RESUMO
BACKGROUND: Microalbuminuria is the main parameter used in diabetic patients for clinical evaluation of early diabetic nephropathy and other complications. The most common method for quantitative urinary protein relies on a 24-hour urine collection or overnight urine collection; however, this method is time consuming and sometimes obtains inaccurate results. This study is aimed to test whether the microalbumin to creatinine ratio (Uma/Ucr) in the first-morning urine samples correlates with the microalbumin content in the 24-hour urine collection. METHODS: 59 urine samples from 59 type 2 diabetic patients were analyzed for Uma/Ucr, and for 24-hour urine microalbumin that were successively collected. RESULTS: Daily microalbumin excretion varied from 2.4 to 168.7 mg/24 hr with a median value of 22.9 mg, and Uma/Ucr ranged from 3.4 to 200 g/mg with a median value of 29.0 g/mg. An excellent correlation was found between the microalbumin excretion measured from the 24-hour urine collections and the first-morning urine Uma/Ucr ratio (R=0.93, P<0.001). All patients that excreted more than 30 mg albumin in the 24-hour urine samples also had an Uma/Ucr of more than 30 g/mg. Patients who had less than 30 g/mg of Uma/Ucr were unlikely candidates for microalbuminuria. CONCLUSIONS: This study indicates that measurements of Uma/Ucr in first-morning urine samples are a simple and reliable alternative to measurements of the urinary albumin excretion rate in the 24-hour urine collections.