DIETARY-PROTEIN RESTRICTION, BLOOD-PRESSURE CONTROL, AND THE PROGRESSION OF POLYCYSTIC KIDNEY-DISEASE

In the Modification of Diet in Renal Disease Study, a follow-up (mean, 2.2 yr) of 200 study participants with autosomal dominant polycystic kidney disease (ADPKD) was conducted to determine the effect of loweri ng protein intake and blood pressure on the rate of decline in GFR. Th e rate of decline was faster in participants with ADPKD than in person s with other diagnoses, reflecting, in part, faster disease progressio n in the ADPKD group. Baseline characteristics that predicted a faster rate of decline in GFR in persons with ADPKD were greater serum creat inine (independent of GFR), greater urinary protein excretion, higher mean arterial pressure (MAP), and younger age. In patients with initia l GFR values between 25 and 55 mL/min per 1.73 m(2), neither assignmen t to a low-protein diet group nor assignment to a low blood pressure g roup significantly reduced the rate of decline of GFR in ADPKD partici pants. Similarly, the decline in GFR was not related to achieved prote in intake or MAP. In participants with GFR values between 13 and 24 mL /min per 1.73 m(2), assignment to the low MAP group led to a somewhat more rapid decline in GFR. However, the more rapid decline in GFR did not appear to be due to a detrimental effect of low blood pressure or the antihypertensive agents used to reach the low blood pressure goal. Lower protein intake, but not prescription of the keto acid-amino aci d supplement, was marginally associated with a slower progression of r enal disease.