Significance of renal function in changes in acid–base metabolism after orthotopic bladder replacement: Colon neobladder compared with ileal neobladder

BACKGROUND: The objective of this study was to determine whether renal function influences the acid-base metabolism in patients undergoing orthotopic bladder replacement using intestinal segment. METHODS: Acid-base balance, serum electrolytes and renal function were studied in 30 patients with colon neobladder and 18 patients with ileal neobladder. Mean follow up was 51 months. Effects of renal function on acid-base metabolism in both types of bladder replacement were compared. Therapeutic efficacy of the sodium bicarbonate administration was also evaluated in cases with hyperchloremic acidosis. RESULTS: No significant differences were observed in any of the variables examined between the colon and ileal neobladder groups, except for potassium concentration. Although metabolic acidosis was detected using the Siggard-Anderson acid-base nomogram in eight (26.7%) and seven (38.9%) patients in the colon and ileal neobladder groups, respectively, this difference was not significant. In both the colon and ileal neobladder groups, the serum creatinine concentrations in patients diagnosed with metabolic acidosis were significantly higher than in those diagnosed with a normal metabolic status. Furthermore, as a result of severe metabolic acidosis, three (10.0%) and three (16.7%) patients in the colon and ileal neobladder groups, respectively, were administered sodium bicarbonate and their metabolic status was fully normalized. CONCLUSIONS: Despite there being no statistical difference, patients with ileal neobladder may more easily develop metabolic acidosis compared with those with colon neobladder. In addition, a close association between the serum creatinine level and the degree of metabolic acidosis was observed in both groups. However, even if severe metabolic acidosis occurs, it is relatively easy to correct using sodium bicarbonate. These findings suggest that it might be safe to use a colon segment for orthotopic bladder reconstruction in patients with higher serum creatinine levels, despite no significant difference in acid-base metabolism and detection rates of metabolic acidosis between the colon and ileal neobladder groups.     

Clinical outcome of orthotopic neobladder replacement in patients with a solitary functioning kidney

OBJECTIVE: To evaluate the outcome of orthotopic neobladder creation in patients with a solitary functioning renal unit at the time of surgery. METHODS: This study included a total of 18 patients (15 men and three women) with a solitary functioning kidney who underwent radical cystectomy for invasive bladder cancer followed by orthotopic neobladder replacement. Of these, an ileal, ileocolic or sigmoid colon neobladder was constructed in 11, three or four patients, respectively. Clinical data from these patients were retrospectively reviewed to clarify the significance of neobladder creation in patients with a solitary functioning kidney. RESULTS: During the observation period of this series (mean, 44.2 months; range, 15-95 months), there were nine early complications in six patients (wound infection, ileus, urine leakage and pulmonary embolism in four, three, one and one, respectively) and 10 late complications in nine patients (severe metabolic acidosis, vesicourethral anastomotic stricture, ureterointestinal anastomotic stricture and neobladder calculi in six, two, one and one, respectively). Severe metabolic acidosis occurred in six (five ileal neobladders and one ileocolic neobladder); however, there were no significant differences in preoperative renal function and serum electrolytes as well as postoperative voiding function between patients with and without severe metabolic acidosis. These six patients required administration of sodium bicarbonate, and their metabolic status was normalized thereafter. Furthermore, there were no significant differences in renal function and serum electrolytes between these two groups throughout the observation period, and none of the patients demonstrated renal deterioration. CONCLUSIONS: These findings suggest, despite the analysis including a small number of patients with a short follow-up period, orthotopic neobladder replacement could provide comparatively satisfactory results in patients with a solitary functioning kidney; hence, a solitary kidney should not be regarded as a contraindicated factor for neobladder creation after radical cystectomy.     

Microsomal liver function declines steadily after kidney grafting: a three to five year follow-up.

