Peritoneal dialysis (PD) technique training: what features influence learning time?

BACKGROUND: Within peritoneal dialysis (PD) complications, peritonitis remains a primary challenge for the long-term success of the technique. Proper technique training is essential, since it reduces peritonitis rates, but the adequacy of training has not been standardized. Furthermore, factors influencing training duration have not been well identified. METHODS: We retrospectively analyzed all consecutive training sessions of incident PD patients in our Unit from January 2001 to December 2018. RESULTS: Our analysis included 135 patients, 25.9% were diabetic and median Charlson index (CCI) was 4 (IQR 2-6). Above 13 sessions was chosen as the cut off between usual and prolonged training, as it was our cohort's 75th percentile: 23% (31) had an extended training duration as per our study definition and 77% (104) had a usual training duration. The number of training sessions required increased with age (Spearman Rho 0.404; p = 0.000001), diabetic status (p = 0.001), unemployment status (p = 0.046) and CCI (Spearman Rho 0.369; p = 0.00001). Neither gender, cohabitation status, scheduled PD start, education level nor referral origin, were significant factors impacting training duration. Requiring longer training (> 13 sessions) was a significant risk factor for higher peritonitis risk, but extended training was not related to a shorter technique survival. CONCLUSION: Number of PD training sessions depends on the patient's age and comorbidities, but is not related to social, educational or employment status. Prolonged training duration was a statistically significant predictor of higher peritonitis risk, but it was not related to shorter permanence in PD in our series. Identifying these patients since the training period would be useful to adapt training schedule as an early prevention strategy to minimize the risk of peritonitis and plan a preemptive retraining.

Renal Transplant Artery Stenosis and Kinking: An Unusual Association.

Renal artery stenosis of the kidney allograft associated with kinking is not a frequent finding. As a correctable cause of graft dysfunction, it is important to diagnose it as soon as possible to avoid further graft damage and improve graft and patient survival. As pulsed wave Doppler ultrasound mapping of the graft's renal arteries is essential to diagnose possible alterations, point of care ultrasound (POCUS) is a highly useful tool for early diagnosis. We present a case in which nephrologists performed this examination promptly allowing a timely diagnosis and treatment plan.

[Treatment of uraemic anorexia with megestrol acetate]. / Tratamiento de la anorexia urémica con acetato de megestrol.

BACKGROUND: Anorexia is a common disorder in patients treated with regular haemodialysis and is a contributing factor to malnutrition. The aim of this study was to evaluate the effectiveness of megestrol acetate, an appetite stimulant used in cancer patients, as a treatment for anorexia in dialysis patients. MATERIAL AND METHOD: In 2009, 16 patients in our haemodialysis unit, three with diabetes mellitus, were treated with megestrol (160 mg/day single dose) for anorexia defined according to a Likert scale of appetite. The schedule and dialysis dose were not changed during the study. RESULTS: In the third month of treatment there was, in the overall group, an increase in dry weight (60.8 vs 58.9 kg, P<.01), in albumin concentration (4.02 vs 3.8 g/dl, P<.05), in creatinine concentration (9.73 vs 8.26 mg/dl, P<.01), and protein catabolic rate (1.24 vs. 0.97 g/kg/day, P<.0001). Non-significant variations in the concentration of haemoglobin, erythropoietin dose, and lipid concentrations were found. One patient with diabetes mellitus had to increase the dose of insulin and two other patients suffered mild hyperglycaemia. Megestrol acetate did not suppress the secretion of pituitary sex hormones, but in 3 of 10 patients studied was found inhibition of ACTH secretion. The response was not homogeneous: one patient did not respond and reduced his dry weight, in 5 the weight gain was minimal (less than 1 kg) and in the remaining ten the response was good, with an increase in dry weight ranging between 1.5 and 5.5 kg. CONCLUSIONS: Megestrol acetate can improve appetite and nutritional parameters in patients treated with periodic haemodialysis who report anorexia. Megestrol acetate may induce hyperglycaemia and inhibit the secretion of ACTH in some patients. These side effects should be assessed when administering this treatment.

Initiating renal replacement therapy through incremental haemodialysis: Protocol for a randomized multicentre clinical trial.

