Heida JE, Gansevoort RT, Messchendorp AL, et al. - Whether urine-to-plasma urea ratio, as a reflection of the urine-concentrating capacity, can serve as a marker to predict progression of autosomal dominant polycystic kidney disease (ADPKD), was inquired herein. Experts calculated urine-to-plasma urea ratio by dividing levels of early morning fasting spot urine urea by plasma urea. A significant association of urine-to-plasma urea ratio with the rate of eGFR reduction, during a median observation of 4.0 years, was evident both crude as well as following correction for established predictors. For every 10 units reduction in urine-to-plasma urea ratio, the odds ratio of rapidly progressive disease was estimated to be 1.35, with adjustment for predictors. Overall, findings revealed that disease progression in ADPKD was predicted by urine-to-plasma urea ratio, which was calculated from routine laboratory measurements, besides other risk markers.