Hospital admissions in elderly patients on chronic hemodialysis.

BACKGROUND: The purpose of this study was to determine whether number of hospital admissions per patient per year (n/[pt-yr]) and hospital days per patient per year (d/[pt-yr]) differ between elderly and younger patients on chronic hemodialysis (HD). PATIENTS AND METHODS: In a retrospective cohort analysis of incident HD patients in one dialysis unit over 15 years, we compared 166 HD patients older than 70 years (77.1 ± 4.7 yrs) at the onset of HD (group A) and 216 patients younger than 70 years both at onset (57.1 ± 7.6 yrs) and at the end of the HD period (group B). Eighty (48.2%) of group A and 141 (65.3%) patients of group B had diabetes mellitus. RESULTS: No differences were noted in the overall hospitalization rate, presented as mean, {95% Confidence interval} (group A 2.40 {2.04-2.75}, group B 2.03 {1.89-2.16} n[pt-yr]) and days/[pt-year] (group A 33.6 {25.3-41.8}, group B 24.1 {18.9-29.23}). Group A had higher number of hospitalization days (P = 0.012) for surgery or trauma and higher rate (P = 0.045) and days (P = 0.041) of hospitalization for miscellaneous causes, primarily pulmonary disease, or malignancy. Among diabetic patients, group A had only a greater number of hospital days for cardiac disease (P = 0.050). Among patients without diabetes, group A had a higher number for hospital days for surgery or trauma (P = 0.027). All other univariate comparisons were not significant. Multiple linear regression identified comorbidity, quantified by the Charlson index, Caucasian race and poor compliance with the HD schedule as predictors of admission rate and days per year for vascular access issues and comorbidity, poor compliance, and advanced age at onset of HD as predictors of admission for causes other than vascular access related. CONCLUSION: Hospitalizations, which affect quality of life, differ little between elderly and younger patients on HD. Therefore, hospitalizations do not constitute an argument for restricting access to HD to elderly patients.

The prescription of peritoneal dialysis.

In addition to the maintenance of normal extracellular electrolyte composition, the prescription of continuous peritoneal dialysis (CPD) should address four other specific issues: (i) prevention of uremia by achievement of adequate clearance of azotemic substances, (ii) prevention of progressive expansion of the extracellular volume by adequate peritoneal ultrafiltration, (iii) prevention of loss of residual renal function, and (iv) prevention of deterioration of the peritoneal membrane structure and function. Urea clearance, in the form of Kt/V(Urea), is the index of removal of azotemic substances proposed by current guidelines. The target total (renal plus peritoneal) Kt/V(Urea) is >or=1.7 weekly. To provide the desired peritoneal Kt/V(Urea) (K(p)t/V(Urea)), the prescription of peritoneal dialysis must provide a daily drain volume (Dv) defined by the clearance equations as Dv = V x (K(p)t/V(Urea))/(D/P(Urea)), where V is body water obtained from published anthropometric formulas, K(p)t/V(Urea) = (1.7 - renal Kt/V(Urea))/7 and D/P(Urea) is the dialysate-to-plasma urea concentration ratio at the dwell time prescribed. Computer programs obtain the relevant D/P(Urea) values from formal studies of peritoneal transport. In the absence of these studies (for example, at initiation of CPD), D/P(Urea) values can be obtained from published studies with similar dwell times. Body size, indicated by V, is the major determinant of the K(p)t/V(Urea) limit provided by a given CPD schedule. Other obstacles to achievement of adequate urea clearance are created by poor patient compliance, inaccuracies of the anthropometric formulas estimating V, and mechanical complications of CPD that lead to retention of dialysate in the body. The main requirements for the prescription of adequate ultrafiltration are knowledge of the individual peritoneal transport characteristics, monitoring of urinary volume, and restriction of dietary sodium intake. Excessive dietary sodium intake is the major cause of extracellular volume expansion in CPD. Ideally, sodium intake should be kept at the level of total (peritoneal plus renal) sodium removal. Preventing the loss of residual renal function involves avoidance of nephrotoxic influences in the form of medications, radiocontrast agents, urinary obstruction and infection, and possibly other influences, such an elevated calcium-phosphorus product and anemia. Use of the lowest dialysate dextrose concentration that will allow adequate ultrafiltration is currently the most widespread practical measure of prevention of peritoneal membrane deterioration. Formulation of biocompatible dialysate is a major ongoing research effort and may greatly enhance the success of CPD in the future.

Hydration abnormalities in Nigerian patients on chronic hemodialysis.

