Glucose metabolism in renal transplant recipients on tacrolimus: the effect of steroid withdrawal and tacrolimus trough level reduction

The relative role of steroids and tacrolimus in the development of glucose metabolic disorders and hyperlipidemia after renal transplantation has not yet been clearly established. Therefore, glucose metabolism was prospectively evaluated by intravenous glucose tolerance test, as was lipid profile, in fifteen white nondiabetic renal transplant recipients three times: before and after steroid withdrawal and after tacrolimus trough level reduction. After withdrawal of 10 mg of prednisolone, insulin resistance decreased (fasting C-peptide, 0.99 to 0.77 nmol/L [P < 0.0009]; fasting insulin, 9.5 to 8.1 mU/L [P = 0.09]; insulin/glucose ratio, 1.85 to 1.45 mU/mmol [P = 0.10]) and lipid levels decreased (total cholesterol, 5.1 to 4.2 mmol/L [P = 0.006]); HDL cholesterol, 1.4 to 1.1 mmol/L [P = 0.01]; LDL cholesterol, 3.0 to 2.5 mmol/L [P = 0.15]; triglycerides, 1.52 to 0.91 mmol/L [P = 0.02]). After tacrolimus trough level reduction from 9.5 to 6.4 ng/ml, pancreatic beta-cell secretion capacity improved (C-peptide secretion increased from 49.0 to 66.6 nmol x min/L [P = 0.04] and insulin secretion increased from 1134 to 1403 mU x min/L [P = 0.06]). HbA1c improved also, from 5.9 to 5.3% (P = 0.002). Lipids did not change. In conclusion, steroid withdrawal resulted in a decrease in insulin resistance and a reduction in lipids, and tacrolimus trough level reduction resulted in an improved pancreatic beta-cell secretion capacity. Therefore, these therapeutic measurements may contribute to the reduction of the cardiovascular morbidity and mortality in renal transplant recipients.

Minimization of immunosuppressive therapy after renal transplantation: results of a randomized controlled trial

Modern immunosuppressive regimens reduce the acute rejection rate by combining a cornerstone immunosuppressant like tacrolimus or cyclosporine with adjunctive agents like corticosteroids, mycophenolate mofetil (MMF) or azathioprine, often associated with untoward side effects. A 6-month randomized study was conducted in 47 European centers. Triple therapy with tacrolimus (trough levels 5-15 ng/mL), corticosteroids (dosage 10 mg/day) and MMF (1 g/day) was administered for 3 months. From day 92, patients either continued with triple therapy (control, n = 277), or stopped steroids (n = 279), or stopped MMF (n = 277). Surrogate markers for long-term benefits were changes in lipid profiles and occurrence of hematological, gastrointestinal and infectious complications. The 6-month acute rejection incidence (biopsy-proven) was similar in all groups (17.0% vs. 15.1% vs. 14.8%, p = 0.744), although the incidence after month 3 was higher in the steroid stop group than in the two other groups. Mean reductions in total cholesterol (18.9 mg/dL [0.49 mmol/L]) and LDL-cholesterol (8.1 mg/dL [0.21 mmol/L]) between months 4 and 6 were greater in the steroid stop group (p < 0.001). Leukopenia (p = 0.0082), serious CMV infection (p = 0.024), anemia (p = NS) and diarrhea (p = NS) were less frequent in the MMF stop group. In a study population of immunologically low-risk patients' withdrawal of corticosteroids or MMF from a tacrolimus-based therapy at 3 months was feasible. A longer follow-up will be needed to confirm the expected advantages for the long-term outcome and to assess the long-term safety of this minimization of immunosuppressive therapy.

Effect of immunosuppressive agents on long-term survival of renal transplant recipients: focus on the cardiovascular risk

