Testing for albuminuria in 2014

Routine quantification of urinary albumin levels is recommended for all Canadians with diabetes, yet many controversies remain when interpreting these tests. Elevated levels of albuminuria have traditionally been labeled as either microalbuminuria, representing 30 to 300 mg of albuminuria per day (a range not reliably picked up by conventional urine dipsticks), or as overt nephropathy, representing more than 300 mg per day and usually identifiable by dipstick. The random urine albumin-to-creatinine ratio is a convenient test that can predict reliably the total daily protein excretion. The 30 mg per day upper limit of normal was selected to be a threshold far above the normal albumin excretion seen in healthy people. However, recent studies have shown that elevations of albumin excretion below the microalbuminuria threshold are associated with increased cardiorenal risk, suggesting that the 30 mg per day level may be set too high. Recently, the Canadian Diabetes Association Clinical Practice Guidelines changed the threshold for abnormal urine albumin-to-creatinine ratios to be 2.0 mg/mmol for both men and women. As a result, more women will be identified as having abnormal levels of albuminuria. However, these women will be correctly identified as having increased cardiorenal risk. It is important to note that people with diabetes who have abnormal levels of albuminuria are among patients at the highest risk for cardiorenal disease. These risks can be reduced by using the strategies outlined in the guidelines put forth by the Canadian Diabetes Association.