International Journal of Organ Transplantation Medicine Original Article Outcomes of Late Corticosteroid Withdrawal after Renal Transplantation in Patients Exposed to Tacrolimus and/or Mycophenolate Mofetil: Meta-Analysis of Randomized Controlled Trials A. K. Ali 1 *, J. Guo 1 H. Ahn 2 J. Shuster 3 1 Department of Pharmaceutical Outcomes & Policy, College of Pharmacy, 2 Department of Adult & Elderly, College of Nursing, and 3 Department of Health Outcomes & Policy, College of Medicine, University of Florida, USA ABSTRACT Corticosteroids are increasingly used in renal transplant patients to minimize organ rejection after transplantation. In attempts to reduce corticosteroids adverse effects, transplant professionals are customary attempted to taper off, and permanently stop corticosteroids after few months of administra tion with other immunosuppressants. tients treated with tacrolimus (TAC) or mycophenolate mofetil (MMF), or both. A meta-analysis was performed of published randomized controlled trials that reported out drawal under concomitant immunosuppression by TAC, MMF or both. Outcomes included acute graft rejection; graft failure rate; all-cause mortality; incidence of post-transplant diabetes; change in serum creatinine and total cholesterol; and change in pediatric standardized height z-score. PubMed and Google Scholar were used in literature search between 1999 and April 1, 2010. Data were combined using un weighted random effects model. Nine studies randomized 1907 patients met the inclusion criteria: TAC (n=1); MMF (n=6); both (n=2). Compared to maintenance therapy, late corticosteroid withdrawal was associated with 34% in Stopping corticosteroids was associated with better pediatric growth outcomes. diabetes mellitus, and deterioration in serum creatinine levels. KEYWORDS: Steroid withdrawal; Kidney transplantation; Tacrolimus; Mycophenolate mofetil. Ayad K Ali, Pharmaceutical Outcomes and Policy, College of Pharmacy, University of Florida, 101 S Newell Drive, PO Box 100496, Gainesville, FL 32610-0496, USA +1-352-273-6629 +1-352-273-6270 INTRODUCTION O rgan rejection is one of the serious complications of kidney transplanta tion. Corticosteroids are increasingly used to reduce organ rejection after transplan
Int J Org Transplant Med 2011; Vol. 2 (4) www.ijotm.com tation. However, corticosteroids have many adverse effects includingbut not limited tohypertension, hypercholesterolemia, glu cose intolerance, growth retardation in chil dren, greater incidence of infections, and bone weakness. In attempts to reduce the incidence of graft rejection rates as well as the adverse effects of corticosteroids, transplant profes sionals are customary attempted to taper off, and permanently stop corticosteroids after few months of administration. Unfortunately, the randomized controlled trials (RCTs) con ducted in the 1990s showed increasing rates of acute graft rejection [1, 2]. Cyclosporine and azathioprine were also used as concomi tant immunosuppressants for many years. In recent years, both cyclosporine and azathio prine were replaced by more potent agents, tacrolimus (TAC) and mycophenolate mofetil (MMF). Kidney transplant clinicians could taper off corticosteroid under concomitant im munosuppression of either TAC or MMF. In this study, we performed a meta-analysis of RCTs to evaluate clinical benefits and risks of late corticosteroid withdrawal in kidney transplant patients with concomitant immu nosuppression by TAC, MMF, or both. METHODS A comprehensive PubMed and Google Scholar Figure 1: Schematic representation of the study profile for selected trials.