In the control of acute rejection, attention is being focused more and more on the long-term adverse effects of the immunosuppressive agents used. Since cardiovascular disease is the main cause of death in renal transplant recipients, optimal control of cardiovascular risk factors is essential in the long-term management of these patients. Unfortunately, several commonly used immunosuppressive drugs interfere with the cardiovascular system. In this review, the cardiovascular adverse effects of the immunosuppressive agents currently used for maintenance immunosuppression are thoroughly discussed. Optimising immunosuppression means finding a balance between efficacy and safety. Corticosteroids induce endothelial dysfunction, hypertension, hyperlipidaemia and diabetes mellitus, and impair fibrinolysis. The use of corticosteroids in transplant recipients is undesirable, not only because of their cardiovascular effects, but also because they induce such adverse effects as osteoporosis, obesity, and atrophy of the skin and vessel wall. Calcineurin inhibitors are the most powerful agents for maintenance immunosuppression. The calcineurin inhibitor ciclosporin (cyclosporine) not only induces these same adverse effects as corticosteroids but is also nephrotoxic. Tacrolimus has a more favourable cardiovascular risk profile than ciclosporin and is also less nephrotoxic. It has little or no effect on blood pressure and serum lipids; however, its diabetogenic effect is more prominent in the period immediately following transplantation, although at maintenance dosages, the diabetogenic effect appears to be comparable to that of ciclosporin. The diabetogenic effect of tacrolimus can be managed by reducing the dose of tacrolimus and early corticosteroid withdrawal. The effect of tacrolimus on endothelial function has not been completely elucidated. The proliferation inhibitors azathioprine and mycophenolate mofetil (MMF) have little effect on the cardiovascular system. Yet, indirectly, by inducing anaemia, they may lead to left ventricular hypertrophy. MMF is an attractive alternative to azathioprine because of its higher potency and possibly lower risk of malignancies. Sirolimus also induces anaemia, but may be promising because of its antiproliferative features. Whether the hyperlipidaemia induced by sirolimus counteracts its beneficial effects is, as yet, unknown. It may be combined with MMF, however, initial attempts resulted in severe mouth ulcers.

Glucose metabolism in the first 3 years after renal transplantation in patients receiving tacrolimus versus cyclosporine-based immunosuppression

The long-term effects of tacrolimus and cyclosporine on pancreatic islet cell function in renal transplant recipients are unclear. Therefore, a prospective, randomized, longitudinal study was performed that compared glucose metabolism in adult kidney allograft recipients on tacrolimus versus cyclosporine-based immunosuppression. Twenty-three white renal allograft recipients, randomized for either therapy with cyclosporine or tacrolimus, underwent intravenous glucose tolerance tests 6 times during the first 3 yr after transplantation. Concomitant therapy (low-dose steroids and azathioprine) was the same in both groups. Insulin sensitivity index (kG), insulin resistance (insulin/glucose ratio and homeostasis model assessment), and C-peptide and insulin secretion were calculated. Trough levels of tacrolimus and cyclosporine were measured. The occurrence of posttransplantation diabetes mellitus was prospectively monitored. Statistical analysis was performed by ANOVA for repeated measures, and parametric and nonparametric tests were also performed. Although only one patient treated with cyclosporine developed posttransplantation diabetes mellitus, kG levels were below normal in up to one-third of both patients who received tacrolimus and cyclosporine. The only significant difference between patients who received tacrolimus and those who received cyclosporine was in pancreatic secretion capacity at week 3 after transplantation, when the increment of C-peptide secretion was 57% lower and the increment of insulin secretion was 48% lower for patients receiving tacrolimus. In both groups, from week 3 to month 6, there was a tendency toward an increase in kG, despite a significant increase in fasting glucose and insulin resistance calculated by homeostasis model assessment. After month 6, there were no significant changes in any of the parameters of glucose metabolism, indicating that long-term use of either tacrolimus or cyclosporine does not cause chronic, cumulative pancreatic toxicity.

Similarities in skeletal muscle strength and exercise capacity between renal transplant and hemodialysis patients

Exercise intolerance is common in hemodialysis (HD) and renal transplant (RTx) patients. Aim of the study was to assess to what extent exercise capacity and skeletal muscle strength of RTx patients differ from HD patients and healthy controls and to elucidate potential determinants of exercise capacity in RTx patients. Exercise capacity, muscle strength, lean body mass (LBM) and physical activity level (PAL) were measured by cycle-ergometry, isokinetic dynamometry, DEXA and Baecke Questionnaire, respectively, in 35 RTx, 16 HD and 21 controls. VO2peak and muscle strength of the RTx patients were significantly lower compared to controls (p<0.01), but not different compared to HD patients. In RTx patients, strength (p<0.001), PAL (p=0.001) and age (p=0.045) were significant predictors of VO2peak. Muscle strength was related to LBM (p=0.001) and age (p=0.001), whereas gender (p<0.001) and renal function (p=0.01) turned out to be significant predictors of LBM. No effects of corticosteroids were observed. Exercise capacity and muscle strength seem equally reduced in RTx and HD patients compared to controls. In RTx patients, muscle strength and PAL are highly related to exercise capacity. Renal function appears to be a significant predictor of LBM, and through the LBM, of muscle strength and exercise capacity.