We have previously shown that the functioning hepatocyte mass (galactose elimination capacity, GEC) and microsomal liver functions (non-renal clearances of unbound prednisolone and cyclosporin A) are impaired in renal allograft recipients (N = 28) one month and one year after successful transplantation. To assess the natural history of these hepatic functional derangements, we reinvestigated 21 patients with stable renal function three to five years following grafting. GEC remained with 6.07 +/- 0.86 mg/min x kg significantly (P less than 0.001) below that in healthy controls (7.52 +/- 0.78 mg/min x kg), but did not significantly change during follow-up (5.93 +/- 0.96 and 6.26 +/- 0.94 mg/min x kg at 1 year and 1 month, respectively). In contrast, the non-renal clearance of unbound prednisolone declined steadily during follow-up averaging 4.98 +/- 0.71 ml/min x kg at three to five (compared to 5.83 +/- 1.51 and 6.80 +/- 1.73 ml/min x kg at one year and one month, respectively). These values were lower (P less than 0.01) than those observed in healthy control subjects (7.56 +/- 1.59 ml/min x kg). The total body clearance of cyclosporin A decreased similarly with time averaging 4.5 +/- 1.2 ml/min x kg at three to five years (compared to 4.9 +/- 1.2 and 5.9 +/- 2.1 ml/min x kg at 1 year and 1 month, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Direct effect of the correction of acidosis on plasma parathyroid hormone concentrations, calcium and phosphate in hemodialysis patients: a prospective study

BACKGROUND: Metabolic acidosis contributes to renal osteodystrophy and together with hyperphosphatemia, hypocalcemia and altered vitamin D metabolism may result in increased levels of intact parathyroid hormone (iPTH) and metastatic calcifications. However, the impact of the correction of metabolic acidosis on iPTH levels and calcium-phosphate metabolism is still controversial. STUDY DESIGN: The effects of the correction of metabolic acidosis on serum concentrations of iPTH, calcium (Ca), phosphate (PO(4)) and alkaline phosphatase were prospectively studied. Twelve uremic patients on maintenance hemodialysis (HD) for 49 months (median; range 6-243 months) with serum bicarbonate levels < or =20 mmol/l were studied before and after 3 months of oral sodium bicarbonate supplementation. Predialysis serum bicarbonate, arterial pH, ionized calcium, plasma sodium, plasma potassium, serum creatinine, hemoglobin, K(t)/V, postdialysis body weight, predialysis systolic and diastolic blood pressure were also evaluated before and after correction. RESULTS: Serum bicarbonate levels and arterial pH increased respectively from 19.3 +/- 0.6 to 24.4 +/- 1.2 mmol/l (p < 0.0001) and 7.34 +/- 0.03 to 7.40 +/- 0.02 (p < 0.001). iPTH levels decreased significantly from 399 +/- 475 to 305 +/- 353 pg/ml (p = 0.026). No changes in total serum Ca, plasma PO(4), serum akaline phosphatase, K(t)/V, serum creatinine, hemoglobin, body weight, predialysis systolic and diastolic blood pressures were observed. iCa decreased significantly. CONCLUSIONS: Our study demonstrates that the correction of metabolic acidosis in chronic HD patients reduces iPTH concentrations in HD patients with secondary hyperparathyroidism possibly by a direct effect on iPTH secretion.     

Metabolic acidosis: neo-considerations for general surgeons

Hyperchloraemic metabolic acidosis is a documented complication of neobladder formation. However, it usually improves with time and is mild. Severe and persistent metabolic acidosis may manifest when patients undergo further surgery for other reasons. Neobladder formation following radical cystectomy or cystoprostatectomy is becoming increasingly more common, and surgeons treating patients with neobladders should recognise and treat metabolic acidosis with intravenous fluids and bicarbonate.     

Renal function in cyanotic congenital heart disease

We performed renal function tests in 18 young patients, 1.8-14.6 years of age, with cyanotic congenital heart disease (CCHD). Glomerular filtration rate was normal (116 +/- 4.5 ml/min/1.73 m2), and renal plasma flow was decreased (410 +/- 25 ml/min/1.73 m2) with a rise in the filtration fraction (29 +/- 1.1%). The suggested pathophysiologic explanation of these findings is that the blood hyperviscosity seen in patients with CCHD causes an overall increase in renal vascular resistance with a rise in intraglomerular blood pressure. Despite a sluggish flow of blood in the glomerular capillary bed, the effective filtration pressure was adjusted to conserve the glomerular filtration rate. In addition to these renal hemodynamic parameters, we also studied renal acidification and tubular sodium and water handling during a forced water diuresis. Our data indicate that children with CCHD have a mild to moderate normal ion gap metabolic acidosis due to a low proximal tubular threshold for bicarbonate. Proximal tubular sodium and water reabsorption under these conditions were somewhat increased, though not significantly, probably due to intrarenal hydrostatic forces, in particular the rise in the oncotic pressure in the postglomerular capillaries in patients with high hematocrit values. The distal tubular functions such as sodium handling and acidification were not affected.     

