Magnesium retards the progress of the arterial calcifications in hemodialysis patients: a pilot study.

BACKGROUND: The aim of the study was to evaluate the impact of magnesium (Mg) on the evolution of arterial calcifications in hemodialysis patients. PATIENTS AND METHODS: Seventy-two stable hemodialysis patients were randomly allocated to two groups: 36 administered a regimen containing magnesium carbonate plus calcium acetate as a phosphate binder (Mg group), while the rest 36 received calcium acetate alone (Ca group). The presence and the progression of arterial calcifications were evaluated in plain X-rays using a simple vascular calcification score. The duration of the follow-up period was 12 months. RESULTS: Thirty-two patients of the Mg group and 27 of the Ca group completed the study. The mean time average values of the biochemical laboratories did not differ between the two groups, except serum Mg: 2.83 + 0.38 in the Mg group versus 2.52 + 0.27 mg/dl in the Ca group, p = 0.001. In 9/32 (28.12 %) patients of the Mg group and in 12/27 (44.44 %) patients of the Ca group, the arterial calcifications were worsened, p = 0.276. Moreover, in 4/32 (15.6 %) patients of the Mg group and in 0/27 (0 %) patients of the Ca group, they were improved, p = 0.040. The multivariate logistic regression analysis revealed that serum magnesium was an independent predictor for no progression of the arterial calcifications, p = 0.047. CONCLUSIONS: Magnesium probably retards the arterial calcifications in hemodialysis patients. Further clinical studies are needed to clarify whether magnesium provides cardiovascular protection to this group of patients.

Glycemic control and survival in peritoneal dialysis patients with diabetes mellitus.

PURPOSE: The optimal target for glycated hemoglobin (HbA1c) has not been well defined in peritoneal dialysis (PD) patients with diabetes mellitus. METHODS: The objective of our study was to examine the predictive value of predialysis and time-averaged follow-up HbA1c values on technique and patient survival in diabetic PD patients treated in the Toronto General Hospital Home Peritoneal Dialysis Unit, between January 1, 2003 and December 31, 2008 with a median follow-up period of 30±23 months. RESULTS: Ninety-one patients (mean age 64±13 years-old) were included in this retrospective study. Patients were followed between 3 and 91 months (mean duration 30±23 months). During this period, 40 patients died. We found no statistically significant correlation between baseline predialysis HbA1c values and technique and patient survival. Time-averaged follow-up HbA1c in increments<6.5%, 6.5-8%, and >8% showed no significant survival difference among groups. CONCLUSIONS: There was no significant correlation of baseline and time-averaged follow-up HbA1c values with patient and PD technique survival.

Normocalcemic hyperparathyroidism in patients with recurrent kidney stones: a disease entity or vitamin D deficiency?

This retrospective data analysis was undertaken to examine the biochemical differences between renal stone formers with normocalcemic hyperparathyroidism (NHPT) and those with normal parathyroid hormone (PTH) levels. Our goal was to ascertain whether 25-hydroxyvitamin D (25(OH)D) status related to PTH levels in this patient cohort. Our findings among 74 patients with NHPT indicate that stone formers with NHPT had significantly lower 25(OH)D levels compared to 192 controls (p = 0.0001) and that 25(OH)D is positively correlated with 1,25-dihydroxyvitamin D values (R = 0.736, p = 0.015). Sequential measurements (after 3 - 5 years), among 11 patients with NHPT who did not receive vitamin D (VitD) preparations, showed a significant increase in urinary calcium (3.43 ± 1.96 vs. 5.72 ± 3.95, p = 0.0426) without a significant change in PTH levels. VitD supplementation, to 3 patients resulted in significant PTH decrease (11.8 ± 1.8 vs. 9.8 ± 1.3, p = 0.003). Prospective studies are needed to confirm the role of vitamin supplementation in renal stone formers with NHPT.

Vitamin D status in patients with recurrent kidney stones.

