.

Aorta, Abdominal↗

PubMed1998

Multivariate risk estimation for coronary heart disease: the Busselton Health Study.

Coronary heart disease (CHD) is a multifactorial disease and CHD risk should be estimated by assessing all cardiovascular risk factors simultaneously. Simply adding up the number of factors with 'at risk' values fails to identify high-risk subjects with multiple risk factors at moderately elevated values. A more efficient approach is to use a quantitative multivariate risk score. A number of overseas studies have produced CHD risk scoring systems for men. There are few risk scores developed for women and no CHD risk scores have been developed from Australian data. This study used data on CHD risk factors and morbidity/mortality follow-up for the 1978 Busselton Health Survey participants to provide age-specific estimates of absolute risk of CHD hospitalisation or death, and to develop multivariate CHD risk scoring systems for men and women. The scores are based on age, blood pressure, anti-hypertensive medication, total and HDL cholesterol, smoking, diabetes, left ventricular hypertrophy and previous history of CHD. The generalisability and applicability of these risk estimation systems to Australian populations in the late 1990s is discussed.

Adult↗

PubMed1997

Prediction of coronary heart disease mortality in Busselton, Western Australia: an evaluation of the Framingham, national health epidemiologic follow up study, and WHO ERICA risk scores.

STUDY OBJECTIVES: To evaluate the performance of the Framingham, national health epidemiologic follow up study, and the WHO ERICA risk scores in predicting death from coronary heart disease (CHD) in an Australian population. DESIGN: Cohort follow up study. SETTING AND PARTICIPANTS: The cohort consisted of 1923 men and 1968 women who participated in health surveys in the town of Busselton in Western Australia over the period 1966-81. Baseline assessment included cardiovascular risk factor measurement. Mortality follow up to 31 December 1994 was used. MAIN RESULTS: Risk scores for death from CHD within 10 years based on age, systolic blood pressure, cholesterol, smoking, and BMI were derived from the Busselton study data using logistic regression analysis. Similar risk scores developed from the Framingham, the national health epidemiologic follow up study, and the WHO ERICA cohorts were found to perform just as well in Busselton as the Busselton-derived scores, both before and after controlling the effect of age. There was considerable overlap across the different risk scores in the identification of individuals in the highest quintile of risk. Those in the top 20% of scores included about 41% of deaths from CHD among men and about 63% of deaths from CHD among women. CONCLUSION: Although there is variation in risk score coefficients across the studies, the relative risk predictive performance of the scores is similar. The use of Framingham and other similar risk scores will not be misleading in white Australian populations.

Adult↗

PubMed1997

An empirical comparison of multivariable methods for estimating risk of death from coronary heart disease.

BACKGROUND: Logistic regression and, more recently, Cox regression have been the predominant methods for identifying risk factors and developing risk estimation equations for coronary heart disease (CHD). Software for the regression tree method is now available for binary and survival outcomes and thus offers an alternative methodology. This paper compares these four methods for identifying significant risk factors from among a set of candidate factors and for estimating the risk of death from CHD using baseline and mortality follow-up data on 1,701 men participating in the Busselton Health Study. The candidate risk factors were age, body mass index, systolic and diastolic blood pressure, treatment for hypertension, cholesterol and smoking. METHODS: Logistic regression, Cox proportional hazards regression, binary regression tree, and survival regression tree analyses have been applied to data obtained from the same cohort of men for CHD death risk estimation and prediction. The four methods are compared in terms of the variables selected, goodness-of-fit of models, similarity of cross-validated estimated risks for individuals, and ability to discriminate between those who died from CHD and those who did not die from CHD during the follow-up period, including the comparison of Receiver Operating Characteristic (ROC) curves. RESULTS: Although age and a blood pressure variable were selected by all four methods, body mass index was also selected by the regression tree methods and smoking was also selected by Cox regression. There was good, but not excellent, agreement between methods in estimates of risk for individuals, the areas under the ROC curves were 0.66 for the binary tree, 0.72 for logistic regression, 0.71 for the survival tree method and 0.78 for Cox regression. The average differences in estimated risk between those who died from CHD and those who did not die from CHD during the follow-up period were 0.051 for logistic regression, 0.070 for the binary tree method, 0.073 for the survival tree method and 0.088 for Cox regression. CONCLUSION: For a moderately sized cohort typical of many applications of these methods in the literature, the two methods which used the survival outcome performed better than the methods using a binary outcome. Despite selecting some different variables and showing moderate differences in risk estimates for individuals, the two binary approaches were similar in performance. Cox regression appeared to be superior to the survival tree method, but further larger studies of completely separate samples for model development and evaluation of prediction performance are required to confirm this finding.

Age Factors↗

PubMed1996

Risk factors for stroke mortality in men and women: The Busselton Study.

BACKGROUND: Although there have been a number of prospective studies of risk factors for stroke, the Busselton study remains the only Australian study to report such data. The Framingham stroke risk appraisal function has been evaluated in very few populations. This paper presents results of stroke mortality risk factor analyses from the Busselton study and compares the Busselton risk factor coefficients with those based on Framingham data. METHODS: Mortality follow-up to 31 December 1993 on 4872 participants in the Busselton Health Survey 1966-1981 was used for Cox proportional hazards regression analysis of risk factors for death from stroke. Risk factors investigated were systolic and diastolic blood pressures, antihypertensive therapy, diabetes, smoking, body mass index, cholesterol, alcohol, coronary heart disease, atrial fibrillation and left ventricular hypertrophy. RESULTS: The average duration of follow-up was 20 years and a total of 213 individuals died from stroke during the follow-up period. Age, systolic blood pressure, antihypertensive therapy, smoking, cholesterol, alcohol (negatively), coronary heart disease and atrial fibrillation were significantly and independently associated with stroke modality rate. The Cox regression coefficients were generally similar to those from the Framingham study, but there were important differences. CONCLUSIONS: This report has confirmed age, blood pressure, antihypertensive therapy, smoking, and pre-existing cardiovascular disease and diabetes as important risk factors for stroke. The suggestion of a protective effect from moderate alcohol consumption requires further study. The Framingham stroke risk appraisal function should be validated before being recommended for individual stroke risk assessment in other populations.

Adult↗