The state of hydration affects the outcomes of chronic dialysis. Bioelectrical impedance analysis (BIA) provides estimates of body water (V), extracellular volume (ECFV), and fat-free mass (FFM) that allow characterization of hydration. We compared single-frequency BIA measurements before and after 14 hemodialysis sessions in 10 Nigerian patients (6 men, 4 women; 44+/-7 years old) with clinical evaluation (weight removed during dialysis, presence of edema) and with estimates of body water obtained by the Watson, Chertow, and Chumlea anthropometric formulas. Predialysis and postdialysis values of body water did not differ between BIA and anthropometric estimates. However, only the BIA estimate of the change in body water during dialysis (-0.8+/-2.9 L) did not differ from the corresponding change in body weight (-1.3+/-3.0 kg), while anthropometric estimates of the change in body water were significantly lower, approximately one-third of the change in weight. Bioelectrical impedance analysis correctly detected the intradialytic change in body water content (the ratio V/Weight) in 79% of the cases, while anthropometric formula estimates of the same change were erroneous in each case. Compared with patients with clinical postdialysis euvolemia (n=7), those with postdialysis edema (n=5) had higher values of postdialysis BIA ratios V/FFM (0.77+/-0.01 vs. 0.72+/-0.03, p<0.01) and ECFV/V (0.53+/-0.02 vs. 0.47+/-0.06, p<0.05), respectively. Bioelectrical impedance analysis appeared to underestimate body water and extracellular volume in a patient with massive ascites and bilateral pleural effusions. Anthropometric formulas are not appropriate for evaluating the state of hydration in patients on chronic hemodialysis. In contrast, BIA provides estimates of hydration agreeing with clinical estimates in the same patients, although it tends to underestimate body water and extracellular volume in patients with large collections of fluid in central body cavities.

Peritoneal dialysis as salvage renal replacement therapy after complete failure of hemodialysis access in an elderly patient with multiple comorbidities.

Although peritoneal dialysis (PD) has been advocated as a suitable substitution therapy in patients with failure of hemodialysis (HD) blood access, documentation of the performance of PD in such patients is limited. Here, we present an elderly patient with total failure of HD blood access who has had a remarkably successful course on PD. A 78-year-old man with several comorbidities started continuous ambulatory PD after a 3.5-year course of HD complicated by repeated vascular access infections and clotting episodes. These access complications resulted in 8 hospitalizations and led to inability to ambulate following a right femoral shaft fracture sustained in a fall secondary to confusion during an episode of access sepsis, and to superior vena cava (SVC) syndrome following SVC thrombosis after internal jugular catheter insertion. Over approximately 3 years, PD has been very successful in this patient, with 2 early routine episodes of peritonitis and 1 early episode of exit-site infection, control of hematologic and biochemical values, no hospitalizations in the 2.5 years before the time of writing, and good quality of life. A dedicated spouse performing the PD tasks has been a major factor in the success of PD in this patient. Peritoneal dialysis can be successful as a renal replacement procedure in incapacitated elderly patients with failure of HD blood access. In these cases, the success of PD is enhanced by dedicated family members taking on PD tasks that the patient cannot perform.

Computation of the dose of continuous peritoneal dialysis required for adequate peritoneal urea clearance without taking into account peritoneal transport indices.

To test the feasibility of calculating, in the absence of peritoneal transport studies, the dose (daily drain volume) of continuous peritoneal dialysis (CPD) that will produce a high probability of adequate fractional peritoneal urea clearance (Kpt/Vurea), we randomly separated 619 clearance studies in patients on continuous ambulatory peritoneal dialysis (CAPD) with 4 daily exchanges into a derivation (n = 322) and a validation (n = 297) group. In the derivation group, the dialysate-to-plasma urea concentration ratio (D/Purea) was < or = 0.799 within the lowest 5% of the studies. By the urea clearance formula, a D/Purea value of 0.799 will produce weekly Kpt/Vurea values of 1.70 or better if the ratio of the daily drain volume to plasma water (Dv/V) is > or = 0.304 L/L. Among the 56 studies in the validation group with Dv/V values of 0.304 L/L or more, 52 (92.9%) had weekly Kpt/Vurea values of 1.70 or better. Assuming a suitable (low) D/Purea value for a given CPD treatment, it is possible to derive the dose of dialysis (the Dv/V ratio) that will provide adequate peritoneal urea clearance levels regardless of peritoneal transport characteristics. This method is applicable to the prescription of CPD for patients lacking studies of peritoneal transport. Anuric patients on CAPD with 4 daily exchanges require a Dv/V value of 0.304 L/L or better to have a > or = 0.9 probability of achieving a weekly Kpt/Vurea of 1.70 or better.

Immunoglobulin A nephropathy complicating ulcerative colitis.

Ulcerative colitis is rarely associated with immunoglobulin A nephropathy (IgAN). The development of IgA nephropathy complicates further the clinical course of patients with ulcerative colitis. A 72-year old man with a 30-year history of ulcerative colitis requiring colectomy and modest renal insufficiency secondary to complications of nephrolithiasis and renal artery stenosis developed glomerular hematuria, proteinuria and progressive renal failure. Percutaneous kidney biopsy revealed IgAN with extensive glomerular and interstitial sclerotic changes. After resection of a chronically infected ileo-rectal pouch, renal function improved, while hematuria and proteinuria gradually disappeared without specific treatment of the IgAN. The manifestations of IgAN complicating ulcerative colitis can be improved with effective treatment of the bowel disease even when there are extensive sclerotic changes in the kidneys.