Data regarding the prevalence of 25-hydroxyvitamin D (25(OH)D) insufficiency in patients with nephrolithiasis, and the effects of vitamin D supplementation on parathyroid hormone (PTH) are few and conflicting. In this article, we examined the prevalence of vitamin D insufficiency and deficiency in 236 recurrent kidney stone formers and the correlation of vitamin D levels with other parameters of stone formation. The prevalent stone composition was calcium oxalate (80.4%) and uric acid (16.45%). One third of stone formers had vitamin D insufficiency and a quarter of them high PTH levels (PTH >7.5 pmol/l) with normal serum (total and ionized) calcium values. Predictor of high PTH was low 25(OH)D level (r = 0.989, r(2) = 0.977, p < 0.001). Stone formers with hypercalciuria had higher 25(OH)D values (72.26 ± 4.21 vs. 59.29 ± 1.76, p = 0.0013) compared to stone formers with urine calcium within normal ranges. Further studies are needed in order to better define the consequences of vitamin D insufficiency and to evaluate the impact of the therapeutic interventions in this cohort.

Aging and physiological changes of the kidneys including changes in glomerular filtration rate.

In addition to the structural changes in the kidney associated with aging, physiological changes in renal function are also found in older adults, such as decreased glomerular filtration rate, vascular dysautonomia, altered tubular handling of creatinine, reduction in sodium reabsorption and potassium secretion, and diminished renal reserve. These alterations make aged individuals susceptible to the development of clinical conditions in response to usual stimuli that would otherwise be compensated for in younger individuals, including acute kidney injury, volume depletion and overload, disorders of serum sodium and potassium concentration, and toxic reactions to water-soluble drugs excreted by the kidneys. Additionally, the preservation with aging of a normal urinalysis, normal serum urea and creatinine values, erythropoietin synthesis, and normal phosphorus, calcium and magnesium tubular handling distinguishes decreased GFR due to normal aging from that due to chronic kidney disease.

Home dialysis first: a new paradigm for new ESRD patients.

Patients with end-stage renal disease (ESRD) were treated with either in-center hemodialysis (ICH) or one of the modes of home-based dialysis (HBD)-- peritoneal dialysis (PD) or home hemodialysis (HHD). Home-based dialysis modes showed better outcomes than ICH (PD for the first 2-3 years and HHD for the long-term). Home PD has become more attractive with overnight cyclers for PD and the use of home helpers. Home dialysis (PD or HHD) offers a high quality of life and a high degree of independence and is financially attractive. This review will propose a paradigm shift in the initial form of dialysis offered to new patients with ESRD: instead of selecting between in-center dialysis and PD, patients after they are advised of the advantages of dialysis at home (either PD or HHD) should be offered a choice between dialysis at home (PD or HHD) or in hospital. We will review the advantages of home-based dialysis and the arguments for this simple but vital change in the process by which new patients requiring dialysis choose their treatment option.

Encapsulating peritoneal sclerosis: a single-center experience and review of the literature.