www.ijotm.com Int J Org Transplant Med 2011; Vol. 2 (4) search was independently performed by the authors to find human studies published be tween 1999 and April 1, 2010 using the search terms kidney transplant, renal transplant, randomized clinical trial, tacrolimus, myco phenolate mofetil, as well as combinations of these terms. The bibliographies of the re trieved literature were also searched for other relevant studies. Clinical trials that met the following criteria were included: randomized controlled trials in kidney transplant patients regardless of age; kidney transplant patients on corticosteroids with concomitant immunosuppression by ei ther TAC or MMF, or both. Late corticoste roid withdrawal in one comparison group was required, which was defined as withdrawing corticosteroids at least three months after transplantation; and the other comparison group was defined as kidney transplant pa tients who received maintenance corticoste roid therapy with either TAC or MMF, or both. Using either of cyclosporine or azathio prine as concomitant immunosuppressants in addition to the above agents is considered ac ceptable in the study inclusion criteria. Clini cal trials that enrolled organ transplant pa tients other than kidney, early corticosteroid withdrawal (withdrawal before three months after transplantation), or if the concomitant immunosuppression was by cyclosporine and azathioprine in addition to other agents were excluded. Standardized forms are used to extract data from selected studies for patient demograph ics; inclusion and exclusion criteria; treatment regimens; duration of follow-up (time of ran domization post-transplantation; time of data collection post-randomization); total number of patients enrolled; allograft source and char acteristics; and clinical outcomes. Clinical outcomes of interest included the in cidence of acute graft rejection; graft failure rate; all-cause mortality; incidence of posttransplant diabetes mellitus; change in serum creatinine and total cholesterol; and change in pediatric standardized height z-score. The definitions of clinical end-points were simi lar across the trials; three studies reported serum creatinine values in M/L [3-5], and two studies reported total cholesterol val ues in mM/L [4, 5]. Both measurements are converted to mg/dL units by dividing serum creatinine values by 88.4 and multiplying total cholesterol values by 28.7. All clinical outcomes were extracted at 312 months af ter randomization (the time of divergence to corticosteroid withdrawal and maintenance) (Figure 1). Summary odds ratio (OR) and mean differ ence values with their corresponding 95% confidence intervals (CI) were calculated us ing unweighted random effects model to com bine results from selected studies. A priori 5% level of significance for Type-I error ( ) was specified to determine statistical significance. All statistical analyses were conducted using SAS software, ver 9.2 of the SAS System for Windows (2010 SAS Institute Inc, Cary, NC). RESULTS A total of 256 (109 from PubMed ; 136 from Google Scholar ; 11 secondary bibliographies) potentially eligible studies were identified, and 247 were excluded for not meeting the selec tion criteria. Nine RCTs were identified for in clusion (Figure 2) [3-11]. One-thousand ninehundred and seven patients were randomized to late withdrawal or maintenance corticoste roid therapy after kidney transplantation. Six studies included both MMF and cyclosporine [3, 5, 7, 8, 10, 11]; two trials included both TAC and MMF [4, 9]; and one clinical trial included TAC with sirolimus as concomitant immunosuppression therapy . One study did not specify the type of corticosteroid used ; three studies used prednisone [5, 8, 11]; one study used methylprednisolone ; three trials used both methylprednisolone and pred
Int J Org Transplant Med 2011; Vol. 2 (4) www.ijotm.com nisone [6, 7, 9]; and one trial used methylpred nisolone or equivalent corticosteroid . The mean time of randomization after transplanta tion was seven (range: 615) months. Table 1 shows the characteristics of trials included in the analysis. Table 2 describes characteristics of patients enrolled in the selected trials. Two studies did not report patient age and gender [3,9]; and four studies did not report patient race [3, 5, 9, 10]. The mean age of enrollees was 36.7 (range: 11.651.6) years. About 66% (n=1100) of patients were male, and 34% (n=569) were female. The majority of patients were nonAfrican Americans. One clinical trial did not mention the source of the allograft . The majority (77%) of the grafts were from cadaveric sources (n=1354), and about 22% were from live donors (n=403). For most of the patients, the received kidney was their first transplant. Four studies reported donorrecipient mismatch information, with a wellmatched donor-recipient characteristics [4, 5, 8, 10]. All included trials were published in peer-re viewed publications. One study was published in an abstract form . Two studies were dou ble-blind trials [6, 11]; one study was a singleFigure 2: Schematic representation of the review process for study inclusion.