Renal functional adaptation of the adult kidney following transplantation to the child

Nineteen child renal transplant recipients, aged 1.3 to 19.2 years at transplantation, and their adult living-related kidney donors, 27 to 60 years of age at nephrectomy, were investigated simultaneously with regard to renal function. At a median time of three months after transplantation clearances of inulin (GFR) and paraaminohippuric acid (ERPF) were measured, and serum urea and creatinine concentrations were determined. The absolute values for GFR (72 +/- 13 ml/min) and ERPF (369 +/- 76 ml/min) in the donors were significantly higher than those of the recipients (37 +/- 22 and 196 +/- 72 ml/min, respectively). The absolute values of GFR and ERPF were significantly correlated with the body surface areas of the recipients. Thus, in relation to body surface area, the GFR, 68 +/- 11 ml/min/1.73 m2, and ERPF, 348 +/- 65 ml/min/1.73 m2, of the donors did not differ from those of the recipients, 68 +/- 20 and 375 +/- 90 ml/min/1.73 m2, respectively. Because of the greater body mass, the serum creatinine concentrations of the donors were significantly higher than those of the recipients, whereas the serum urea concentrations were significantly higher in the recipients. The results suggest that transplantation of an adult kidney to a child results in a functional adaptation to the smaller body size of the recipient, and that this adaptation occurs within three months after transplantation.     

Influence of ciclosporin A on renal tubular function after kidney transplantation.

There are typical morphological indicators of tubular defects during the administration of ciclosporin A (CSA). Distal tubular function remains unclear although hyperkalemia is a common clinical feature in these patients. We performed renal function studies 3 months after renal transplantation on 35 patients (group 1) treated with CSA. The results were compared to those of a control group consisting of 15 patients transplanted earlier and treated with azathioprine (group 2). Only patients with stable renal function (creatinine less than or equal to 2.0 mg/dl) entered the investigation consisting of: inulin (In) clearance; p-aminohippuric acid (PAH) clearance; ammonium chloride loading; sodium sulfate loading, and sodium bicarbonate loading. Plasma renin activity and aldosterone were measured basally and after stimulation with 40 mg i.v. furosemide. Clearances of In and PAH were significantly impaired during the administration of CSA. Group 1: CIn 73.3 +/- 8.7 ml/min/1.73 m2 (p less than 0.01), CPAH 263 +/- 58.3 ml/min/1.73 m2 (p less than 0.01); group 2: CIn 89.6 +/- 19.1 ml/min/1.73 m2, CPAH 338.7 +/- 63.5 ml/min/1.73 m2. Incomplete distal tubular acidosis could be demonstrated in 8 patients from group 1 but none of group 2. Hyporeninemic hypoaldosteronism could be demonstrated in 4 patients during the administration of CSA. CSA in therapeutic doses significantly impairs renal perfusion, glomerular filtration, distal acidification and the renin-aldosterone axis.     

Renal function after kidney transplantation in children. A comparison of conventional immunosuppression with cyclosporine

Clearance studies were performed in 32 transplanted children treated with CsA in combination with low-dose prednisolone (CsA group), and the results were compared with those of 29 children transplanted earlier and treated with azathioprine and prednisolone (CIS group). Serum creatinine and urea levels 6 weeks and 1 year after transplantation (Tx) were significantly higher in the CsA than in the CIS group. Clearance studies 6 weeks after Tx exhibited significantly lower rates in the CsA group: Cin = 47 +/- 16.5 versus 83 +/- 25 ml/min/1.73 sqm, CPAH = 271 +/- 110 versus 503 +/- 181 ml/min/1.73 sqm (P less than 0.001). The filtration fractions were not different (19.1 versus 17.1%). The tubular phosphate reabsorption per ml GFR (Tp/Cin) was only slightly lower in the CsA group (0.76 +/- 0.23 mumol/ml versus 0.93 +/- 0.29; P = 0.09). The endogenous glucose clearance rates were equally elevated in both groups and returned to normal after 1 year. The creatinine clearance (Ccr) had dropped in both groups by a mean for 13 ml/min/1.73 sqm between 6 weeks and 1 year after Tx. No correlation was found between the Ccr and the CsA blood levels, but Ccr was inversely correlated with the number of rejection episodes (r = -0.72, P = 0.001). In conclusion, renal allografts in CsA-treated children exhibited a significantly lower function than in CIS-treated children. The effect was related to the global kidney function without any signs of additional tubular toxicity and was apparent within the first weeks after Tx. Thereafter, the decline in graft function was comparable in both groups and could not be related to CsA treatment.     