Encapsulating peritoneal sclerosis (EPS) is a serious and often fatal complication of long-term PD with severe malnutrition and poor prognosis. It causes progressive obstruction and encapsulation of the bowel. This retrospective study reviews our experience and that reviewed in the literature concerning EPS. It refers to a total of 1966 patients treated with chronic PD between 1974 and 2008. Twenty one of them (1.1%) developed EPS, with the incidence increasing with the duration of PD. Mean age of our patients with EPS was 43, ranging from 18 to 71 years, 8 were men and 13 women with a mean body mass index (BMI) of 21.6 kg/m(2). Only one patient had Type II diabetes, 15 patients had glomerular disease, and six of these 15 had an autoimmune disease such as Wegener's granulomatosis and SLE. Thirteen patients developed EPS while on PD, 7 within 2 years after transfer to HD, and only one after renal transplantation. However, 7 patients had a previous renal transplant before returning to PD and subsequently developing EPS. Interestingly, we did not observe more episodes of EPS after transplantation. In the patients who developed EPS, the peritonitis rate over the period of observation was 1/15.6 pt-months and was due to Staphylococcus aureus, coagulase-negative staphylococcus, Pseudomonas and fungi. A history of peritonitis was not a prerequisite for developing EPS, since one patient had no episodes of peritonitis and 4 had just one previous episode. Fifteen patients presented with peritonitis within 4 months before the diagnosis of EPS with particularly virulent micro-organisms such as S. aureus, Candida, Pseudomonas, Corynebacterium, and Peptostreptococcus. Eleven patients were treated with hypertonic dextrose solutions (4.25 g/dl of dextrose) and seven with icodextrin, indirectly suggesting problems with ultrafiltration. Nine of 21 patients were on beta-blockers. The diagnosis of EPS was made either surgically or radiologically with signs of small bowel obstruction in combination with severe malnutrition. Eleven of our patients (52%) had evidence of small bowel obstruction and 14 patients required total parenteral nutrition (TPN). Tamoxifen (10-20 mg daily) was started in 6 patients, 4 of whom are alive and 2 deceased 3 and 5 years after EPS was diagnosed. Of the 12 patients who were not given tamoxifen, 2 are alive and 10 died. No side effects of tamoxifen were reported. Only 7 of our patients (33%) died during the first year after the diagnosis of EPS. Currently, 4 patients are on HD and 3 have had a renal transplant. Six patients of the fourteen who underwent surgery (42.8%) died within the first 6 months after operation and five died after an average of 6.6 years, mostly due to cardiovascular causes, three are still alive. As EPS becomes more prevalent with longer duration of PD, large multicenter prospective studies are needed to establish its incidence and identify risk factors, therapeutic approach, and prognosis.

Update on potential medical treatments for encapsulating peritoneal sclerosis; human and experimental data.

Encapsulating peritoneal sclerosis (EPS) is an infrequent but serious complication of peritoneal dialysis (PD). The pathogenesis is unknown but speculation is ongoing. The current management of EPS focuses on prevention and treatment of the inflammatory and fibrotic changes at the level of the peritoneal membrane with immunosuppressive and antifibrotic agents, respectively. This article reviews the currently available human and animal data on potential agents to prevent and/or treat EPS. We propose a strategy for early diagnose EPS in an attempt to avoid the development of the full-blown and potentially life-threatening clinical syndrome of EPS. Future research should focus on studying potential prophylactic and therapeutic agents in humans in large, multicenter, randomized trials but also on early detection of EPS in the inflammatory phase by means of biomarkers and the establishment of a composite EPS score.

Two icodextrin exchanges per day in peritoneal dialysis patients with ultrafiltration failure: one center's experience and review of the literature.

BACKGROUND: At present, only one exchange of an icodextrin-based solution is recommended to increase peritoneal ultrafiltration (UF) during long-dwell exchanges in peritoneal dialysis (PD) patients with impaired UF. AIM: To review our experience with two icodextrin exchanges per day on net UF and body weight in PD patients with poor UF. METHODS: Data were analyzed on nine patients with poor UF on chronic PD who were given two icodextrin exchanges per day for 6 months and had various clinical and biochemical parameters assessed monthly. RESULTS: Administration of icodextrin twice daily reduced the body weight in six of nine patients by an average of 2.9 ± 1.2 kg, a reduction that was maintained throughout the study; two patients gained 0.5 kg; and, in one patient, the measurements were inadequate. Mean blood pressure was reduced. Mean serum creatinine increased slightly. Serum sodium levels decreased from a mean baseline level of 134 ± 3 to 132 ± 4 mmol/L at three and six months. Among the diabetics in this group, average daily insulin requirements were 44 ± 35 units/day at baseline and 40 ± 23 units/day after 6 months. Hb1Ac levels remained stable throughout the study period. CONCLUSION: The use of two icodextrin exchanges per day reduced body weight in six of the nine patients and appeared to be safe. Long-term prospective studies are needed to assess the contribution of twice-daily icodextrin to the management of peritoneal dialysis patients with ultrafiltration failure and its long-term safety.