BACKGROUND: Thrice-weekly haemodialysis is the usual dose when starting renal replacement therapy; however, this schedule is no longer appropriate since it does not consider residual renal function. Several reports have suggested the potential benefit of beginning haemodialysis less frequently and incrementally increasing the dose as the residual renal function decreases. However, all the data published so far are from observational studies. Thus, this clinical trial avoids any potential selection bias and will assess the possible benefits that have been observed in observational studies. METHODS/DESIGN: This report describes the study protocol of a randomized prospective multi-centre open-label clinical trial to evaluate whether starting renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than the standard thrice-weekly regimen. We also explore other clinical parameters, such as concentrations of uremic toxins, dialysis doses, control of anaemia, removal of medium-weight uremic toxins, nutritional status, quality of life, hospital admissions and mortality. Only incident haemodialysis patients who can maintain a urea clearance rate KrU ≥ 2.5 mL/min/1.73 m2 are eligible. Patient recruitment began on 1 January 2017 and will last for 2 years or until the required sample size has been recruited to ensure the established statistical power has been reached. The minimum follow-up period will be 1 year. Anuric patients with acute renal failure and patients who return to haemodialysis after a kidney transplant failure are excluded. It has been calculated that 44 patients should be recruited into each group to achieve a power of 80% in a two-sided comparison of means with a usual significance level of 0.05. A time-to-event analysis will estimate the probability of kidney function survival in both groups using the Kaplan-Meier method. Survival curves will be compared with log-rank tests. This survival analysis will be complemented with a proportional hazard model to estimate the hazard ratio of kidney function survival adjusted for any confounding factors. Analyses will be carried out in accordance with the intention-to-treat principle. DISCUSSION: The incremental initiation of dialysis may preserve residual renal function better than the conventional treatment, with similar or higher survival rates, as reported by observational studies. To our knowledge, this is the first clinical trial to evaluate whether initiating renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than beginning with the standard thrice-weekly regimen. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03302546. Registered on 5 October 2017.

A Mediterranean age-comorbidity prognostic index for survival in dialysis populations.

BACKGROUND: The most widely used prognostic indices for estimation of survival, including for dialysis patients, were described by Charlson, and an adaptation was proposed by Hemmelgarn for dialysis patients. We present the first age-comorbidity prognostic index (ACPI) designed in a Mediterranean incident dialysis population and examine its concordance with other prognostic indices. METHODS: Incident dialysis patients were scored in relation to age and 11 diseases. Cox regression analysis was performed to construct multiple regression models, and diseases with a hazard ratio (HR) higher than 1.2 were included in the index. The impact of age was assessed by including it in a separate multivariate model. Scores were categorized in 3 levels of risk: low (0-1 points), medium (2-4 points) and high levels (5 or more points). The probability of survival of each group was calculated according to the Kaplan-Meier method, and receiver operating characteristic (ROC) curves were plotted to examine the concordance with other prognostic indices. RESULTS: A cohort of 304 patients on hemodialysis (80%) and peritoneal dialysis was analyzed. Global mortality rate was 31% (93/304). The mean score was 4.41 +/- 2.84. Diseases that received the highest scores were ischemic heart disease (IHD) with chronic heart failure (CHF), and malignancies of less than 5 years of evolution. With regard to age, the maximum score was received by patients over 60 years old. The probability of survival at 3 years was 89%, 77% and 54% for low-, medium- and high-risk groups, respectively (log-rank test, 19; p=0.0001). The ROC curves showed similar areas for our index (0.749), the Charlson index (0.758) and Hemmelgarn index (0.708), but our index scored higher than Charlson in older patients, IHD with CHF, CHF, peripheral vascular disease and systemic diseases. CONCLUSIONS: Although prospective external validation of this new index is required, this index adequately estimates the probability of survival at 3 years. The prognostic power of ACPI is similar to that of the Charlson index; however, relevant differences were found, concerning the weight of factors age, cardiovascular diseases and myocardial dysfunction. In end-stage renal disease we recommend estimating survival by indices established in incident dialysis patients, due to the particular comorbid conditions of this population.

[The Cockcroft-Gault equation is better than MDRD equation to estimate the glomerular filtration rate in patients with advanced chronic renal failure]. / La ecuación de Cockcroft-Gault es preferible a la ecuación MDRD para medir el filtrado glomerular en la insuficiencia renal crónica avanzada.