Better correction of metabolic acidosis, blood pressure control, and phagocytosis with bicarbonate compared to lactate solution in acute peritoneal dialysis

Lactate solution has been the standard dialysate fluid for a long time. However, it tends to convert back into lactic acid in poor tissue-perfusion states. The aim of this study was to evaluate the efficacy of magnesium (Mg)- and calcium (Ca)-free bicarbonate solution compared with lactate solution in acute peritoneal dialysis (PD). Renal failure patients who were indicated for dialysis and needed acute PD were classified as shock and nonshock groups, and then were randomized to receive either bicarbonate or lactate solution. Twenty patients were enrolled in this study (5 in each subgroup). In the shock group, there were more rapid improvements and significantly higher levels of blood pH (7.40 +/- 0.04 versus 7.28 +/- 0.05, p < 0.05), serum bicarbonate (23.30 +/- 1.46 versus 18.37 +/- 1.25 mmol/L, p < 0.05), systolic pressure (106.80 +/- 3.68 versus 97.44 +/- 3.94 mm Hg, p < 0.05), mean arterial pressure (80.72 +/- 2.01 versus 73.28 +/- 2.41 mm Hg, p < 0.05), percentages of phagocytosis of circulating leukocytes (65.85% +/- 2.22 versus 52.12% +/- 2.71, p < 0.05), and percentages of positive nitroblue tetrazolium (NBT) reduction test without and with stimulation (14.43 +/- 1.93 versus 9.43 +/- 2.12, p < 0.05 and 65.08 +/- 6.80 versus 50.23 +/- 4.21, p < 0.05, respectively) in the bicarbonate subgroup compared with the lactate subgroup. In the nonshock group, blood pH, serum bicarbonate, and phagocytosis assays in both subgroups were comparable. Lactic acidosis was more rapidly recovered and was significantly lower with bicarbonate solution for both shock and nonshock groups (3.63 +/- 0.37 versus 5.21 +/- 0.30 mmol/L, p < 0.05 and 2.92 +/- 0.40 versus 3.44 +/- 0.34 mmol/L, p < 0.05, respectively). Peritoneal urea and creatinine clearances in both subgroups were comparable for both shock and nonshock groups. There was no peritonitis observed during the study. Serum Mg and Ca levels in the bicarbonate subgroup were significantly lower, but no clinical and electrocardiographic abnormality were observed. We concluded that Mg- and Ca-free bicarbonate solution could be safely used and had better outcomes in correction of metabolic acidosis, blood pressure control, and nonspecific systemic host defense with comparable efficacy when compared to lactate solution. It should be the dialysate of choice for acute PD especially in the poor tissue-perfusion states such as shock, lactic acidosis, and multiple organ failure.     

Prospective study on renal outcome of IgA nephropathy superimposed on diabetic glomerulosclerosis in type 2 diabetic patients.

BACKGROUND AND METHODS: In order to examine the clinical outcome of IgA nephropathy (IgAN) superimposed on diabetic glomerulosclerosis in type 2 patients we studied 36 Chinese patients (26 men, 10 women), who were recruited for renal biopsy when they had proteinuria of more than 1 g/day. Twenty-seven had isolated diabetic glomerulosclerosis and nine had IgAN superimposed on diabetic glomerulosclerosis (combined). Renal function was assessed by serial serum creatinine, 24-h urine protein and creatinine measurements. Patient survival rate, incidence of end-stage renal disease (ESRD), blood pressure, and glycaemic control status were determined. RESULTS: The age at the time of renal biopsy was younger for the combined group when compared with the diabetic glomerulosclerosis group (44+/-3.6 vs 58+/-2.1 years, P=0.006). The duration of diabetes was, however, similar for the two groups (8.0+/-2.3 vs 6.7+/-1.2 years, P=NS). After a mean follow-up of 31.6+/-15.3 months, 15 patients (one in the combined group and 14 in the diabetic glomerulosclerosis group) developed ESRD. Nine patients (all in the diabetic glomerulosclerosis group) died during follow-up. With similar glycaemic and blood pressure control, the two groups had comparable rate of decline of creatinine clearance (CrCl) (-0.73+/-0.26 vs -0.73+/- 0.18 ml/min/1.73 m(2)/month, P=NS), final serum creatinine (363+/-134 vs 426+/-52 micromol/l, P=NS) and proteinuria levels (4.3+/-0.9 vs 4.4+/-0.6 g/day, P=NS), as well as CrCl (44.1+/-19.0 vs 33.4+/-6.9 ml/min/ 1.73 m(2), P=NS). CONCLUSION: It is concluded that the superimposed IgAN does not significantly alter the medium-term clinical outcome of patients with diabetic glomerulosclerosis.     

