Gavin I. Russell

Comorbidity, urea kinetics, and appetite in continuous ambulatory peritoneal dialysis patients: Their interrelationship and prediction of survival

Comorbidity, urea kinetics (Kt/V and normalized protein catabolic rate), dietary protein, total calorie intake, and plasma albumin were measured in 97 continuous ambulatory peritoneal dialysis patients followed prospectively for 30 months. Comorbid disease was graded severe in 12 patients, intermediate in 29, and absent in 56. At entry to the study comorbidity was associated with increased age (P = 0.001), lower dietary protein (P = 0.015) and calorie intake (P = 0.02), and a lower plasma creatinine (P = 0.026). Trends toward lower Kt/V and albumin were not significant, and normalized protein catabolic rate was unaffected. Ability of these measures to predict mortality was assessed by univariate and multivariate analysis using Coxs proportional hazard model. On univariate analysis, comorbidity (P < 0.0001), age (P = 0.0001), Kt/V (P = 0.009), plasma albumin (P = 0.009), calorie intake (P = 0.035), and dietary protein intake (P = 0.03) predicted outcome, whereas normalized protein catabolic rate did not (P = 0.46). Multivariate analysis indicated that comorbidity (P = 0.0003) and age (P = 0.0085) were the only independent predictors of outcome. The addition of plasma albumin and Kt/V increased the significance of the Cox model. Further analysis of comorbidity demonstrated the relative importance of vascular disease and left ventricular dysfunction. This study illustrates the profound influence of comorbid disease on mortality in continuous ambulatory peritoneal dialysis patients and suggests that it causes suppression of appetite independent of the dialysis dose.

Better blood pressure control: how to combine drugs.

Prospective comparisons of different drug classes have shown that differences in blood pressure control, rather than differences between drug classes, have the over-riding influence on overall outcome. The same studies have also reinforced the need, in the majority of patients, to use combinations of drugs in order to achieve the target of <140/85 mmHg. By contrast, most patients in routine practice receive single agents and consequently fail to achieve target blood pressure. This failure reflects in part the emphasis in individual studies and subsequent guidelines on comparison of individual drugs. In this article we show how the consistency of both theory and a broad range of evidence permits a didactic approach to combination therapy. Our advice is based on the growing recognition that essential hypertension and its treatment fall into two main categories. Younger Caucasians usually have renin-dependent hypertension that responds well to angiotensin-converting-enzyme inhibition or angiotensin receptor blockade (A) or ß blockade (B). Most other patients have low-renin hypertension that responds better to calcium channel blockade (C) or diuretics (D). These latter drugs activate the renin system rendering patients responsive to the addition of renin suppressive therapy. Coincidence of the initials of these main drug classes with the first four letters of the alphabet permits an AB/CD rule, according to which recommended combinations are one drug from each of the ‘AB’ and ‘CD’ categories of drugs. However, the diabetogenic potential of the older ‘B’ and ‘D’ classes leads us to advise against combining ‘B’ and ‘D’ in older patients, and to recommend ‘A’ + ‘C’ + ‘D’ as standard triple therapy for resistant hypertension.

The role of continuous ambulatory peritoneal dialysis in end-stage renal failure due to multiple myeloma.

A study in 10 patients (eight male, two female; mean age 61.9 +/- 10.7 years) suffering from multiple myeloma (MM) and end-stage renal failure (ESRF) is detailed. Continuous ambulatory peritoneal dialysis (CAPD) was the preferred mode of chronic dialysis in all the patients. Survival after diagnosis was 32.2 +/- 23.9 months. Survival after starting dialysis was 24.6 +/- 20.6 months. All patients on CAPD were adequately dialyzed and in good fluid control. Peritonitis was the main problem on CAPD (one episode per 5.6 patient-months). The majority of peritonitis episodes responded to intraperitoneal antibiotic therapy. One patient with Staphylococcus aureus peritonitis, septicemia, and neutropenia secondary to chemotherapy, died. Recommendations for prophylaxis and treatment of peritonitis are given. Three patients were transferred to hemodialysis. The use of subclavian vein catheters during hemodialysis was associated with a high incidence of gram-positive septicemia. Alkylating agent-based chemotherapy resulted in hematological responses in five patients. Survival after diagnosis in those responders was 47.4 +/- 25.6 months, compared with 17.0 +/- 7.2 months in the nonresponders (P less than 0.05). All responders subsequently relapsed. Four patients died with progressive myeloma. Bone marrow suppression resulted in a high blood transfusion requirement, neutropenia, and thrombocytopenia associated with bleeding into the gastrointestinal tract and central nervous system. Uremic myeloma patients can be adequately dialyzed using CAPD. Those patients who do not have an initial hematological response have a poor prognosis.