www.ijotm.com Int J Org Transplant Med 2011; Vol. 2 (4) blind trial ; and six studies were open-label RCTs [3, 5, 7-10]. Four studies did not report the source of funding [3, 8-10]; and five of the trials were partially or completely funded by pharmaceutical companies [4-7, 11]. During an average follow-up of 15 (range: 624) months after transplantation, a total of 86 acute graft rejections (60 in the corticoste roid withdrawal group, and 26 in the cortico steroid maintenance group); 48 graft failures (20 and 28, respectively); 26 all-cause deaths (12 and 14, respectively); and 34 post-trans plant diabetes mellitus (16 and 18, respectively) were observed (Table 3). Compared to mainte nance therapy, late corticosteroid withdrawal is associated with statistically non-significant 34% increased risk of acute graft rejection (OR=1.34; 95% CI: 0.473.82). Absolute risk reduction (ARR) was 4.25% and the number needed to treat (NNT) was about 24. Late corticosteroid withdrawal was associ ated with both statistically non-significant 35% and 5% reductions in the risks of graft failure and all-cause mortality (OR=0.65; 95% CI: 0.261.60; OR=0.95; 95% CI: 0.233.93, respectively). ARR and NNT for graft failure were 1.03% and 97, and those for all-cause mortality were 0.19% and 526. Stopping corticosteroids at least three months after kidney transplantation was associated with statistically non-significant 4% increased risk of post-transplant diabetes mellitus com pared to the corticosteroid maintenance ther apy (OR=1.04; 95% CI: 0.452.41). ARR was 0.93%, and NNT was about 108. A statistically significant reduction in the mean total cholesterol was greater in the cor ticosteroid withdrawal group (mean differ ence: 18.1 mg/dL; 95% CI: 7.129.0 mg/dL), however; no reduction in serum creatinine was observed ( 0.00 mg/dL; 95% CI, 0.17 to 0.17 mg/dL) in comparison to the maintenance therapy group. Table 3 compares the two corticosteroid strat egies in terms of NNT; Figures 3 and 4 dis play the pooled meta-analysis estimates for the clinical outcomes of interest. Furthermore, two clinical trials involved pediatric patients, which reported the change in standardized height z-score as a measure for intervention effect on growth [6, 7]. Both studies showed that late corticosteroid withdrawal is associ ated with better growth outcomes compared to corticosteroid maintenance therapy. We did not pool the estimates of both studies. Table 1: Characteristics of trials included in the meta-analysis. Trial (Yr) No. of Patients Randomized Follow-Up Time (Months) Treatment Regimen PostTransplantation PostRandomization Benfield, et al (2010) 132 6 6 CS**+TAC+SIR Hocker, et al (2010) 42 12 9 CS**+CSA+MMF Del Castillo, et al (2006) 146 6 6 CS+CSA+MMF Pelletier, et al (2006) 118 15 6-12 CS # +CSA+MMF Vanrenterghem, et al (2005) 833 3 3 CS*+TAC+MMF Smak Gregoor, et al (2002) 212 6 3-6 CS # +CSA+MMF Sola, et al (2002) 92 3 24 CS**+TAC+MMF Boletis, et al (2001) 66 3 3 CS +CSA+MMF Ahsan, et al (1999) 266 3 9 CS # +CSA+MMF Total 1907 *Methylprednisolone or equivalent, # Prednisone, **Methylprednisolone and prednisone Methylprednisolone, CSA: Cyclosporine, SIR: Sirolimus
Int J Org Transplant Med 2011; Vol. 2 (4) www.ijotm.com Table 2: Characteristics of patients included in the selected trials. Trial (Year) Mean Age (Yrs) Gender, n (%) Race, n (%) Allograft Source, n (%) Allograft Characteristics Female Male Black White Live Donor Deceased Donor First Transplant n (%) HLA Mismatch meanSD Benfield, et al (2010) 11.6 54 (41) 78 (59) 20 (15.2) 99 (75) 88 (66.7) 40 (30.3) N/A N/A Hocker, et al (2010) 12.7 14 (33.3) 28 (66.7) N/A 41 (97.6) 11 (26.2) 31 (73.8) N/A N/A Del Castillo, et al (2006) N/A N/A N/A N/A N/A N/A N/A 146 (100)** N/A Pelletier, et al (2006) 45 31 (26.3) 87 (73.7) 14 (11.8) 104 (88)* 43 (36.4) 75 (63.6) N/A 3.8.8 Vanrenterghem, et at (2005) 46.3 285 (34.2) 548 (65.8) N/A 818 (98.2) 65 (7.8) 768 (92.2) 751 (90.2) 2.7(N/A) Smak Gregoor, et al (2002) 51.6 72 (34) 140 (66) N/A N/A 52 (24.5) 160 (75.5) 189 (89.1) 0.8.6 Sola, et al (2002) N/A N/A N/A N/A N/A N/A 92 (100) N/A N/A Boletis, et al (2001) 40.1 20 (30.3) 46 (69.7) N/A N/A 30 (45.4) 36 (54.5) N/A 8.3.8 Ahsan, et al (1999) 49.9 93 (45) 173 (65) 48 (18.4) 218 (82)* 114 (42.8) 152 (57.2) N/A N/A **The study reads de novo renal transplant patients HLA: Human leukocyte antigens SD: Standard deviation