Higher serum bicarbonate levels within the normal range are associated with better survival and renal outcomes in African Americans

Recent studies suggest that correcting low serum bicarbonate levels may reduce the progression of kidney disease; however, few patients with chronic kidney disease have low serum bicarbonate. Therefore, we examined whether higher levels of serum bicarbonate within the normal range (20-30 mmol/l) were associated with better kidney outcomes in the African American Study of Kidney Disease and Hypertension (AASK) trial. At baseline and during follow-up of 1094 patients, the glomerular filtration rates (GFR) were measured by iothalamate clearances and events were adjudicated by the outcomes committee. Mean baseline serum bicarbonate, measured GFR, and proteinuria were 25.1 mmol/l, 46 ml/min per 1.73 m(2), and 326 mg/g of creatinine, respectively. Each 1 mmol/l increase in serum bicarbonate within the normal range was associated with reduced risk of death, dialysis, or GFR event and with dialysis or GFR event (hazard ratios of 0.942 and 0.932, respectively) in separate multivariable Cox regression models that included errors-in-variables calibration. Cubic spline regression showed that the lowest risk of GFR event or dialysis was found at serum bicarbonate levels near 28-30 mmol/l. Thus, our study suggests that serum bicarbonate is an independent predictor of CKD progression. Whether increasing serum bicarbonate into the high-normal range will improve kidney outcomes during interventional studies will need to be considered.     

Assessment of glomerular filtration rate in healthy subjects and normoalbuminuric diabetic patients: validity of a new (MDRD) prediction equation.

BACKGROUND: Based on the data derived from the Modification of Diet in Renal Disease (MDRD) study, a new equation was developed for the estimation of glomerular filtration rate (GFR). This equation, which takes into account body weight, age, sex, serum creatinine, race, serum urea, and serum albumin, provided a more accurate estimation of GFR in patients with renal insufficiency. However, this prediction equation has not been validated in subjects with normal or supra-normal GFR. METHODS: In a cross-sectional study, we measured GFR by inulin clearance in 46 healthy controls and 46 non-complicated type 1 diabetic patients. In this study population, GFR was predicted by measured creatinine clearance, the Cockcroft-Gault formula, and the MDRD equation. RESULTS: In the healthy subjects, mean GFR (+/-SD) was 107+/-11 as compared to 122+/-18 ml/min per 1.73 m(2) in the diabetic patients. This difference in GFR was reflected by a lower serum creatinine (76+/-8 vs 71+/-8 micro mol/l) in the diabetic patients. In the healthy controls, median absolute differences (and the 50th-75th-90th percentile of percentage absolute differences) between predicted and measured GFR were 5.2 ml/min per 1.73 m(2) (4.9-9.8-18.5%) for creatinine clearance, 9.0 ml/min per 1.73 m(2) (8.6-14.3-24.6%) for the Cockcroft-Gault formula, and 10.7 ml/min per 1.73 m(2) (10.9-16.3-25.5%) for the MDRD equation. In the diabetic patients, these differences were 8.3 ml/min per 1.73 m(2) (7.6-9.3-13.0%) for creatinine clearance; 11.8 ml/min per 1.73 m(2) (10.1-16.0-22.5%) for the Cockcroft-Gault formula, and 18.8 ml/min per 1.73 m(2) (16.0-24.2-31.9%) for the MDRD equation. CONCLUSIONS: In subjects with a normal or increased GFR, the new MDRD-prediction equation of GFR is less accurate than creatinine clearance or the Cockcroft-Gault formula, and offers no advantage.     

Glomerular filtration rate estimation from plasma creatinine after inhibition of tubular secretion: relevance of the creatinine assay.

