Albumin Creatinine Ratio as Screening Test for Microalbuminuria in Patients with Type 2 Diabetes

Lee, Jung Eun; Park, Jung Hwan; Park, Dong Jun; Seong, Eun Young; Joo, Kwon Wook; Kim, Yon Su; Ahn, Curie; Han, Jin Suk; Kim, Suhnggwon; Lee, Jung Sang

Abstract

OBJECTIVE
Albumin creatinine ratio (ACR) in a spot urine is replacing albumin excretion rate (AER) in 24 hour-collected urine as screening test for microalbuminuria because of simplicity and reliance. There are some controversies about the most relevant ACR value in detecting microalbuminuria. Most commonly recommended cut-off value is 30 mg/gm. Some recommends sex-specific ACR cut-off value: 17 mg/gm for men, 25 mg/gm for women. In this report, we evaluated diagnostic characteristics of ACR according to above different cut-off values and estimated most relevant ACR cut-off value for microalbuminuria in patients with type 2 diabetes. METHODS: Urine was collected for 24hours for the measurement of microalbumin in type 2 diabetes who admitted in SNUH. The next day, first morning urine was obtained for microalbumin and creatinine concentration in patients with albumin excretion rate (AER) below 300 mg/day. RESULTS: 33% of total 156 patients had microalbuminuria. ACR correlated positively with AER. According to regression equations of AER and ACR, an AER of 30 mg/day corresponded to an ACR of 32 mg/gm. Positive and negative predictive values of ACR 30 mg/gm for microalbuminuria were 81% and 84% in men. In women, these were 80% and 86% respectively. Using recommended sex-specific ACR cutoff values, these were 52% and 94% in men, 68% and 91% in women. The most relevant ACR cutoff from receiver operating characteristics curve was 32 mg/gm in our study. CONCLUSION: Using ACR 30 mg/gm as cut-off values of microalbuminuria, positive and negative predictive value were above 80% in both men and women. In patients visiting SNUH, ACR 32 mg/gm may be more relevant in screening microalbuminuria in type 2 diabetes.