Incidence of end-stage renal disease in type 2 (non-insulin-dependent) diabetes mellitus in Pima Indians

Genome-wide SNP genotyping study using pooled DNA to identify candidate markers mediating susceptibility to end-stage renal disease attributed to Type 1 diabetes

AIMS

Genetic factors play a major role in the progression of kidney disease in diabetes. To identify candidate single nucleotide polymorphisms (SNPs) with potential effects on susceptibility to end-stage renal disease (ESRD), we performed a whole genome association scan using pooled DNA from Caucasian individuals with Type 1 diabetes.

METHODS

We utilized the Illumina Infinium II HumanHap 550 beadchip platform to genotype 555 352 SNPs in DNA pools comprised of 547 cases with ESRD and 549 control subjects with Type 1 diabetes duration > 20 years and no ESRD. Pooled probe intensity was used to predict mean allele frequency (MAF) for each locus. Individual genotyping was performed using the iPLEX assay in conjunction with the MassARRAY platform (Sequenom).

RESULTS

We identified 2870 markers showing substantial differences in MAF (5.0-10.7%) between pools. To initiate validation of these findings, we genotyped 22 high-ranking markers in 462 individuals with ESRD and 470 unaffected control subjects selected from the genome-wide SNP genotyping study sample. We observed the strongest evidence for association between ESRD and rs1749824, located in the ZMIZ1 gene [OR = 1.47 (1.21-1.78) per copy of T allele; P = 8.1 x 10(-5)] and rs9298190, located in the musculin gene [OR = 1.56 (1.28-1.91) per copy of C allele; P = 1.6 x 10(-5)]. Evidence for nominal association with markers in or near the IRS2, TMPO, BID, KLRA1, ELMO1 and CNDP1 genes was also observed (P < or = 0.0006).

CONCLUSIONS

These findings identify several novel loci which may contribute to ESRD susceptibility in individuals with Type 1 diabetes.

Genome-wide scan for estimated glomerular filtration rate in multi-ethnic diabetic populations: the Family Investigation of Nephropathy and Diabetes (FIND)

OBJECTIVE

Diabetic nephropathy, the most common cause of end-stage renal disease, aggregates in families and specific ethnic groups. Deconstructing diabetic nephropathy into intermediate, quantitative phenotypes may increase feasibility of detecting susceptibility loci by genetic screens. Glomerular filtration rate (GFR), which characterizes diabetic nephropathy, was employed as a quantitative trait in a preliminary whole-genome scan.

RESEARCH DESIGN AND METHODS

Estimated GFR (eGFR) was calculated for 882 diabetic sibpairs (mean age 57 years) of African-American (25.6% of total), American Indian (8.6%), European-American (14.2%), and Mexican-American (51.6%) descent enrolled in the initial phase of the Family Investigation of Nephropathy and Diabetes (FIND). A whole-genome scan was performed using 404 microsatellite markers (average spacing 9 cM) and model-free linkage analysis.

RESULTS

For all ethnicities combined, strong evidence for linkage was observed on chromosomes 1q43 (P = 3.6 x 10(-3)), 7q36.1 (P = 2.1 x 10(-4)), 8q13.3 (P = 4.6 x 10(-4)), and 18q23.3 (P = 2.7 x 10(-3)). Mexican-American families, who comprised the major ethnic subpopulation in FIND, contributed to linkage on chromosomes 1q43, 2p13.3, 7q36.1, 8q13.3, and 18q23.3, whereas African-American and American-Indian families displayed linkage peaks on chromosomes 11p15.1 and 15q22.3, respectively.

CONCLUSIONS

We have demonstrated multiple chromosomal regions linked to eGFR in a multi-ethnic collection of families ascertained by a proband with diabetic nephropathy. Identification of genetic variants within these loci that are responsible for the linkage signals could lead to predictive tests or novel therapies for subsets of patients at risk for diabetic nephropathy.

Overview of epidemiologic studies of diabetic retinopathy

Diabetic retinopathy has been an important cause of blindness in young and middle age adults in the United States. Epidemiologic studies have quantitated the risk and have described potentially causal factors associated with many ocular complications of diabetes and other facets of this disease. A review of recent advances in diagnosis, treatment, temporal trends, and health care for diabetic retinopathy was conducted. Since the early 1980's, there have been studies of the variability of diabetic retinopathy in populations around the world and subpopulations in the United States which have demonstrated the high prevalences and incidences of this condition. Observational studies and clinical trials have documented the importance of glycemic and blood pressure control in the development and progression of this disease. There are some differences in the importance of confounders in different populations. Epidemiologic data have helped understand the importance of health care and health education in prevention and treatment of this condition. Observational studies have documented the importance of this disease on quality of life. Although there have been advances in understanding the distribution, causes, and severity of diabetic retinopathy, this is ever changing and requires continued monitoring. This is important because the increasing burden of diabetes will place a greater burden on the population and the medical care systems that will be caring for them.

Preprocedural imaging: new options to reduce need for contrast angiography

In vascular surgery, the gold standard for evaluation of the lower-extremity arterial tree has long been contrast arteriography (CA). Associated risks of CA are well-documented and include severe allergic reactions, arterial injury and/or hemorrhage, and contrast-induced nephropathy. Increasingly, less-invasive techniques, with fewer inherent risks for complication, are being explored as diagnostic alternatives. Magnetic resonance angiography, computed tomography angiography, and duplex arteriography, each offer distinct advantages, though are not without limitation. This review explores the indications, advantages, and disadvantages of these newer technologies and provides a comparison to CA as a means for defining the anatomic features of patients undergoing lower-extremity revascularization. This data suggests that noninvasive imaging technologies may, in the future, play an increasingly important role in the surgical evaluation of the patient with lower-extremity ischemia.

Proteome analysis of serum from type 2 diabetics with nephropathy

Diabetic nephropathy (DN) is a renal disease which develops as a consequence of diabetes mellitus. Microalbuminuria is the earliest clinical sign of DN. There are no specific diagnostic biomarkers for type 2 diabetics with nephropathy other than microalbuminuria and macroalbuminuria. However, microalbuminuria does not constitute a sole independent indicator for type 2 diabetics with nephropathy, and thus, another screening method, such as a biomarker assay, is required in order to diagnose it more correctly. Therefore, we have utilized two-dimensional electrophoresis (2-DE) to identify human serum protein markers for the more specific and accurate prediction of progressive nephropathy in type 2 diabetes patients, via comparisons of the serum proteome in three experimental groups: type 2 diabetes patients without microalbuminuria (DM, n = 30), with microalbuminuria (MA, n = 29), and with chronic renal failure (CRF, n = 31). As a result, proteins which were differentially expressed with statistical significance (p < 0.05) in MA and CRF groups as compared to those in DM group were selected and identified by ESI-Q-TOF MS/MS. Among these identified proteins, two proteins which might be useful as diagnostic biomarkers of type 2 diabetics with nephropathy were verified by Western blotting: extracellular glutathione peroxidase (eGPx) and apolipoprotein (ApoE) were found to exhibit a progressive reduction in MA and CRF groups. Notably, eGPx was further verified by ELISA using DM (n = 100) and MA (n = 96) patient samples. Collectively, our results show that the two proteins identified in this study may constitute potential biomarkers for the diagnosis of type 2 diabetics with nephropathy.

Identification of PVT1 as a candidate gene for end-stage renal disease in type 2 diabetes using a pooling-based genome-wide single nucleotide polymorphism association study

To identify genetic variants contributing to end-stage renal disease (ESRD) in type 2 diabetes, we performed a genome-wide analysis of 115,352 single nucleotide polymorphisms (SNPs) in pools of 105 unrelated case subjects with ESRD and 102 unrelated control subjects who have had type 2 diabetes for > or =10 years without macroalbuminuria. Using a sliding window statistic of ranked SNPs, we identified a 200-kb region on 8q24 harboring three SNPs showing substantial differences in allelic frequency between case and control pools. These SNPs were genotyped in individuals comprising each pool, and strong evidence for association was found with rs2720709 (P = 0.000021; odds ratio 2.57 [95% CI 1.66-3.96]), which is located in the plasmacytoma variant translocation gene PVT1. We sequenced all exons, exon-intron boundaries, and the promoter of PVT1 and identified 47 variants, 11 of which represented nonredundant markers with minor allele frequency > or =0.05. We subsequently genotyped these 11 variants and an additional 87 SNPs identified through public databases in 319-kb flanking rs2720709 ( approximately 1 SNP/3.5 kb); 23 markers were associated with ESRD at P < 0.01. The strongest evidence for association was found for rs2648875 (P = 0.0000018; 2.97 [1.90-4.65]), which maps to intron 8 of PVT1. Together, these results suggest that PVT1 may contribute to ESRD susceptibility in diabetes.