BACKGROUND: Estimation of glomerular filtration rate (GFR) from plasma creatinine concentration after inhibition of tubular creatinine secretion with cimetidine provides a good assessment in patients with various nephropathies and with non-insulin-dependent diabetes mellitus (NIDDM). The aim of this study was to compare cimetidine-aided GFR estimations using various creatinine assays. METHODS: In 30 outpatients with NIDDM GFR was measured as the urinary clearance of continuously infused [125I]iothalamate. Plasma creatinine concentration was analysed after oral cimetidine with an alkaline picrate (AP) method, with an enzymatic (PAP) assay and with HPLC. GFR estimations were calculated with the Cockcroft Gault formula (CG). RESULTS: AP creatinine concentrations were significantly higher than PAP or HPLC values. GFR estimations by AP (CG(AP) 66 +/- 19 ml/min/1.73 m2, mean SD) were significantly lower than GFR (89 +/- 30), whereas CG(PAP) (85 +/- 30) and CG(HPLC) (84 +/- 34 ml/min/1.73 m2) were not. Bland and Altman analysis showed a difference between CG(AP) and GFR of -22.4 +/- 17.7 ml/min/1.73 m2; this difference becomes larger when the GFR increases. The difference between CG and GFR was only -3.8 +/- 14.8 ml/min/1.73 m2 for PAP and -4.4 +/- 17.5 ml/min/1.73 m2 for HPLC, without any systematic difference. CONCLUSION: A good assessment of the GFR from plasma creatinine after cimetidine administration is possible when creatinine is measured with an enzymatic assay or with the less convenient HPLC method. The more widespread and cheaper alkaline picrate assay is not suitable for GFR-estimation.     

Renal tubular acidosis after kidney transplantation--incidence, risk factors and clinical implications.

BACKGROUND: Renal tubular acidosis (RTA) is a non-anion gap metabolic acidosis and is generally mild and asymptomatic in kidney recipients. Although calcineurin inhibitors, suboptimal allograft function, donor age and acute rejection have been associated with RTA, no detailed study has been conducted to investigate the prevalence and clinical implications of RTA in long-term kidney recipients. METHODS: In this cross-sectional study, we enrolled 109 patients (74 males, 35 females) for the study [patients with glomerular filtration rate (GFR) <30 ml/min/1.73 m(2), unstable allograft function, diarrhoea, and respiratory disease were excluded]. Thirty-six patients (33%) were found to have RTA on the basis of plasma bicarbonate, arterial pH, urine and serum anion gap measurements. RESULTS: Deceased donor transplantation [P = 0.034, 95% confidence interval (CI): 1.10-13.27], female gender (P = 0.017, 95% CI: 1.23-8.50), and lower GFR (55.8 +/- 19.4 in RTA and 66.1 +/- 15.9 ml/min/1.73 m(2) in non-RTA, P = 0.002, 95% CI: 1.10-13.27) were independent risk factors for RTA. Also, C-reactive protein was found to be higher in the RTA group (2.7 +/- 1.5 vs 2.0 +/- 1.5 mg/dl, P = 0.03), while no difference was noticed in body mass index or serum albumin. Analysis of the prevalence of osteoporosis and osteopenia in patients with RTA and without RTA, respectively, revealed no difference in frequency of osteoporosis (33% vs 31%) or osteopenia (33% vs 47%). CONCLUSION: Although long-term kidney recipients have a relatively high prevalence of RTA, it is usually mild and subclinical. Further studies are needed to clarify long-term effects of RTA in kidney recipients.     

Must metabolic acidosis be associated with malnutrition in haemodialysed patients?

BACKGROUND: Metabolic acidosis was evaluated in the past as an independent variable of catabolism in haemodialysis (HD) patients. Nevertheless, it could in theory reflect a higher acid production from protein oxidation. The aim of this study was to evaluate the incidence and basis of metabolic acidosis in conjunction with a nutritional assessment in a HD population (n=120). METHODS: Three groups were identified based on three consecutive monthly predialysis plasma bicarbonate concentrations (P(HCO3)) and pH values. The effect of correction of metabolic acidosis on nutritional parameters was also studied in acidotic patients. RESULTS: The mean P(HCO3) ranged from 19.2+/- 0.4 mmol/l in group A (n=21) to 24.4+/-0.3 mmol/l in group B (n=80) and 27.5+/-0.4 mmol/l in group C (n=19). The adequency of dialysis (Kt/V) and ultrafiltration rates was comparable in the three groups. When compared with group B, group A had significantly higher body mass index (BMI), triceps skin fold thickness (TSF), dietary protein intake (DPI), normalized protein catabolic rate (nPCR) as well as serum creatinine, K(+) and intact parathyroid hormone (I-PTH). In contrast, when compared with group B, group C had a significantly lower DPI, nPCR, plasma creatinine and albumin. There was no significant difference in plasma inflammatory markers such as C-reactive protein (CRP) and interleukin 6 (IL-6) among all three groups. There was a significant negative correlation between P(HCO3) and nPCR (P<0.001), DPI (P<0.001), creatinine (P<0.001). Over a period of 6 months, the correction of metabolic acidosis in the HD patients did not affect nutritional parameters. CONCLUSION: These findings suggest that metabolic acidosis as a result of a higher protein intake does not detrimentally affect nutritional status.     

