Registry of Randomized Controlled Trials in Transplantation

Comparison of protocols and registry entries to published reports for randomised controlled trials

BACKGROUND

Publication of complete trial results is essential if people are to be able to make well-informed decisions about health care. Selective reporting of randomised controlled trials (RCTs) is a common problem.

OBJECTIVES

To systematically review studies of cohorts of RCTs to compare the content of trial reports with the information contained in their protocols, or entries in a trial registry.

SEARCH STRATEGY

We conducted electronic searches in Ovid MEDLINE (1950 to August 2010); Ovid EMBASE (1980 to August 2010); ISI Web of Science (1900 to August 2010) and the Cochrane Methodology Register (Issue 3, 2010), checked reference lists, and asked authors of eligible studies to identify further studies. Studies were not excluded based on language of publication or our assessment of their quality.

SELECTION CRITERIA

Published or unpublished cohort studies comparing the content of protocols or trial registry entries with published trial reports.

DATA COLLECTION AND ANALYSIS

Data were extracted by two authors independently. Risk of bias in the cohort studies was assessed in relation to follow up and selective reporting of outcomes. Results are presented separately for the comparison of published reports to protocols and trial registry entries.

MAIN RESULTS

We included 16 studies assessing a median of 54 RCTs (range: 2 to 362). Twelve studies compared protocols to published reports and four compared trial registry entries to published reports. In two studies, eligibility criteria differed between the protocol and publication in 19% and 100% RCTs. In one study, 16% (9/58) of the reports included the same sample size calculation as the protocol. In one study, 6% (4/63) of protocol-report pairs gave conflicting information regarding the method of allocation concealment, and 67% (49/73) of blinded studies reported discrepant information on who was blinded. In one study unacknowledged discrepancies were found for methods of handling protocol deviations (44%; 19/43), missing data (80%; 39/49), primary outcome analyses (60%; 25/42) and adjusted analyses (82%; 23/28). One study found that of 13 protocols specifying subgroup analyses, 12 of these 13 trials reported only some, or none, of these. Two studies found that statistically significant outcomes had a higher odds of being fully reported compared to nonsignificant outcomes (range of odds ratios: 2.4 to 4.7). Across the studies, at least one primary outcome was changed, introduced, or omitted in 4-50% of trial reports.

AUTHORS' CONCLUSIONS

Discrepancies between protocols or trial registry entries and trial reports were common, although reasons for these were not discussed in the reports. Full transparency will be possible only when protocols are made publicly available or the quality and extent of information included in trial registries is improved, and trialists explain substantial changes in their reports.

Mycophenolate mofetil decreases acute rejection and may improve graft survival in renal transplant recipients when compared with azathioprine: a systematic review

BACKGROUND

Mycophenolate mofetil (MMF) has increasingly replaced azathioprine (AZA) as the antimetabolite of choice in immunosuppressive protocols. Initial trials comparing MMF with AZA in patients receiving cyclosporine A sandimmune showed a clinical benefit in reducing the incidence of acute rejections. It has been questioned whether this benefit remains significant when using newer formulations of cyclosporine A (neoral) and tacrolimus.

METHODS

Literature searches were performed using the Transplant Library, Cochrane library, Medline, and Embase for all randomized controlled trials directly comparing MMF with AZA in renal transplant recipients. Trials were assessed for quality using the Jadad scoring system. Trials were pooled using meta-analysis software. Confidence intervals were set at 95%.

RESULTS

Nineteen relevant studies were identified, including a total of 3143 patients. MMF significantly reduces the risk of acute rejection when used in combination with any calcineurin inhibitor (relative risk 0.62, 0.55-0.87, P<0.00001). The hazard for graft loss, including death with a functioning graft, is also significantly reduced in patients treated with MMF (hazard ratio 0.76, 0.59-0.98, P=0.037). There is no significant difference in patient survival or renal transplant function between groups. Risk of adverse events, including cytomegalovirus infection, anemia, leukopenia or rates of malignancy, does not differ significantly. A greater risk of diarrhea is seen in MMF-treated patients.

CONCLUSIONS

We have shown that MMF used with a calcineurin inhibitor does indeed confer a clinical benefit over AZA by reducing the risk of acute rejection and also possibly reducing graft loss. This effect is independent of whether MMF is used in combination with sandimmune, neoral or tacrolimus.

The Clinical Benefits of Cyclosporine C2-Level Monitoring: A Systematic Review

BACKGROUND

Monitoring of cyclosporine microemulsion (Neoral) using 2-hour postdose (C2) levels is alleged to improve clinical outcomes, but the efficacy of this strategy is uncertain.

METHODS

A systematic literature search was performed for trials directly comparing patients monitored with C2 levels with those monitored by trough (C0) levels. Primary outcomes assessed were renal function and acute rejection.

RESULTS

A total of 29 studies met the inclusion criteria. Only 10 of these were randomized controlled trials. Overall quality was poor and this precluded meta-analysis. The most consistent finding in de novo renal, hepatic, and cardiac transplant recipients is a higher mean cyclosporine dose in the early postoperative period in C2 monitored patients. There is no clear evidence that this leads to impaired renal function. In the majority of studies, the monitoring strategy had no significant effect on the rate of acute rejection. In stable transplant recipients, the majority of studies show a reduction in mean cyclosporine dose with adoption of C2 monitoring. No obvious clinical benefit was derived from this reduction in dose.

CONCLUSION

In de novo transplant patients, there is little evidence from prospective studies to support the theoretical benefits of C2 monitoring. Potential dose reductions in stable patients may reduce costs, but no short-term clinical benefit is seen. Quality of studies in this area is poor, and the practical limitations of C2 monitoring mean that further evidence is required before a strategy for the administration of cyclosporine based on C2 levels can be recommended.

Reporting of Rejection after Renal Transplantation in Large Immunosuppressive Trials: Biopsy-Proven, Clinical, Presumed, or Treated Rejection?

BACKGROUND

Prevention of acute rejection still is an important endpoint in randomized controlled trials. Poor study reporting may create confusion and render decision-making difficult. The present study thoroughly analyses the presentation and definition of rejection in reports on large multicenter immunosuppressive trials published in the field of renal transplantation.

METHODS

Publications of large immunosuppression trials in kidney transplantation were identified by a predefined search strategy. The reported acute and biopsy-proven acute rejection (BPAR) episodes and additional information on number of patients recruited, publication year, impact factor, definition of acute rejection and the reporting of efficacy analyses were extracted. All reports were scanned for (a) at what point and (b) for which signs or reasons a biopsy was performed.

RESULTS

Eight of 41 (19.5%) papers investigating rejection rates reported a sufficient definition of acute rejection. Twenty-eight of 41 (68.3%) presented more than one rejection rate and were published in significantly higher impact journals. The absolute difference between clinical rejection and BPAR had a median of 6.5% and a wide range (0-16.9%). Efficacy analysis was presented in all but four (90.2%) reports. Thirteen of 35 (37.1%) papers did report the timing of the biopsies and 25 of 35 (71.4%) publications gave specifications of when a biopsy sample should be taken.

CONCLUSIONS

The requirements of proper reporting of rejection episodes are not fulfilled in most of the publications and the use of many different terms for the description of rejection rates is confusing at present. Our comprehensive review clearly demonstrates the need for improved and standardized reporting of rejection episodes and we suggest to report both acute rejection and BPAR.