A community-based study of chronic kidney disease among type 2 diabetics in Kinmen, Taiwan

Diabetic nephropathy is the major cause of end-stage renal disease. Many studies show that chronic kidney disease can be prevented, or its progression to end-stage renal disease delayed, by effective intervention. The aim of this study was to estimate the prevalence of proteinuria and renal impairment in patients with type 2 diabetes. A community-based screening for chronic kidney disease in type 2 diabetic patients was conducted in 1999-2001. Proteinuria was defined in terms of urine protein-to-creatinine ratio. The glomerular filtration rate per 1.73m(2) body surface area was calculated using an equation from the Modification of Diet in Renal Disease Study. The overall response rate was about 78.6%. Prevalence rates of proteinuria and renal impairment were 29.4% and 15.1%, respectively. Females had higher prevalence of proteinuria and renal impairment than males. And prevalence increased with increasing age. Hypertension was associated with both proteinuria and renal impairment. Only 43.0% of patients with stages 3-5 chronic kidney disease had proteinuria. Proteinuria and renal impairment screening may identify different segments of the diabetic population. Both a glomerular filtration rate and proteinuria test are recommended as screening tools for early detection of chronic kidney disease in type 2 diabetics.

Clinical spectrum of chronic renal failure in the elderly: a hospital based study from eastern India

The aim of this study was to describe the clinical spectrum of chronic renal failure (CRF) in the elderly. The diagnosis of CRF was made using standard clinical criteria. The elderly was defined as person with over 60 years of age. In total, 200 elderly patients with CRF were evaluated between July 2002 and February 2004. Their age (male: 146; female: 54) ranged between 60 and 90 (mean 64.31+/-4.18) years. Diabetic nephropathy was the most common (46%) cause of CRF. Hypertensive nephrosclerosis, chronic interstitial nephritis and obstructive uropathy were responsible for CRF in 18%, 14% and 13% of patients, respectively. We observed chronic glomerulonephritis in 7% of elderly CRF. Urinary tract infection (55.5%), hypovolemia (22.2%), accelerated hypertension (11.1%) and sepsis (11.1%) were responsible for acute exacerbation of renal failure in 36 (18%) patients. Associated co-morbid conditions were noted in 93 (46.5%) patients. They included; coronary artery disease 46 (49.46%), cerebrovascular disease 20 (21.50%), osteoarthritis 13 (13.97%), chronic obstructive pulmonary disease 6 (6.45%), dilated cardiomyopathy 5 (5.37%), and malignancy in 3 (3.22%) patients. Acute dialytic support was required in 164 (82%) cases and remaining 36 (18%) patients received conservative management. Mortality was noted in 25 (12.5%) cases. The coronary artery disease (48%), acute pulmonary edema (20%) and hyperkalemia (12%) were the main causes of death. Subsequent evaluation revealed that 102 (51%) patients had ESRD of which only 3 (2.94%) patients could afford CAPD. A total of 11 (10.7%) patients underwent chronic maintenance hemodialysis for 3-4 months and then discontinue dialysis mainly because of financial constraints. Remaining 88 (86.27 %) patients with ESRD were discharged from hospital after symptomatic improvement with acute dialysis. Thus, diabetic nephropathy related to type-2 diabetes was the commonest cause of CRF in our elderly patients. Chronic renal failure in elderly was associated with a number of co-morbid conditions, which contributed significantly to morbidity and mortality. Acute on chronic renal failure with severe uremic complications were an important cause of hospitalization. The financial constraint was the major limiting factor for the management of elderly ESRD patients.

Indigenous health: update on the impact of diabetes and chronic kidney disease

PURPOSE OF REVIEW

With respect to chronic diseases such as diabetes and its complications, indigenous populations are known to suffer from poor health outcomes in comparison with whites. The purpose of this review is to highlight recent epidemiologic and intervention studies that have occurred in the areas of diabetes and renal disease among indigenous populations.

RECENT FINDINGS

The burden of diabetes is increasing among younger indigenous groups with epidemic levels of end-stage kidney disease. As dialysis therapy has contributed to prolong life among indigenous patients, cardiovascular disease has now become the leading cause of mortality in these populations. Clear preventive intervention strategies to improve rates of progression to end-stage kidney disease are not prevalent nor are they emerging over time. Access to kidney transplantation is also reduced among indigenous populations in Australia, New Zealand, the USA and Canada. Reasons for this disparity are unclear but likely multifactorial.

SUMMARY

Diabetes and its complications have produced a health crisis among indigenous populations. The impact on healthcare systems in countries where these indigenous populations reside will be substantial unless significant efforts are made to improve diabetic renal disease outcomes in the near future.

Insulin resistance and microalbuminuria: a cross-sectional, case-control study of 158 patients with type 2 diabetes and different degrees of urinary albumin excretion

Microalbuminuria is a risk factor for renal and cardiovascular disease. A role for insulin resistance in the pathogenesis of microalbuminuria has been suggested but is still unproven. In this case-control, cross-sectional study, we compared glucose disposal rate (GDR), measured by hyperinsulinemic-euglycemic clamp, in 50 pairs of matched type 2 diabetic patients with micro- or normoalbuminuria (main study) and in 29 matched pairs of diabetic patients with macro- or microalbuminuria (substudy). In the main study, GDR was approximately 25% lower in micro- than in normoalbuminuric patients (5.20 +/- 1.91 vs. 6.86 +/- 2.88 mg . kg(-1) . min(-1), P < 0.05) and was independently associated with microalbuminuria (P = 0.002), with each 1 mg . kg(-1) . min(-1) decrease predicting approximately 40% increased prevalence (odds ratio 1.37 [95% CI 1.14-1.70]). Microalbuminuria was threefold more frequent in patients with GDR < or =7.50 +/- 2.56 mg . kg(-1) . min(-1) than in those with higher GDR (60% vs. 20%, P < 0.005). In the substudy, GDR in macro- and microalbuminuric patients was comparable (5.52 +/- 2.56 vs. 5.16 +/- 1.61 mg . kg(-1) . min(-1)) and independent of macroalbuminuria. GDR was significantly correlated with urinary albumin excretion rate in the main study (P = 0.004) but not in the substudy (P = 0.60). In type 2 diabetes, more severe insulin resistance is independently associated with microalbuminuria. Longitudinal studies are needed to clarify the role of insulin resistance in the pathogenesis of microalbuminuria and related complications.

Variants in the gene encoding aldose reductase (AKR1B1) and diabetic nephropathy in American Indians

AIMS

The aldose reductase gene (AKR1B1) is a strong candidate for diabetic nephropathy, and the T allele at rs759853 and the Z-2 allele at an [AC]n microsatellite are associated with diabetic kidney disease in some populations. As AKR1B1 is located on 7q35, where we have previously reported linkage to diabetic nephropathy in Pima Indians, this study examined the association of AKR1B1 variants with diabetic nephropathy in this population.

METHODS

AKR1B1 variants were identified by sequencing and genotyped using allelic discrimination and pyrosequencing. Genotype distributions were compared between 107 cases with diabetic end-stage renal disease and 108 control subjects with diabetes for > or = 10 years and no evidence of nephropathy, and between 141 individuals with nephropathy and 416 individuals without heavy proteinuria in a family study of 257 sibships.

RESULTS

We identified 11 AKR1B1 single nucleotide polymorphisms (SNPs) and the [AC]n microsatellite polymorphism. Three SNPs were rare and two were in 100% genotypic concordance; thus, eight polymorphisms were genotyped. No variant was associated with diabetic kidney disease in the case-control or family-based study. For example, the T allele at rs759853 had an allele frequency of 0.165 in cases and 0.171 in control subjects (OR = 0.96, 95% CI, 0.57-1.59, P = 0.86); in the family study its frequency was 0.140 and 0.169 in affected and unaffected individuals, respectively (OR = 0.90, 95% CI, 0.53-1.54 P = 0.71). Corresponding values for the Z-2 allele at the [AC]n microsatellite were OR = 1.09 (95% CI 0.72-1.66, P = 0.67) and OR = 1.25 (95% CI 0.81-1.95, P = 0.31) in the case-control and family studies, respectively.