Follow-up of GFR estimated from plasma creatinine after cimetidine administration in patients with diabetes mellitus type 2

BACKGROUND: The glomerular filtration rate (GFR) can be estimated from plasma creatinine according to the formula of Cockcroft and Gault (CG). When tubular secretion of creatinine is inhibited by cimetidine the mean difference between the Cockcroft-Gault clearance (CG(Cim) and GFR approximates zero, but there is still some interindividual difference, especially in type-2-diabetic patients. We studied during longitudinal follow-up, whether the discrepancies between CG(Cim) and GFR per patient are consistent in time in type-2-diabetic patients. PATIENTS AND METHODS: In 1996 and 1998 (interval 20-26 months) GFR was measured in 21 patients as the urinary clearance of continuously infused 125I-iothalamate. Plasma creatinine was analyzed with an enzymatic assay before and after oral cimetidine 800 mg t.i.d. during 24 hours. GFR estimations were calculated with the Cockcroft-Gault formula before (CG) and after cimetidine (CG(Cim)) and expressed as means +/- SEM. RESULTS: GFR deteriorated from 89.7 +/- 5.7 to 81.3 + 5.8 ml/min/1.73 m2 and CG(Cim) from 85.3 +/- 5.7 to 81.1 +/- 6.6 ml/min/1.73 m2, whereas CG decreased from 102.4 +/- 6.8 to 98.4 +/- 7.0 ml/min/1.73 m2. Changes in GFR and changes in CG(Cim) were correlated (r = 0.72, p < 0.001) and were not significantly different from each other. The discrepancy between CG(Cim) and GFR per patient in 1996 also correlated with the discrepancy between CG(Cim) and GFR in 1998 (r = 0.85, p < 0.001 ). CONCLUSIONS: In individual patients the discrepancies between the CG(Cim) and GFR are consistent in time and the change in GFR is reflected by the change in CG(Cim). This small variability means that CG(Cim), based on an enzymatic plasma creatinine assay, would be suitable for follow-up of GFR in type-2-diabetic patients, independent of albuminuria.     

Effect of dietary protein restriction and influence of proteinuria on progression of type 2 diabetic renal failure

PURPOSE: This study investigated the effect of dietary protein restriction on disease progression and how it is influenced by proteinuria in patients with type 2 diabetic nephropathy(DN) and renal failure. METHODS: One hundred and six type 2 DN patients whose baseline creatinine clearance(Ccr) values were 29 +/- 12 ml/min/1.73 m2 were maintained on a diet containing 0.66 +/- 0.05 g/kg/day of protein. They were classified into 3 groups according to mean dietary protein intake(DPI) estimated from urinary urea nitrogen excretion during the follow-up period of 23 +/- 14 months(I, < 0.7 g/kg/day; II, 0.7-0.89 g/kg/day; III, > or = 0.9 g/kg/day). Furthermore, they were divided into 3 subgroups according to mean urinary protein excretion(UP) during the follow-up period (a, > or = 5.0 g/day; b, 2.0-4.99 g/day; c, < 2.0 g/day). Their rates of decline of Ccr(D-Ccr) and the changes in UP were examined. RESULTS: There were no significant differences in D-Ccr among Group Ia, IIa, and IIIa(1.1 +/- 0.6, 1.5 +/- 0.7, 1.2 +/- 0.6 ml/min/1.73 m2/month), among Group Ib, IIb, and IIIb(0.6 +/- 0.3, 0.7 +/- 0.4, 0.8 +/- 0.4 ml/min/1.73 m2/month), and also among Group Ic, IIc, and IIIc(0.1 +/- 0.3, 0.2 +/- 0.2, 0.2 +/- 0.6 ml/min/1.73 m2/month). On the other hand, significant differences were revealed in D-Ccr among Group Ia, Ib, and Ic, among Group IIa, IIb, and IIc, and among Group IIIa, IIIb, and IIIc. There were no significant differences in final UP and minimum UP during follow-up among 3 groups of different DPI levels in patients with 5.0 g/day < or = baseline UP(n = 49) and in patients with 2.0 < or = baseline UP < 5.0 g/day(n = 37). However, significant correlations were demonstrated between D-Ccr and the relative changes in UP between baseline and minimum during the follow-up period in both patients(r = 0.49, 0.48, p < 0.001, p < 0.01). CONCLUSIONS: Irrespective of the level of dietary protein restriction, proteinuria has a great influence on disease progression, and the reduction in UP correlates with retardation of renal function loss in patients with type 2 DN and renal failure.     

