Six-year incidence of proteinuria in type 1 diabetic African Americans

Insights into Diabetic Kidney Disease Using Urinary Proteomics and Bioinformatics

A number of proteomic and peptidomic analyses of urine from diabetic subjects have been published in the quest for a biomarker that predicts progression of nephropathy. Less attention has been paid to the relationships between urinary proteins and the underlying biological processes revealed by the analyses. In this review, we focus on the biological processes identified by studying urinary proteins and protein-protein interactions at each stage of diabetic nephropathy to provide an overview of the events underlying progression of kidney disease reflected in the urine. In uncomplicated diabetes, proteomic/peptidomic analyses indicate that early activation of fibrotic pathways in the kidney occurs before the onset of microalbuminuria. In incipient nephropathy, when albumin excretion rates are abnormal, proteomic/peptidomic analyses suggest that changes in glomerular permselectivity and tubular reabsorption account, at least in part, for the proteins and peptides that appear in the urine. Finally, overt nephropathy is characterized by proteins involved in wound healing, ongoing fibrosis, and inflammation. These findings suggest that there is a spectrum of biological processes in the diabetic kidney and that assessing protein networks may be more informative than individual markers with respect to the stage of disease and the risk of progression.

Markers of endothelial dysfunction and inflammation predict progression of diabetic nephropathy in African Americans with type 1 diabetes

African Americans with early-onset type 1 diabetes mellitus are at a high risk for severe diabetic nephropathy and end-stage renal disease. In order to determine whether baseline plasma levels of inflammatory markers predict incidence of overt proteinuria or renal failure in African Americans with type 1 diabetes mellitus, we re-examined data of 356 participants in our observational follow-up study of 725 New Jersey African Americans with type 1 diabetes. At baseline and 6-year follow-up, a detailed structured clinical interview was conducted to document medical history including kidney dialysis or transplant, other diabetic complications, and renal-specific mortality. Plasma levels of 28 inflammatory biomarkers were measured using a multiplex bead analysis system. After adjusting for baseline age, glycohemoglobin, and other confounders, the baseline plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) in the upper two quartiles were, respectively, associated with a three- to fivefold increase in the risk of progression from no albuminuria or microalbuminuria to overt proteinuria. Baseline plasma levels of the chemokine eotaxin in the upper quartile were significantly associated with a sevenfold increase in risk of incident renal failure. These associations were independent of traditional risk factors for progression of diabetic nephropathy. Thus, in type 1 diabetic African Americans, sICAM-1 predicted progression to overt proteinuria and eotaxin-predicted progression to renal failure.

Medical and psychological risk factors for incident hypertension in type 1 diabetic african-americans

Objective. To determine risk factors for the development of hypertension among African-Americans living with type 1 diabetes. Methods. African-Americans with type 1 diabetes (n = 483) participated in a 6-year followup. At both baseline and followup blood pressure was measured twice in both sitting and standing positions using a standard protocol. Patients had a structured clinical interview, ocular examination, retinal photographs, and blood and urine assays and completed the Hostility and Direction of Hostility Questionnaire (HDHQ) and the Beck Depression Inventory (BDI). Results. Of the 280 diabetic patients with no hypertension at baseline, 82 (29.3%) subsequently developed hypertension over the 6-year followup. Baseline older age, longer duration of diabetes, family history of hypertension, greater mean arterial blood pressure, overt proteinuria, increasing retinopathy severity, peripheral neuropathy, smoking, and higher hostility scores were significantly associated with the development of hypertension. Multivariate analyses showed that higher hostility scores and overt proteinuria were significantly and independently associated with the development of hypertension in this population. Conclusions. The development of hypertension in African-Americans living with type 1 diabetes appears to be multifactorial and includes both medical (overt proteinuria) as well as psychological (high hostility) risk factors.

Depression and incident lower limb amputations in veterans with diabetes

PROBLEM

Depression is associated with a higher risk of macrovascular and microvascular complications and mortality in diabetes, but whether depression is linked to an increased risk of incident amputations is unknown. We examined the association between diagnosed depression and incident non-traumatic lower limb amputations in veterans with diabetes.

METHODS

This was a retrospective cohort study from 2000-2004 that included 531,973 veterans from the Diabetes Epidemiology Cohorts, a national Veterans Affairs (VA) registry with VA and Medicare data. Depression was defined by diagnostic codes or antidepressant prescriptions. Amputations were defined by diagnostic and procedural codes. We determined the HR and 95% CI for incident non-traumatic lower limb amputation by major (transtibial and above) and minor (ankle and below) subtypes, comparing veterans with and without diagnosed depression and adjusting for demographics, health care utilization, diabetes severity and comorbid medical and mental health conditions.

RESULTS

Over a mean 4.1 years of follow-up, there were 1289 major and 2541 minor amputations. Diagnosed depression was associated with an adjusted HR of 1.33 (95% CI: 1.15-1.55) for major amputations. There was no statistically significant association between depression and minor amputations (adjusted HR 1.01, 95% CI: 0.90-1.13).

CONCLUSIONS

Diagnosed depression is associated with a 33% higher risk of incident major lower limb amputation in veterans with diabetes. Further study is needed to understand this relationship and to determine whether depression screening and treatment in patients with diabetes could decrease amputation rates.

Depression and incident diabetic foot ulcers: a prospective cohort study

OBJECTIVE

To test whether depression is associated with an increased risk of incident diabetic foot ulcers.

