Kidney prevention recipes for your office practice

Abstract

Renal replacement therapy by hemodialysis, peri- toneal dialysis, or renal transplantation prolongs survival in patients with end-stage renal disease (ESRD) and, in most cases, provides a good quality of life. In all rich coun- tries, new dialysis patients outnumber those who die, and the group of patients on renal replacement therapy is growing. The provision of adequate treatment to all is ab- sorbing a large proportion of the health care budget and is being looked at with concern by policymakers. Since rationing of dialysis or deciding that some patients can- not be treated is out of the question, clinicians should be looking for ways to prevent the need for dialysis in as many patients as possible. an important correlation between urinary protein ex- cretion and rate of glomerular filtration rate (GFR) de- cline in patients with diabetic (5) and nondiabetic chronic nephropathy (6). The role of proteinuria as a strong, in- dependent predictor of ESRD has been also recently documented in a mass screening setting (7). By screen- ing more than 100,000 healthy individuals in 1983 in Okinawa, Japan, and following them for up to 17 years, a positive relationship was found between baseline pro- teinuria (by dipstick urine test) and the risk of developing ESRD. Even a slight increase in proteinuria was an inde- pendent risk factor for ESRD. Moreover, the predictive value of the protein excretion rate was independent of the baseline GFR levels (abstract; Iseki K et al, JA m Soc Nephrol 14:194A, 2003). Whenever proteinuria is decreased, progression to ESRD is reduced (8, 9-11). Results of the Modification of Diet in Renal Disease (MDRD) study (8) established that a reduction of proteinuria was associated with a decrease in the rate of decline in GFR, and that the protection of renal function achieved by lowering blood pressure was dependent on the extent of initial proteinuria. The role of proteinuria as a promoter of progression, and its impact on renal outcome, was also explored by the Ramipril Efficacy in Nephropathy (REIN) study (11). This study was designed to assess the hypothesis that ACE inhibition could be superior to other antihyperten- sive drugs in reducing proteinuria, limiting the decline in GFR, and preventing ESRD in patients with chronic nephropathies. In this study, patients were randomly as- signed to receive ramipril or conventional antihyperten- sive therapy to maintain diastolic blood pressure at 90 mm Hg or less. A prestratification strategy recognized 2 levels of proteinuria (stratum 1: >1 and <3 g/24 hours; stratum 2: ≥3 g/24 h). The study showed that while blood pres- sure control was similar in the 2 treatment groups, ACE inhibitor therapy decreased the progression to ESRD by 50% (11, 12). Patients who had more proteinuria to start with benefited more from blood pressure-lowering treatment than those who had less proteinuria. A meta- analysis (abstract; Jafar TH et al, JA mSoc Nephrol