Configural frequency analysis as a method of determining patients' preferred decision-making roles in dialysis

BACKGROUND

Numerous studies examined factors in promoting a patient preference for active participation in treatment decision making with only modest success. The purpose of this study was to identify types of patients wishing to participate in treatment decisions as well as those wishing to play a completely active or passive role based on a Germany-wide survey of dialysis patients; using a prediction typal analysis method that defines types as configurations of categories belonging to different attributes and takes particularly higher order interactions between variables into account.

METHODS

After randomly splitting the original patient sample into two halves, an exploratory prediction configural frequency analysis (CFA) was performed on one-half of the sample (n = 1969) and the identified types were considered as hypotheses for an inferential prediction CFA for the second half (n = 1914). 144 possible prediction types were tested by using five predictor variables and control preferences as criterion. An α-adjustment (0.05) for multiple testing was performed by the Holm procedure.

RESULTS

21 possible prediction types were identified as hypotheses in the exploratory prediction CFA; four patient types were confirmed in the confirmatory prediction CFA: patients preferring a passive role show low information seeking preference, above average trust in their physician, perceive their physician's participatory decision-making (PDM)-style positive, have a lower educational level, and are 56-75 years old (Type 1; p < 0.001) or > 76 years old (Type 2; p < 0.001). Patients preferring an active role show high information seeking preference, a higher educational level, and are < 55 years old. They have either below average trust, perceive the PDM-style negative (Type 3; p < 0.001) or above average trust and perceive the PDM-style positive (Type 4; p < 0.001).

CONCLUSIONS

The method prediction configural frequency analysis was newly introduced to the research field of patient participation and could demonstrate how a particular control preference role is determined by an association of five variables.

Long-term safety and tolerability of epoetin zeta, administered intravenously, for maintenance treatment of renal anemia

INTRODUCTION

The aim of this trial was to gather data on the long-term safety of a new erythropoietin preparation (epoetin zeta), focusing on the formation of anti-erythropoietin antibodies, when administered intravenously for maintenance of target hemoglobin concentration in anemic patients with end-stage renal failure receiving chronic hemodialysis. In addition, we aimed to provide information on the efficacy of epoetin zeta under open, noncontrolled conditions.

METHODS

Patients received epoetin zeta intravenously, 1-3 times/week for 56 weeks (overall patient group, n=745) or 108 weeks (Bulgarian subgroup, n=164). The aim of treatment was to maintain hemoglobin values between 10.5 and 12.5 g/dL with constant epoetin dosage. Primary (safety) endpoints were the occurrence of anti-erythropoietin antibodies and the evaluation of adverse events (AEs). Secondary (efficacy) endpoints included the mean weekly dose of epoetin per kg of body weight and mean hemoglobin concentrations.

RESULTS

No patients developed neutralizing anti-erythropoietin antibodies. The most commonly reported AEs were infections and infestations (34.1%); followed by injury, poisoning, and procedural complications (25.8%); and gastrointestinal disorders (21.9%); 37.3% of patients reported serious AEs. The hemoglobin values remained stable, with mean values after 56 weeks of 11.3-11.6 g/dL for the overall group and 11.1-11.6 g/dL for the Bulgarian subgroup. The dosage of epoetin zeta was stable throughout the course of the trial. No cases of lack of (or loss of ) efficacy were observed in the course of the trial.

CONCLUSIONS

The evaluation of the primary endpoints provided data supporting the intravenous administration of epoetin zeta in patients with chronic renal failure. Neutralizing antibodies against erythropoietin were not detected, and there were no reports of patients with increasing erythropoietin resistance. Our results suggest that intravenous administration of epoetin zeta is effective regarding its ability to maintain stabilized hemoglobin levels within the target range of 10.5-12.5 g/dL.

Comparison of the therapeutic effects of epoetin zeta to epoetin alfa in the maintenance phase of renal anaemia treatment

OBJECTIVE

To evaluate the therapeutic efficacy and safety of epoetin zeta, compared with epoetin alfa, in maintaining target haemoglobin (Hb) concentrations in patients with anaemia and chronic kidney disease (CKD) maintained on haemodialysis.

METHODS

Patients received epoetin zeta or epoetin alfa intravenously, 1-3 times/week for 12 weeks, then the alternative treatment for 12 weeks, in this double-blind, crossover, phase III trial. Eligible patients were 18-75 years old with CKD stage 5 maintained on haemodialysis. Patients had received epoetin for > or = 3 months upon study entry and had achieved a target Hb level of 10.5-12.5 g/dL with a stable epoetin dose.

