Relationship between renal volume growth and renal function in autosomal dominant polycystic kidney disease: a longitudinal study

Abstract

In autosomal dominant polycystic kidney disease (ADPKD), renal function remains normal for many years into adult life while cysts form and expand progressively, starting in childhood. The longitudinal relationships between renal volume growth, hypertension, and renal function loss have not been examined in detail. At the University of Colorado (Denver, CO), 229 adult subjects with ADPKD participated in a longitudinal study from 1985 to 2001. Sequential ultrasound examinations were performed at a mean interval of 7.8 +/- 3.1 years (range, 2.6 to 15.1 years). Renal volume was calculated using a standard formula for a modified ellipsoid. The Modified Diet in Renal Disease equation was used to calculate glomerular filtration rate (GFR). The mean annual increase in renal volume was 46 +/- 55 cm3, and mean annual decline in GFR was 2.4 +/- 2.8 mL/min/1.73 m2. Men had faster renal growth, more severe hypertension, and a faster decline in GFR than women of similar ages. Multiple linear regression showed a significant relationship between rate of change in GFR and renal volume growth rate, initial renal volume, proteinuria, and age at entry. Correlational analysis showed a significant correlation between GFR and renal volume over time (R = -0.53) and between follow-up renal volume and follow-up GFR (R = -0.50) for both men and women. We conclude that renal volume and rate of renal volume growth may be useful markers for disease progression in early stages of ADPKD when GFR is preserved.