CONCLUSIONS

Common AKR1B1 polymorphisms are unlikely to be major determinants of diabetic nephropathy in this population.

Impact of lifestyle on prevalence of kidney disease in Pima Indians in Mexico and the United States

Pima Indians in the United States and Mexico share a common genetic background but have very different lifestyles. Comparisons were made of the frequency of obesity, diabetes, hypertension, and kidney disease in these geographically separated but susceptible populations. Mexican Pimas had higher levels of physical activity, less obesity, and a lower prevalence of diabetes than their US Pima counterparts. Mean blood pressure rose with worsening glucose tolerance, and the prevalence of elevated urinary albumin excretion was higher in patients with diabetes than in those without, regardless of whether they lived in the United States or Mexico. These findings illustrate the importance of lifestyle in the development of diabetes and in the subsequent occurrence of diabetic kidney disease.

Predominant effect of kidney disease on mortality in Pima Indians with or without type 2 diabetes

BACKGROUND

We examined the effect of kidney disease (KD) on mortality in nondiabetic and diabetic Pima Indians aged > or = 45 years old.

METHODS

Deaths and person-years of follow-up were stratified in a time-dependent fashion into categories of (1) no proteinuria and normal serum creatinine (SCr); (2) proteinuria and normal SCr; (3) high SCr [SCr > or = 133 micromol/L (1.5 mg/dL) in men, > or = 124 micromol/L (1.4 mg/dL) in women] but not on renal replacement therapy (RRT); or (4) RRT.

RESULTS

Among 1993 subjects, 55.8% had type 2 diabetes at baseline. Overall death rates increased with declining kidney function in both the nondiabetic and diabetic subjects (P < 0.0001). Death rates were similar in nondiabetic and diabetic subjects with comparable levels of kidney function, although the number of deaths among nondiabetic subjects with advanced KD was small. Infections and malignancy were the leading causes of death in nondiabetic subjects with KD. Among diabetic subjects, overall mortality increased with diabetes duration (P = 0.0001) and was highest in those on RRT (P < 0.0001). High SCr was associated with higher death rates from cardiovascular disease (CVD), diabetic nephropathy (DN), infections, and malignancy.

CONCLUSION

Death rates increased comparably with worsening kidney function in both nondiabetic and diabetic subjects and were similar in nondiabetic and diabetic subjects without KD. KD was associated with excess mortality from DN, CVD, infections, and malignancy in diabetic subjects, and from infections in those without diabetes.

Diabetes outcomes in the Indian health system during the era of the Special Diabetes Program for Indians and the Government Performance and Results Act

OBJECTIVES

We reviewed changes in blood glucose, blood pressure, and cholesterol levels among American Indians and Alaska Natives between 1995 and 2001 to estimate the quality of diabetes care in the Indian Health Service (IHS) health care delivery system.

METHODS

We conducted a cross-sectional analysis of data from the Indian Health Service Diabetes Care and Outcomes Audit.

RESULTS

Adjusted mean Hemoglobin A1c (HbA1c) levels (7.9% vs 8.9%) and mean diastolic blood pressure levels (76 vs 79 mm Hg) were lower in 2001 than in 1995, respectively. A similar pattern was observed for mean total cholesterol (193 vs 208 mg/dL) and triglyceride (235 vs 257 mg/dL) levels in 2001 and 1995, respectively.

CONCLUSIONS

We identified changes in intermediate clinical outcomes over the period from 1995 to 2001 that may reflect the global impact of increased resource allocation and improvements in processes on the quality of diabetes care, and we describe the results that may be achieved when community, health program, and congressional initiatives focus on common goals.

Ethnicity and renal disease

BACKGROUND

Sexual function is one aspect of physical functioning. Sexual dysfunction, no matter the etiology, could cause distress. In female hemodialysis patients, sexual problems have often been neglected in clinical performance and research.

METHODS

We conducted this study by use of self-reported questionnaires. A total of 578 female hemodialysis patients in northern Taiwan were included in this study. Demographic data, comorbid diseases, medications in use, biochemical, and hematologic parameters were analyzed. All patients were asked to complete by themselves three questionnaires: (1) the Index of Female Sexual Function (IFSF) to assess sexual function; (2) the Beck Depression Inventory (BDI) (Chinese version) to rate the severity of depressive symptoms; and (3) the 36-item Short Form Health Survey Questionnaire (SF-36, Taiwan Standard Version 1.0) to survey their quality of life.

RESULTS

A total of 138 female patients were enrolled into further analysis. The mean age was 48.7 +/- 11.2 years old. The mean IFSF score was 24.5 +/- 9.3. Age, BDI score, and serum triglyceride levels were the independent factors of dysfunction in each sexual functional dimension. Patients with higher IFSF scores had significantly higher scores in physical functioning and mental health (P= 0.007 and 0.018, respectively). Patients with higher intercourse satisfaction had significantly higher general health scores (P= 0.001).

CONCLUSION

Sexual dysfunction is frequent in the female hemodialysis population. It is strongly associated with increasing age, dyslipidemia, and depression. The subjects with sexual dysfunction had poorer quality of life. The diagnosis and treatment of sexual dysfunction should be included in the clinical assessment.

The familial clustering of renal disease and related phenotypes

This article reviews the familial aggregation of chronic kidney diseases including end-stage renal disease and albuminuria, along with variation in glomerular filtration rate. In addition to environmental influences on the progression of nephropathy, epidemiologic evidence in support of the existence of renal failure susceptibility genes is presented.

Preventing microalbuminuria in type 2 diabetes

BACKGROUND

The multicenter double-blind, randomized Bergamo Nephrologic Diabetes Complications Trial (BENEDICT) was designed to assess whether angiotensin-converting-enzyme inhibitors and non-dihydropyridine calcium-channel blockers, alone or in combination, prevent microalbuminuria in subjects with hypertension, type 2 diabetes mellitus, and normal urinary albumin excretion.

METHODS

We studied 1204 subjects, who were randomly assigned to receive at least three years of treatment with trandolapril (at a dose of 2 mg per day) plus verapamil (sustained-release formulation, 180 mg per day), trandolapril alone (2 mg per day), verapamil alone (sustained-release formulation, 240 mg per day), or placebo. The target blood pressure was 120/80 mm Hg. The primary end point was the development of persistent microalbuminuria (overnight albumin excretion, > or =20 microg per minute at two consecutive visits).

RESULTS

The primary outcome was reached in 5.7 percent of the subjects receiving trandolapril plus verapamil, 6.0 percent of the subjects receiving trandolapril, 11.9 percent of the subjects receiving verapamil, and 10.0 percent of control subjects receiving placebo. The estimated acceleration factor (which quantifies the effect of one treatment relative to another in accelerating or slowing disease progression) adjusted for predefined baseline characteristics was 0.39 for the comparison between verapamil plus trandolapril and placebo (P=0.01), 0.47 for the comparison between trandolapril and placebo (P=0.01), and 0.83 for the comparison between verapamil and placebo (P=0.54). Trandolapril plus verapamil and trandolapril alone delayed the onset of microalbuminuria by factors of 2.6 and 2.1, respectively. Serious adverse events were similar in all treatment groups.

CONCLUSIONS

In subjects with type 2 diabetes and hypertension but with normoalbuminuria, the use of trandolapril plus verapamil and trandolapril alone decreased the incidence of microalbuminuria to a similar extent. The effect of verapamil alone was similar to that of placebo.

