Subgroup analyses in randomized controlled trials: the need for risk stratification in kidney transplantation

The Likely Underestimated Impact of Lifestyle Intervention: Diabetes Prevention Program Translation Examples

INTRODUCTION

Lifestyle interventions promoting weight loss and physical activity are important elements of prevention efforts with the evaluation of program impact typically limited to weight loss. Unfortunately, diabetes/cardiovascular disease risk factors and activity are infrequently reported and inconsistent in findings when examined. This inconsistency may partially be due to a lack of consideration for ceiling effects because of broad risk profile inclusion criteria in community translation efforts. To demonstrate this, change in each individual cardiometabolic risk factor limited to those who, at baseline, had a clinically defined abnormal value for that risk factor was examined in 2 cohorts using identical community translations of the Diabetes Prevention Program lifestyle intervention.

METHODS

For both studies (2010-2014, 2014-2019), adults with prediabetes and/or metabolic syndrome were recruited through community centers. Outcome measures collected at baseline and 6 months included BMI, activity, blood pressure, lipids, and fasting glucose. Data analyses examined pre-post change in each variable after 6 months of intervention and change within randomized groups at 6 months.

RESULTS

Change results were examined for the entire cohort and separately for participants with baseline values outside the recommended range for that risk factor. Whether assessing the pre-post intervention change or change within the randomized groups at 6 months, often the risk factor-specific approach demonstrated a greater effect size for that variable and sometimes newly reached statistical significance.

CONCLUSIONS

When examining the effectiveness of community translation efforts, consideration of the individual's baseline profile with risk factor-specific analysis is suggested to understand the full extent of the impact of the intervention.

Complement-Binding Donor-Specific Anti-HLA Antibodies: Biomarker for Immunologic Risk Stratification in Pediatric Kidney Transplantation Recipients

Antibody-mediated rejection is a common cause of early kidney allograft loss but the specifics of antibody measurement, therapies and endpoints have not been universally defined. In this retrospective study, we assessed the performance of risk stratification using systematic donor-specific antibody (DSA) monitoring. Included in the study were children who underwent kidney transplantation between January 1, 2010 and March 1, 2018 at Stanford, with at least 12-months follow-up. A total of 233 patients were included with a mean follow-up time of 45 (range, 9–108) months. Median age at transplant was 12.3 years, 46.8% were female, and 76% had a deceased donor transplant. Fifty-two (22%) formed C1q-binding de novo donor-specific antibodies (C1q-dnDSA). After a standardized augmented immunosuppressive protocol was implemented, C1q-dnDSA disappeared in 31 (58.5%). Graft failure occurred in 16 patients at a median of 54 (range, 5–83) months, of whom 14 formed dnDSA. The 14 patients who lost their graft due to rejection, all had persistent C1q-dnDSA. C1q-binding status improved the individual risk assessment, with persistent; C1q binding yielding the strongest independent association of graft failure (hazard ratio, 45.5; 95% confidence interval, 11.7–177.4). C1q-dnDSA is more useful than standard dnDSA as a noninvasive biomarker for identifying patients at the highest risk of graft failure.

Value of Donor-Specific Anti-HLA Antibody Monitoring and Characterization for Risk Stratification of Kidney Allograft Loss

The diagnosis system for allograft loss lacks accurate individual risk stratification on the basis of donor-specific anti-HLA antibody (anti-HLA DSA) characterization. We investigated whether systematic monitoring of DSA with extensive characterization increases performance in predicting kidney allograft loss. This prospective study included 851 kidney recipients transplanted between 2008 and 2010 who were systematically screened for DSA at transplant, 1 and 2 years post-transplant, and the time of post-transplant clinical events. We assessed DSA characteristics and performed systematic allograft biopsies at the time of post-transplant serum evaluation. At transplant, 110 (12.9%) patients had DSAs; post-transplant screening identified 186 (21.9%) DSA-positive patients. Post-transplant DSA monitoring improved the prediction of allograft loss when added to a model that included traditional determinants of allograft loss (increase in c statistic from 0.67; 95% confidence interval [95% CI], 0.62 to 0.73 to 0.72; 95% CI, 0.67 to 0.77). Addition of DSA IgG3 positivity or C1q binding capacity increased discrimination performance of the traditional model at transplant and post-transplant. Compared with DSA mean fluorescence intensity, DSA IgG3 positivity and C1q binding capacity adequately reclassified patients at lower or higher risk for allograft loss at transplant (category-free net reclassification index, 1.30; 95% CI, 0.94 to 1.67; P<0.001 and 0.93; 95% CI, 0.49 to 1.36; P<0.001, respectively) and post-transplant (category-free net reclassification index, 1.33; 95% CI, 1.03 to 1.62; P<0.001 and 0.95; 95% CI, 0.62 to 1.28; P<0.001, respectively). Thus, pre- and post-transplant DSA monitoring and characterization may improve individual risk stratification for kidney allograft loss.

