PubMed Health⌕ Search

Biomedical subjects

Wendy E Hoy

Publications and source records attributed to Wendy E Hoy.

At least 19 recordsLinked to original sources
PubMed2006

A comparison of pathomolecular markers of fibrosis and morphology in kidney from autopsies of African Americans and whites.

African Americans have an increased incidence of chronic kidney disease (CKD) due to hypertension and arteriosclerosis and increased death due to coronary artery disease, compared with whites. The pathogenesis of CKD involves the increased presence and activation of myofibroblasts and macrophages, promotion of tubulointerstitial fibrosis, and effects of tubulointerstitial cell mitosis and apoptosis. We hypothesized that increased risk of hypertensive vascular disease may be identified by renal pathomolecular markers that are associated with progressive CKD. Renal sections were available from 50 autopsies of 33 African Americans (55% males) and 17 whites (76% males) undergoing forensic autopsy for unexpected death. Sclerotic glomeruli, severity of cortical fibrosis, and renal arteriolosclerosis, total glomerular number (N (glom)), average glomerular volume (V (glom)), birth weights, and blood pressure were known. Presence and locality of markers for myofibroblasts (alpha-SMA), macrophages (CD68), collagen, pro-fibrotic transforming growth factor-beta1 were scored in renal autopsies, and tubulointerstitial apoptosis was recorded. The results demonstrated a strong positive correlation between age, cortical fibrosis and alpha-SMA (p<0.05), and between CD68 and hypertension and coronary artery disease (p<0.05). The findings confirm the role of myofibroblasts and macrophages in pathogenesis of human CKD. However, the markers showed no significant relationships to V (glom), N (glom), birth weight, or race.

Actins↗
PubMed2006

C-reactive protein and the risk of developing type 2 diabetes in Aboriginal Australians.

OBJECTIVE: To investigate the association between C-reactive protein (CRP) and the risk of developing diabetes in Aboriginal Australians. RESEARCH DESIGN AND METHODS: High sensitivity CRP levels were measured in 620 Aboriginal participants aged 20-74 years free from diabetes at baseline in a remote community in the Northern Territory of Australia. Participants were followed for a median of 11 years to identify newly diagnosed cases of diabetes. Cox proportional hazards models were used to assess the relationship of CRP levels with the risk of developing diabetes over the follow-up period. RESULTS: A total of 109 participants were newly diagnosed with diabetes. Incident rates were 10.8, 16.6 and 28.8 per 1000 person-years for people in the lower, middle and upper tertile groups of baseline CRP levels, respectively. After adjusting for age, sex, BMI, baseline glucose regulation status, total cholesterol, urine albumin to creatinine ratio, systolic blood pressure, smoking and alcohol drinking, the association between diabetes and CRP remained significant, with a hazard ratio of 1.23 (95% confidence interval (CI) 1.05, 1.45) corresponding to a doubling in CRP values. Similarly, the adjusted hazard ratio for development of diabetes in people in the upper tertile versus the bottom two tertiles of CRP was 1.75 (95% CI 1.19, 2.56). CONCLUSIONS: CRP is independently associated with the development of diabetes in Aboriginal people. Our findings support a role of inflammation in the etiology of diabetes in the high risk population of Aboriginal Australians.

Adult↗
PubMed2006

Albuminuria as a marker of the risk of developing type 2 diabetes in non-diabetic Aboriginal Australians.

BACKGROUND: Aboriginal Australians experience a higher risk of diabetes than the general Australian population. In this paper, we conducted a nested case-control study to determine whether the presence of microalbuminuria and macroalbuminuria is associated with the development of diabetes among diabetes-free Aboriginal people at baseline. METHODS: Urine albumin to creatinine ratios (ACRs) were obtained from 882 Aboriginal people aged 20-74 years from one community. Among them 750 were free of either clinical known diabetes or newly diagnosed diabetes according to WHO 1999 criteria. Over an 11 year follow-up period, 117 participants developed diabetes. They were defined as cases. Each case was matched by an individual control with same sex and body mass index (BMI) category, and age within 2 years. Conditional logistic regression was used to assess the association between albuminuria and diabetes. RESULTS: The baseline level of ACR was significantly higher among cases than among controls. The odds ratios for future diabetes were 2.36 [95% confidence interval (95% CI) 1.01-5.50] and 3.27 (95% CI 1.38-7.77) for middle and upper tertiles, respectively, with adjustment for age, BMI, serum total cholesterol, serum C-reactive protein values, and fasting plasma glucose at the baseline. The adjusted odds ratios were 1.90 (95% CI 0.88-4.06) and 2.51 (95% CI 1.08-5.87) for those with microalbuminuria and macroalbuminuria, respectively. CONCLUSIONS: The presence of microalbuminuria and macroalbuminuria predicts diabetes independent of other known risk markers of development of type 2 diabetes in Aboriginal people.