Role of Duplex Arteriography as the Sole Preoperative Imaging Modality Prior to Lower Extremity Revascularization Surgery in Diabetic and Renal Patients

The limitations and complications associated with contrast angiography (CA) prior to lower extremity revascularization have led to an increased interest in duplex arteriography (DA) as a potential replacement. We report our experience with DA in patients with diabetes and/or chronic renal insufficiency (CRI) that would particularly benefit from a noninvasive approach to preoperative evaluation of the arterial tree. From January 1998 to November 2000, DA was performed in 145 patients with diabetes mellitus and/or CRI prior to 180 arterial reconstructions. One hundred twenty-one procedures were performed on 91 patients with diabetes alone, 41 on 33 patients with diabetes and CRI, and 18 on 15 patients with CRI alone. Patient ages ranged from 36 to 98 years (mean 72 +/- 12 years). Indications for surgery were severe claudication in 33 (18%), rest pain in 37 (21%), nonhealing ischemic ulcers in 52 (29%), and limb gangrene in 58 (32%). Optimal inflow and outflow anastomotic sites were selected according to a diagram based on DA that included arterial tree imaging from mid-aorta to the pedal vessels. Preoperative contrast arteriography was performed in 16 cases (9%) because of extremely poor runoff based on DA and limited visualization of outflow vessels. The distal anastomosis was to the popliteal artery in 89 cases (49%) and to the tibial and pedal arteries in 91 (51%). Intraoperative findings confirmed the preoperative DA results with the exception of one (0.6%) where the distal anastomosis was placed proximal to a significant stenosis requiring an extension graft. The use of DA presents a safe and reliable option to prebypass CA for many patients with diabetes or CRI. The ease of use and favorable patient outcomes achieved by this imaging modality may rival the use of CA for these patients.

An explanation for the increase in heart disease mortality rates in diabetic Pima Indians: effect of renal replacement therapy

OBJECTIVE

Diabetic nephropathy (DN) became the leading cause of death in diabetic Pima Indians in the 1970s, but was superseded by ischemic heart disease (IHD) in the 1980s. This study tests the hypothesis that the rise in the IHD death rate between 1965 and 1998 is attributable to access to renal replacement therapy (RRT).

RESEARCH DESIGN AND METHODS

Underlying causes of death were determined among 2,095 diabetic Pima Indians > or = 35 years old during four 8.5-year time intervals. To assess the effect of access to RRT on IHD death rates, trends were reexamined after subjects receiving RRT were classified as if they had died of DN.

RESULTS

During a median follow-up of 11.1 years (range 0.01-34), 818 subjects died. The age- and sex-adjusted DN death rate decreased over the 34-year study (P = 0.05), whereas the IHD death rate increased from 3.3 deaths/1,000 person-years (95% CI 1.4-5.2) to 6.3 deaths/1,000 person-years (95% CI 4.5-8.0; P = 0.03). After 151 subjects on RRT were reclassified as if they had died of DN, the death rate for DN increased from 4.8 deaths/1,000 person-years (95% CI 2.6-7) to 11.3 deaths/1,000 person-years (95% CI 9-13.6; P = 0.0007), whereas the increase in the IHD death rate disappeared (P = 0.57).

CONCLUSIONS

The incidence rate of renal failure attributable to diabetes has increased rapidly over the past 34 years in Pima Indians. IHD has emerged as the leading cause of death due largely to the availability of RRT and to changes in the pattern of death among those with DN.

Development of evidence-based clinical practice guidelines for diabetes: the Department of Veterans Affairs/Department of Defense guidelines initiative

OBJECTIVE

To describe the Veterans Affairs (VA)/Department of Defense (DoD) Clinical Practice Guidelines for diabetes and contrast selected recommendations with those of the American Diabetes Association (ADA).

RESEARCH DESIGN AND METHODS

We summarize the general structure of the VA/DoD Guidelines and describe the rationale for recommendations issued in 2003 for glycemic control, management of hypertension, and retinopathy screening. We compare the synthesis of evidence and resulting recommendations for these content areas with the 2004 American Diabetes Association Clinical Practice Recommendations.

RESULTS

The VA/DoD Guidelines and the ADA Clinical Practice Recommendations reported similar strength of evidence findings by content area, but clinical recommendations varied. The VA/DoD Guidelines and practice recommendations emphasize the use of data on absolute risk reduction from available published randomized clinical trials rather than relative risk reduction from observational analyses. The VA/DoD Guidelines employ an algorithm-based methodology to guide clinicians through a risk-stratified approach to managing individual patients rather than promoting a single standard for most or all patients without explicit consideration of competing comorbidities.

CONCLUSIONS

The VA/DoD Guidelines are intended to guide diabetes care by providing Internet-ready, evidence-based annotations in algorithmic form to help clinicians set and revise individual treatment goals for their patients.

Effects of gender, Helicobacter pylori and hepatitis B virus serology status on cardiovascular and renal complications in Chinese type 2 diabetic patients with overt nephropathy

BACKGROUND

The aim of this study was to investigate whether chronic infections with Helicobacter pylori and hepatitis B virus (HBV) might affect clinical outcomes in Chinese type 2 diabetic patients with advanced nephropathy.

METHODS

A prospective study of 97 type 2 diabetic patients with clinical proteinuria and renal insufficiency (median serum creatinine 200 micro mol/l).

RESULTS

During a median follow-up period of 2 years, 34 developed end-stage renal disease (ESRD), 28 had cardiovascular endpoints and 11 patients had died (seven men and four women), and 52.7% developed a combined endpoint. Female patients had longer disease duration, higher blood pressure, lower body weight but higher serum creatinine and spot urine albumin : creatinine ratio as well as lower haemoglobin than male patients. On logistic regression analysis, female gender (hazard ratio: 5.91, p = 0.02), negative H. pylori serology (8.39, p = 0.004), baseline serum creatinine (1.04, p = 0.001) and haemoglobin (1.86, p = 0.01) were independent predictors for ESRD. Systolic blood pressure (1.04, p = 0.003), prior treatment with angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists (3.41, p = 0.04) and positive hepatitis B surface antigen (4.88, p = 0.025) were independent predictors for cardiovascular endpoints. Female gender (7.89, p = 0.002) and baseline serum creatinine (1.05, p < 0.001) were independent predictors for combined death and cardio-renal endpoints.

CONCLUSIONS

In Chinese type 2 diabetic patients with clinical proteinuria renal insufficiency, there were high rates of death and cardio-renal outcomes. Female gender, low haemoglobin and negative H. pylori serology were important predictors for ESRD, whereas chronic HBV infection was associated with increased cardiovascular risks.

Diabetes and renal disease in veterans

OBJECTIVE

To describe the frequency and sequelae of diabetic renal disease in veterans who receive health care from the Veterans Administration (VA).

RESEARCH DESIGN AND METHODS

Veterans with a diagnosis of diabetes, diabetic nephropathy, other kidney diseases, and end-stage renal disease (ESRD) were identified by diagnosis codes from national VA databases for FY1998. Data were obtained and analyzed for prevalence of renal disease, comorbid conditions, and 1-year mortality.

RESULTS

A total of 44,671 (10.7%) of the 415,910 veterans with diabetes had a concomitant diagnosis of any renal disease. The average age was 67 years; 98% were male and 60% were white. The prevalence of diabetic nephropathy was 6.0% (n = 25,263). ESRD secondary to diabetes was present in 4.2% (17,636) of subjects. The age-standardized prevalence of diabetes and any renal disease was 72.6/1,000 persons and differed by race (white 76.1/1,000, black 103.4/1,000 persons). Diabetes-associated ESRD prevalence was higher among black versus white veterans and male versus female veterans. One-year age-standardized mortality was 10.7%.

CONCLUSIONS

Nephropathy is prevalent in veterans with diabetes. Greater mortality is observed among those with renal disease compared with those without renal disease. Additional surveillance is needed to identify persons likely to progress to diabetic nephropathy and to plan for appropriate and timely health care for these individuals.

Disparity in outcomes for adult Native American hemodialysis patients? Findings from the ESRD Clinical Performance Measures Project, 1996 to 1999

BACKGROUND

There is a paucity of information regarding the quality of care for Native American hemodialysis patients. Outcomes, including 1-year hospitalization and mortality, for adult Native American in-center hemodialysis patients selected for the Centers for Medicare and Medicaid (CMS) end-stage renal disease (ESRD) Clinical Performance Measures (CPM) Project were compared to those for white and black patients to determine if disparity in care existed for this group.

METHODS

Clinical data were abstracted from medical records for the last quarters of 1995 to 1998 and linked to United States Renal Data System (USRDS) data files for data on comorbidities and 1-year hospitalization and mortality. Associations of race were tested by bivariate analyses and multivariate logistic regression and Cox proportional hazard modeling.