www.ijotm.com Int J Org Transplant Med 2011; Vol. 2 (4) DISCUSSION It is known that continued immunosuppres sion therapy with corticosteroids in kidney transplant patients reduces the risk of acute graft rejection, however; the long-term com plications of such therapy are well-established . Prolonged corticosteroid therapy is as sociated with a spectrum of adverse outcomes, including opportunistic infections, hypergly cemia, hyperlipidemia, hypertension, glauco ma, cataracts, hypercoagulability of the blood, muscle wasting and weakness, osteoporosis, Cushings syndrome, and growth retardation in children. It is hypothesized that minimiz ing immunosuppression by gradually with drawing corticosteroids contributes to a re duction in long-term risks . We conducted a meta-analysis of published RCTs of kidney transplant patients, who were randomized to late corticosteroid withdrawal (at > 3 months post-transplantation) therapy or corticoste roid maintenance therapy under continuation of concurrent immunosuppression by either TAC or MMF, or both. The clinical outcomes of interest included the incidence of acute graft rejection; graft failure; all-cause mortality; post-transplant diabetes; changes in serum creatinine and total cholesterol levels; and changes in standardized z-score of height in pediatric patients. Although statistically not significant, our findings indicate that late corticosteroid with drawal in kidney transplant patients is asso ciated with 34% increase in the risk of acute graft rejection (95% CI for OR: 0.473.82); and 4% increase in the risk of post-transplant diabetes mellitus (95% CI for OR: 0.452.41). However, this strategy resulted in 35% and 5% reductions in the risk of graft failure and patients all-cause mortality, respectively (95% CI for OR: 0.261.60; and 95% CI for OR: 0.233.93, respectively). Stopping corticoste roid therapy was associated with a statistically significant substantial reduction in total cho lesterol levels (mean difference: 18.05 mg/dL; 95% CI: 7.1229.0 mg/dL), but did not reduce serum creatinine levels ( 0.00 mg/dL; 95% CI: 0.17 to 0.17). Two studies showed that cor ticosteroids withdrawal was presented with better growth outcomes in pediatric kidney transplant patients [6, 7]. Moreover, late corticosteroid withdrawal can be compared with maintenance therapy in terms of more clinically significant measure, the NNT (Table 3), which can be interpreted as the average number of patients that is re quired to withdraw corticosteroid therapy at least three months after kidney transplanta Table 3: Comparing the two corticosteroid therapy strategies in terms of number needed to treat (NNT) Clinical Outcome Corticosteroid Withdrawal Group Corticosteroid Maintenance Group ARR # NNT** No. of Events No. of Patients AR* No. of Events No. of Patients AR* Acute Graft Rejection 60 705 8.51 26 610 4.26 4.25 23.5 Graft Failure 20 537 3.72 28 589 4.75 1.03 97 All-Cause Mortality 12 561 2.14 14 600 2.33 0.19 526 PTDM 16 345 4.64 18 323 5.57 0.93 107.5 *Values are in percentages #Calculated by subtracting the AR values in the maintenance group from the AR values in the withdrawal group AR: Absolute risk, ARR: Absolute risk reduction NNT: Number needed to treat, PTDM: Post-transplant diabetes mellitus
Int J Org Transplant Med 2011; Vol. 2 (4) www.ijotm.com Figure 3: Analysis of clinical outcomes following late corticosteroid withdrawal therapy vs. corticosteroid maintenance therapy in renal transplant patients. Acute graft rejection (A); graft failure (B); and all-cause mortality (C).