From Humoral Theory to Performant Risk Stratification in Kidney Transplantation

The purpose of the present review is to describe how we improve the model for risk stratification of transplant outcomes in kidney transplantation by incorporating the novel insights of donor-specific anti-HLA antibody (DSA) characteristics. The detection of anti-HLA DSA is widely used for the assessment of pre- and posttransplant risks of rejection and allograft loss; however, not all anti-HLA DSA carry the same risk for transplant outcomes. These antibodies have been shown to cause a wide spectrum of effects on allografts, ranging from the absence of injury to indolent or full-blown acute antibody-mediated rejection. Consequently, the presence of circulating anti-HLA DSA does not provide a sufficient level of accuracy for the risk stratification of allograft outcomes. Enhancing the predictive performance of anti-HLA DSA is currently one of the most pressing unmet needs for facilitating individualized treatment choices that may improve outcomes. Recent advancements in the assessment of anti-HLA DSA properties, including their strength, complement-binding capacity, and IgG subclass composition, significantly improved the risk stratification model to predict allograft injury and failure. Although risk stratification based on anti-HLA DSA properties appears promising, further specific studies that address immunological risk stratification in large and unselected populations are required to define the benefits and cost-effectiveness of such comprehensive assessment prior to clinical implementation.

Autophagy in kidney transplants of sirolimus treated recipients

Background

Mammalian target of rapamycin (mTOR) inhibitors are increasingly used as immunosuppressive agents in kidney transplantation. In the experimental setting it has been shown that mTOR inhibitors promote autophagy, but the concept that this might also occur in transplant patients has not been addressed.

Objectives

This study was designed to investigate the association between mTOR inhibition and autophagy in renal transplants under routine clinical conditions.

Materials and Methods

Protocol transplant biopsies of patients receiving sirolimus were compared to biopsies of patients treated without mTOR inhibitor. Electron microscopy was used for quantitative stereological analysis of autophagosomal volume fractions. Ultrastructural analysis was focused on podocytes to avoid cell type bias. Autophagy-related gene products were profiled by QPCR from laser assisted microdissected glomeruli and by immunohistochemistry for semiquantitative evaluation.

Results

By electron microscopy, we observed a significant > 50% increase in podocytic autophagosomal volume fractions in patients treated with sirolimus. Evaluation of biopsy material from the same patients using transcriptional profiling of laser capture microdissected glomeruli revealed no differences in autophagy-related gene expressions. Immunohistochemical evaluation of autophagic degradation product p62 was also unaltered whereas a significant increase was observed in podocytic LC3 positivity in biopsies of sirolimus treated patients.

Conclusions

These results indicate an association of sirolimus treatment and autophagosome formation in transplant patients. However, they might reflect autophagosomal buildup rather than increased autophagic flux. Further research is needed to investigate the potential functional consequences in short- and long-term outcome of patients treated with mTOR inhibitors.

LEADER 7: cardiovascular risk profiles of US and European participants in the LEADER diabetes trial differ

AIMS

To determine whether US and European participants in the Liraglutide Effect and Action in Diabetes: Evaluation of cardiovascular outcome Results (LEADER) trial differ regarding risk factors for cardiovascular mortality and morbidity.

METHODS

Baseline data, stratified for prior cardiovascular disease (CVD), were compared using multivariable logistic regression analysis to establish whether region is an independent determinant of achieved targets for glycated hemoglobin (HbA1c), blood pressure (BP), and low-density lipoprotein (LDL)-cholesterol.

RESULTS

Independent of CVD history, US participants were more often of non-White origin and had a longer history of type 2 diabetes, higher body weight, and higher baseline HbA1c. They had substantially lower systolic and diastolic BP, and a marginally lower LDL-cholesterol level. Fewer US participants were diagnosed with left ventricular dysfunction. In the largest group of patients, those with prior CVD and the highest cardiovascular risk, US participants were more often female, had a higher waist circumference, and had a decreased estimated glomerular filtration rate, but less frequently prior myocardial infarction or angina pectoris.