ABSTRACT The aim of this study was to compare the accuracy of three kidney function estimating equations: classic Cockcroft-Gault (classic CG), corrected Cockcroft-Gault (corrected CG) and simplified Modification of Diet in Renal Disease (MDRD), in patients with advanced chronic renal failure. The study was made in 84 nondialyzed patients with chronic renal disease in stage 4 or 5. The glomerular filtration rate was measured on a 24-hour urine collection as the arithmetic mean of the urea and creatinine clearances (CUrCr). In each patient, the difference between each estimating equation and the measured glomerular filtration rate was calculated. The absolute difference expressed as a percentage of the measured glomerular filtration rate indicates the intermethod variability. In the total group the glomerular filtration rate measured as the CUrCr was de 13,5+/-5,1 ml/min/1.73 m(2); and the results of the estimating equations were: classic CG 14,2+/-5 (p<0,05); corrected CG 12+/-4,2 (p<0,01) and MDRD : 12,1+/-4,8 ml/min/1.73 m(2) (p<0,01). The variability of the estimating equations was 15,2+/-12,2%, 17,1+/-13,4 % and 19,3+/-13,3% (p<0,05), for classic CG, corrected CG and MDRD respectively. The percent of estimates falling within 30% above o below the measured glomerular filtration rate was 90% for CG classic, 87% for corrected CG and 79% for MDRD. The intraclass correlation coefficients respect to CUrCr were 0,86 for classic CG, 0,81 for corrected CG and 0,77 for MDRD. The MDRD variability, but not classic CG variability or corrected CG variability, showed a positive correlation with the glomerular filtration rate (r=0,25, p<0,05). In patients with chronic renal disease in stage 5, the variability of the different estimating equations was similar. We conclude that in our population with advanced chronic renal failure the classic CG equation is more accurate than the MDRD equation. Corrected CG equation has not any advantage respect to classic CG equation.

[Control of the dialysis dose by ionic dialysance and bioimpedance]. / Control de la dosis de diálisis mediante dialisancia iónica y bioimpedancia.

INTRODUCTION: The ionic dialysance monitor allows an automated measure of Kt in each dialysis session. Bioelectrical impedance analysis (BIA) determines the total body water which it is equivalent to the urea volume of distribution (V). If the Kt, determined by ionic dialysance, is divided by the V, estimated by bioelectrical impedance, a Kt/V at the end of dialysis session (Kt/VDiBi) is obtained. AIM OF THE STUDY: To evaluate the agreement between the Kt/VDiBi and the Kt/V obtained by two simplified formulas: the monocompartimental (Kt/Vm) and the equilibrated (Kt/Ve) Daugirdas equations. METHODS: The Kt/VDiBi, the Kt/Vm and the Kt/Ve were determined in 38 hemodialysis patients (27 males and 11 females) in the same hemodialysis session. The patients were on dialysis three times a week for 3.5 to 4 hours. The V was determined by monofrequency bioelectrical impedance (50 kHz) at the end of the dialysis session. RESULTS: The Kt/VDiBi, Kt/Vm and Kt/Ve were 1.29+/-0.26, 1.54+/-0.29 and 1.36+/-0.25, respectively (p<0.001 between the Kt/VDiBi and the KtVm, and p<0.001 between the KtV/DiBi and the Kt/Ve). The intraclass correlation coefficient showed better concordance between the KtV/DiBi and the Kt/Ve (coefficient 0.88) than between the Kt/VDiBi and the KtVm (coefficient 0.65). The relative difference of the Kt/VDiBi was 8.3+/-6.4% with respect to the Kt/Ve and 18.4+/-7.8 % with respect to the Kt/Vm (p<0.001). The relative difference between the Kt/VDiBi and the Kt/Ve was lower than 15% in the 84% of the patients and lower than 10% in the 64% of the patients. CONCLUSIONS: If the V obtained by bioelectrical impedance analysis is included in the ionic dialysance monitor, we can obtain a Kt/V for each patient in real time, which is similar to the equilibrated Kt/V obtained from the Daugirdas equation.

[Chronic renal failure secondary to hyperoxaluria following small bowel syndrome]. / Insuficiencia renal crónica secundaria a hiperoxaluria tras resección intestinal por trombosis mesentérica.