www.ijotm.com Int J Org Transplant Med 2011; Vol. 2 (4) Figure 4: Analysis of clinical outcomes following late corticosteroid withdrawal therapy vs. corticosteroid maintenance therapy in renal transplant patients. Post-transplant diabetes (A); change in serum creatinine (B); and change in total cholesterol (C).
Int J Org Transplant Med 2011; Vol. 2 (4) www.ijotm.com tion and followed for an average of 15 months to observe one less clinical outcome of inter est by the end of the 15-month period. To il lustrate, for acute graft rejection, the kidney transplant specialist would need 24 kidney transplant patients, on average, to withdraw corticosteroid in order to prevent one acute re jection of the transplanted kidney. The same applies for graft failure, all-cause mortality, and post-transplant incidence of diabetes mel litus; on average, 97 patients are needed to stop corticosteroid treatment to prevent the occurrence of one case of graft failure; 526 pa tients are needed to withdraw corticosteroid treatment to observe one less death event; and about 108 patients are required to stop cor ticosteroid therapy in order to prevent one case of new-onset diabetes mellitus at the end of the follow-up time. It is clear that larger NNT values are indicators of less effective in terventions. In another word, it requires sev eral patients to be exposed to the intervention (corticosteroid withdrawal) to observe one ad ditional success, on average, compared to the standard alternative (corticosteroid mainte nance). Our study demonstrates statistically non-sig nificant results that show late corticosteroid withdrawal could reduce the risks of long-term complications associated with immunosup pression in kidney transplant patients, how ever; it did not show that such strategy could reduce the risk of acute graft rejections and the incidence of diabetes mellitus after kidney transplantation. Nevertheless, it shows clini cally significant end-points in terms of NNT values for acute rejection and graft failure. The present meta-analysis has several limita tions. First, the results should be interpreted with caution, because many variables were not uniformly distributed across the selected trials. Heterogeneity was apparent in terms of study population characteristics, follow-up and randomization times, outcome measure ment time, and treatment regimen charac teristics. These differences imparted to the statistical differences in the effect size be tween the individual studies (Figures 3 and 4). Second, our analysis did not have suffi cient statistical power to detect statistically significant differences between the late corti costeroid withdrawal group and the cortico steroid maintenance group. This was mainly attributed to the fact that included trials did not have large number of enrollees. Third, we did not include unpublished evidence, which might have more recent findings, however, un published literatures more likely have statisti cally non-significant findings, which prevent them from reaching the information database, i.e. publication bias. Unlike published studies, unpublished works could impart bias because they are not subjected to the peer review pro cess. Finally, meta-analysis is a retrospective research that is highly dependent upon the inherent limitations, strengths, and quality of the included studies. A detailed study protocol was developed prior to the literature search, data extraction, and data analysis phases, which minimized the potential for systematic errors. Given the heterogeneity between the trials, a random effects model was deemed appropriate. In addition, unweighted method is considered more valid in meta-analysis research, because the weights are random entities, and should not be treated as fixed alternatives, which un fortunately is the case in most of the published meta-analyses. CONCLUSIONS Late corticosteroid withdrawal under TAC and/or MMF-lead immunosuppression after kidney transplantation could provide benefits in terms of total cholesterol, patient and graft survival, and pediatric growth. This strategy, however did not reduce the risk of acute graft rejection, post-transplant diabetes mellitus, and deterioration in serum creatinine levels. Additional large scale, multicenter RCTs are required to further evaluate the long-term clinical outcomes associated with late corti costeroid withdrawal and assessing cortico steroid-sparing effects of TAC and MMF in kidney transplant patients.
