Effect of age on protein catabolic rate, morbidity, and mortality in uraemic patients with adequate dialysis.

To test the validity of the assumption that the protein catabolic rate (PCRn g/kg/day) is dependent on the normalized dose of dialysis (Kt/V urea), and to try to define the characteristics of the patients in the undefined domain A of the mechanistic map of the National Cooperative Dialysis Study (NCDS), which should include patients with adequate amount of dialysis but inadequate PCRn, urea kinetic modelling was performed over 12 months on 85 patients undergoing haemodialysis. All the patients were managed to maintain a Kt/V urea > or = 0.9. During the entire period of study the total number of hospitalizations and the number of days of hospitalization were recorded. Total serum proteins and serum albumin concentrations were measured at the start and at the end of the study. The results of the study show that there was no correlation between Kt/V and PCRn nor between Kt/V and patient's age, but there was a strong inverse correlation between age and PCRn (r = 0.578; P < 0.0001). Further division of the patients into four groups according to age showed that the lowest values of PCRn were for the group of patients > or = 75 years old. Twelve patients with PCRn < or = 0.8 and Kt/V > or = 0.9 were included in domain A of the mechanistic map. Eleven (92%) of these 12 patients were > or = 65 years old. No correlations were found between the total number of hospitalizations, the total days of hospitalization, Kt/V, time on HD, body weight and PCRn by multiple regression analysis, while the inverse correlation between PCRn and age was confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of hematocrit in efficiency of dialysis.

To test the role of hematocrit (Hct), particularly when in the nearly normal range, on efficiency of dialysis, we analyzed the urea kinetics for 36 metabolically and hematologically stable patients on regular dialysis treatment and for 7 patients from this group before and after 3 months of treatment with human recombinant erythropoietin (rHuEPO). The volume of distribution of urea (V), the dialyzer clearance (Kd) and Kt/V were plotted against Hct. Hct showed a significant inverse correlation with Kd (r = 0.479, p = 0.003) and Kt/V (r = 0.572, p = 0.0002). Further division of the patients into groups with respect to Hct showed that the lowest Kt/V values were in the group with Hct greater than or equal to 37%. In the patients treated with rHuEPO, Hct rose from 18 +/- 1 to 35 +/- 5% (p less than 0.0001), and Kt/V decreased from 1.22 +/- 0.21 to 1.09 +/- 0.18 (p = 0.037). We conclude that Hct exerts a negative influence on efficiency of dialysis as evaluated by Kt/V. This is important for patients with normal or nearly normal Hct levels as well as for patients treated with rHuEPO, for whom normalization of Hct is pursued.

Is CAPD competitive with haemodialysis for long-term treatment of uraemic patients?

Although there are only 10 years of clinical experience with CAPD, compared to about 30 years of clinical practice with haemodialysis, it is time to compare the results obtained from the two methods. In this review, after briefly summarising the state of the art for some worrisome aspects of CAPD (peritonitis, loss of ultrafiltration and peritoneal clearance, malnutritional status), the ability of CAPD and haemodialysis to control the uraemic abnormalities are compared. Anaemia, blood pressure, cardiac function, renal bone disease, beta 2-microglobulin, and uraemic neuropathy are examined in the light of our personal experience and the literature; data so far published seem to indicate that the two methods are roughly similar for controlling these conditions. A survey of the studies comparing patient and method survival is also included. Patient survival on CAPD or on haemodialysis does not differ by more than 6 years. Method survival is better for haemodialysis; this is primarily due to the high drop-out rate from CAPD because of peritonitis, and the difference is very much reduced in CAPD centres with a low incidence of peritonitis. On the whole, CAPD seems to be able to compete, sometimes favourably, with haemodialysis. However, in our opinion the two methods are not in competition; each has its preferential indications, limits and complications, and both should be offered to uraemic patients in accordance with their medical or social needs. One should be ready to shift the patient from one method to the other when necessary, either for short periods of time or indefinitely.

Which treatment for which patient in the future? Possible modifications in CAPD.

On 578 unselected new patients followed from 1981 through 1993, 51% on CAPD and 49% on HD, long-term patient and method survivals, cause of death, and drop-out in the two methods were compared. Survival, adjusted for patient selection biases, was not different on CAPD and HD up to 10 years. 50% of the patients were still in their first treatment after 3.5 years on CAPD and after 7 years on HD, and 5 and 28% respectively, after 10 years. Patient survival on CAPD was not falsely improved by drop-outs. Drop-out is increasing for CAPD, mainly due to patient/partner burn-out, which should be relieved by a more liberal application of automated PD. Malnutrition is more frequent on CAPD than on HD but not for the elderly. In a 3 year prospective study on 60 CAPD and 34 HD patients serum albumin, nPCR and nutritional status, as assessed by SGA did not influence survival in each modality. Survival was similar with K(p,r)t/V > or = 1.7/week on CAPD and Kt/V > or = 1/treatment on HD, and worse below these values. On CAPD, a Kp,rt/V > or = 1.96 gave better survivals.