CONCLUSIONS

There were baseline differences between US and European participants. These differences may result from variation in regional targets for cardiovascular risk factor management, and should be considered in the analysis and reporting of the trial results. Clinical trial identifier: ClinicalTrials.gov, NCT01179048.

A Preliminary Analysis of Individuals With Serious Mental Illness and Comorbid Diabetes

OBJECTIVE

To understand factors related to managing illness in older individuals with serious mental illness (SMI).

METHODS

Baseline data from 200 individuals with SMI and diabetes enrolled in a study were used to compare characteristics between older (age >55) vs. younger (age ≤55) individuals.

RESULTS

Older individuals had better diabetes control compared to younger individuals, those with major depressive disorder had diabetes for a longer duration, worse diabetic control, and more emergency department encounters.

CONCLUSIONS

Helping younger individuals with SMI learn to manage their mental and physical health early-on might minimize the negative and cumulative effect of diabetes.

Risk Stratification for Rejection and Infection after Kidney Transplantation

BACKGROUND AND OBJECTIVES

Definition of individual risk profile is the first step to implement strategies to keep the delicate balance between under- and overimmunosuppression after kidney transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used data from the Efficacy Limiting Toxicity Elimination Symphony Study (1190 patients between 2002 and 2004) to model risk of rejection and infection in the first year after kidney transplantation. External validation was performed in a study population from the Fixed-Dose Concentration-Controlled Trial (630 patients between 2003 and 2006).

RESULTS

Despite different temporal dynamics, rejections and severe infections had similar overall incidences in the first year after transplantation (23.4% and 25.5%, respectively), and infections were the principal cause of death (43.2% of all deaths). Recipient older age, deceased donor, higher number of HLA mismatches, and high risk for cytomegalovirus disease were associated with infection; deceased donor, higher number of HLA mismatches, and immunosuppressive therapy including cyclosporin A (compared with tacrolimus), with rejection. These factors were integrated into a two-dimensional risk stratification model, which defined four risk groups: low risk for infection and rejection (30.8%), isolated risk for rejection (36.1%), isolated risk for infection (7.0%), and high risk for infection and rejection (26.1%). In internal validation, this model significantly discriminated the subgroups in terms of composite end point (low risk for infection/rejection, 24.4%; isolated risk for rejection and isolated risk for infection, 31.3%; high risk for infection/rejection, 54.4%; P<0.001), rejection episodes (isolated risk for infection and low risk for infection/rejection, 13.0%; isolated risk for rejection and high risk for infection/rejection, 24.2%; P=0.001), and infection episodes (low risk for infection/rejection and isolated risk for rejection, 12.0%; isolated risk for infection and high risk for infection/rejection, 37.6%; P<0.001). External validation confirmed the applicability of the model to an independent cohort.

CONCLUSIONS

We propose a two-dimensional risk stratification model able to disentangle the individual risk for rejection and infection in the first year after kidney transplantation. This concept can be applied to implement a personalized immunosuppressive and antimicrobial treatment approach.

Mycophenolic acid versus azathioprine as primary immunosuppression for kidney transplant recipients

BACKGROUND

Modern immunosuppressive regimens after kidney transplantation usually use a combination of two or three agents of different classes to prevent rejection and maintain graft function. Most frequently, calcineurin-inhibitors (CNI) are combined with corticosteroids and a proliferation-inhibitor, either azathioprine (AZA) or mycophenolic acid (MPA). MPA has largely replaced AZA as a first line agent in primary immunosuppression, as MPA is believed to be of stronger immunosuppressive potency than AZA. However, treatment with MPA is more costly, which calls for a comprehensive assessment of the comparative effects of the two drugs.

OBJECTIVES

This review of randomised controlled trials (RCTs) aimed to look at the benefits and harms of MPA versus AZA in primary immunosuppressive regimens after kidney transplantation. Both agents were compared regarding their efficacy for maintaining graft and patient survival, prevention of acute rejection, maintaining graft function, and their safety, including infections, malignancies and other adverse events. Furthermore, we investigated potential effect modifiers, such as transplantation era and the concomitant immunosuppressive regimen in detail.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register (to 21 September 2015) through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

All RCTs about MPA versus AZA in primary immunosuppression after kidney transplantation were included, without restriction on language or publication type.