Three-Year Observational Follow-up of a Multicenter, Randomized Trial on Tacrolimus-Based Therapy with Withdrawal of Steroids or Mycophenolate Mofetil after Renal Transplant

BACKGROUND

The challenge in renal transplantation is to improve long-term patient and graft survival without increasing early acute rejection by minimizing immunosuppression.

METHODS

This multicenter, observational study investigated the effects of withdrawal of steroids or mycophenolate mofetil (MMF) from a tacrolimus-based triple regimen (tac/MMF/steroids) 3 months posttransplant at 3 years; no additional interventions or assessments were undertaken. Adult patients, included in the intent-to-treat population of the THOMAS study, participated. Patient and graft survival, adverse events, rejection episodes, and immunosuppressive and concomitant medications were assessed.

RESULTS

Data at Year 3 was available for 718 patients (triple therapy, n=237; steroid stop, n=235; MMF stop, n=246). The original randomized regimen was maintained in 45.6% of patients in the triple, 62.6% in the steroid stop, and 53.9% in the MMF stop groups. Graft survival rates were 88.1% (triple), 86.4% (steroid stop), and 85.8% (MMF stop); patient survival was 96.1%, 95.9%, and 95.7%, respectively. The incidence of biopsy-proven acute rejection was similar in all groups between Month 7 and Year 3: 1.2% (triple), 2.0% (steroid stop) and 2.0% (MMF stop). Patients in the steroid stop group had less hypertension and significantly lower mean total cholesterol and LDL-cholesterol at Year 3 compared with Month 3 (P=0.02). Median serum creatinine levels remained stable throughout the follow-up and were comparable between groups.

CONCLUSION

Immunosuppression minimization initiated at Month 3 was maintained at Year 3 in over half of the patients. Steroid withdrawal was advantageous in reducing the cardiovascular risk factors hyperlipidemia, hypertension and diabetes mellitus. Renal function was stable in all groups.

Increase in tacrolimus trough levels after steroid withdrawal

Although there are experimental reports of cytochrome P450 3A4 iso-enzyme (CYP3A4) induction by glucocorticoids, there are no clinical reports about an interaction between tacrolimus and steroids. Therefore, tacrolimus trough level and dose were compared after dose-normalization before and after withdrawal of prednisolone. After withdrawal of 5 mg prednisolone, the median tacrolimus dose-normalized level increased by 14% in the retrospective ( n=54), and by 11% in the prospective ( n=8) part of the study. After withdrawal of 10 mg, this increase was 33% ( n=30) and 36% ( n=14), respectively. An additional pharmacokinetic part of the study ( n=8) revealed an 18% increase in AUC ( P=0.05) after withdrawal of 5 mg prednisolone, which is compatible with a reduced metabolism after steroid withdrawal. The significant increase in tacrolimus exposure after steroid withdrawal may on the one hand counteract the reduction in immunosuppression intended by steroid withdrawal, and, on the other hand, may result in an increase of serum creatinine which could be misinterpreted as rejection.

Tacrolimus and Posttransplant Diabetes Mellitus in Renal Transplantation

The most prominent side effect of tacrolimus is the induction of posttransplant diabetes mellitus (PTDM). In this review, the authors discuss the incidence, mechanism, prevention, and treatment of tacrolimus-induced PTDM in renal patients.

A prospective randomized multicenter study of tacrolimus in combination with sirolimus in renal-transplant recipients

BACKGROUND

Recently, sirolimus (SRL) was introduced as an immunosuppressant in solid-organ transplantation. This study evaluated combinations of SRL and tacrolimus (Tac).

METHODS

This 6-month study investigated the safety and efficacy of Tac and steroids in combination with three different doses of SRL in renal-transplant recipients. A total of 104 patients were randomized in four groups: one group received Tac and steroids (control n=28), and three groups also received the following daily SRL doses: 0.5 mg (TacSRL0.5, n=25), 1 mg (TacSRL1, n=25), or 2 mg (TacSRL2, n=26). Tac doses were adjusted to whole-blood trough levels. Steroids were tapered from 20 mg per day to 5 mg per day. The SRL groups underwent a second randomization to discontinue SRL at either month 3 or 5.