A 70-year-old woman was admitted in the Department of Nephrology because of renal insufficiency. Six years previously, as consequence of a venous mesenteric thrombosis, she underwent an extense intestinal resection with subsequent short intestine syndrome. Five years after the surgery an increase in the creatinine concentration was observed (1.4 mg/dl). One year later, it increased up to 3.1 mg/dl and the patient was remitted to our Department. The radiological study revealed calcifications on both kidney silhouettes. In the next year, renal function worsened and the calcifications increased. Coinciding with the beginning of the chronic hemodialysis treatment she suffered a renal colic with passage of a calcium oxalate stone.

[Temperature dialysate and hemodialysis tolerance]. / Temperatura del baño y tolerancia a la hemodiálisis.

In this study, the effect of dialysate temperature on hemodynamic stability, patients' perception of dialysis discomfort and postdialysis fatigue were assessed. Thirty-one patients of the morning shift were eligible to participate in the study. Three patients refused. Patients were assessed during 6 dialysis sessions: in three sessions the dialysate temperature was normal (37 degrees C) and in other three sessions the dialysate temperature was low (35.5 degrees C). To evaluate the symptoms along the dialysis procedure and the postdialysis fatigue, specific scale questionnaires were administered in each dialysis session and respective scores were elaborated. Low temperature dialysate was associated with higher postdialysis systolic blood pressure (122 +/- 24 vs. 126 +/- 27 mmHg, p < 0.05), and lower postdialysis heart rate (82 +/- 13 vs. 78 +/- 9 beats/min, p < 0.05) with the same ultrafiltration rate. Dialysis symptoms score and postdialysis fatigue score were better with the low dialysate temperature (0.7 +/- 0.9 vs. 0.4 +/- 1 vs. p < 0.05, and 1.3 +/- 1 vs. 1 +/- 0.9 p < 0.05, respectively). Furthermore, low temperature dialysate shortened the post-dialysis fatigue period (5.4 +/- 6.3 vs. 3.1 +/- 3.3 vs. hours, p < 0.05). The clinical improvement experimented with the low temperature dialysate was not universal. A beneficial effect was exclusively observed in the patients with higher dialysis symptoms and postdialysis fatigue scores or having more than one episode of hypotension in a week. The patients were asked about their temperature preference, 7 patients (23%) request a dialysate at 37 degrees C, 19 patients (61%) prefered to be dialysed with the low temperature dialysate, and 5 patients (16%) were indifferent. The later two groups of the patients continued with the low temperature dialysate during other 4 weeks. At the end of that period, the clinical improvement remained unchanged. In summary, low temperature dialysate is particularly beneficial for highly symptomatic patients.

[Urea distribution volume calculated by ionic dialysance]. / Cálculo del volumen de distribución de la urea mediante dialisancia iónica.

BACKGROUND: Direct dialysis quantification is considered the gold standard for determining urea distribution volume, but it is impractical for routine use. So, urea distribution volume in hemodialysis patients is usually estimated from anthropometric equations. Ionic dialysance allows to calculate the urea distribution volume dividing the Kt obtained by ionic dialysance by the Kt/V obtained by a simplified formula. The aim of the present work was to analyse the concordance between the ionic dialysance and the direct dialysis quantification methods to estimate de urea distribution volume. MATERIAL AND METHODS: In 15 hemodialysis patients (10 males and 5 females), we have estimated the urea distribution volume by the direct dialysis quantification (Vurea), by the anthropometrics equations of Watson (VWatson) and Chertow (VChertow) and by the ionic dialysance method (VDI). To obtain VDI we have used two simplified Kt/V formulas: the monocompartimental and the equilibrated Daugirdas equations (VDIm and VDIe respectively). The intermethod variability was assessed by the relative difference (absolute difference between VUrea and the other methods, divided by the mean). RESULTS: VUrea (26,2 L) was statistically different from theVDIe (30,6 L, p < 0.01), VWatson 35.2 L (p < 0.001) and VChertow (38 L, p < 0.001). VDIm was 26.3 L (p = ns). VUrea represents the 42% of the body weight for the males (range 36 to 49%) and the 33% of the body weight for the female (range 28 to 38%). The intermethod variability was high for the VDIe (21.6%), VWatson (37.4%) and VChertow (48. 1%), but it was low for the VDIm (9.9%). CONCLUSIONS: Urea distribution volume calculated by the ionic dialysance method using the monocompartimental Daugirdas Kt/V equation has an acceptable agreement with the urea distribution volume calculated by the direct dialysis quantification. Anthropometry-based equations overestimate the urea distribution volume in hemodialysis patients.

