INFLUENCE OF PROTEIN CATABOLIC RATE ON NUTRITIONAL-STATUS, MORBIDITY AND MORTALITY IN ELDERLY UREMIC PATIENTS ON CHRONIC-HEMODIALYSIS - A PROSPECTIVE 3-YEAR FOLLOW-UP-STUDY

It has been recently reported that elderly chronic haemodialysis (CHD) patients have a reduced protein catabolic rate (PCRn) in spite of an adequate K-t/V. However until now the long-term consequences of this f act on the nutritional status, morbidity, and mortality were not known , This prospective study evaluates, over a period of 3 years, the effe ct of the reduced PCRn on some nutritional parameters, morbidity and m ortality in CHD patients older than 65 years with adequate and stable K-t/V. Over the period 1990-1993 we evaluated 42 CHD patients over 65 years (mean+/-SD 72+/-5 years). PCRn, total serum proteins, serum albu min concentration, body weight, body mass index (BMI) and serum transf errin were determined at the start of the study and followed yearly un til the end of observation. The incidence of hospitalization/patient-y ear, the mortality rate and the causes of death were also recorded. Al l the patients were managed to maintain a K-t/V>0.9 throughout the stu dy. Twenty-two patients (Group A), mean age 70+/-4 years, completed th e entire period of observation. Their K-t/V was 1.10+/-0.12, PCRn was 0.95+/-0.12 g/kg/day, and serum albumin concentration was 40.2+/-1.5 g /l, and these did not change significantly. The other parameters also remained stable over time. Twenty patients (Group B) died. Their mean age was 74+/-6 years. This group's K-t/V was 1.11+/-0.15, PCRn was 0.9 4+/-0.18 g/kg/day, and serum albumin concentration was 39+/-3.1 g/l, a nd there were no significant variations between the start and the end of observation for all the parameters studied. There were no differenc es between the two groups of patients at the start of observation for all the parameters with the exception of age, which was significantly higher in patients in Group B (P=0.017). The data derived by the Cox p roportional hazards regression model showed that PCRn and serum albumi n concentration were not significant predictors of death, as well as K -t/V, total serum proteins, BMI, total number of risk factors and numb er of hospital admissions/patient-year, but confirmed the predominant role of age (P<0.009) in predicting and conditioning the survival of p atients. In conclusion this prospective study shows that elderly CHD p atients with adequate and stable K-t/V have PCRn values lower than tho se commonly suggested as necessary to prevent chronic malnutrition. Ho wever, this reduced protein intake did not exert any specific negative influence on the nutritional status, morbidity and mortality after a follow-up of 3 years. It is possible that, in this group of patients, a declining PCRn with age does not indicate impending malnutrition and does not influence morbidity and mortality. Therefore age remains the strongest factor influencing mortality.