OBJECTIVE: To assess the urine protein/creatinine ratio in urine samples of pregnant women with hypertension in regard to: 1) the presence of significant variation at different periods of the day; 2) the differences if they exist, to identify the most reliable period of the day for sampling; and 3) whether the first sample, obtained when the patient arrives at the clinic, correlates with the same accuracy, with the 24-hour proteinuria. DESIGN: Cross-sectional study. PLACE: Obstetrics Emergency Department, Hospital de Clínicas de Porto Alegre, a teaching hospital in Porto Alegre, Brazil. POPULATION: Seventy-five women with hypertension with 20-week gestation or over. METHODS: Urine samples for determination of the protein/creatinine ratio were obtained on arrival (first specimen) and every 6 hours thereafter, totaling four samples in 24 hours. Four sampling periods were established: 1) from 8 am to 2 pm, 2) from 2 pm to 8 pm, 3) from 8 pm to 2 am, and 4) from 2 am to 8 am. The protein/creatinine ratio in the four different day periods were compared with the 24-hour proteinuria obtained simultaneously. The results were analyzed by the Spearman correlation and the receiver-operator characteristic (ROC) curve. RESULTS: The urine protein/creatinine ratio is strongly correlated (Spearman correlation equal to 0.8 or greater) with the 24-hour proteinuria at all four periods of the day (p<0.001), as well as the first sample obtained on arrival (p=0.003). These findings were corroborated by the ROC curve in which the values of four day periods and that of the first sample were equal to or greater than 0.930. CONCLUSION: In hypertensive pregnant women, the single voided urine sample protein/creatinine ratio, irrespective of sampling time, is strongly correlated with the 24-hour proteinuria, as is the sample obtained on arrival.
OBJECTIVE: To assess the urine protein/creatinine ratio in urine samples of pregnant women with hypertension in regard to: 1) the presence of significant variation at different periods of the day; 2) the differences if they exist, to identify the most reliable period of the day for sampling; and 3) whether the first sample, obtained when the patient arrives at the clinic, correlates with the same accuracy, with the 24-hour proteinuria. DESIGN: Cross-sectional study. PLACE: Obstetrics Emergency Department, Hospital de Clínicas de Porto Alegre, a teaching hospital in Porto Alegre, Brazil. POPULATION: Seventy-five women with hypertension with 20-week gestation or over. METHODS: Urine samples for determination of the protein/creatinine ratio were obtained on arrival (first specimen) and every 6 hours thereafter, totaling four samples in 24 hours. Four sampling periods were established: 1) from 8 am to 2 pm, 2) from 2 pm to 8 pm, 3) from 8 pm to 2 am, and 4) from 2 am to 8 am. The protein/creatinine ratio in the four different day periods were compared with the 24-hour proteinuria obtained simultaneously. The results were analyzed by the Spearman correlation and the receiver-operator characteristic (ROC) curve. RESULTS: The urine protein/creatinine ratio is strongly correlated (Spearman correlation equal to 0.8 or greater) with the 24-hour proteinuria at all four periods of the day (p<0.001), as well as the first sample obtained on arrival (p=0.003). These findings were corroborated by the ROC curve in which the values of four day periods and that of the first sample were equal to or greater than 0.930. CONCLUSION: In hypertensive pregnant women, the single voided urine sample protein/creatinine ratio, irrespective of sampling time, is strongly correlated with the 24-hour proteinuria, as is the sample obtained on arrival.