Lithium-induced renal disease: a prospective study

Considerable controversy exists as to whether lithium maintenance therapy is associated with the development of renal insufficiency. In 1980 we initiated a prospective study of renal function in manic-depressive patients beginning lithium therapy. None of the patients had evidence of pre-existing renal disease. Sixty-five patients were entered, and 51 and 18 patients completed 1 and 3 years of follow-up, respectively. Lithium doses were titrated to the lowest level consistent with control of psychiatric symptoms; there were no episodes of overt lithium intoxication. Serum creatinine levels in all patients, and endogenous creatinine clearance in women, remained stable over the course of the study. In contrast, creatinine clearances (mean +/- SEM, ml/min/1.73 m2) in men significantly decreased over both 1 year (110 +/- 4 to 95 +/- 5, n = 21, p = 0.0126) and 3 years (107 +/- 4 to 80 +/- 11, n = 8, p = 0.0385) of evaluation. Although all patients demonstrated a mild reduction in renal concentrating ability after initiation of lithium, the decrease was not progressive over the course of the study. Quantitative urinary protein excretion did not change, and repeated urinalyses did not reveal any evidence of renal disease. Thus, lithium therapy appears to result in modestly reduced rates of glomerular filtration, as measured by endogenous creatinine clearance, in men receiving lithium maintenance therapy for manic-depressive illness. Whether this reduction is progressive and leads to clinically significant renal insufficiency requires further investigation.     

Reversal of left ventricular hypertrophy with angiotensin converting enzyme inhibition in hypertensive patients with autosomal dominant polycystic kidney disease.

BACKGROUND: Hypertension occurs commonly and early in the natural history of autosomal dominant polycystic kidney disease (ADPKD), affecting both renal and patient outcome. Activation of the renin angiotensin aldosterone system due to cyst expansion and local renal ischaemia plays an important role in the development of ADPKD related hypertension and left ventricular hypertrophy (LVH), a known important risk factor for cardiovascular morbidity and mortality. The aim of this study was to investigate the effects of an angiotensin converting enzyme (ACE) inhibitor, enalapril, on renal function, blood pressure and LVH in hypertensive ADPKD patients. METHODS: Fourteen hypertensive ADPKD patients (11 men, 3 women; mean age: 40 years) were included in the study. All patients had LVH and creatinine clearance (Cer) greater than 50 ml/min/1.73 m2. The patients were followed for 7 years on enalapril therapy. The effects of enalapril on renal function, blood pressure and LVH were investigated. RESULTS: Baseline measurements of mean arterial pressure (MAP), Ccr and left ventricular mass index (LVMI) were 110 +/- 2 mmHg, 84 +/- 6 ml/min/1.73 m2 and 146 +/- 4 g/m2, respectively. After one year of enalapril therapy there was a significant decrease in MAP (94 +/- 3 mmHg, P < 0.005) which remained stable until the end of the study at 7 years (94 +/- 1 mmHg, P < 0.005 vs baseline). There was also a significant decrease in LVMI (131 +/- 6 g/m2, P < 0.05) after year 1 which continued to decrease until the end of the study reaching 98 +/- 6 g/m2 (P < 0.01 vs year 1 and baseline). Although Ccr remained stable after year 1, a significant decrease was observed after 7 years of follow-up (59 +/- 6 ml/min, P < 0.001 vs year 1 and baseline). CONCLUSIONS: ACE inhibition in hypertensive ADPKD patients provided long-term reversal of LVH in association with a mean 3.6 ml/min/year decline of Ccr. These preliminary results have potential important implications for cardiovascular and renal protection in ADPKD.