Prevalence of Nephropathy in Black Patients with Type 2 Diabetes mellitus

Abstract

The prevalence of nephropathy in black patients with type 2 diabetes mellitus is poorly defined. We performed a cross-sectional analysis of 98 unrelated and unselected black type 2 diabetic patients treated in indigent care internal medicine clinics to determine the prevalence of proteinuria and nephropathy. Serum creatinine, blood urea nitrogen, urine albumin and urine creatinine concentrations were measured. A Spearman’s rank correlation was computed to test for a relationship between diabetes duration and continuous outcomes. For binary outcomes, an odds ratio and 95% confidence interval were computed for a change of 10 years diabetes duration based on logistic regression. Cases were 61% female, and had mean (± SD) age 59.9 ± 12.5 years, diabetes duration 12.6 ± 9.4 years, body mass index 32.4 ± 9.3 kg/m², hemoglobin A1C (HbA1C) 9.2 ± 2.3%, and serum creatinine concentration 1.60 ± 1.1 mg/dl. For continuous variables, diabetes duration was positively associated with albuminuria (r = 0.31; p = 0.0017), serum creatinine (r = 0.36; p = 0.0003) and blood urea nitrogen concentration (r = 0.36; p = 0.0003). For binary variables, cases with longer diabetes duration were at increased risk for urinary albumin:creatinine >300 µg/mg (p = 0.006), elevated serum creatinine concentration (≧1.4 mg/dl in women or ≧1.6 mg/dl in men; p = 0.045), elevated blood urea nitrogen concentration (≧20 mg/dl; p = 0.026), and clinical cerebrovascular disease (p = 0.028). HbA1C, body mass index, and blood pressure did not correlate with diabetes duration in this population. Among the cases, 33.7% had elevated serum creatinine concentration and 71.5% had abnormal levels of albuminuria (27.6% > 300 µg albumin/mg Cr and 43.9% 30–300 µg albumin/mg Cr). Abnormal proteinuria was seen in the majority of black patients with poorly controlled type 2 diabetes mellitus treated in indigent care clinics. This prevalence may be conservative, due to the widespread use of angiotensin-converting enzyme inhibitor therapy and exclusion of cases treated only by nephrologists. Approximately 70% of black patients with type 2 diabetes cared for in indigent care clinics have abnormal proteinuria and are at heightened risk for ESRD and death.

Improving life expectancy and decreasing the incidence of complications associated with type 2 diabetes: a modelling study of HbA1c targets

“… Scenario 1: reduction in mean HbA1c from 9.5% to 8.0% vs. no reduction (patients remained at an HbA1c level of 9.5%). The starting value of 9.5% was based on several recent prospective, cross‐sectional analyses in poorly controlled type 2 diabetes patients that focused on the extent to which intensification of glycaemic control improved outcomes (13–15). These studies were designed to include patients with mean baseline HbA1c levels between 9.0% and 9.5%, corresponding to the definition of poor glycaemic control in adults by the National Quality Measures Clearinghouse of the Agency for Healthcare Research and Quality. Scenario 2: reduction in mean HbA1c from 8.0% to 7.0% (ADA recommended target HbA1c level) vs. no reduction (patients remained at an HbA1c level of 8.0%). Scenario 3: reduction in mean HbA1c from 7.0% to 6.5% (IDF and AACE recommended target HbA1c level) vs. no reduction (patients remained at an HbA1c level of 7.0%). …”

“…Scenario 1: reduction in mean HbA1c from 9.5% to 8.0% vs. no reduction (patients remained at an HbA1c level of 9.5%). The starting value of 9.5% was based on several recent prospective, cross‐sectional analyses in poorly controlled type 2 diabetes patients that focused on the extent to which intensification of glycaemic control improved outcomes (13–15). These studies were designed to include patients with mean baseline HbA1c levels between 9.0% and 9.5%, corresponding to the definition of poor glycaemic control in adults by the National Quality Measures Clearinghouse of the Agency for Healthcare Research and Quality.…”

A genome-wide association study for diabetic nephropathy genes in African Americans

“…While this study design might be appropriate for other ethnicities, it has serious limitations for African Americans. African Americans with T2DM and preserved renal function for 10 years or more (“hypernormal” controls) are perhaps the ideal control group, but are rare (24). We estimate that less than 10% of African American T2DM-affecteds of 10 years duration have preserved renal function.…”

Insights into the Genetic Architecture of Diabetic Nephropathy

“…The authors acknowledge that study design may not be ideal given that studies of DN have typically used controls with T2D lacking nephropathy. However, African Americans with T2D and normal albuminuria after 10 or more years of disease are ideal but uncommon [66]. …”