Reversal of left ventricular hypertrophy following recombinant human erythropoietin treatment of anaemic dialysed uraemic patients.

To clarify the role of chronic anaemia in the pathogenesis of the left ventricular hypertrophy (LVH) of chronic uraemia, nine normotensive dialysed patients were studied before and 3 and 6 months after start of intravenous treatment with recombinant human erythropoietin (rHuEpo). M-Mode echocardiographic estimations of left ventricular mass indices (LVMi) and plasma noradrenaline determinations were made at 3 and 6 months, and total blood volume (TBV) only at 6 months. Resting haemoglobin values were 5.9 +/- 1.3 (SD) g/dl, increased within 3 months to 10.2 +/- 1.2 (P less than 0.001), then remained unchanged. Baseline LVMi was 115 +/- 18 g/m2 body surface area (b.s.a.) and decreased significantly (P less than 0.0025) over the entire period to a final value of 78 +/- 13 g, which did not differ from the average value for 19 healthy controls. Resting plasma noradrenaline was 1.45 +/- 0.44 pmol/ml and did not change significantly, although values were reduced at the 3rd month, when decreased heart rates and slightly and non-significantly increased blood pressures were recorded. TBV did not vary because the increased erythrocyte mass was compensated for by parallel decreases in plasma volume. These data demonstrate the existence of a cause-effect relationship between uraemic anaemia and LVH, although the precise mechanism remains unknown. Amelioration of anaemia with rHuEpo, by allowing recovery from the attendant LVH, might improve long-term cardiovascular prognosis in some dialysed uraemic patients.

Acute visual disorders in patients on regular dialysis given desferrioxamine as a test.

Aluminium (Al) overload has been recognised as a frequent complication in uraemic patients on regular dialysis treatment. We report how acute visual disorders occurred after performing a desferrioxamine (DFO) test in patients on regular dialysis treatment suspected of having aluminium overload. Fifteen patients on regular dialysis treatment for 132 +/- 73 (range 17-250) months, aged 61 +/- 10 (range 47-79) years were given DFO as a test at standard dosage. In the 13 patients who complained of visual disorders, we performed ophthalmologic examinations soon after DFO administration, and again 5 months later in 11 of them. A decrease in visual acuity and/or dyschromatopsia, transient or permanent, were present in ten patients. Four had permanent maculopathy and three also had a permanent alteration of VEP (visual evoked potential). Visual fields were normal in all patients except one who presented a permanent central scotoma. The EOG (electro-oculogram) was permanently impaired in five patients and some of them had fluoroangiographic alterations due to damage of the pigmented epithelium. Six to eight months after the DFO test four patients still complained of visual acuity reduction. We conclude that there is a high rate of visual disorders after giving DFO at the standard doses; therefore we stress the need to modify the doses commonly used and/or the mode of infusion.

Clinical and morphological features of kidney involvement in primary Sjögren's syndrome.

BACKGROUND: Primary Sjögren's syndrome is a connective tissue disorder affecting primarily the lacrimal and salivary glands, resulting in xerophtalmia and xerostomia. Extraglandular manifestations are frequent and may include renal involvement. METHODS: We studied the prevalence and nature of kidney involvement in 60 Italian patients with primary Sjögren's syndrome, diagnosed according to the European classification criteria. The following renal laboratory tests were performed in all patients: electrolytes in serum and in 24-h urine, creatinine in serum and in 24-h urine, venous pH and HCO(3)(-), urinalysis, urine culture, urinary osmolality and urine pH. A water deprivation test was performed in patients with morning urine osmolalities below the reference values adjusted for age. An oral ammonium chloride loading test was performed in patients with urine pH above 5.5 from morning samples. Renal biopsy was performed in patients with renal involvement. RESULTS: Sixteen patients (27%) had laboratory evidence of tubular and/or glomerular dysfunction. A variable degree of creatinine clearance reduction was found in eight patients (13%); frank distal tubular acidosis in three (5%); hypokalaemia in four (7%); and pathological proteinuria in 12 (20%). Urine concentrating capacity was defective in 10 out of 48 (21%) tested patients. Only four patients presented with overt clinical manifestations, including hypokalaemic tetraparesis (1), nephrotic syndrome (2), recurrent renal stones with flank pain and haematuria (1). In two patients, signs of renal involvement preceded the onset of sicca syndrome. Renal biopsies from nine patients showed tubulo-interstitial nephritis in six and glomerular disease in three. Patients with renal involvement had a significantly shorter disease duration compared with patients without renal abnormalities. CONCLUSIONS: Kidney involvement is a frequent extraglandular manifestation of primary Sjögren's syndrome. It is rarely overt and may precede the onset of subjective sicca syndrome.