Discordant PD catheter and effluent culture results. The limited clinical relevance of culturing PD catheters.

OBJECTIVES: To determine if discordance in culture results between the effluent and the tip of the peritoneal catheter had an effect on outcome in patients whose peritoneal dialysis (PD) catheter was removed mostly for nonresolving peritonitis. Reasons for and outcomes of PD catheter removal were also analyzed. METHODS: We retrospectively reviewed the charts of all PD patients with recent peritonitis for which the PD catheter was removed between 1 January 2003 and 30 April 2009. Data including basic demographics, the organism isolated from effluent and from the PD catheter, reason for catheter removal, duration of hospitalization, and development of intra-abdominal collection were extracted as well as mortality within 8 weeks post removal and return to PD after catheter removal. RESULTS: Fungal peritonitis was the most common reason for PD catheter removal. 20% of the patients developed an intra-abdominal collection. Mortality related to PD catheter removal was low (3/53; 5.6%). The patients (n =53) were divided into 3 groups: group 1 (n = 20) had the same culture result of effluent and catheter tip; group 2 (n = 19) had a negative culture of the catheter tip; and group 3 (n = 14) had different organism(s) growing from effluent and catheter tip. We found no remarkable differences in duration of PD, catheter age, peritonitis rate, or mortality. Patients in group 1 had significantly more fungal peritonitis than the other 2 groups. In only 4 of the 53 patients (7.5%), the anti-infectious management was changed according to the catheter culture result. CONCLUSIONS: Discordant results between catheter tip culture and effluent culture did not have a significant impact on patient outcome. Sending PD catheters for culture has limited clinical importance.

Dialysis modality choices among chronic kidney disease patients: identifying the gaps to support patients on home-based therapies.

BACKGROUND: Home dialysis is a cost-effective renal replacement strategy, which provides improved quality of life compared to conventional in-center hemodialysis (CHD). To date, most studies support the use of multidisciplinary chronic kidney disease (CKD) clinics to facilitate timely initiation of dialysis. This is an observational cohort study examining 486 patients with CKD over the period of 2001-2007 to ascertain potential demographic differences among patients transitioned to in-center versus home dialysis. SUBJECTS AND METHODS: From January 2001 to December 2007, 486 patients with CKD attended the multidisciplinary renal management clinic at the University Health Network in Toronto. RESULTS: One hundred and fifty-three of the 486 patients were initiated on renal replacement therapy [59 to center hemodialysis (CHD), 15 to home hemodialysis (HHD) and 79 to home peritoneal dialysis (PD)]. HHD patients were younger (48 ± 15 years) than those who selected CHD (62 ± 16 years) or PD (64 ± 16 years). Although the gender distribution was similar overall, the percentage of single males was higher in CHD versus home dialysis patients (29 vs. 15%, P < 0.05). There were no significant differences in other demographic, clinical and biochemical parameters at the time of dialysis initiation. Disinterest in home dialysis by patients and their families (25.4%) and lack of social support (12.1%) constituted the main barriers to home dialysis. Medical contraindications for home dialysis were present among 11% of the patients. Other less frequent barriers were inadequate space, communication barrier and inability to perform their own dialysis. CONCLUSIONS: Sixty-one percent of patients requiring dialysis chose a home dialysis modality. Patients' and their families' disinterest in home dialysis and lack of support (either perceived or actual) represented the major overall barriers to adoption of home dialysis.

Diabetic patients on peritoneal dialysis.

During the past two decades, a number of studies have tried to evaluate the clinical status of dialyzed diabetic patients and the factors that may affect their outcomes. However, only a small number of diabetic patients on peritoneal dialysis (PD) have been followed for over 5 years, which is largely because of the presence of various comorbid conditions at the start of dialysis, the coexisting, far-advanced, target-organ damage that may gradually progress during the course of dialysis and limit the long-term survival on PD. On the contrary, among renal replacement therapies, survival of diabetic patients undergoing either PD or hemodialysis (HD) is probably similar, while diabetic patients on PD and HD have a lower actuarial survival than nondiabetic counterparts. This paper reviews our experience and the literature concerning the long-term outcome of diabetic patients on PD.