RESULTS

Two percent (467 of 27876) of patients were Native American, 37% black, and 51% white. Native American, compared to black and white patients, were more likely to have diabetes mellitus as the cause of ESRD (72%, 37%, and 38%, respectively, P < 0.01). In multivariate analyses, Native American patients were more likely to achieve a mean urea reduction ratio (URR) > or = 65% compared to whites (referent) [hazards ratio (HR) (95% CI) 1.7 (1.3, 2.2)] and be dialyzed with an arteriovenous fistula [HR (95% CI) 1.7 (1.2, 2.5)]. They were as likely as Whites to achieve a mean hematocrit > or =33% and a mean serum albumin > or =4.0/3.7 g/dL. In multivariate analyses, Native Americans were no more likely to be hospitalized or die during the follow-up period than whites.

CONCLUSION

These data suggest that adult Native American hemodialysis patients experience equivalent or better dialytic care and are no more likely to experience 1-year hospitalization or mortality compared to whites.

Racial differences in diabetic nephropathy, cardiovascular disease, and mortality in a national population of veterans

OBJECTIVE

To determine racial differences in the prevalence of diabetic nephropathy, cardiovascular disease (CVD), and risk of mortality in a national health care system.

RESEARCH DESIGN AND METHODS

A longitudinal cohort study was conducted in 429,918 veterans with diabetes. Racial minority groups were analyzed for baseline differences in prevalence of early diabetic nephropathy, diabetic end-stage renal disease (ESRD) and CVD, and longitudinal risk of mortality compared with Caucasians.

RESULTS

The 429,918 patients identified with diabetes were of the following racial groups: Caucasian (56.2%), African American (15.3%), Asian (0.5%), Native American (0.4%), and unknown race (21.4%). Minority individuals were, on average, younger and less likely to have CVD but were more likely to have renal disease than Caucasians. After adjustment for age, sex, and economic status, African Americans (adjusted odds ratio [OR] = 1.3, 95% CI 1.2-1.4) and Native Americans (1.5, 1.1-2.1) were more likely to have early diabetic nephropathy than Caucasians. Diabetic ESRD was more likely to be present in African Americans (1.9, 1.9-2.0), Hispanics (1.4, 1.3-1.4), Asians (1.8, 1.5-2.1), and Native Americans (1.9, 1.5-2.3) than Caucasians. Concurrently, the adjusted OR of CVD in racial minority groups was 27-49% less than in Caucasians, whereas the 18-month risk of mortality among people from most racial minority groups was 7-12% lower than in Caucasians.

CONCLUSIONS

We conclude that when access to care is comparable, microvascular complications, macrovascular disease, and subsequent death occur with different frequencies among various racial groups.

Association of transforming growth factor-beta (TGF-beta) T869C (Leu 10Pro) gene polymorphisms with type 2 diabetic nephropathy in Chinese

INTRODUCTION

Transforming growth factor-beta (TGF-beta) is known to play a pivotal role in the regulation of extracellular matrix (ECM) accumulation. Since diabetic nephropathy (DMN) is characterized by basement membrane thickening and mesangial expansion, control of ECM deposition is believed to be important in the pathogenesis of the disease. Recently, TGF-beta T869C (Leu 10Pro) gene polymorphism has been identified which may be associated with circulating TGF-beta levels.

METHODS

In order to examine the relationship between TGF-beta gene polymorphism with DMN in Chinese, we carried out a case-control study, which recruited 123 Chinese type 2 diabetic patients with an average duration of diabetes for 12 years. A total of 58 patients who developed DMN (micro- or macroalbuminuria, with or without renal impairment) were compared with 65 diabetic patients without DMN despite similar duration of disease (normoalbuminuric and creatinine <120 micromol/L). TGF-beta T869C (Leu 10Pro) gene polymorphism was determined by polymerase chain reaction (PCR).

RESULTS

Both groups of patients had similar baseline characteristics, including blood pressure, diabetic control, and duration of diabetes. Distribution of TGF-beta T869C (Leu 10Pro) genotype among the whole group is confined to Hardy Weinberg equilibrium. The DMN+ group has higher frequency of TGF-beta CC/CT genotypes than the DMN- group [CC, CT, TT = (DMN+) 46, 45, 9 (%) vs. (DMN-) 37, 37, 26 (%), P < 0.05]. C allele frequency is also higher in the DMN+ group than DMN- group (69% vs. 55%, P < 0.05). The adjusted odds ratio for TGF-beta CC/CT vs. TT genotype to develop DMN is 3.8 (3.2 to 4.4). Multivariate logistic regression analysis [hypertension, gender, age, duration of diabetes, hemoglobin (HbA1c), usage of angiotensin-converting enzyme (ACE) inhibitor, and cholesterol level] showed that TGF-beta genotype (P = 0.03) is an independent predictor for type 2 DMN. Among patients with DMN, those with TGF-beta CC/CT genotypes also had worse renal function and increased risk for macroalbuminuria.

CONCLUSION

Our results suggest that TGF-beta T869C (Leu 10Pro) gene polymorphism is associated with DMN in Chinese.

The risk of developing end-stage renal disease in patients with type 2 diabetes and nephropathy: the RENAAL study

BACKGROUND

Diabetic nephropathy has become the single most important cause of end-stage renal disease (ESRD) worldwide. Strategies to slow the rate of loss of renal function in these patients have been developed. We examined the risk factors that predict loss of kidney function (doubling of serum creatinine) or ESRD (dialysis or transplantation) in patients with type 2 diabetes in whom blood pressure was controlled.

METHODS

We evaluated risk factors for doubling of serum creatinine or the development of ESRD in the Reduction of End Points in NIDDM with the Angiotensin II Receptor Antagonist Losartan (RENAAL) study, which included 1513 patients with type 2 diabetes and nephropathy.

RESULTS

Univariate analyses demonstrated a group of 23 risk factors that significantly predicted doubling of serum creatinine or ESRD. From these univariate analyses, a multivariate model was developed that demonstrated four independent risk factors: proteinuria, serum creatinine, serum albumin, and hemoglobin level. Proteinuria was the strongest and most consistent risk factor. The multivariate risk model was derived from only the placebo group and was similar to that derived for the total population, suggesting that the risk predictors for progression of kidney disease were independent of therapy.

CONCLUSION

After control of blood pressure in type 2 diabetic patients with nephropathy, proteinuria, degree of renal failure, serum albumin, and hemoglobin level are independent risk factors that predict renal outcomes. The level of proteinuria proved to be the most important risk for progressive kidney injury in these diabetic patients.

A basis for accelerated progression of diabetic nephropathy in Pima Indians

The Pima Indians of Arizona not only have a much higher incidence of nephropathy due to type 2 diabetes than Caucasians, but they also lose their renal function at an accelerated rate after they develop diabetic nephropathy. This rapid loss of renal function occurs despite a younger age of onset of nephropathy and lower blood pressures and lipid levels, all of which would seem to predict a slower rate of progression of nephropathy. These findings suggest that other factors contribute to the rapid progression of renal disease in this population. In particular, glomerulomegaly in this population may contribute to the high rate of glomerular filtration rate (GFR) loss during the terminal, clinically manifest phase of nephropathy, because of the greater incremental loss of single-nephron GFR (SNGFR) with each nephron lost to sclerosis. In nine Pima Indians with type 2 diabetic nephropathy who underwent renal biopsy followed by serial iothalamate clearances for up to ten years, we examined the relationship between glomerular tuft volume at initial biopsy and the rate of GFR loss during the terminal phase. By multivariate analysis, significant independent effects of both glomerular volume (P=0.006) and podocyte density (P=0.043) were evident in these individuals. The effect of glomerular volume may result from a greater loss of intrinsic filtration capacity with each glomerulus lost, while the effect of podocyte density may reflect the destabilizing influence of "podocyte insufficiency" on the glomerular tuft. Similar factors may play a role in the rapid loss of GFR associated with progressive glomerular diseases in other indigenous populations in whom glomerulomegaly and glomerulopenia coexist.