DATA COLLECTION AND ANALYSIS

Two authors independently determined study eligibility, assessed risk of bias and extracted data from each study. Statistical analyses were performed using the random-effects model and the results were expressed as risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

We included 23 studies (94 reports) that involved 3301 participants. All studies tested mycophenolate mofetil (MMF), an MPA, and 22 studies reported at least one outcome relevant for this review. Assessment of methodological quality indicated that important information on factors used to judge susceptibility for bias was infrequently and inconsistently reported.MMF treatment reduced the risk for graft loss including death (RR 0.82, 95% CI 0.67 to 1.0) and for death-censored graft loss (RR 0.78, 95% CI 0.62 to 0.99, P < 0.05). No statistically significant difference for MMF versus AZA treatment was found for all-cause mortality (16 studies, 2987 participants: RR 0.95, 95% CI 0.70 to 1.29). The risk for any acute rejection (22 studies, 3301 participants: RR 0.65, 95% CI 0.57 to 0.73, P < 0.01), biopsy-proven acute rejection (12 studies, 2696 participants: RR 0.59, 95% CI 0.52 to 0.68) and antibody-treated acute rejection (15 studies, 2914 participants: RR 0.48, 95% CI 0.36 to 0.65, P < 0.01) were reduced in MMF treated patients. Meta-regression analyses suggested that the magnitude of risk reduction of acute rejection may be dependent on the control rate (relative risk reduction (RRR) 0.34, 95% CI 0.10 to 1.09, P = 0.08), AZA dose (RRR 1.01, 95% CI 1.00 to 1.01, P = 0.10) and the use of cyclosporin A micro-emulsion (RRR 1.27, 95% CI 0.98 to 1.65, P = 0.07). Pooled analyses failed to show a significant and meaningful difference between MMF and AZA in kidney function measures.Data on malignancies and infections were sparse, except for cytomegalovirus (CMV) infections. The risk for CMV viraemia/syndrome (13 studies, 2880 participants: RR 1.06, 95% CI 0.85 to 1.32) was not statistically significantly different between MMF and AZA treated patients, whereas the likelihood of tissue-invasive CMV disease was greater with MMF therapy (7 studies, 1510 participants: RR 1.70, 95% CI 1.10 to 2.61). Adverse event profiles varied: gastrointestinal symptoms were more likely in MMF treated patients and thrombocytopenia and elevated liver enzymes were more common in AZA treatment.

AUTHORS' CONCLUSIONS

MMF was superior to AZA for improvement of graft survival and prevention of acute rejection after kidney transplantation. These benefits must be weighed against potential harms such as tissue-invasive CMV disease. However, assessment of the evidence on safety outcomes was limited due to rare events in the observation periods of the studies (e.g. malignancies) and inconsistent reporting and definitions (e.g. infections, adverse events). Thus, balancing benefits and harms of the two drugs remains a major task of the transplant physician to decide which agent the individual patient should be started on.

Massage for low-back pain

BACKGROUND

Low-back pain (LBP) is one of the most common and costly musculoskeletal problems in modern society. It is experienced by 70% to 80% of adults at some time in their lives. Massage therapy has the potential to minimize pain and speed return to normal function.

OBJECTIVES

To assess the effects of massage therapy for people with non-specific LBP.

SEARCH METHODS

We searched PubMed to August 2014, and the following databases to July 2014: MEDLINE, EMBASE, CENTRAL, CINAHL, LILACS, Index to Chiropractic Literature, and Proquest Dissertation Abstracts. We also checked reference lists. There were no language restrictions used.

SELECTION CRITERIA

We included only randomized controlled trials of adults with non-specific LBP classified as acute, sub-acute or chronic. Massage was defined as soft-tissue manipulation using the hands or a mechanical device. We grouped the comparison groups into two types: inactive controls (sham therapy, waiting list, or no treatment), and active controls (manipulation, mobilization, TENS, acupuncture, traction, relaxation, physical therapy, exercises or self-care education).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures and followed CBN guidelines. Two independent authors performed article selection, data extraction and critical appraisal.