RESULTS

At month 6, patient survival rates were 100%, 100%, 96.0%, and 100%, and graft survival rates were 96.4%, 84.0%, 88.0%, and 84.6%, respectively. The overall safety profile was similar in all groups. The incidences of infections during months 1 to 3 were similar in all groups (control 46.4%, TacSRL0.5 32.0%, TacSRL1 56.0%, TacSRL2 46.2%). The 3-month incidences of hypercholesteremia (cholesterol >240 mg/dL or low-density lipoprotein cholesterol >160 mg/dL) were 21.4%, 36.0%, 48.0%, and 50.0% (P=0.019). Lipid levels improved after withdrawal of SRL. The 3-month incidences of biopsy-proven acute rejection were 28.6% (control), 8.0% (TacSRL0.5), 8.0% (TacSRL1), and 3.8% (TacSRL2) (P=0.014).

CONCLUSION

Tac in combination with low doses of SRL provides a very effective and safe regimen.

The Effects of FK778 in Combination With Tacrolimus and Steroids: A Phase II Multicenter Study in Renal Transplant Patients

BACKGROUND

In animal and in vitro models, FK778 inhibits acute rejection, modifies vasculopathy, and shows anti-viral activity. We report first efficacy and safety data of FK778 in human kidney transplant recipients at two concentration-controlled ranges.

METHODS

In a double-blind manner, 149 patients were randomized to a 12-week treatment with FK778 in combination with tacrolimus (Tac) and corticosteroids (S). Of the high-level group (H), 49 patients received 2 x 600 mg/day FK778 and continued on 150 mg/day, 54 patients of the low-level group (L) got 1 x 600 mg/day followed by 75 mg/day, and 46 patients received placebo (P). Subsequent FK778 doses were adjusted to trough levels of 100-200 microg/mL (H) and 10-100 microg/mL (L). The primary endpoint was the incidence of biopsy proven acute rejection (AR).

RESULTS

In 93% of the patients in group L, targeted plasma trough levels were reached by Day 3; in half of the patients in group H, the targeted levels were reached by Day 9. Graft survival at week 16 was 89.7%, 88.8%, and 91.3%, and the incidences of AR were 26.5%, 25.9%, and 39.1% for groups H, L, and P. For the subgroup of patients in which target levels were reached by week 2, incidences were 7.7%, 27.1%, and 39.1%, respectively. Anemia, the most frequently reported adverse event especially in group H, was reversible. Mean total cholesterol and LDL-cholesterol levels were reduced during FK778 treatment compared with group P.

CONCLUSION

FK778 is pharmacologically active, well-tolerated, and safe. To fully benefit from this promising new drug, FK778 dosing will be optimized in subsequent studies.

Tacrolimus pharmacokinetics and pharmacogenetics: influence of adenosine triphosphate-binding cassette B1 (ABCB1) and cytochrome (CYP) 3A polymorphisms

Tacrolimus, an immunosuppressant used after organ transplantation, has a narrow therapeutic range and its pharmacokinetic variability complicates its daily dose assessment. P-glycoprotein (P-gp), encoded by the adenosine triphosphate-binding cassette B1 (ABCB1) and the cytochrome (CYP) 3A4 and 3A5 enzymes appears to play a role in the tacrolimus metabolism. In the present study, two different renal transplant recipient groups were used to examine the influence of ABCB1 and CYP3A polymorphisms on the daily tacrolimus dose and several pharmacokinetic parameters. In total 63 Caucasian renal transplant recipients divided into 26 early [median (range) of the days since transplantation - 16 (3-74)] and 37 late [median (range) of the days since transplantation - 1465 (453-4128)] post-transplant recipients were genotyped for ABCB1 and CYP3A polymorphisms. The pharmacokinetic parameters of tacrolimus were determined for all renal transplant recipients and correlated with their corresponding genotypes. A significant difference in allele frequencies of the CYP3A4*1B (P = 0.028) and CYP3A5*1 (P = 0.022) alleles was observed between the early and late post-transplant recipient groups. Significantly higher dose-normalized trough levels (dnC(0)), dose-normalized area under the curve (dnAUC(0-12)), and dose-normalized maximum concentration (dnC(max)) were observed for carriers of the CYP3A5*3 variant allele in both renal transplant patient groups. Except for the daily tacrolimus dose (P = 0.025) no significant differences were observed for carriers of the CYP3A4*1B variant allele. Neither the individual ABCB1 polymorphisms nor the ABCB1 haplotypes were associated with any pharmacokinetic parameter. We noticed that patients carrying a CYP3A5*1 allele require a twofold higher tacrolimus dose compared with homozygous carriers of the CYP3A5*3 variant allele to maintain the target dnAUC(0-12). Therefore, genotyping for the CYP3A5*3 variant allele can contribute to a better and more individualized immunosuppressive therapy in transplant patients.