Adult↗
PubMed2006

Population distribution of high sensitivity C-reactive protein values in Aboriginal Australians: a comparison with other populations.

OBJECTIVES: To examine the distribution of C-reactive protein (CRP) values in Aboriginal Australians and its relation to age and gender. METHODS: High sensitivity CRP levels were measured in 954 Aboriginal participants aged 5-74 years. Fractional polynomial regressions were used to explore the relationship between CRP and age. RESULTS: CRP values changed with age and reached its lowest level around 10 years and then increased with age. Geometric means of CRP were 7.3 (95% confidence interval (CI): 6.6, 8.1) and 4.1 (95% CI: 3.7, 4.6) for female and male adults, respectively. Adjusting for age, the ratio of female to male CRP concentrations was 1.67 (95% CI: 1.45, 1.99) for adults, and 1.09 (95% CI: 0.84, 1.42) for children 5 to 19 years. CONCLUSIONS: CRP changes with age. Females have higher CRP values than males. CRP values in Aboriginal people are substantially higher than other populations.

Adolescent↗
PubMed2006

How many glomerular profiles must be measured to obtain reliable estimates of mean glomerular areas in human renal biopsies?

The objective of this study was to investigate the number of glomerular profiles that are required for accurate estimates of mean profile area in a renal biopsy series. Slides from 384 renal biopsies from one center were reviewed. They contained a median of seven glomerular profiles or of four profiles without sclerosis. Profile areas were measured using stereologic point counting. The "true individual mean" for each biopsy was calculated and the "true population mean" for groups of biopsies derived. Individual and population "random sample means" then were calculated from a random sampling of profiles in each biopsy and were compared with true means for the same biopsies. The effect on the true population means of the entire group of biopsies was also assessed, as the minimum number of glomerular profiles that were required for inclusion was changed. In a single biopsy, random sampling of > or =10 profiles without exclusions and of eight profiles or more without sclerosis reliably estimated the true mean areas. In a group of 30 biopsies, random sampling of five or more glomeruli per biopsy reliably estimated the true population mean. In the aggregate series, inclusion of all 384 biopsies produced the most robust true population mean; the reliability of the estimates decreased as the numbers of eligible biopsies diminished with increasing requisite minimum numbers of profiles per biopsy. We conclude that, while > or =10 profiles might be needed for reliable area estimates in a single biopsy, far fewer profiles per biopsy can suffice when groups of biopsies are studied. In analyses of groups of biopsies, all available biopsies should be used without consideration of the number of glomerular profiles in each. Stipulation of a specific minimum number of glomeruli in each biopsy for inclusion reduces the power of analyses because fewer biopsies are available for evaluation.

Adult↗
PubMed2006

Does nephron number matter in the development of kidney disease?

The total number of nephrons in normal human kidneys varies over a 10-fold range. This variation in total nephron number leads us to question whether low nephron number increases the risk of renal disease in adulthood. This review considers the available evidence in humans linking low nephron number/reduced nephron endowment and the susceptibility to renal disease. Total nephron number in humans has been directly correlated with birth weight and inversely correlated with age, mean glomerular volume, and hypertension. Low nephron number may be the result of suboptimal nephrogenesis during kidney development and/or loss of nephrons once nephrogenesis has been completed. Low nephron number is frequently, but not always, associated with hypertrophy of remaining glomeruli. This compensatory hypertrophy has also been associated with a greater susceptibility for kidney disease. Three human studies have reported reduced nephron number in subjects with a history of hypertension. This correlation has been observed in White Europeans, White Americans (but not African Americans) and Australian Aborigines. Studies in additional populations are required, as well as a greater understanding of the fetal environmental and genetic determinants of low nephron number.

