Diabetic Nephropathy and Microalbuminuria in the Community: The South Auckland Diabetes Survey

Abstract

OBJECTIVE To compare the clinical, anthropometric, and metabolic characteristics of New Zealand Europeans, Maori, and Pacific Islanders with non-insulin-dependent diabetes mellitus (NIDDM) with emphasis on risk factors for the development of diabetic nephropathy. RESEARCH DESIGN AND METHODS A cross-sectional survey of 555 (74% of 750 available) diabetic patients attending diabetes clinics and randomly selected primary care centers was conducted in Auckland, New Zealand. RESULTS Among those with NIDDM, Maori and Pacific Islanders were younger at diagnosis, more obese, and had poorer glucose control when compared with the Europeans (fructosamine in μmol/l: Maori 335 ± 78, Pacific Islanders 367 ± 90, Europeans 318 ± 55; overall P < 0.001). Systolic blood pressure (sBP) was higher in Maori (145 ± 31 mmHg) and lower in Pacific Islanders (135 ± 25 mmHg) when compared with Europeans (141 ± 25 mmHg; overall P < 0.005). Mean estimated daily urinary albumin excretion (UAE) was 18.2 (15.5–1.3) mg/day in Europeans, 94.8 (60.5–148.7) mg/day in Maori, and 44.2 (32.3–60.3) mg/day in Pacific Islanders. The prevalence of proteinuria and end-stage renal failure were also higher in Maori and Pacific Islanders. The excess prevalence of microalbuminuria and proteinuria in Maori was present within 5 years of diagnosis. Europeans with impaired renal function were least likely to have associated proteinuria or microalbuminuria. Microalbuminuria and nephropathy were not consistently associated with either higher blood pressure or worse glucose control. CONCLUSIONS NIDDM in Maori and Pacific Islanders is associated with a greater degree of proteinuria and end-stage renal failure than that in Europeans. This observation is not explained by conventional risk factors.