Targeted disruption of the meprin beta gene in mice leads to underrepresentation of knockout mice and changes in renal gene expression profiles

Meprins are multidomain zinc metalloproteases that are highly expressed in mammalian kidney and intestinal brush border membranes and in leukocytes and certain cancer cells. Mature meprins are oligomers of evolutionarily related, separately encoded alpha and/or beta subunits. Homooligomers of meprin alpha are secreted; oligomers containing meprin beta are plasma membrane associated. Meprin substrates include bioactive peptides and extracellular matrix proteins. Meprins have been implicated in cancer and intestinal inflammation. Additionally, meprin beta is a candidate gene for diabetic nephropathy. To elucidate in vivo functions of these metalloproteases, meprin beta null mice were generated by targeted disruption of the meprin beta gene on mouse chromosome 18q12. Analyses of meprin beta knockout mice indicated that (i) 50% fewer null mice are born than the Mendelian distribution predicts, (ii) null mice that survive develop normally and are viable and fertile, (iii) meprin beta knockout mice lack membrane-associated meprin alpha in kidney and intestine, and (iv) null mice have changes in renal gene expression profiles compared to wild-type mice as assessed by microarray analyses. Thus, disruption of the meprin beta allele in mice affects embryonic viability, birth weight, renal gene expression profiles, and the distribution of meprin alpha in kidney and intestine.

Intrauterine determinants of diabetic kidney disease in disadvantaged populations

Disadvantaged populations worldwide are experiencing an increasing incidence of kidney disease, much of which is attributable to diabetes. This report reviews the evidence that intrauterine exposure to growth retardation, diabetes, and vitamin A deficiency contribute disproportionately to the rising incidence of kidney disease in disadvantaged people, because they encounter these exposures more frequently than people from developed countries. These abnormal intrauterine exposures reduce nephron mass by impairing nephrogenesis, thereby increasing the susceptibility to kidney damage from diseases such as hypertension and diabetes that commonly affect disadvantaged people.

HbA(1c) levels among American Indian/Alaska Native adults

OBJECTIVE

Type 2 diabetes is a major public health problem among many American Indian/Alaska Native communities. Elevated levels of HbA(1c) have been observed in younger American Indian/Alaska Native adults. The objectives of this study were: 1) to determine whether HbA(1c) levels were elevated among younger American Indian/Alaska Native adults nationally and, if so, 2) to determine the relationship between HbA(1c) levels and age due to treatment type, BMI, renal disease, duration of diabetes, survival, or a poor diabetes health care index.

RESEARCH DESIGN AND METHODS

The national Indian Health Service Diabetes Care and Outcomes Audit was completed for a total of 11,419 American Indian/Alaska Native adults with type 2 diabetes from tribes across the U.S. in 1998. Glucose control was assessed by HbA(1c). BMI, diabetes duration, treatment type, and proteinuria were assessed from the Diabetes Care and Outcomes Audit data. To assess diabetes quality of care, an index was developed from six standard of care Diabetes Care and Outcomes Audit variables.

RESULTS

We found HbA(1c) level decreased with increasing age. HbA(1c) levels were 9.2, 8.9, 8.8, 8.3, and 7.8 for ages 18-39, 40-49, 50-59, 60-69, and > or =70 years, respectively (P < 0.0001). This inverse relationship was not accounted for by differences in BMI, diabetes duration, treatment type, proteinuria, or health care index.

CONCLUSIONS

Among American Indian/Alaska Native adults, HbA(1c) levels were highest in the youngest age-group. With increasing numbers of young American Indian/Alaska Native adults with diabetes, poorer glucose control is expected to bring concomitant increased morbidity and mortality unless more effective and efficient interventions are developed to improve glucose control among young American Indian/Alaska Native adults.

The role of angiotensin II antagonism in type 2 diabetes mellitus: a review of renoprotection studies

BACKGROUND

Diabetic nephropathy is the leading cause of end-stage renal disease (ESRD) in Western and Asian countries. Effective antihypertensive therapy reduces the rate of decline in renal function and postpones ESRD in patients with diabetic nephropathy.

OBJECTIVE

This review presents evidence from studies on how blood pressure control, plasma glucose control, and the presence of proteinuria determine outcomes in diabetic patients. The role of angiotensin II (All) in the development of diabetic nephropathy and the reno- and cardiobeneficial effects of AII antagonism in patients with type 2 diabetes mellitus (DM-2) and diabetic nephropathy also are addressed.

METHODS

Articles included in this review were found using a MEDLINE search for studies published from 1991 to 2001 and including the search terms diabetic nephropathy, type 2 diabetes mellitus, microalbuminuria, proteinuria, angiotensin receptor blockade, angiotensin-converting enzyme inhibition, and cardiovascular disease. Articles reporting new data, new mechanisms, major clinical trials, and our own data were included.

RESULTS

Recently, the Reduction of Endpoints in NIDDM (non-insulin-dependent diabetes mellitus) with the Angiotensin II Antagonist Losartan (RENAAL) trial provided sufficient data to conclude that the blockade of the All AT1 receptor with losartan confers renoprotection in patients with DM-2 and nephropathy. Similar results were obtained with irbesartan in the Irbesartan Diabetic Nephropathy Trial (IDNT) and the Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria study (IRMA 2). The results of RENAAL indicate that the renoprotective effects of losartan were attributable to effects beyond blood pressure control. In addition to the favorable impact of the All blockade on blood pressure and renal hemodynamics, the blockade of the growth-promoting, profibrotic, nonhemodynamic actions of AII also may be important for renoprotection. Intensive blood pressure control also confers cardiovascular protection in pa- tients with DM-2. Some studies suggest that the blockade of the renin-angiotensin system confers superior cardioprotective effects in patients with DM-2. The RENAAL study also showed cardioprotection with losartan, with an important reduction in the risk for first hospitalization for heart failure.

CONCLUSION

Evidence supports the importance of an effective blockade of AII action for both reno- and cardioprotection in patients with DM-2.

Strong in body and spirit: lifestyle intervention for Native American adults with diabetes in New Mexico

OBJECTIVE

To determine the effects of a culturally appropriate diabetes lifestyle intervention for Native Americans on risk factors for complications of diabetes.

RESEARCH DESIGN AND METHODS

A nonrandomized, community-based diabetes intervention trial was conducted in three Native American sites in New Mexico from 1993-1997. Participants were assigned to intervention or control based on community of residence. Intervention sessions were held approximately 6 weeks apart over approximately 10 months. The intervention was delivered in site A in family and friends (FF) groups (n = 32); site B received the same intervention in one-on-one (OO) appointments (n = 39); and site C received usual medical care (UC) (n = 33) (total participants, n = 104). Primary change in HbA(1c) level was assessed at 1 year.

RESULTS

Adjusted mean change in HbA(1c) value varied significantly across the three arms at 1 year (P = 0.05). The UC arm showed a statistically significant increase in adjusted mean HbA(1c) change (1.2%, P = 0.001), whereas both intervention arms showed a small nonsignificant (P > 0.05) increase in the adjusted mean change (0.5% and 0.2% for FF and OO arms, respectively). The increase was statistically significantly smaller in the combined intervention arms (0.4%) compared with the UC arm (1.2%, P = 0.02).

CONCLUSIONS

Lifestyle intervention has the potential to substantially reduce microvascular complications, mortality, and health care utilization and costs if the change is sustained over time.

Development of a culturally sensitive, locality-based program to increase kidney donation

Diabetic kidney disease has become an epidemic in American Indian communities. In Central Arizona, the Salt River Pima-Maricopa, Gila River, and Ak-Chin Indian communities have the highest incidence rate of diabetes in the world. Over 200 diabetic people in these communities receive dialysis because of kidney disease, a frequency that is 10 to 15 times the national average. Very few of these patients ever receive a kidney transplant. The communities formed the Organ Donation and Kidney Transplant Education Committee, which designed culturally sensitive educational materials and trained tribal members to disseminate the information. The goals were to educate tribal members about the choices they have when faced with kidney failure and to increase organ donation within the communities. The committee also produced a 10- to 15-minute educational video presentation for use at community district meetings, health fairs, and local health clinics in the communities. One unexpected early outcome has been the opportunity to reflect on some assumptions and stereotypes about American Indians and organ donation commonly held by health care providers. The local organ procurement organization plans to use the video in training hospital donor requestors. What difference would it make to educate the communities and not change the assumptions of those in the hospitals requesting donation?