MAIN OUTCOME MEASURES

Primary efficacy endpoints were intra-individual differences (test-reference) in mean Hb levels and mean weekly dose/kg of body weight. Safety endpoints included occurrence of neutralizing anti-erythro poietin antibodies, tolerability, and adverse events (AEs).

RESULTS

In total, 313 patients were randomized to receive epoetin zeta (n = 155) or epoetin alfa (n = 158); 146 and 145 patients (respectively) switched treatment after 12 weeks. Mean (range) Hb levels were 11.35 (8.96-14.22) g/dL and 11.54 (8.74-13.84) g/dL for patients receiving epoetin zeta and epoetin alfa, respectively (95% confidence interval [CI] [test-reference]: 0.09-0.28 g/dL, within the predefined equivalence range of +/-0.6 g/dL). Mean (range) weekly doses were 92.68 (12.74-398.41) IU/kg/wk and 92.58 (10.53-393.07) IU/kg/wk for patients receiving epoetin zeta and epoetin alfa, respectively (95% CI [test-reference]: -4.67 and 4.29 IU/kg/wk, within the equivalence range of +/-45.00 IU/kg/wk). Patients underwent minor nominal dose adjustments during treatment crossover. AE profile was similar for both products; the most commonly reported AEs were infections and infestations (in 26.5% of patients receiving epoetin zeta and 23.6% receiving epoetin alfa). No patients developed neutralizing anti-erythropoietin antibodies.

CONCLUSIONS

Epoetin zeta is therapeutically equivalent to epoetin alfa in the maintenance of target Hb levels in patients with renal anaemia. No unexpected AEs were seen.

A rationale for an individualized administration frequency of epoetin beta: a pharmacological perspective

Several studies have compared the efficacy of once-weekly subcutaneous (s.c.) epoetin treatment with two or three times weekly treatment in renal anaemia. Epoetin administration frequency has attracted a high level of attention in recent years, and numerous small-scale studies have shown comparable efficacy and tolerability of once-weekly vs more frequent administration. The results of two large-scale, randomized, controlled trials of once-weekly administration of epoetin beta became available recently. One of these studies, by Locatelli et al., was the first to be designed specifically to demonstrate therapeutic equivalence between once-weekly and three times weekly epoetin beta treatment, using rigorous statistical methods. This was a large, multicentre, randomized, parallel group, 24-week study in 173 chronic renal failure patients. Treatment regimens were considered equivalent if: (i) the 90% confidence interval (CI) of the difference between treatment groups was within +/-2% for the time-adjusted area under the haematocrit (Hct) curve (AUC); and (ii) for mean weekly epoetin beta dose, the 90% CI of the ratio of the groups was between 0.8 and 1.25. As recommended by current guidelines for statistical analysis of clinical trial data, multiple analysis populations were examined in order to demonstrate robustness of the results with regard to the population chosen for analysis. Findings from the primary analysis, the per-protocol population, were confirmed by both the intent-to-treat analysis and an exploratory analysis that examined the influence of five patients who received dose increases above the mean. In all three analyses, the 90% CIs were within the pre-specified equivalence ranges for both the difference between treatment groups for Hct AUC and the ratio of mean weekly epoetin beta dose. In conclusion, once-weekly and three times weekly s.c. epoetin beta treatment regimens are statistically equivalent in terms of maintaining stable Hct levels and dose requirements in haemodialysis patients. The agreement of the three analysis populations provides a convincing demonstration of the robustness of the results. These results confirm that a once-weekly epoetin beta regimen is an effective option for management of renal anaemia that may improve patient convenience and compliance.

CMV prophylaxis after renal transplantation with immunoglobulin or CMV-hyperimmunoglobulin--a prospective clinical trial

Three groups of 40 patients each entered this prospective randomized trial. Patients of group A received 2 ml/kg body weight CMV-Polyglobulin, patients of group B 15 g Intraglobin and patients of group C, serving as controls, received no specific anti-CMV prophylaxis. All patients were given the same sequential immunosuppressive therapy. Patient survival and graft function did not show any significant differences at 2 years follow up. The incidence of fever, CMV infections, dialysis and steroid bolus therapy were lower in group A, but without statistical significance. Patients receiving a graft from a CMV-AK-positive donor were at high risk of developing an infection or reactivation of CMV. A study examining this subgroup seems appropriate.