Outcome of nonheart-beating donor kidneys with prolonged delayed graft function after transplantation

Nonheart-beating donor (NHBD) kidneys are frequently associated with delayed graft function (DGF), with a deleterious effect on kidney function and allograft survival. The influence and the duration of DGF on the outcome of NHBD kidneys are assessed. All recipients of an NHBD kidney in the period 1993-2003 were reviewed. Excluded from analysis were patients with primary nonfunction (PNF). One hundred and five patients with a functioning NHBD graft were reviewed: 23 (22%) had immediate function (group 1), 40 (38%) had DGF < or = 2 weeks (group 2), 31 (30%) had DGF 15 days to 4 weeks (group 3) and 11 (10%) had DGF for > 4 weeks (group 4). Creatinine clearance at 3 months was higher in groups 1 and 2 versus group 4 (p = 0.015 and p = 0.006, respectively) and was higher in group 2 versus group 4, at 1 year (p = 0.01). Graft survival was 95%, 98%, 97% and 89%, respectively, at 1 year and 95%, 85%, 77% and 89%, respectively, at 5 years, which was not significantly different. The duration of DGF in NHB kidneys has a negative effect on creatinine clearance, but no effect on graft survival.

Early loss of peritubular capillaries after kidney transplantation

Inflammation, interstitial fibrosis (IF), and tubular atrophy (TA) precede chronic transplant dysfunction, which is a major cause of renal allograft loss. There is an association between IF/TA and loss of peritubular capillaries (PTCs) in advanced renal disease, but whether PTC loss occurs in an early stage of chronic transplant dysfunction is unknown. Here, we studied PTC number, IF/TA, inflammation, and renal function in 48 patients who underwent protocol biopsies. Compared with before transplantation, there was a statistically significant loss of PTCs by 3 months after transplantation. Fewer PTCs in the 3-month biopsy correlated with high IF/TA and inflammation scores and predicted lower renal function at 1 year. Predictors of PTC loss during the first 3 months after transplantation included donor type, rejection, donor age, and the number of PTCs at the time of implantation. In conclusion, PTC loss occurs during the first 3 months after renal transplantation, associates with increased IF and TA, and predicts reduced renal function.

Evaluating mechanisms of post-transplant diabetes mellitus

Post-transplant diabetes mellitus (PTDM) is a frequent complication in renal transplantation. While both tacrolimus and ciclosporin are known to be associated with PTDM, the mechanisms underlying this metabolic disturbance and the relative contribution of concomitant corticosteroids have been unclear. At the University Hospital Maastricht, a series of studies have been conducted to investigate these issues. Administering tacrolimus to non-diabetic, dialysis patients was shown to result in a dose-related reduction in insulin secretion without altering insulin resistance. The patients who developed diabetes after transplantation already had impaired glucose metabolism pre-transplant. In a second study, corticosteroid withdrawal from tacrolimus-based immunosuppression reduced insulin resistance without changing insulin secretion. Moreover, reducing tacrolimus blood levels by 30% within the therapeutic window increased both insulin and C-peptide secretion by 24 and 36%, respectively. Accordingly, the effects of tacrolimus on insulin secretion are both dose dependent and reversible. A comparison of the effects of tacrolimus and ciclosporin on glucose metabolism revealed reduced insulin release with tacrolimus at week 3 post-transplant, but for the remainder of the 3 year follow-up there were no significant differences between the two treatment arms. Also, no difference was reported in glucose metabolism following conversion of stable renal recipients from ciclosporin to tacrolimus. Therefore, replacing tacrolimus with ciclosporin in patients experiencing glucose metabolism disturbances is unlikely to be helpful. In a recent study, early corticosteroid withdrawal from tacrolimus-based therapy resulted in a significantly lower incidence of new-onset diabetes mellitus than that achieved with a corticosteroid dose-tapering regimen. In conclusion, corticosteroid minimization plus dose-optimized tacrolimus immunosuppression is likely to be the best option for patients at risk of developing PTDM.