Black or African American↗
PubMed2006

Renal disease, the metabolic syndrome, and cardiovascular disease.

OBJECTIVES: To describe the association between renal disease and other features of the metabolic syndrome and its derivative illnesses among Australian Aborigines in remote settings. METHODS: Volunteering adults (N = 2019) in four remote communities were screened for risk factors and markers of renal disease, hypertension, and diabetes, and their cross-sectional associations were evaluated. Rates of the metabolic syndrome were estimated in one community with comprehensive screening data. The associations of albuminuria with hospitalizations, coronary heart events, and non-renal deaths were then followed for > 7 years in that same community. RESULTS: Rates of renal disease, hypertension, and diabetes all increased dramatically with age. They all overlapped. Renal disease and hypertension were the most prominent and earliest features of the syndrome, while diabetes was a later, less common and more variable manifestation. All were strongly correlated with waist measurements, and high waist measurements more comprehensively characterized those with illnesses than did the more restrictive definitions of the metabolic syndrome. Albuminuria predicted non-renal hospitalizations, first time coronary heart disease events, and all-cause death. CONCLUSION: Albuminuria/proteinuria is an early and dominant element of a symptom complex that is marked by higher waist measurements, and it strongly predicts all-cause and cardiovascular illnesses and deaths. This finding implies a common background of risk factors for renal disease, hypertension, diabetes, and cardiovascular risk. The findings support integrated, rather than disease-specific, surveillance programs, an important role for albuminuria in predicting non-renal risk, and a unified approach for primary and secondary prevention of all elements of the syndrome.

Adult↗
PubMed2006

Setting up chronic disease programs: perspectives from Aboriginal Australia.

OBJECTIVE: To share some perspectives on setting up programs to improve management of hypertension, renal disease, and diabetes in high-risk populations, derived from experience in remote Australian Aboriginal settings. PRINCIPLES: Regular integrated checks for chronic disease and their risk factors and appropriate treatment are essential elements of regular adult health care. Programs should be run by local health workers, following algorithms for testing and treatment, with back up from nurses. Constant evaluation is essential. COMPONENTS: Theses include testing, treatment, education for individuals and communities, skills and career development for staff, ongoing evaluation, program modification, and advocacy. Target groups, elements, and frequency of testing, as well as the reagents and treatment modalities must be designed for local circumstances, which include disease burden and impact, competing priorities, and available resources. Pilot surveys or record reviews can define target groups and conditions. Opportunistic testing will suffice if people are seen with some regularity for other conditions; otherwise, systematic screening is needed, preferably embedded in primary care streams. The chief goal of treatment is to lower blood pressure, and if the patient is diabetic, to control hyperglycemia. Many people will need multiple drugs for many years. CHALLENGES: Challenges include lack of resources, competing demands of acute care, the burden of treatment when disease rates are high, problems with information systems, and in our setting, health worker absenteeism. FUNDING: Businesses, altruistic organizations, and pharmaceutical and biotechnology companies might fund feasibility studies. Where governments or insurance companies already support health services, they must ultimately commit to chronic disease services over the long- term. Effective advocacy requires the presentation of an integrated view of chronic disease and a single cross-disciplinary program for its containment. Arguments based on preserving the economic base of societies by preventing or delaying premature death will carry most weight, as will the costs of dialysis avoided in countries that already support open-access programs.

Adult↗
PubMed2005

Clinical outcomes associated with changes in a chronic disease treatment program in an Australian Aboriginal community.

In late 1995, a treatment program for renal disease and hypertension was introduced into a remote Aboriginal community. Over the next 3.5 years, mean blood pressure levels were markedly reduced, renal function stabilised, and rates of both renal and non-renal deaths declined significantly. In 1999-2000, responsibility for the program was passed to the community's local Health Board, which subsequently faced deficiencies in clinical information systems and a shortfall in funding. After the handover, the intensity of the program declined, and compliance with medicines fell. Blood pressures in the treatment cohort increased, renal function deteriorated, and rates of deaths from natural causes subsequently rose. From 2002 to mid-2003, the adjusted risks of renal and non-renal deaths in the treatment cohort were three and 9.5 times the respective risks of people during the first 18 months of treatment in the systematic phase of the program. Sustained vigorous activity, both in treatment of people already identified and in community screening for treatment eligibility, is required to maintain good results in any chronic disease program. Adequate resources and well supported staff are essential, and constant evaluation is needed to follow outcomes and modify strategies as necessary.

