Urine cortisol/creatinine ratio in controlled insulin-induced hypoglycemia.

An elevated urine cortisol/creatinine ratio has been presented as a simple laboratory method to detect nocturnal hypoglycemia. The present study examines the time course of the rise and fall of the urine cortisol/creatinine ratio in 11 patients following insulin-induced hypoglycemia. The mean urine cortisol/creatinine ratios at 1 and 3 h after the onset of symptomatic hypoglycemia were 170 +/- 103 and 62 +/- 23, respectively. These were significantly greater (P less than 0.01) than the basal ratio of 13 +/- 7. By 5 h, the ratio had fallen to 19 +/- 11, which was similar to basal values. The study documents the sensitivity of the urine cortisol/creatinine ratio in detecting hypoglycemia but indicates that after 3 h, the ratio may return to normal despite a previous hypoglycemic episode.