MAIN RESULTS

In total we included 25 trials (3096 participants) in this review update. The majority was funded by not-for-profit organizations. One trial included participants with acute LBP, and the remaining trials included people with sub-acute or chronic LBP (CLBP). In three trials massage was done with a mechanical device, and the remaining trials used only the hands. The most common type of bias in these studies was performance and measurement bias because it is difficult to blind participants, massage therapists and the measuring outcomes. We judged the quality of the evidence to be "low" to "very low", and the main reasons for downgrading the evidence were risk of bias and imprecision. There was no suggestion of publication bias. For acute LBP, massage was found to be better than inactive controls for pain ((SMD -1.24, 95% CI -1.85 to -0.64; participants = 51; studies = 1)) in the short-term, but not for function ((SMD -0.50, 95% CI -1.06 to 0.06; participants = 51; studies = 1)). For sub-acute and chronic LBP, massage was better than inactive controls for pain ((SMD -0.75, 95% CI -0.90 to -0.60; participants = 761; studies = 7)) and function (SMD -0.72, 95% CI -1.05 to -0.39; 725 participants; 6 studies; ) in the short-term, but not in the long-term; however, when compared to active controls, massage was better for pain, both in the short ((SMD -0.37, 95% CI -0.62 to -0.13; participants = 964; studies = 12)) and long-term follow-up ((SMD -0.40, 95% CI -0.80 to -0.01; participants = 757; studies = 5)), but no differences were found for function (both in the short and long-term). There were no reports of serious adverse events in any of these trials. Increased pain intensity was the most common adverse event reported in 1.5% to 25% of the participants.

AUTHORS' CONCLUSIONS

We have very little confidence that massage is an effective treatment for LBP. Acute, sub-acute and chronic LBP had improvements in pain outcomes with massage only in the short-term follow-up. Functional improvement was observed in participants with sub-acute and chronic LBP when compared with inactive controls, but only for the short-term follow-up. There were only minor adverse effects with massage.

Predictability of persistent frequent attendance in primary care: a temporal and geographical validation study

BACKGROUND

Frequent attenders are patients who visit their general practitioner exceptionally frequently. Frequent attendance is usually transitory, but some frequent attenders become persistent. Clinically, prediction of persistent frequent attendance is useful to target treatment at underlying diseases or problems. Scientifically it is useful for the selection of high-risk populations for trials. We previously developed a model to predict which frequent attenders become persistent.

AIM

To validate an existing prediction model for persistent frequent attendance that uses information solely from General Practitioners' electronic medical records.

METHODS

We applied the existing model (N = 3,045, 2003-2005) to a later time frame (2009-2011) in the original derivation network (N = 4,032, temporal validation) and to patients of another network (SMILE; 2007-2009, N = 5,462, temporal and geographical validation). Model improvement was studied by adding three new predictors (presence of medically unexplained problems, prescriptions of psychoactive drugs and antibiotics). Finally, we derived a model on the three data sets combined (N = 12,539). We expressed discrimination using histograms of the predicted values and the concordance-statistic (c-statistic) and calibration using the calibration slope (1 = ideal) and Hosmer-Lemeshow tests.

RESULTS

The existing model (c-statistic 0.67) discriminated moderately with predicted values between 7.5 and 50 percent and c-statistics of 0.62 and 0.63, for validation in the original network and SMILE network, respectively. Calibration (0.99 originally) was better in SMILE than in the original network (slopes 0.84 and 0.65, respectively). Adding information on the three new predictors did not importantly improve the model (c-statistics 0.64 and 0.63, respectively). Performance of the model based on the combined data was similar (c-statistic 0.65).

CONCLUSION

This external validation study showed that persistent frequent attenders can be prospectively identified moderately well using data solely from patients' electronic medical records.

Biomarkers as a tool for management of immunosuppression in transplant patients

Therapeutic drug monitoring is a well-established approach in transplantation medicine to guide immunosuppressive therapy. However, it cannot always predict the effects of immunosuppressive drugs on immune cells, because it does not reflect any aspect of an individual patient's immune system. Pharmacodynamic monitoring is a more recent strategy to provide information about the biologic effect of a specific drug or drug combination on the individual transplant patient. Currently, there is a large number of different biomarkers that either directly (specific markers) or indirectly (global markers) relate to the pharmacodynamic effects of immunosuppressive drugs and are under investigation as potential candidates to be introduced in clinical practice. Such biomarkers may be useful to identify patients at risk of developing acute rejection, infection, or cancer as well as patients who are suitable for minimization of immunosuppressant therapy and may be helpful to manage the timing and rate of immunosuppressant weaning. Serial longitudinal monitoring may allow maintenance of an individualized immunosuppressive regimen. Thus, biomarker monitoring is a potential complementary tool to therapeutic drug monitoring. This review summarizes the current state of knowledge about the use of a number of global or drug-specific pharmacodynamic biomarkers. It is not a comprehensive overview of the literature available, but rather an evidence-based reflection by experts who are intensively involved in scientific work in this field.