The functional, metabolic, and anabolic responses to exercise training in renal transplant and hemodialysis patients

BACKGROUND

Exercise intolerance is common in hemodialysis (HD) and renal transplant (RTx) patients and is related to muscle weakness. Its pathogenesis may vary between these groups leading to a different response to exercise. The aim of the study was to compare intrinsic muscular parameters between HD and RTx patients and controls, and to assess the response to exercise training on exercise capacity and muscular structure and function in these groups.

METHODS

Quadriceps function (isokinetic dynamometry), body composition (dual-energy x-ray absorptiometry), and vastus lateralis muscle biopsies were analyzed before and after a 12-week lasting training-program in 35 RTx patients, 16 HD patients, and 21 healthy controls.

RESULTS

At baseline, myosin heavy chain (MyHC) isoform composition and enzyme activities were not different between the groups. VO2peak and muscle strength improved significantly and comparably over the training-period in RTx, HD patients and controls (p(time)<0.05). The proportion of MyHC type I isoforms decreased (p(time)<0.001) and type IIa MyHC isoforms increased (p(time)<0.05). The 3-hydroxyacyl-CoA-dehydrogenase activity increased (p(time)=0.052). Intrinsic muscular changes were not significantly different between groups. In the HD group, changes in lean body mass were significantly related to changes in muscle insulin-like growth factor (IGF)-II and IGF binding protein-3.

CONCLUSIONS

Abnormalities in metabolic enzyme activities or muscle fiber redistribution do not appear to be involved in muscle dysfunction in RTx and HD patients. Exercise training has comparable beneficial effects on functional and intrinsic muscular parameters in RTx patients, HD patients, and controls. In HD patients, the anabolic response to exercise training is related to changes in the muscle IGF system.

Four-year experience with tacrolimus once-daily prolonged release in patients from phase II conversion and de novo kidney, liver, and heart studies

INTRODUCTION

This study assessed the long-term effects of prolonged-release tacrolimus (Advagraf(®) [Tacrolimus QD]), which has been developed to provide similar efficacy and safety to twice-daily tacrolimus (Prograf(®) [Tacrolimus BID]) with the added benefit of once-daily dosing.

METHODS

Adult participants from four phase II de novo (kidney, liver) or Tacrolimus BID to QD conversion (kidney, heart) studies were enrolled into the follow-up study. Patients remained on the immunosuppressive regimen they were receiving on entry, unless medical needs required otherwise. The primary endpoint was patient and graft survival, and secondary endpoints were biopsy-confirmed acute rejection (BPAR) and safety.

RESULTS

The full analysis set comprised 240 patients. Tacrolimus mean total daily dose and whole-blood trough levels decreased over time, particularly in de novo patients. At four yr, Kaplan-Meier estimates of patient and graft survival were over 90%. Freedom from BPAR was 90.9/92.6% and 100/87.0% in the de novo kidney/liver and conversion kidney/heart patients, respectively. There were 13 deaths, and 20% patients withdrew from the study, mainly because of adverse events.

CONCLUSIONS

The efficacy and safety of Tacrolimus QD was maintained for four yr in kidney, liver, and heart transplant recipients. Therefore, this formulation offers a convenient alternative to Tacrolimus BID.

High Rejection Rate during Calcineurin Inhibitor-Free and Early Steroid Withdrawal Immunosuppression in Renal Transplantation

Morbidity and mortality due to cardiovascular disease are major problems after renal transplantation. The effects of three immunosuppressive protocols on cardiovascular end points were investigated in a single-center, randomized, parallel (1-1-1) group. Acute rejection was a secondary safety endpoint. Groups were as follows: group one, tacrolimus+sirolimus; group two, tacrolimus+mycophenolate mofetil (MMF); group three, sirolimus+MMF+daclizumab. All groups received two days methylprednisolone only. The Ethical Committee demanded an interim analysis when 50% of the patients were included. In this analysis, 54 patients with a median follow-up of 9.2 months were studied. The Kaplan-Meyer analysis showed a difference in rejection free survival between group one (82%) and group three (34%, P=0.03) and between groups one and two (tacrolimus-based, 76%) and group three (calcineurin-free, 34%, P=0.04). Calcineurin-free immunosuppression with two days of steroids only showed an unacceptable high incidence of acute rejection and re-rejection, and the study had to be stopped.