www.ijotm.com Int J Org Transplant Med 2011; Vol. 2 (4) ACKNOWLEDGEMENTS The authors thank Vikas Dharnidharka, MD, Division of Pediatric Nephrology, College of Medicine; Caprice Knapp, PhD, Department of Health Outcomes and Policy; and Teba Mo hammad, BA, College of Education, Univer sity of Florida, for their valuable comments on the review. This work was partially supported by grants 1UL1RR029890 and U54RR02508 from the National Center of Research Re sources (NCRR), National Institutes of Health (NIH), USA. CONFLICT OF INTEREST: None. REFERENCES 1. Hollander AA, Hene RJ, Hermans J, et al Late prednisolone withdrawal in cyclosporine-treated kidney transplant patients: A randomized study. J Am Soc Nephrol 1997; 8 :294-301. 2. Ratcliffe PJ, Dudley CR, Higgins RM, et al Ran domised controlled trial of steroid withdrawal in renal transplant recipients receiving triple immu nosuppression. Lancet 1996; 348 :643-8. 3. Del Castillo D, Franco A, Tabernero JM, et al Ste roid withdrawal assessment in mycophenolate so dium versus standard regimen to prevent acute re jection in de novo kidney transplantation (abstract 2252). Am J Transplant 2008; 6(s2) :810-1. 4. Vanrenterghem Y, van Hooff JP, Squifflet JP, et al Minimization of immunosuppressive therapy af ter renal transplantation: results of a randomized controlled trial. Am J Transplant 2005; 5 :87-95. 5. Smak Gregoor PJH, De Sevaux RGL, Ligtenberg G, et al Withdrawal of cyclosporine or predni sone six months after kidney transplantation in patients on triple drug therapy: a randomized, prospective, multicenter study. J Am Soc Nephrol 2002; 13 :1365-73. 6. Benfield MR, Bartosh S, Ikle D, et al A random ized double-blind, placebo controlled trial of ste roid withdrawal after pediatric renal transplanta tion. Am J Transplant 2010; 10 :81-8. 7. Hocker B, Weber LT, Feneberg R, et al Improved growth and cardiovascular risk after late steroid withdrawal: 2-year results of prospective, ran domised trial in pediatric renal transplantation. Nephrol Dial Transplant 2010; 25 :617-24. 8. Pelletier RP, Akin B, Ferguson RM. Prospective, randomized trial of steroid withdrawal in kidney recipients treated with mycophenolate mofetil and cyclosporine. Clin Transplant 2006; 20 :10-8. 9. Sola E, Alferez MJ, Cabello M, et al Low-dose and rapid steroid withdrawal in renal transplant pa tients treated with tacrolimus and mycophenolate mofetil. Transplant Proc 2002; 34 :1689-90. 10. Boletis JN, Konstadinidou I, Chelioti H, et al Suc cessful withdrawal of steroid after renal trans plantation. Transplant Proc 2001; 33 :1231-3. 11. Ahsan N, Hricik D, Matas A, et al Prednisone withdrawal in kidney transplant recipients on cyclosporine and mycophenolate mofetila prospective randomized study. Transplantation 1999; 68 :1865-74. 12. Pascual M, Theruvath T, Kawai T, et al Strategies to improve long-term outcomes after renal trans plantation. N Engl J Med 2002; 346 :580-90. 13. Rang HP, Dale MM, Ritter JM, Flower RJ. The pi tuitary and the adrenal cortex. In: Rang HP, Dale MM, Ritter JM, Flower RJ, ed. Rang and Dales Pharmacology 6 th ed. Philadelphia, PA: Churchill Livingstone, Elsevier, 2007 :420-36. 14. Miller BW. Solid organ transplant medicine. In: Green GB, Harris IS, Lin GA, Moylan KC, ed. The Washington Manual of Medical Therapeutics 31 st ed. USA: Lippincott William & Wilkins, 2004 :341.