The potential organ donor pool: international figures.

By understanding the size and characteristics of the potential donor pool, the concentration and location of the potential donors and factors influencing low rates of donation, it is possible to identify opportunities to improve the organ donation system. The exact donor gap needs to be established for each hospital/area, as published figures do not necessary reflect local potential. Nevertheless, marked differences with respect to the minimum standards in the number, location, and characteristics of organ donors should be considered as suggestive of low performance. The first stage where potential donors are lost is the detection of people who can be diagnosed as brain dead and, hence, could be considered a potential organ donor. Improving the donor identification implies the development of donor detection programmes. That and other initiatives to improve the donation rate need to be started in hospitals after the assessment of the local potential and local factors specifically implicated in the local performance.

[Ionic dialysance to control the dose of dialysis. One year experience]. / Utilidad de la dialisancia iónica para control de la dosis de diálisis. Experiencia de un año.

The Diascan equipment (Hospal) measures ionic dialysane which it derives the K and the Kt. If we divide the Kt obtained with Diascan between the Kt/V obtained by a simplified formula, it result a value of V for every patient. Entering this V in the Diascan software we can obtain a Kt/V (Diascan Kt/V), similar in theory to the simplified Kt/V. In the year 2002 we have controlled the delivered dialysis in our unit with the Diascan Kt/V. The aim of the present study was to study the agreement between de Diascan Kt/V and the Lowrie Kt/V. During the year 2002, 63 patients have been dialyzed in monitors with Diascan equipment. We calculated the V of each patient by dividing the Kt Diascan between the Lowrie Kt/V in the same dialysis session. The mea of the two consecutive measurements was considered the V value. Throughout the year 2002, 7 agreement studies were realized. The inter-method variability was assessed by the relative difference (absolute difference Diascan Kt/V-Lowrie Kt/V, divided by the average of both tests). A good agreement was considered when the relative difference was equal or lower than 10%. In the 7 agreement studies realized, the mean of the relative difference oscilled between 5.2 and 6.6%, and the percentage of patients with a relative difference equal or lower than 10% oscilled between 83 and 91%. During a month, the Diascan Kt/V was controlled in all dialysis sessions in 41 patients (554 sessions in total). Failure in the lecture of Kt/V Diascan was observed in 41 sessions (7%). A Diascan Kt/V greater than 1 (the minimum delivered dialysis considered in our unit) was obtained in 93% of the valid sessions. 38 of 41 patients had a mean monthly Diascan Kt/V greater than 1. The coefficient of variability of any patient oscilled between 2.1 and 12.4% (mean 5.1%). Diascan Kt/V is good procedure for the monitoring the delivered dialysis without blood sampling or any additional costs.

[Membranous nephropathy associated to autoimmune thyroiditis, chronic pancreatitis and suprarrenal insufficiency]. / Nefropatía membranosa asociada a tiroiditis, pancreatitis crónica e insuficiencia suprarrenal de etiología inmune.

A 33 year old female was admitted to the hospital to study aedema and bocio, A nephrotic syndrome was diagnosed and the renal biopsy demonstrated membranous glomerulonephritis, stage II. She was also diagnosed of Hashimoto's autoinmmune thyroiditis: TSH (41.5 uUl/ml), T4 (0.07 ng/dl), antithyroglobuline (1/2560) and antimicrosome (1/6400). Four year latter she was diagnosed of autoinmmune pancreatitis, without evidence of diabetes mellitus or exocrine pancreatic insufficiency. Eight years latter she was diagnosed of primary autoimmune suprarrenal insufficiency: basal cortisol: 2.7 mcg/dl, post ACTH estimulated cortisol: 5.6 mcg/dl, antinuclear antibody (1/160) and antiparietal (1/320). We present a pluriglandular autoimmune syndrome with membranous glomerulonephritis, thyroiditis, pancreatitis and suprarrenal insufficiency. To the best of our knowledge this complex syndrome has not been previously described.

[Relationship between ionic dialysance and urea clearance]. / Relación entre la dialisancia iónica y el aclaramiento de urea.