Evaluation of limited sampling strategies for tacrolimus

Objective

In literature, a great diversity of limited sampling strategies (LSS) have been recommended for tacrolimus monitoring, however proper validation of these strategies to accurately predict the area under the time concentration curve (AUC_0–12) is limited. The aim of this study was to determine whether these LSS might be useful for AUC prediction of other patient populations.

Methods

The LSS from literature studied were based on regression equations or on Bayesian fitting using MWPHARM 3.50 (Mediware, Groningen, the Netherlands). The performance was evaluated on 24 of these LSS in our population of 37 renal transplant patients with known AUCs. The results were also compared with the predictability of the regression equation based on the trough concentrations C₀ and C₁₂ of these 37 patients. Criterion was an absolute prediction error (APE) that differed less than 15% from the complete AUC_0–12 calculated by the trapezoidal rule.

Results

Thirteen of the 18 (72%) LSS based on regression analysis were capable of predicting at least 90% of the 37 individual AUC_0–12 within an APE of 15%. Additionally, all but three LSS examined gave a better prediction of the complete AUC_0–12 in comparison with the trough concentrations C₀ or C₁₂ (mean 62%). All six LSS based on Bayesian fitting predicted <90% of the 37 complete AUC_0–12 correctly (mean 67%).

Conclusions

The present study indicated that implementation of LSS based on regression analysis could produce satisfactory predictions although careful evaluation is necessary.

Pre-kidney-transplant blood transfusions do not improve transplantation outcome: a Dutch national study

BACKGROUND

Female renal transplant candidates are prone to be sensitized by prior pregnancies, and undetected historical sensitization might decrease transplantation outcome. Hypothesis of our study was that pre-transplant blood transfusions (PTFs) can elucidate historical sensitization and that the avoidance of the associated antigens can improve transplantation outcome.

METHODS

Data from all female non-immunized renal transplant candidates who received a random PTF (rPTF) (n = 620), matched PTF (mPTF) (one HLA-A and B and one HLA-DR match) (n = 86) or donor-specific blood transfusion (DST) (n = 100) between 1996 and 2006 were collected. Complement-dependent cytoxicity was used to detect anti-HLA antibodies. Sensitization and transplantation outcomes after a PTF were analyzed. Non-immunized female renal transplant recipients who did not receive a PTF were used as the control group.

RESULTS

In 165 patients, anti-HLA antibodies (IgG) were detected after the PTF. Both historical and primary sensitizations were found. A DST induced donor-specific anti-HLA antibodies in 25% of the DST recipients. Our policy did not improve transplantation outcome in recipients of a kidney from a deceased donor (n = 368) or in recipients of a living donor [DST (n = 49) and mPTF (n = 66)].

CONCLUSIONS

A PTF did elucidate historical sensitization but induce primary sensitization as well. No beneficial effect of PTFs on transplantation outcome was found, and PTFs with the intention to detect historical sensitization are therefore not suggested.

Nutritional considerations in renal transplant patients

In renal transplant patients, weight gain generally increases after renal transplantation, which will be influenced by improved appetite and a reversal of the uremic state. However, at least in the early posttransplant period, the increase in body weight is mainly due to an increase in body fat mass. This phenomenon may be partly due to relatively high doses of steroids in the early period after renal transplantation, possibly mediated by their inhibiting effect on lipid peroxidation, but also appears to be related to physical inactivity. The increase in body fat mass may contribute to posttransplant hyperlipidemia, which is improved but not completely normalized by dietary intervention. Current dietary recommendations in stable renal transplant patients do not generally differ from those of the general population, although intense dietary counselling may be indicated in patients with excessive posttransplant weight gain. The effect of supervised exercise training on body composition is currently under investigation.