A comparison of two methods of dietary assessment in peritoneal dialysis patients

OBJECTIVE To conduct a comparison of two methods of dietary assessment in patients on peritoneal dialysis. DESIGN Comparative, cross-sectional study of two methods of dietary assessment (3-day diet diary and 24-hour recall). Data was collected simultaneously by a single experienced dietitian. Each assessment was coded and analyzed blind. SETTING Regional speciality peritoneal dialysis training unit. PATIENTS In this study, 30 peritoneal dialysis patients recruited prospectively and consecutively as they attended for out-patient assessment of dialysis adequacy. Age range was 22 to 77 years. Patients were excluded if unwell, younger than 18 years, or had peritonitis. OUTCOME MEASURES Total energy and protein intakes from both methods were compared. Protein intakes from both methods were compared with the protein catabolic rate generated from urea kinetics. Data obtained from both methods were compared using paired t tests, linear regression, and Bland and Altman techniques. RESULTS There were no significant differences in the mean daily protein (72.4 g v 76.6 g) and total energy (1757 kcals (7.35 MJ) v. 1897 kcals (7.94 MJ)) intakes determined by the two methods. Positive correlations were seen between the measurements for protein intake (r =.58, P =.0026) energy intake (r =.78, P <.00001), with mean differences of.066 g/kg/d (SD.38) 2.04 kcal/kg/day (SD 6.67), respectively. For both methods there was a similar positive correlation between dietary protein intake and protein catabolic rate. A 24-hour recall was more likely to result in successful collection of data (29 of 30) than 3-day diet diaries (25 of 30) and was less time consuming. CONCLUSION These two methods of determining dietary protein and energy intake do not differ significantly in the information they provide. The relative success in obtaining completed records of intake, the shorter time taken and the opportunity for patient education and assessment of other nutrition related factors has led to the adoption of the 24-hour recall method in our institution.

Use of the Tesio catheter for hemodialysis in patients with end-stage renal failure: a 2-year prospective study

BACKGROUND The Tesio catheter system has been proposed to be a reliable source of vascular access for the dialysis patient with low rates of infection and other complications. Whether such catheters provide reliable short- and long-term access remains undetermined. METHODS This study prospectively examined all Tesio lines inserted over a 2-year period in patients with end-stage failure with careful recording of all catheter complications and reasons for catheter loss. RESULTS 100 catheters were inserted in 82 patients giving a total experience of 13,749 catheter days; 74 catheters were inserted into the jugular veins, the remainder into the femoral veins; 82 insertions were covered with antibiotics. At the end of the study, 29 catheters remained in situ. Of the remaining 71 catheters, 27 catheters were removed because of fashioning of definitive access. Nine catheters were lost due to infection and 10 were lost due to non-function; 19 patients died with a functioning catheter. Episodes ofnon-function were the major complications, although catheter patency was restored in 90% of cases utilizing urokinase and warfarin. Overall 80% of femoral and 16% of jugular catheters required anticoagulation. CONCLUSIONS Tesio catheters inserted into the jugular or femoral veins can provide excellent access whilst awaiting definitive dialysis access. They are well-tolerated with a low complication rate compared to standard temporary central venous catheters. Non-function remains a significant problem, especially in femoral catheters, which should be anticoagulated following insertion. Because of our results we suggest that these catheters be used as part of the co-ordinated approach to the management of vascular access in end-stage renal failure patients without definitive access.