Glucoregulatory hormones and choice of osmotic agent in peritoneal dialysis.

OBJECTIVE: The present study was performed to explore the range of effects of amino acid-based peritoneal dialysis (PD) solutions on glucoregulatory hormones in comparison with an osmotically equivalent glucose-based solution. ♢ METHODS: 13 adult nondiabetic patients on PD underwent 2 peritoneal dwells of 2 hours' duration with either 1.5% dextrose solution or 1.1% amino acid solution. Serial sampling for glucoregulatory hormones was done throughout the duration of the dwell. ♢ RESULTS: Instillation of the 1.5% dextrose solution resulted in a modest change in plasma glucose, paralleled by a small increase in plasma insulin levels and plasma insulin-like growth factor (IGF-1). Plasma glucagon was not changed and plasma growth hormone level declined. Instillation of the 1.1% amino acid solution resulted in an increase in plasma glucose, plasma insulin, plasma glucagon, and plasma IGF-1. Plasma growth hormone level declined. Both solutions led to an increase in plasma norepinephrine but no changes were observed in epinephrine or dopamine. ♢ CONCLUSIONS: Our observations suggest that the mere replacement of glucose by amino acids in PD solutions does not necessarily imply "glucose sparing" from the perspective of induction of a glucoregulatory hormonal response because of the aminogenic stimulation of secretion of multiple hormones.

Peritoneal dialysis in the nursing home.

UNLABELLED: The mean age of patients with end-stage renal disease increases steadily. The elderly on dialysis have significant comorbidity and require extra attention to meet their dialysis, dietary, and social needs, and some may need to be treated at a long-term care facility such as a nursing home (NH). Providing dialysis and caring for elderly patients in a nursing home (NH) presents a number of challenges. Few data are available in the literature about elderly patients on peritoneal dialysis (PD) in an NH. This paper describes our experience of starting and maintaining a peritoneal dialysis program in three community-based nursing homes. RESULTS: During the period 2004-2008, after the nursing home personnel had received appropriate training, we established a PD program in three community-based nursing homes and admitted 38 patients on peritoneal dialysis. We educated 112 NH staff over the three-year period. Mean age of the patients at entry was 77.3 + or - 8.5(18.4%) were male. The main causes of end-stage renal disease were diabetes mellitus (DM) 21 (55.8%) and hypertension 13 (34.2%). Comorbid conditions included DM (27, 71.1%), hypertension (26, 68.4%), coronary artery disease (18.5%), chronic heart failure (11, 28.9%), cerebrovascular event (12, 31.6%), and cancer(3, 7.9%). The average total time on chronic peritoneal dialysis was 36.5 + or - 29.8 months, (median 31, range: 1-110 months) of which the average time in the NH program, as of the time of this report, was 18.4 + or - 13.1 months (median 15.5, range: 1-45 months). During the study period, 16 (42.1%) of the patients died, 2 (5.3%) transferred to HD, 2 (5.3%) stopped treatment, and 18 (47.4%) are still in the program. Actuarial patient survival from entry into the NH program was 89.5% at six months, 60.5% at 12 months, 39.5% at 24 months and 13.2% at 36 months. Patient survival from initiation of chronic dialysis was 89.5% at six months, 76.3% at 12 months, 63.1% at 24 months, and 39.5% at 36 months. We observed 28 episodes of peritonitis with a rate of one episode every 40.3 treatment-months. Two PD catheters had to be replaced, giving a rate of one in every 362.5 patient months. CONCLUSION: Our results with elderly patients in a nursing home show an excellent patient and technique survival and a low peritonitis rate. With appropriate training of the NH nursing staff, peritoneal dialysis could be performed successfully in these nursing homes. Successful peritoneal dialysis in a nursing home requires a close collaboration between the nursing home staff and PD dialysis unit.