Adult↗
PubMed2005

Determinants of glomerular volume in different cortical zones of the human kidney.

Enlarged glomerular size is a feature of focal segmental glomerulosclerosis, obesity-related glomerulopathy, diabetic nephropathy, and hypertension. The distribution of glomerular volumes within different cortical zones and glomerular volume alterations with age and obesity may contribute to understanding the evolution of these diseases. We analyzed the distributions of volumes of individual glomeruli in the superficial, middle, and juxtamedullary cortex of normal human kidneys using the disector/Cavalieri method. Volumes (V(glom)) of 720 nonsclerotic glomeruli (30 per kidney, 10 per zone) were estimated in autopsy kidneys of 24 American men, 12 aged 20 to 30 yr and 12 aged 51 to 69 yr. Black and white individuals were represented equally. The range of individual V(glom) within subjects varied from two- to eight-fold. There were no significant zonal differences in V(glom) in the young or those with body surface area (BSA) < or = 2.11 m(2). In contrast, superficial glomeruli in the older age group, in those with BSA > 2.11 m(2), and in white subjects were significantly larger than juxtamedullary glomeruli. Black subjects tended toward larger V(glom) than white subjects, and this difference was significant and most marked in the juxtamedullary zone and independent of age, BSA, and glomerular number. There is a wide range in individual V(glom) in adults. BSA, race, and age independently influence V(glom) in different zones of the renal cortex. These findings might reflect processes of aging and susceptibility factors to renal disease.

Adult↗
PubMed2005

Is the Framingham coronary heart disease absolute risk function applicable to Aboriginal people?

OBJECTIVE: To determine the extent to which the Framingham function predicts the risk of coronary heart disease (CHD) in Aboriginal people. DESIGN AND SETTING: Cohort study in an Aboriginal community in the Northern Territory. PARTICIPANTS: 687 Aboriginal people aged 20-74 years were followed up from a baseline examination in 1992-1995 through to 31 December 2003. MAIN OUTCOME MEASURE: First CHD events were identified through hospital and death records during the follow-up period. METHODS: An original Framingham function was used to predict CHD risk according to the duration of follow-up and the values of traditional risk factors, which included age, sex, total cholesterol level, high-density lipoprotein (HDL) cholesterol level, blood pressure, the presence of diabetes, and smoking status. The predicted CHD incidence using the Framingham function was 4.4 per 1000 person-years, while the observed incidence was 11.0 (95% CI, 8.7-13.9) per 1000 person-years. The observed number of CHD events (68) was 2.5 times the number predicted (27) using the Framingham function. The observed incidence was about four and three times the predicted incidence for age groups < 35 and 35-44 years, respectively, and about twice the predicted incidence for those over 45 years of age. The Framingham function was a particularly unreliable predictor for women, especially younger women, in whom the observed CHD rate was 30 times the predicted rate. CONCLUSIONS: The Framingham function substantially underestimates the actual risk of CHD observed in Aboriginal people in a remote community, especially for women and younger adults. This implies that traditional risk factors have different degrees of impact and/or that other factors are contributing to risk. A population-specific risk function is needed.

Adult↗
PubMed2005

Cost-effectiveness analysis of a kidney and cardiovascular disease treatment program in an Australian Aboriginal population.