Genetics of diabetic nephropathy in the Pima Indians

Diabetic nephropathy is the leading cause of renal failure in industrialized countries. There is strong evidence that diabetic nephropathy is influenced by genetic factors. Studies in the Pima Indians as well as in other populations demonstrate that diabetic nephropathy aggregates in families. The hypothesis that the familial aggregation reflects the effect of a major gene was formally tested by segregation analysis of diabetic nephropathy in Pima Indians with type 2 diabetes. The segregation analysis provided strong evidence for a major genetic effect on the prevalence of diabetic nephropathy; this suggests that some of the genetic determinants of diabetic nephropathy may have effects of sufficient magnitude to be detected by linkage analysis. Therefore, we analyzed data from a genome-wide scan to identify susceptibility loci for nephropathy in diabetic Pima Indians. Analyses conducted by both parametric (model-based) and nonparametric methods revealed tentative evidence for nephropathy susceptibility loci on chromosomes 3q, 7q, 18q, and 20p.

Angiotensin-converting enzyme gene polymorphism and microvascular complications in Turkish type 2 diabetic patients

The aim of this study was to investigate whether an association exists between the angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism and microvascular complications of type 2 diabetes mellitus in Turkish patients. A total of 239 type 2 diabetic patients and 138 sex and age matched control subjects were included into the study. The I/D polymorphism was determined by polymerase chain reaction (PCR). Nephropathy status was determined according to urinary albumin/creatinine ratio (microg/mg) (<30 normoalbuminuria, 30-300 microalbuminuria, >300 macroalbuminuria) and retinopathy was evaluated by fundoscopic examination and by flourescein fundus angiography. The distribution of ACE I/D polymorphism and allele frequencies in diabetic patients were not significantly different from controls, DD genotype 32.2 versus 37.2%; ID genotype 50.6 versus 47.1%; and II 17.2 versus 15.2%; D allele 57.5 versus 61.2%; I allele 42.5 versus 38.8%. Genotype distribution between normo-, micro- and macroalbuminuric patients did not differ significantly (DD:ID:II (%), normoalbuminuria, 35:46:19; microalbuminuria, 28:55:17; macroalbuminuria, 31:55:14). There was also no difference in genotype distribution between patients with and without retinopathy (DD:ID:II (%), retinopathy positive, 32:51:17; retinopathy negative, 33:49:18). In conclusion, the ACE I/D polymorphism does not seem to be associated with diabetic nephropathy and retinopathy in Turkish type 2 diabetic patients.

The impact of diabetes on economic costs in dialysis patients: experiences in Taiwan

Diabetes mellitus carries a great burden on healthcare costs due to its growing population and high co-morbidity. This adverse effect sustains even when patients develop end-stage renal disease (ESRD). We here present data showing the effect of diabetes on economic costs in dialysis therapy in Taiwan. As of the end of 1997, we have 22,027 ESRD patients with a prevalence and incidence rate of 1013 and 253 per million populations, respectively. Diabetic nephropathy is the second most common cause of the underlying renal diseases, but accounts for 24.8% of the prevalent patients and 35.9% of the incident cases. The diabetic patients engendered 11.8% more expense for care of dialysis than the non-diabetic patients (US $26,988 vs. US $24,146 per patient-year). Higher inpatient cost mainly account for the difference. As compared to non-diabetic patients, the diabetic patients had 3.5 times more inpatients costs (US $1325 vs. US $4677 per patient-year), and higher proportion of inpatient-to-annualized cost ratio (5.5 vs. 17.3%) resulting from their more frequent hospitalization (0.59 vs. 1.13 times per patient-year) and longer hospital stay (6.7 vs. 18.9 days per patient-year). The major causes responsible for a more frequent hospitalization were cardiovascular disease, poorly controlled hyperglycemia, sepsis and failure of vascular access. The annualized costs for care of dialysis patients in Taiwan, including inpatient and outpatient costs, averaged US $25,576 per patient-year. This value is approximately half of that in most of the western countries and Japan. Thus, a more cost-effective way to achieve savings is to reduce the high incidence rate of dialysis population and to maximize the quality of dialysis treatment for avoiding hospitalization. Recent studies had shown that tight blood pressure control, intensive glycemic control, and use of angiotensin converting enzyme inhibitors in diabetic patients significantly reduced not only the rate of progressive renal failure, but also substantially reduced the cost of complications and led to higher cost effectiveness. Once diabetic patients reach stage of ESRD, an optimized pre-ESRD care and consideration of kidney transplantation are essential in terms of better patient survival and cost savings.

Nitric oxide system is involved in glomerular hyperfiltration in Japanese normo- and micro-albuminuric patients with type 2 diabetes

Glomerular hyperfiltration plays a pathogenic role in the early stages of diabetic nephropathy. Experimental studies in laboratory animals suggest that nitric oxide (NO) might be involved in the pathogenesis of glomerular hyperfiltration. We performed a cross-sectional study to determine the relationship between diabetic glomerular hyperfiltration and the NO system. Normoalbuminuric (n=41), microalbuminuric (n=25), and macroalbuminuric (n=16) patients with type 2 diabetes were recruited in this study and compared with age-matched 84 non-diabetic control subjects. Creatinine clearance and urinary NO(2)(-)/NO(3)(-) excretion (urinary NOx) were measured, and the expression of endothelial cell nitric oxide synthase (ecNOS) was evaluated in human renal tissues. Glomerular hyperfiltration was present in 19 (37.5%) and nine (36.6%) of normoalbuminuric and microalbuminuric type 2 diabetic patients, respectively. The urinary NOx was significantly higher in normoalbuminuric patients compared with normal subjects. Creatinine clearance correlated significantly with urinary NOx in normoalbuminuric and microalbuminuric patients. Immunohistochemical staining intensities for ecNOS were significantly increased in glomerular endothelial cells of microalbuminuric type 2 diabetic patients as compared with the control subjects. These results suggest that NO may contribute to the pathogenesis of glomerular hyperfiltration in Japanese type 2 diabetic patients.

Renal function and renal disease in the elderly: Part I

In all industrialized countries, life expectancy has risen in the past 100 years. The incidence of elderly patients reaching end-stage renal disease (ESRD) and requiring renal replacement therapy has also increased. During the past few decades, the pattern of ESRD has changed significantly with the emerging predominance of elderly patients. The causes of this phenomenon are manifold and include an increasing number of chronic diseases typical of the 'third age', such as type 2 diabetes mellitus and vascular disease. In many species, a consequence of aging includes deterioration of renal function, partly due to structural alterations, and partly as the result of a diminishing blood flow. In humans, the aging kidney is characterized by modifications resulting from organic and functional disturbances. In particular, type 2 diabetes mellitus has emerged as an important condition, the microvascular and macrovascular complications of which are a common cause of morbidity and mortality in older patients. In part I of this review, the morphological and functional changes of the aging kidney will be reviewed, as well as the pathological conditions leading to the loss of renal function in the elderly.

Higher incidence of diabetic nephropathy in type 2 than in type 1 diabetes in early-onset diabetes in Japan

BACKGROUND

Whether the type of diabetes, race, and year and age of diagnosis affect the incidence of diabetic vascular complications is unknown. That both type 1 and type 2 diabetes occur in the young Japanese population prompted us to investigate whether the type of diabetes and the year of diagnosis are related to the incidence of nephropathy.

METHODS

Of the 17,256 diabetic patients who visited the outpatient clinic at our diabetes center between 1965 and 1990, 1578 (9.1%) had early-onset diabetes (diagnosed before the age of 30); of these, 620 (39%) had type 1, and 958 (61%) had type 2 diabetes. The incidence of nephropathy was analyzed in the patients according to postpubertal duration and year of diagnosis.

RESULTS

The cumulative incidence of nephropathy after 30 years of postpubertal diabetes was significantly higher (P < 0.0001) in type 2 diabetic patients (44.4%, 95% CI, 37.0 to 51.8%) than in type 1 diabetic patients (20.2%, 95% CI, 14.9 to 25.8%). The incidence of nephropathy among type 1 diabetic patients has declined during the past two decades, whereas it has not among type 2 diabetic patients. The rate ratio for type 2 diabetic patients diagnosed between 1980 and 1984 relative to type 1 diabetic patients diagnosed in the same period was 2.74 (95% CI, 1. 17 to 6.41).