Sources of variation in estimates of lean body mass by creatinine kinetics and by methods based on body water or body mass index in patients on continuous peritoneal dialysis.

OBJECTIVE: We identified factors that account for differences between lean body mass computed from creatinine kinetics (LBM(cr)) and from either body water (LBM(V)) or body mass index (LBM(BMI)) in patients on continuous peritoneal dialysis (CPD). DESIGN: We compared the LBM(cr) and LBM(V) or LBM(BMI) in hypothetical subjects and actual CPD patients. PATIENTS: We studied 439 CPD patients in Albuquerque, Pittsburgh, and Toronto, with 925 clearance studies. INTERVENTION: Creatinine production was estimated using formulas derived in CPD patients. Body water (V) was estimated from anthropometric formulas. We calculated LBM(BMI) from a formula that estimates body composition based on body mass index. In hypothetical subjects, LBM values were calculated by varying the determinants of body composition (gender, diabetic status, age, weight, and height) one at a time, while the other determinants were kept constant. In actual CPD patients, multiple linear regression and logistic regression were used to identify factors associated with differences in the estimates of LBM (LBM(cr)LBM(V). The differences in determinants of body composition between groups with high versus low LBM(cr) were similar in hypothetical and actual CPD patients. Multivariate analysis in actual CPD patients identified serum creatinine, height, age, gender, weight, and body mass index as predictors of the differences LBM(V)-LBM(cr) and LBM(BMI)-LBM(cr). CONCLUSIONS: Overhydration is not the sole factor accounting for the differences between LBM(cr) and either LBM(V) or LBM(BMI) in CPD patients. These differences also stem from the coefficients assigned to major determinants of body composition by the formulas estimating LBM.

Elderly diabetic patients on peritoneal dialysis.

Diabetes mellitus is the fastest-growing cause of end-stage renal disease (ESRD) among patients requiring renal replacement therapy (RRT). While diabetes mellitus has become the leading cause of ESRD, the number of elderly patients who need dialysis has grown almost exponentially. Most elderly patients with diabetes are treated with hemodialysis; only a small percentage are treated with peritoneal dialysis (PD). Elderly PD patients with diabetes have a lower survival rate than do nondiabetic patients and younger diabetic patients, perhaps because of the increased comorbidity seen in diabetic patients at dialysis initiation. Also, diabetic patients on RRT are at higher risk of developing de novo cardiovascular disease, one of the major causes of mortality. In Canada, survival in elderly diabetic patients undergoing PD is similar to that in hemodialysis patients; in the United States, patients over 45 - 55 years of age with diabetes have experienced higher mortality on PD than on hemodialysis. It is important, however to emphasize that survival on PD in these elderly patients has greatly improved in recent years. Fluid volume expansion may be one of the reasons for the higher mortality in elderly diabetic patients in some countries; but overall, PD remains a viable form of long-term RRT for elderly diabetic patients with ESRD.

Assisted peritoneal dialysis: what is it and who does it involve?

Together with the obvious increase of elderly patients with end-stage renal disease (ESRD), utilization of peritoneal dialysis (PD) has declined since the mid-1990s in a number of countries--a decline that is particularly marked in this elderly ESRD population. A major obstacle that affects any dialysis modality in elderly patients is the greater disease burden than is seen in younger patients. However; this factor may be overcome if patients start PD with assistance provided by visiting helpers (nurses or others) or people at home, mostly family members. Assisted PD (aPD) is suitable for; but not limited to, elderly patients who are unable to perform PD for themselves at home. Important considerations of an assisted model of care include frequency of visits, type of health care, and tasks to be performed for the patient at home. Clinical experience worldwide shows that aPD offers acceptable survival for most elderly and disabled patients, with no significant difference in modality-related complications from those seen in self-performed PD. Elderly patients on aPD experience more frequent hospitalizations, with longer hospital stays. Costs of aPD vary from country to country, depending on the frequency of visits and on reimbursement policies. Most authors believe that aPD can be cost-effective when compared with in-center hemodialysis.