Justifying the high prevalence of microalbuminuria for type 2 diabetic patients in Taiwan with conditional probability approach--a DEMAND II study.

Background: To examine the prevalence of microalbuminuria (MAU) and chronic kidney disease as well as the correlation between MAU and renal and cardiovascular risks of Type 2 diabetes mellitus (T2DM) patients for public health policy making in Taiwan.

Methods: This was a multicenter, hospital-based, randomly selected, and cross-sectional study. T2DM patients aged 18-80 years without a known diagnosis of proteinuria were eligible. MAU was defined as urinary albumin-to-creatinine ratio (ACR) within 30-299 mg/g, and macroalbuminuria as that greater than or equal to 300 mg/g. Two positive out of three urinary screening results were required to make the diagnosis of MAU. The adjusted prevalence of MAU was calculated by conditional probability approach.

Results: 51.1% of the analyzed population (n=1,827) were women, with a mean (standard deviation) age of 59.16 years (11.19 years) and mean hemoglobin A1c (HbA1c) of 8.15% (1.83%). Median duration of DM history was 6 years (interquartile range, 3-11 years). The adjusted prevalence of MAU was 26.9%. Overall prevalence of chronic kidney disease Stage 3 or higher (estimated Glomerular filtration rate (eGFR) less than 60/mL/min/1.73 m²) was 13.8%. Only 4.7% of the T2DM patients had serum albumin test recorded and 68.7% with serum creatinine test recorded within the last 6 months. After adjustment for center and gender, the odds ratios for MAU or macroalbuminuria were 1.73 (95% CI, 1.27-2.36) for age greater than or equal to 60 years, 1.54 (1.13-2.10) for abnormal waist circumference, 1.10 (1.02-1.19) for every 1% increase in hemoglobin A1c, 1.91 (1.38-2.65) for higher systolic blood pressure, and 1.92 (1.19-3.07) for abnormal serum creatinine level.

Conclusion: This study demonstrates the application of "conditional probability" method to justify the rationale of adopting two positive out of three urinary screening tests for the diagnosis of MAU. An adjusted prevalence rate of MAU as 26.9% is reported. These results may provide a basis for cost-benefit consideration in designing preventive and interventional policies in public health. Furthermore, the awareness and practice of early monitoring of MAU for DM patients should be strengthened.