Survival during renal replacement therapy of patients previously treated with a very low-protein diet supplemented with ketoacids : the Italian experience.

In the course of chronic renal failure, low protein-diets allow better control of metabolic disorders and may delay the start of renal replacement therapy (RRT). However, concerns exist that a very low protein diet supplemented with ketoacids (sVLPD) worsens survival after starting RRT. To evaluate whether a prolonged sVLPD regimen may affect all-cause mortality during the following RRT period, we studied time to all-cause death during RRT in patients previously followed in renal clinics either treated with sVLPD (sVLPD group, n=184, age 67±18 yrs) or not (CKD group, n=334, age 66±14 yrs). A Control group including 9,092 patients (age 66±14 yrs) was selected from the Italian dialysis & transplantation registry (RIDT).In sVLPD, CKD and Control groups, the prevalence of an history of cardiovascular disease was 41, 31, 25% and of diabetes was 18%, 31%, 17%, respectively; the median follow-up time in RRT (36, 32, 36 months) did not differ among groups.Cumulative survival was similar in sVLPD and CKD groups (p=0.638), but significantly higher than in the Control group (Long-rank test, 20,62; p<0.0001). These results persisted in the Cox model adjusted for age, gender, diabetes, history of cardiovascular disease; as compared with controls, the HRs [95% CI] for death were 0.57 [0.45−0.74] (p=0.0001) in sVLPD and 0.65 [0.53−0.80] (p=0.001) in CKD group. Due to age interaction with survival in sVLPD (p=0.024), HRs for death reduced to 0.34 [0.16−0.73] and 0.58 [0.37−0.92] in sVLPD and CKD pts <70 yrs.In conclusion, prescription of sVLPD during the conservative phase of chronic renal failure does not worsen, or even improves, survival after starting RRT. This survival advantage is more evident in patients younger than 70 years