The objective of the study was to assess, from a health service perspective, whether a systematic program to modify kidney and cardiovascular disease reduced the costs of treating end-stage kidney failure. The participants in the study were 1,800 aboriginal adults with hypertension, diabetes with microalbuminuria or overt albuminuria, and overt albuminuria, living on two islands in the Northern Territory of Australia during 1995 to 2000. Perindopril was the primary treatment agent, and other medications were also used to control blood pressure. Control of glucose and lipid levels were attempted, and health education was offered. Evaluation of program resource use and costs for follow-up periods was done at 3 and 4.7 years. On an intention-to-treat basis, the number of dialysis starts and dialysis-years avoided were estimated by comparing the fate of the treatment group with that of historical control subjects, matched for disease severity, who were followed in the before the treatment program began. For the first three years, an estimated 11.6 person-years of dialysis were avoided, and over 4.7 years, 27.7 person-years of dialysis were avoided. The net cost of the program was 1,210 dollars more per person per year than status quo care, and dialyses avoided gave net savings of 1.0 million dollars at 3 years and 3.4 million dollars at 4.6 years. The treatment program provided significant health benefit and impressive cost savings in dialysis avoided.

Adult↗
PubMed2005

Interfaces between cardiovascular and kidney disease among Aboriginal Australians.

Rates of kidney disease among several indigenous groups have been shown to be substantially higher than corresponding non-indigenous groups. This excess has been clearly shown among Aboriginal Australians with respect to both end-stage kidney disease and early kidney disease. Rates of cardiovascular disease among Aboriginal Australians are also very high, as are rates of diabetes, smoking, and possibly overweight and obesity. These factors have been traditionally linked with cardiovascular and renal disease as part of a broader "metabolic syndrome." However, the links and interfaces between cardiovascular and kidney disease in this environment extend beyond these "traditional" factors. The factors associated with atherosclerosis have expanded in recent years to include markers of inflammation, some infection, antioxidants, and other "non-traditional" risk factors. Given the high rates of acute infection and poor living conditions endured by many indigenous people, one might expect these "non-traditional" risk factors to be highly prevalent. In this review, we explore the relationships between markers of inflammation, some serological markers of infection, and other selected markers and both cardiovascular and renal disease. In doing so, we demonstrate links between kidney and cardiovascular disease at a number of levels, beyond the "traditional" cardiovascular/renal risk factors. Many of these factors are beyond the control of the individual or even community; addressing these issues a broader focus and biopsychosocial model.

Australia↗
PubMed2005

Renal ultrasound findings in an Australian Aboriginal population with high rates of renal disease.

BACKGROUND: Rates of albuminuria and haematuria are extremely high with haematuria prevalence as high as 30-50% in adults of some Aboriginal groups. Dipstick testing of urine is routinely carried out in Aboriginal communities and as part of school screening programmes. Evaluation of the many affected individuals has traditionally included renal ultrasound examination, which involves considerable expense and logistic problems in remote communities. The present study was conducted to evaluate the usefulness of ultrasound in this setting. METHODS: A population survey was conducted in a remote community. Urine dipstick analysis and the albumin:creatinine ratio (ACR; g/mol) were measured in 1440 people over 5 years of age (89% of the eligible population), and a detailed renal ultrasound examination was performed in a random subset of 647 people (41.1% of the whole group), 276 aged 5-19 years and 371 over 20 years of age. RESULTS: Urine dipstick proteinuria (>1+) was present in 8.5% (23/271) of those aged 5-19 years and 37.9% (132/348) in those aged over 20 years; pathological albuminuria (ACR>3.4) was present in 7.6% (21/276) and 54.7% (203/371), respectively, and isolated haematuria was present in 7.7% (21/273) and 11.5% (40/347), respectively. Eight ultrasound abnormalities were found. Ultrasound findings did not change the management of any individual. CONCLUSION: Renal ultrasound added little to the evaluation of people with asymptomatic proteinuria or haematuria in this setting. In this scenario, ultrasound examination could be reserved for the cases with an unusual presentation where findings are likely to influence the prognosis or treatment, or in preparation for a renal biopsy.

Adolescent↗
PubMed2005

Albuminuria and incident coronary heart disease in Australian Aboriginal people.