Weight changes after renal transplantation: a comparison between patients on 5-mg maintenance steroid therapy and those on steroid-free immunosuppressive therapy

After renal transplantation (RTx), an increase in body weight (BW) is usually observed, in which corticosteroids may play an important role. However, the effects of a low maintenance dosage of corticosteroids on BW have not been studied longitudinally in RTx patients. The aim of this study was to compare changes in BW after RTx in patients on steroid- or steroid-free immunosuppressive therapy and to assess the relationship between post-transplant weight changes and other potentially important factors. The charts of 123 RTx patients (72 male, 51 female) were retrospectively examined for BW changes in the first 5 years after RTx. Sixty-six patients were on 5-mg maintenance steroid dose and 57 patients underwent steroid-free immunosuppression. Mean post-transplant BW gain was 3.0+/-5.3 kg after 6 months, 3.9+/-6.2 kg after 1 year and 6.2+/-8.6 kg after 5 years. Weight gain in the first year after RTx was related neither to maintenance- nor to cumulative steroid dose, age, gender, occurrence of rejection, or renal function. Weight gain was, however, significantly related to pre-transplant BMI and dialysis modality. After the first year, weight gain was significantly and positively related only to the cumulative steroid dose. The course of weight gain in the first year after RTx turned out to be independent from factors such as maintenance- or cumulative steroid dose, age, gender, occurrence of rejection, and renal function; weight gain was, however, dependent on pre-transplant BMI and dialysis modality. After the first year, the weight course was significantly affected by cumulative steroid dose.

Nonadherence with Immunosuppressive Drugs: Us Compared with European Kidney Transplant Recipients

Background

System factors increasingly are suggested as important yet understudied correlates of nonadherence.

Objective

To explore the relationship between healthcare system and prevalence of nonadherence with immunosuppressive regimen by studying variation in nonadherence between European and US kidney transplant recipients and as well as nonadherence in European countries.

Methods

We performed a secondary data analysis on data collected in 3 independent cross-sectional studies using comparable methodology including patients from the United States, the Netherlands, Belgium, and Switzerland. Nonadherence was measured using 1 item of the Siegal questionnaire. Patients were categorized as nonadherent if they reported missing a dose of immunosuppression in the last 4 weeks. Analyses were performed by multiple mixed logistic regression, with center as a random effect and clinical and demographical differences between groups as fixed effects.

Results

1563 US and 614 European patients from 3 different countries (Belgium [n=187], the Netherlands [n=85], and Switzerland [n=342]) were included. Prevalence of nonadherence in the United States and Europe was 19.3% and 13.2.%, respectively. This higher nonadherence in US patients was confirmed in a multiple logistic regression analysis (OR=1.78; 95% CI, 1.10–2.89). Nonadherence differed between Belgium (16%) and the Netherlands (14.1%) (OR=0.27; 95% CI, 0.09–0.80) and between Belgium and Switzerland (11.4%; OR=0.17; 95% CI, 0.0–0.42).

Conclusion

This is the first study showing differences in prevalence of nonadherence between European and US patients and among European patients. Further research should aim at unraveling the dynamics explaining these differences.

The influence of early steroid withdrawal on body composition and bone mineral density in renal transplantation patients

Corticosteroid treatment may have an important effect on body composition and bone mineral density (BMD) in renal transplantation (RTx) patients. We investigated the effect of early steroid withdrawal on body composition and BMD of RTx patients in a prospective design. Post-transplant immunosuppression consisted of tacrolimus, mycophenolate mofetil, and prednisolone. Three months after RTx, 27 patients participating in a multi-center trial were randomized either to continue steroids (at a dose of 10 mg/day, n=17; steroid+) or be withdrawn from steroids within 2 weeks (n=10; steroid-). Body composition and BMD (lumbar spine (L2-L4) and femoral neck) were measured by dual-energy X-ray absorptiometry (DEXA) just before and 3 months after randomization. With regard to body composition, fat mass tended to increase in the steroid+ group (1.1+/-2.3 kg; P=0.084), but did not change in the steroid- group. Increase in body fat percentage tended to be higher (P=0.08) in the steroid+ group (0.6+/-2.7%) than in the steroid- group (-0.7+/-2.1%). The change in lean body mass was not significantly different between the two groups. BMD of the lumbar spine and femoral neck decreased significantly in the steroid+ group (-1.4+/-3.2% and -2.3+/-2.9%, respectively, P<0.05) while no changes were observed in the steroid- group. The change in BMD of the lumbar spine was significantly different between the steroid+ and the steroid- group, whereas the change in BMD of the femoral neck was not significantly different. Thus, the increase in fat mass tended to be higher in the group continuing on steroids, though not significant, due to large inter-individual variation. In general, the effect of early steroid withdrawal on body composition after RTx appears to be modest. In addition, early steroid withdrawal seems to have beneficial effects on BMD in RTx patients, especially in the lumbar region.