METHODS

The Pathways Epidemiologic Study is a population-based prospective cohort study of 4839 patients with diabetes in 2000-2007. The present analysis included 3474 adults with type 2 diabetes and no prior diabetic foot ulcers or amputations. Mean follow-up was 4.1 years. Major and minor depression assessed by the Patient Health Questionnaire-9 were the exposures of interest. The outcome of interest was incident diabetic foot ulcers. We computed the hazard ratio and 95% confidence interval (CI) for incident diabetic foot ulcers, comparing patients with major and minor depression with those without depression and adjusting for sociodemographic characteristics, medical comorbidity, glycosylated hemoglobin, diabetes duration, insulin use, number of diabetes complications, body mass index, smoking status, and foot self-care. Sensitivity analyses also adjusted for peripheral neuropathy and peripheral arterial disease as defined by diagnosis codes.

RESULTS

Compared with patients without depression, patients with major depression by Patient Health Questionnaire-9 had a 2-fold increase in the risk of incident diabetic foot ulcers (adjusted hazard ratio 2.00; 95% CI, 1.24-3.25). There was no statistically significant association between minor depression by Patient Health Questionnaire-9 and incident diabetic foot ulcers (adjusted hazard ratio 1.37; 95% CI, 0.77-2.44).

CONCLUSION

Major depression by Patient Health Questionnaire-9 is associated with a 2-fold higher risk of incident diabetic foot ulcers. Future studies of this association should include better measures of peripheral neuropathy and peripheral arterial disease, which are possible confounders or mediators.

Racial and ethnic differences in an estimated measure of insulin resistance among individuals with type 1 diabetes

OBJECTIVE Insulin resistance is greater in racial/ethnic minorities than in non-Hispanic whites (NHWs) for those with and without type 2 diabetes. Because previous research on insulin resistance in type 1 diabetes was limited to NHWs, racial/ethnic variation in an estimated measure of insulin resistance in type 1 diabetes was determined. RESEARCH DESIGN AND METHODS The sample included 79 individuals with type 1 diabetes diagnosed at age <18 years (32.9% NHWs, 46.8% non-Hispanic black [NHB], 7.6% other/mixed, and 12.7% Hispanic) and their families. Estimated glucose disposal rate (eGDR) (milligrams per kilogram per minute; a lower eGDR indicates greater insulin resistance) was calculated using A1C, waist circumference, and hypertension status. RESULTS Mean current age was 13.5 years (range 3.2-32.5) and diabetes duration was 5.7 years (0.1-19.9). eGDR was inversely associated with age. Compared with that in NHWs, age-adjusted eGDR was significantly lower among nonwhites (NHB, other/mixed, and Hispanic: Delta = -1.83, P = 0.0006). Age-adjusted eGDR was negatively associated with body fat, triglycerides, urinary albumin/creatinine, acanthosis nigricans, parental obesity, and parental insulin resistance and positively related to HDL and sex hormone-binding globulin. In multivariable analysis, lower eGDR was significantly associated with older age, nonwhite race/ethnicity, acanthosis, and lower HDL. CONCLUSIONS Minorities with type 1 diabetes are significantly more insulin resistant, as measured by eGDR, than NHWs. Exploring potential mechanisms, including disparities in care and/or physiological variation, may contribute to preventing racial/ethnic differences in insulin resistance-associated outcomes.

[Prevalence and determinants of microalbuminuria and macroalbuminuria in children and young adults with type 1 diabetes in Kinshasa]

AIM

To determine the prevalence and determinants of microalbuminuria and macroalbuminuria in type 1 Congolese diabetics aged less than 30 years.

METHODS

Cross sectional study (june-july 2008) at the Primary Health Care Center Boyambi in Kinshasa, The Democratic Republic of the Congo. HbA(1c) and urine albumin excretion (UAE) were measured by an enzyme immunoassay method. Determinants of microalbuminuria and macroalbuminuria were assessed by logistic regression.

RESULTS

One hundred and eighty-one type 1 diabetics (female gender: 61.3%) were included in this study. They were aged 19.1+/-5.8 years and were diabetics for 57.6+/-45.1 months. HbA(1c) was superior or equal to 10% in 88%, between 7 and 10% in 4% and inferior to 7% in 8%. Prevalence of microalbuminuria and macroalbuminuria was 21.9% and 7.3%, respectively. Diabetes duration superior to 5 years (OR: 4.1; 95% CI [1.9-8.4]), age superior to 18 years (OR: 2.9 [1.3-6.2]) and HbA(1c) superior to 10% (OR: 2.6 [1.1-6.4]) were independent determinants of pathological UAE.

CONCLUSION

Microalbuminuria and even macroalbuminuria are very frequent in type 1 Congolese diabetics aged above or equal to 30 years, especially in those aged above 18 years and diabetics for more than 5 years. Improving diabetes control and treating microalbuminuria is urgently needed to prevent renal insufficiency among children and young adults with type 1 diabetes of The Democratic Republic of the Congo.

Early nephropathy in type 1 diabetes: the importance of early renal function decline

PURPOSE OF REVIEW

The results of recent clinical trials in early diabetic nephropathy demonstrate that current therapies designed to suppress microalbuminuria do not prevent renal function decline. However, recent observational studies refined the traditional model of early nephropathy in type 1 diabetes and may inform more effective therapies for the prevention of chronic kidney disease.

RECENT FINDINGS

A contemporary model of early nephropathy in type 1 diabetes has emerged in which initiation of renal function decline occurs soon after the onset of microalbuminuria and is not conditional on progression to proteinuria. Early renal function decline can be diagnosed using serial measurement of serum cystatin C. Abnormal levels of markers of protein glycation, uric acid metabolism, and chronic inflammation appear to represent mechanisms unique to early renal function decline and distinct from those involved in microalbuminuria.

SUMMARY

Recent findings refine the existing paradigm of early nephropathy in type 1 diabetes and have significant implications for research. Clinical tests--such as an algorithm for the serial determination of serum cystatin C--should be developed for monitoring early renal function decline for use as an outcome in clinical trials.