Early or delayed onset of cyclosporine by sequential immunosuppression?

In a prospective randomized trial, 57 renal transplant patients (group A) received a sequential course of 14 days conventional immunosuppression (anti-lymphocyte globulin (ALG), azathioprine and steroids) and cyclosporine and steroids thereafter, while 57 patients (group B) received the conventional immunosuppression for 2 days followed by cyclosporine and steroids. In group A, ALG was tolerated for a mean of 7.8 days while, in group B, conventional therapy had to be changed to cyclosporine therapy after a mean of 2.1 days due to ALG intolerance. Patient survival rates 1 and 2 years after transplantation were 95% and 92% in group A and 96% and 92% in group B, and graft survival rates were 79% and 79% in group A and 89% and 82% in group B. In group A, the dialysis frequency in the second, third and fourth weeks after transplantation was significantly higher than in group B. Serum creatinine 1 year post-transplant showed no significant difference between the two groups.

The risk of infection following OKT3 and antilymphocyte globulin treatment for renal transplant rejection: results of a single center prospectively randomized trial

Some 43 of 60 (72%) renal allograft recipients who were prospectively randomized to receive either OKT3 monoclonal antibody (n = 30) or ALG (antilymphocyte globulin) polyclonal antibody (n = 30) for steroid-resistant rejection suffered from infection, 25 (83%) following OKT3 and 18 (60%) following ALG treatment (P < 0.05). Clinically evident herpes infection was most frequently seen (9 and 7, respectively), followed by pneumonia (6 and 1, respectively P < 0.05), urinary tract infection and wound infection (2 of each in both groups) fungal (Candida) and multibacterial infections. One patient died in each group due to cytomegalovirus (CMV) pneumonia, giving a mortality of 4.3% in each group. Actuarial 1-year graft and patient survival rates were 80% and 97% in both groups, respectively. It is concluded that ALG and OKT3 are equally effective in renal allograft rejection resistant to steroid treatment, however, the risk of infection appears to be higher with OKT3.

Donor conditions and graft survival--a retrospective study

In a retrospective study (one centre) the influence of donor and recipient factors were evaluated (n = 308). Head injury as the cause of death and anastomotic time less than 35 min were associated with a significantly better graft survival rate (P < 0.05). Although some of the donor factors influence graft survival, a stricter selection of grafts is not advisable, firstly because fewer kidneys would then be offered, and secondly because even comparatively bad graft survival rates are still better than dialysis.

Graft survival and long-term renal function after sequential conventional cyclosporin A therapy in cadaver kidney transplantation--a prospective randomized trial

In a prospective randomized trial 50 renal transplant patients (group A) received a sequential course of 14 days conventional immunosuppression (Lymphocytoglobulin (ALG), azathioprine, steroids) and cyclosporin and steroids thereafter, while 50 patients (group B) received the conventional immunosuppression for 7 days followed by cyclosporin and steroids. In the latter group ALG was tolerated for the whole period while in the first group conversion from conventional to cyclosporin A therapy had to be performed after a mean of 11 days, due to ALG intolerance. Actual patient survival rates 1 year posttransplant were 100% in both groups and graft survival rates 96% in group A and 86% in group B (P less than 0.05). There was a mean dialysis frequency per patient of 0.7 +/- 2.0 in group A and 1.8 +/- 3.4 in group B (P = 0.064). Serum creatinine 1 year posttransplant was 1.8 +/- 0.8 mg/dl in group A and 2.2 +/- 1.4 in group B. A total of 58 patients had a serum creatinine of less than 2 mg/dl at the time of conversion to cyclosporin. These patients had a significantly better graft survival rate (98.3%) and serum creatinine 1 year posttransplant (1.6 +/- 0.5 mg/dl) than the 40 patients with a serum creatinine of more than 2 mg/dl at the time of conversion (85%; 2.4 +/- 1.4 mg/dl), indicating that a delayed onset of cyclosporin therapy might benefit the kidney in the immediate posttransplant period when it is susceptible to nephrotoxicity due to the damage from hypothermic storage.

[Postoperative asystole caused by malfunction of an external demand pacemaker during hemofiltration]

We report on a 54-year-old patient with chronic renal failure, in whom complete AV block occurred after aortic valve replacement. During hemofiltration an external demand pacemaker sensed spikes induced by the employed machine. This caused an asystole. Fixed rate pacing re-established regular ventricular contractions.