INTRODUCTION: Ionic dialysance is a method of continuous on-line monitoring of delivered dialysis without blood sampling. To compare the results obtained by ionic dialysance and those obtained by the traditional measurements of the dialysis dose, it is necessary to know the relationship between the ionic dialysance and urea clearance. MATERIAL AND METHODS: Ionic dialysance and the urea clearance were determined in 18 patients (13 dialyzed with cuprophan and 5 patients with AN69). Urea clearance was measured by 6 different methods: urea clearance in whole blood calculated with the arteriovenous difference in the urea concentration rates and the arterial flow measured by the rolling pump (KBAVb) or by ultrasounds (KBAVu); urea clearance in whole blood measured by the urea concentration in the dialysate (KBD); urea blood water clearance measured by the arteriovenous difference in the concentration rates using the arterial flow measured by the roller pump (KwBAVb) or by ultrasounds (KwBAVu) and urea blood water clearance measured by the urea concentration in dialysate (KwBD). RESULTS: The mean arterial flow measured by the roller pump was 314.4 +/- 16.2 ml/min and 275.1 +/- 13.8 ml/min when measured by ultrasounds (p < 0.001). The data of ionic dialysance and urea clearances were as follow (ml/min): ionic dialysance 185.6 +/- 11.7; KBAVb 245.7 +/- 15.7; KBAVu 215.4 +/- 13.2; KBD 231.6 +/- 13.1; KwBAVb 218.1 +/- 14; KwBAVu 191.2 +/- 11.8; KwBD 183.1 +/- 11.7. The absolute difference of ionic dialysance with the KwBAVu was 8.4 +/- 6 ml/min (range between -17.8 and 11.5 ml) and with the KwBD was 7.6 +/- 5.4 ml (range between -12.9 and 21.4 ml). CONCLUSIONS: There was a relationship between ionic dialysance and urea blood water clearance. The best concordance was obtained when the clearance was calculated with the urea concentration of dialysate, or with the arteriovenous difference of the urea concentration rates and the arterial blood flow measured by ultrasounds.

[Therapy with interferon plus ribavirin in hemodialysis patient with PCR-positive viral hepatitis C]. / Tratamiento con interferón a y ribavirina en un paciente de hemodiálisis virus C, PCR positivo.

Traditionally, the treatment of viral hepatitis C (positive Polymerase Chain Reaction -PCR-) was with Interferon. A combination of Interferon plus Ribavirin has been producing better results in last years. Currently, Ribavirin is not indicated for patients with Chronic Kidney Disease because of a high risk of severe anaemia. In a few cases, this treatment is producing good results with previous dose adjustment. We show a case of a 28-year-old man with Chronic Kidney Disease on treatment with periodical hemodialysis and chronic hepatopathy HCV Positive RNA HCV (> 1,000,000 copies/ml) and persistent transaminase elevation. Before kidney transplantation, we decided to use Interferon (3,000,000 IU/48 hours) and Ribavirin (200 mg/24 hours) treatment. After 15 days, we saw normal transaminase values and HCV RNA was negative. The patient required temporary suspension of Ribavirin and two red blood cell transfusions due to severe anaemia. Ribavirin was reintroduced 200 mg/48 h posthemodialysis. The patient did not present any complication again, and could be treated for 14 months. After next 11 months of evolution the patient has normal rates of liver function and negative HCV RNA values.

[Estimate of the dialysis dose using ionic dialysance]. / Cálculo de la dosis de diálisis mediante dialisancia iónica.