CONCLUSIONS

The incidence of nephropathy has declined in Japanese patients with type 1 but not in those with type 2 diabetes. In young Japanese patients, because of the higher incidence of nephropathy in type 2 diabetes and the higher prevalence of type 2 than type 1 diabetes, type 2 diabetes is likely the major cause of diabetic nephropathy.

Effect of hypertension on mortality in Pima Indians

BACKGROUND

The effect of hypertension on mortality was examined in 5284 Pima Indians, 1698 of whom had type 2 diabetes at baseline or developed it during follow-up.

METHODS AND RESULTS

During a median follow-up of 12.2 years (range, 0.01 to 24.8 years), 470 nondiabetic subjects and 488 diabetic subjects died. In the nondiabetic subjects, 45 of the deaths were due to cardiovascular disease, 208 to other natural causes, and 217 to external causes; in the diabetic subjects, 106 of the deaths were due to cardiovascular disease, 85 to diabetic nephropathy, 226 to other natural causes, and 71 to external causes. In the nondiabetic subjects, after adjusting for age, sex, body mass index, and serum cholesterol concentration in a proportional hazards model, hypertension predicted death from cardiovascular disease (death rate ratio [DRR]=2.8; 95% CI, 1.4 to 5. 6; P=0.003). In the diabetic subjects, after additional adjustment for duration of diabetes, plasma glucose concentration, and proteinuria, hypertension strongly predicted deaths from diabetic nephropathy (DRR=3.5; 95% CI, 1.7 to 7.2; P<0.001), but it had little effect on deaths from cardiovascular disease (DRR=1.4; 95% CI, 0.88 to 2.3; P=0.15).

CONCLUSIONS

We propose that the weak relationship between hypertension and cardiovascular disease in diabetic Pima Indians is not because of a diminished effect of hypertension on cardiovascular disease in diabetes, but because of a relatively greater effect of hypertension on the progression of diabetic nephropathy. Factors that may account for this finding in Pima Indians include a younger age at onset of type 2 diabetes, a low frequency of heavy smoking, favorable lipoprotein profiles and, possibly, enhanced susceptibility to renal disease.

Genetic susceptibility to end-stage renal disease

New methods have been developed to uncover the genotypes that result in complex diseases. End-stage renal disease is a complex disease, without a simple correspondence between genotype and phenotype. Both population-based and family-based epidemiological studies and analysis of model organisms suggest that the pathogenesis of end-stage renal disease may have a genetic component. A number of studies have analyzed candidate nephropathy genes with little success, but recently several well-designed studies of multiplex families with diabetic nephropathy have identified candidate nephropathy susceptibility loci. To date, kidney disease-oriented research has focused on effector mechanisms responsible for the initiation and progression of chronic renal disease. However, because end-stage renal disease is a complex disease, interruption of a single effector pathway is unlikely to result in significant therapeutic benefit. Further understanding of the pathogenesis of kidney disease and the development of new kidney disease therapies will require continued application of genetic and genomic tools to kidney disease research.

Lack of association of angiotensin-converting enzyme (DD/II) and angiotensinogen M235T gene polymorphism with renal function among Chinese patients with type II diabetes

The prevalence of diabetic nephropathy is greater in nonwhite patients with type II diabetes, including the Chinese, and genetic variation appears to have a role. We examined angiotensin-converting enzyme (ACE) DD/II and angiotensinogen (Atg) M235T polymorphism in a cohort of Chinese patients with type II diabetes with an average duration of diabetes of 14 years. Group A (n = 88) did not have significant diabetic nephropathy (creatinine levels </= 130 micromol/L [</=1.48 mg/L], without macroalbuminuria), and group B (n = 80) had significant diabetic nephropathy (macroalbuminuria or creatinine level >130 micromol/L [>1.48 mg/d], and those undergoing dialysis). The two groups were matched in different aspects, including age, duration of diabetes, blood pressure, and glycemic control. The results showed: (1) no difference of genotype distribution between groups A and B (DD:DI:II, 14%:45%:41% v 8%:38%:54%; P = 0.20; TT:TM/MM, 70%:30% v 76%:24%; P = 0.43), (2) no evidence of synergistic effect of ACE (DD/II) and Atg M235T gene polymorphisms, (3) no difference of allele frequencies between groups A and B (D:I, 36%:64% v 27%:73%; P = 0.20 and T:M, 86%:16% v 86%:14%; P = 0.73), and (4) ACE activity was greatest in patients with DD genotype and least in those with II genotype (DD:DI:II = 66. 9 +/- 13.3 U/L:61.5 +/- 19.9 U/L:45.0 +/- 17.0 U/L; P < 0.005). The data do not support a role of ACE (DD/II) or Atg M235T polymorphism in the development of diabetic nephropathy in Chinese patients with type II diabetes, and no synergistic effect was found between them. Greater ACE activity was associated with DD genotype, and its role in diabetic nephropathy remains to be elucidated.

Should all Pima Indians with type 2 diabetes mellitus be prescribed routine angiotensin-converting enzyme inhibition therapy to prevent renal failure?

OBJECTIVE

To determine how effective angiotensin-converting enzyme (ACE) inhibitors must be in preventing diabetic nephropathy to warrant early and routine therapy in all Pima Indians with type 2 diabetes mellitus.

DESIGN

A computerized medical decision analysis model was used to compare strategy 1, screening for microalbuminuria and treatment of incipient nephropathy as currently recommended with ACE inhibitor therapy, with strategy 2, a protocol wherein all patients were routinely administered an ACE inhibitor 1 year after diagnosis of type 2 diabetes mellitus. The model assumed that ACE inhibitors can block, at least in part, the pathogenic mechanisms responsible for early diabetic nephropathy (microalbuminuria).

RESULTS

The model predicted that strategy 2 would produce more life-years at less cost than strategy 1, if routine drug therapy reduced the rate of development of microalbuminuria by 21% in all patients. Only a 9% reduction in the rate of development of microalbuminuria was cost-effective at $15,000 per additional life-year gained, and only a 2.4% reduction was cost-effective at $75,000 per additional life-year gained for strategy 2 over strategy 1.

CONCLUSIONS

Routine ACE inhibitor therapy in Pima Indians with type 2 diabetes mellitus could prove more effective and even cost saving than the currently recommended approach of microalbuminuria screening. A prospective trial examining this goal should be considered.

Renal disease and hypertension in non-insulin-dependent diabetes mellitus

Recent epidemiologic data demonstrate a dramatic increase in the incidence of end-stage renal disease (ESRD) in patients with non-insulin-dependent diabetes mellitus (NIDDM), thus dispelling the mistaken belief that renal prognosis is benign in NIDDM. Currently, the leading cause of ESRD in the United States, Japan, and in most industrialized Europe is NIDDM, accounting for nearly 90% of all cases of diabetes. In addition to profound economic costs, patients with NIDDM and diabetic nephropathy have a dramatically increased morbidity and premature mortality. NIDDM-related nephropathy varies widely among racial and ethnic groups, genders and lifestyles; and gender may interact with race to affect the disease progression. While the course of insulin-dependent diabetes mellitus (IDDM) progresses through well-defined stages, the natural history of NIDDM is less well characterized. NIDDM patients with coronary heart disease have a higher urinary albumin excretion rate at the time of diagnosis and follow-up. This greater risk may also be associated with hypertension and hyperlipidemia, and genes involved in blood pressure are obvious candidate genes for diabetic nephropathy. Hyperglycemia appears to be an important factor in the development of proteinuria in NIDDM, but its role and the influence of diet are not yet clear. Tobacco smoking can also be deleterious to the diabetic patient, and is also associated with disease progression. Maintaining euglycemia, stopping smoking and controlling blood pressure may prevent or slow the progression of NIDDM-related nephropathy and reduce extrarenal injury. Treatment recommendations include early screening for hyperlipidemia, appropriate exercise and a healthy diet. Cornerstones of management should also include: (1) educating the medical community and more widely disseminating data supporting the value of early treatment of microalbuminuria; (2) developing a comprehensive, multidisciplinary team approach that involves physicians, nurses, diabetes educators and behavioral therapists; and (3) intensifying research in this field.