FACTORS AFFECTING NPCR IN HEMODIALYZED PATIENTS

The determination of dialysis adequacy is difficult and definitions ar e in a state of flux (Lindsay). In fact, after fifteen years from the introduction of urea kinetics into clinical practice, nephrologists st ill do not agree on recognizing the real utility of it. Gotch and Sarg ent in their mechanistic analysis of the NODS indicated that the dose of small molecules removal could be defined by Kt/V urea. The results of the NODS were depicted in a three-variable plot in which six domain s could be seen. Several reports have documented malnutrition as being frequently present in patients on maintenance hemodialysis. It is gen erally accepted that a suboptimal nutritional status is associated wit h an increased morbidity and may adversely affect rehabilitation and t he quality of life. In 1989 Lindsay et al showed that low levels of Kt /V corresponded with low levels of nPCR and found a direct correlation between the two parameters. On this basis, they suggested the hypothe sis of nPCR dependence on Kt/V. The Authors showed a good correlation (r=0.73) between nPCR and Kt/V in 55 patients. This work aims to evalu ate the correlation between Kt/V and nPCR, real age and dialytic age i n a dialytic population in Southern Italy, during a long period of obs ervation (six years, follow up 2,692 months). One hundred and thirty-f our patients were studied in six years of observation. Follow up: 2692 months. Twenty-six patients died during the observation period. The s imple regression analysis of nPCR vs. Kt/V, real age and dialytic age was performed in 63 anuric patients. nPCR showed a statistical differe nce (p<0.01) versus reall age, but no difference versus dialytic age a nd Kt/V. Our research data show that increasing Kt/V administration do es not modify the nPCR of patients with initial and steady low protein intake over a medium time of observation. The same happens in patient s with initial and steady high protein intake, when decreasing Kt/V ad ministration in a short period of observation. We confirm that nPCR an d Kt/V do not show any mathematical correlation in short and medium ti mes of observation. It is also stressed by the simple regression analy sis of data for a selected population of anuric uremics on dialysis th rice weekly for long observation times (between three and six years). Variance analysis (in 8 patients who had used all the membranes) showe d differences between Kt/V and dialytic age, but not nPCR and real age . Kt/V and biocompatibility do not appear to be correlated directly wi th nPCR, because other factors are important in determining the genera l well-being in uremic patients. Such factors have to be considered wh en prescribing the dialytic ''dose'' and in clinically evaluating a ur emic patient.