Original Investigations
Risk factors for microalbuminuria in black americans with newly diagnosed type 2 diabetes

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Abstract

We conducted a cross-sectional analysis to describe the prevalence of and risk factors for microalbuminuria among blacks with newly diagnosed type 2 diabetes. Black adults with diagnosed type 2 diabetes mellitus of 2 years’ duration or less who presented for care to the Grady Diabetes Clinic (Atlanta, GA) between January 1, 1994, and December 31, 1996, were eligible (n = 1,167). Information obtained at the initial visit included age; sex; body mass index (BMI); serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, C-peptide, serum creatinine, and hemoglobin A1c (HbA1c ) levels; and seated systolic and diastolic blood pressures. Outcome was urine albumin-creatinine (Alb/Cr) ratio at the initial visit. Alb/Cr ratios were categorized as normal (Alb/Cr <25μg/mg), microalbuminuric (Alb/Cr, 25 to 250 μg/mg), and macroalbuminuric (Alb/Cr >250 μg/mg). Patients with macroalbuminuria or creatinine levels of 2 mg/dL or greater were excluded. We used multiple linear regression to assess the joint association between HbA1c level, mean arterial pressure (MAP), and log-transformed Alb/Cr, controlling for other covariates. Of 1,044 patients studied, macroalbuminuria was present in 3.8%, and microalbuminuria, in 23.4%. Alb/Cr was independently associated with increased HbA1c level (P = 0.0070), MAP (P = 0.0001), BMI (P = 0.0156), log-transformed triglyceride levels (P = 0.0031), C-peptide level of 6.5 ng/mL or greater (P = 0.0007), serum creatinine level (P = 0.0068), and male sex (P = 0.0220). The relationship between HbA1c level and microalbuminuria was stronger in patients with lower BMIs. Microalbuminuria prevalence was high in this population of urban blacks with newly diagnosed type 2 diabetes. Risk factors associated with increased Alb/Cr included male sex, poor glycemic control, endogenous hyperinsulinemia, high blood pressure, elevated triglyceride levels, and obesity.

Section snippets

Study population

We studied black patients with type 2 diabetes from an economically disadvantaged urban population with low levels of literacy and poor health insurance coverage.14, 31 Patients with a diabetes diagnosis for 2 years or less who presented to the Grady Diabetes Clinic (Atlanta, GA) for the first time between January 1, 1994, and December 31, 1996, were eligible for inclusion. Patients with both urine albumin and urine creatinine measurements at this visit were included in the analyses; patients

Results

Record review identified 1,167 eligible patients. Adequate information was available to calculate the Alb/Cr ratio for 1,055 of these patients (90.4%). Eleven patients with serum creatinine levels of 2 mg/dL or greater were excluded. Of the remaining 1,044 patients, 40 patients (3.8%) had clinical nephropathy (Alb/Cr >250 μg/mg) at the initial visit, 244 patients (23.4%) had microalbuminuria, and 760 patients (72.8%) had normoalbuminuria (Table 1).

. Prevalence of Microalbuminuria and

Discussion

The urban black Americans with type 2 diabetes in our study had a high prevalence of microalbuminuria despite short duration (≤2 years) of diagnosed diabetes. Studies of other nonwhite type 2 diabetic populations have also noted a high prevalence of microalbuminuria; however, these studies did not focus solely on those with short diabetes duration.14, 15, 38, 39 Few studies have examined microalbuminuria in black Americans with type 2 diabetes.

Patients with type 2 diabetes are believed to have

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    Received September 20, 1999; accepted in revised form May 26, 2000.

    Address reprint requests to William M. McClellan, MD, Georgia Medical Care Foundation, 57 Executive Park South NE, Ste 200, Atlanta, GA 30329-2224. E-mail: [email protected]

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