UNLABELLED: The Diascan equipment (Hospal) measures ionic dialysance from which it derives the Kt/V. It is automatic, does not need blood samples and displays the results in real time. The aim of the present study was to compare the Diascan Kt/V with the Kt/V obtained with four simple formulas: two based on a single pool model of urea kinetics (Lowrie 1983 and Daugirdas 1993) and the other based on the two pool model (Maduell formulation applied to Lowrie Kt/V and that proposed by Daugirdas 1995). We have analyzed the inter-method variability, the degree of relationship among the different procedures for Kt/V calculation and the intra-individual variability. The intermethod variability between Kt/V Diascan and Kt/V calculated by the four simple formulas were studied in one hemodialysis session in 19 patients. The Kt/V Diascan was statistically different from that calculated by the four formulas (1,021 +/- 0.140 Diascan vs 1,147 +/- 0.124 for Lowrie-83; vs 1,373 +/- 0.164 for Daugirdas-93; vs 0.963 +/- 0.105 for Maduell and vs 1,173 +/- 0.143 for Daugirdas-95, p < 0.01). The lowest inter-method variability was obtained with the Maduell's Kt/V (relative difference 9%) but even in this case 37% of patients had a variability above 10%. The correlation coefficient was not high enough to allow an estimation of the different Kt/V measurements from the Diascan Kt/V by a regression equation. To study the individual relationship between the Diascan Kt/V and the Kt/V calculated by the four formulations, we have determined the Kt/V every 30 minutes in one hemodialysis session in 30 patients. In all patients we observed a good relationship between the Diascan Kt/V and the other four (correlation coefficient of 0.9952 for Lowrie-83, 0.9976 for Daugirdas-93, 0.9961 for Maduell and 0.9971 for Daugirdas-95); with these correlation coefficientes it was possible to derive regression equations and to obtain an estimation of the four Kt/V's from the Diascan Kt/V. To study the individual variability of each procedure used in the Kt/V calculations we determined the coefficient of variation of the different methods in 5 consecutive hemodialysis sessions performed under identical conditions in 19 patients. The coefficient of variation was 3.7 +/- 1.8% for the Diascan Kt/V; 6.0 +/- 2.8 for the Lowrie-83 Kt/V; 5.8 +/- 2.4 for the Daugirdas-93 Kt/V; 6.5 +/- 2.6% for the Maduell Kt/V; and 5.7 +/- 2.2% for the Daugirdas-95 Kt/V (p < 0.01 between the Diascan Kt/V and the other four). CONCLUSIONS: Although the Diascan Kt/V was statistically different from the other four Kt/V's calculated by the usual formulas, the Diascan Kt/V has an excellent correlation with all of them and showed a lower intra-individual variability. It is possible to obtain an estimation of the calculated Kt/V for each patient by linear regression equation.

[Relationship between the 1993 Daugirdas Kt/V method and other methods to calculate the dialysis dose]. / Relación entre el Kt/V Daugirdas de 1993 y otros métodos para calcular la dosis de diálisis.

INTRODUCTION: There are several shortcut formulas to calculate Kt/V, the most widely used because of its simplicity is the logarithmic formula proposed by Lowrie in 1983. The DOQI report recommends use of the formula proposed by Daugirdas's in 1993 to estimate the Kt/V, it must be > or = 1.2. The aim of the present work was to analyse the concordance between the second generation Daugirdas's formula and the other shortcut formulas. MATERIAL AND METHODS: In 208 hemodialysis sessions performed on 61 patients, Kt/V was estimated by thirteen formulas: 10 single-pool modeling and three double-pool modeling. RESULTS: The Kt/V values obtained by Daugirdas's formula was different from those obtained with the other single-pool based formulas (p < 0.01). When the dialysis sessions were classified in 4 groups according to the Kt/V values calculated by Daugirdas's formula, most of the single-pool formulas gave Kt/V values statistically different from those given by Daugirda's formula in all ranges examined. The concordance among Kt/V calculated by every one of the single-pool formulas and Daugirdas's formula was variable. The highest agreement was with Keshaviah's and Lowrie's 1992 formulas and the lowest with Calzavare's and Lowrie's 1983 formulas. The linear multivariate analysis showed that the two factors which influenced the concordance were the Kt/V value obtained by the Daugirdas's formula, and the quotient between the postdialysis body weight and the ultrafiltration rate. Despite the weak concordance with Daugirdas's formula, the Kt/V obtained by Lowrie's 1983 formula and the urea reduction ratio (URR) are still useful tools to monitor the adequacy of dialysis: a Kt/V > 1.065 calculated by the Lowrie's 1983 formula and a PRV > 65% are equivalent to a Kt/V > or = 1.2 calculated by Daugirdas's formula. CONCLUSIONS: The shortcut formulas used to calculate Kt/V give different results with high inter-method variability. When Kt/V is reported it is absolutely necessary to indicate the formula used to calculate it. The Kt/V obtained by Lowrie's 1983 formula and the URR are useful tools to monitor dialysis adequacy.