Prediction of cardiovascular events, diabetic nephropathy, and mortality by albumin concentration in a spot urine sample in patients with type 2 diabetes.

AIMS

To analyze in a random urine spot the predictive value of urinary albumin concentration (UAC) for cardiovascular events, diabetic nephropathy (DN), and death in patients with type 2 diabetes.

METHODS

In this cohort, urinary albumin (immunoturbidimetry) was measured as 24-h urinary albumin excretion (UAE) and, in a random spot urine, as UAC and albumin:creatinine ratio (ACR). Primary outcomes were: 1) cardiovascular events, 2) DN defined as a composite outcome [macroalbuminuria and/or decreased glomerular filtration rate (GFR) <60 ml/min/1.73 m²], and 3) death.

RESULTS

A total of 199 type 2 diabetic patients, aged 59.9 ± 9.9 years, were followed for 6.1 ± 2.7 years. UAC ≥14.4 mg/l, as determined by ROC curve, predicted DN and prediction for this and other outcomes were compared with traditional microalbuminuria cutoffs for ACR and UAE. The outcomes frequency was: cardiovascular events = 26.4%, DN = 31.7% (23.5% decreased GFR; 13.6% macroalbuminuria) and death = 8.50%. In Cox analyses, UAC ≥14 mg/l increased the risk (hazard ratio, HR) for cardiovascular events 3.25 times (95% CI 1.43-7.38; P = 0.005), 4.30 for DN composite outcome (95% CI 2.22-8.32; P <0.001), and 5.51 for death (95% CI 1.16-26.22; P = 0.032). Corresponding HRs of ACR ≥30 mg/g were: 2.89 (95% CI 1.29-6.45; P = 0.009) for cardiovascular events, 4.67 (95% CI 2.34-9.34; P <0.001) for DN composite outcome and 5.07 (95% CI 1.01-24.88; P = 0.049) for death. HRs of UAE ≥30 mg/24-h were: 2.20 (95% CI 2.08-2.49; P = 0.030) for cardiovascular events, 6.76 (95% CI 3.32-13.77; P <0.001) for DN composite outcome, and 2.47 (95% CI 0.72-8.42; P = 0.150) for death.

CONCLUSIONS

In conclusion, random UAC ≥14 mg/l predicted cardiovascular events, diabetic nephropathy, and mortality just as well as ACR. UAC may be used to assess cardiovascular and renal risks in patients with type 2 diabetes.