BACKGROUND: It has been suggested that albuminuria is useful in identifying persons at increased risk of coronary heart disease (CHD). Australian Aborigines have exceedingly high rates of renal failure together with increased CHD mortality. We undertook this prospective cohort study to assess the independent effect of albuminuria on CHD risk in Aboriginal people in the Northern Territory of Australia. METHODS: We examined the relation between micro- and macroalbuminuria and incident CHD in a sample of 870 Aboriginal adults aged 20 to 74 years old without prevalent baseline CHD. Cox proportional hazards models were used to assess the association between baseline albuminuria and CHD incidence. RESULTS: During a median of 9.2 years of follow-up, 89 CHD events occurred during the follow-up period (1992 to 2003). The incidence of CHD increased significantly across categories of albuminuria (4.4, 10.9, and 29.8 per 1000 person-years for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively). The multiple Cox proportional hazards regression showed the hazard ratio was 3.4 (95% CI 1.6, 7.3), adjusting for age, gender, body mass index (BMI), blood pressure, total cholesterol, diabetes status, cigarette smoking, and alcohol consumption, for macroalbuminuria group. Hazard ratio for microalbuminuria group was not significantly different from unity during the first 6 years of follow-up but significantly higher during the follow-up period > or = 6 years with adjusted hazard ratio 9.0 (95% CI 2.0, 40.0). CONCLUSION: Independent of traditional cardiovascular risk factors, both microalbuminuria and macroalbuminuria may be useful in identifying persons at increased risk of CHD in Aboriginal people.

Adult↗
PubMed2005

A chronic disease outreach program for Aboriginal communities.

BACKGROUND: Our objective is to describe a program to improve awareness and management of hypertension, renal disease, and diabetes in 3 remote Australian Aboriginal communities. METHODS: The program espouses that regular integrated checks for chronic disease and their risk factors are essential elements of regular adult health care. Programs should be run by local health workers, following algorithms for testing and treatment, with backup, usually from a distance, from nurse coordinators. Constant evaluation is essential to develop community health profiles and adapt program structure. RESULTS: Participation ranged from 65% to 100% of adults. Forty-one percent of women and 72% of men were current smokers. Body weight varied markedly by community. Although excessive in all, rates of chronic diseases also differed markedly among communities. Rates increased with age, but the greatest numbers of people with morbidities were middle age and young adults. Multiple morbidities were common by middle age. Hypertension and renal disease were early features, whereas diabetes was a variable and later manifestation of this integrated chronic disease syndrome. Adherence to testing and treatment protocols improved markedly over time. Substantial numbers of new diagnoses were made. Blood pressure improved in people in whom antihypertensive agents were started or increased. Components of a systematic activity plan became more clearly defined with time. Treatment of people in the community with the greatest disease burden posed a large additional workload. Lack of health workers and absenteeism were major impediments to productivity. CONCLUSION: We cannot generalize about body habitus, and chronic disease rates among Aboriginal adults. Pilot data are needed to plan resources based on the chronic disease burden in each community. Systematic screening is useful in identifying high-risk individuals, most at an early treatable stage. Community-based health profiles provide critical information for the development of rational health policy and needs-based health services.

Adult↗
PubMed2004

Association between diabetes and coronary heart disease in Aboriginal people: are women disadvantaged?

OBJECTIVES: To determine the incidence rate of coronary heart disease (CHD) in Australian Aboriginal people with type 2 diabetes, and to compare the impact of diabetes on CHD risk in Aboriginal women and men. DESIGN: Cohort study. SETTING: A remote Aboriginal community in the Northern Territory. PARTICIPANTS: 889 Aboriginal people aged 20-74 years followed up to 31 May 2003 after baseline examination in 1992-1995. MAIN OUTCOME MEASURES: Incidence rates of CHD (estimated for 123 participants with diabetes at baseline and 701 "non-diabetes" participants); rate ratios for diabetes risk (95% CI), with "non-diabetes" participants as the reference group. RESULTS: Participants with diabetes at baseline had a higher rate of CHD (37.5 per 1000 person-years) than those without diabetes (7.3 per 1000 person-years). Adjustment for multiple CHD risk factors, such as age, smoking, alcohol consumption, systolic blood pressure, body mass index, high-density lipoprotein cholesterol and total cholesterol levels, resulted in a CHD rate ratio for women of 3.7 (95% CI, 1.6-8.9) (comparing women with diabetes with those without) and a CHD rate ratio for men of 1.4 (95% CI, 0.4-4.1) (comparing men with diabetes with those without). CONCLUSIONS: Aboriginal women with diabetes experienced a significantly higher risk of CHD than women without diabetes. Although the difference was not statistically significant, women with diabetes had a higher CHD risk than men with diabetes.

Adult↗