Missing Data in Randomized Clinical Trials for Weight Loss: Scope of the Problem,State of the Field,and Performance of Statistical Methods

Background

Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods.

Methodology/Principal Findings

We searched PubMed and Cochrane databases (2000–2006) for articles published in English and manually searched bibliographic references. Articles of pharmaceutical randomized controlled trials with weight loss or weight gain prevention as major endpoints were included. Two authors independently reviewed each publication for inclusion. 121 articles met the inclusion criteria. Two authors independently extracted treatment, sample size, drop-out rates, study duration, and statistical method used to handle missing data from all articles and resolved disagreements by consensus. In the meta-analysis, drop-out rates were substantial with the survival (non-dropout) rates being approximated by an exponential decay curve (e^−λt) where λ was estimated to be .0088 (95% bootstrap confidence interval: .0076 to .0100) and t represents time in weeks. The estimated drop-out rate at 1 year was 37%. Most studies used last observation carried forward as the primary analytic method to handle missing data. We also obtained 12 raw obesity randomized controlled trial datasets for empirical analyses. Analyses of raw randomized controlled trial data suggested that both mixed models and multiple imputation performed well, but that multiple imputation may be more robust when missing data are extensive.

Conclusion/Significance

Our analysis offers an equation for predictions of dropout rates useful for future study planning. Our raw data analyses suggests that multiple imputation is better than other methods for handling missing data in obesity randomized controlled trials, followed closely by mixed models. We suggest these methods supplant last observation carried forward as the primary method of analysis.     

Comparison of Results from Different Imputation Techniques for Missing Data from an Anti-Obesity Drug Trial

Background

In randomised trials of medical interventions, the most reliable analysis follows the intention-to-treat (ITT) principle. However, the ITT analysis requires that missing outcome data have to be imputed. Different imputation techniques may give different results and some may lead to bias. In anti-obesity drug trials, many data are usually missing, and the most used imputation method is last observation carried forward (LOCF). LOCF is generally considered conservative, but there are more reliable methods such as multiple imputation (MI).

Objectives

To compare four different methods of handling missing data in a 60-week placebo controlled anti-obesity drug trial on topiramate.

Methods

We compared an analysis of complete cases with datasets where missing body weight measurements had been replaced using three different imputation methods: LOCF, baseline carried forward (BOCF) and MI.

Results

561 participants were randomised. Compared to placebo, there was a significantly greater weight loss with topiramate in all analyses: 9.5 kg (SE 1.17) in the complete case analysis (N = 86), 6.8 kg (SE 0.66) using LOCF (N = 561), 6.4 kg (SE 0.90) using MI (N = 561) and 1.5 kg (SE 0.28) using BOCF (N = 561).

Conclusions

The different imputation methods gave very different results. Contrary to widely stated claims, LOCF did not produce a conservative (i.e., lower) efficacy estimate compared to MI. Also, LOCF had a lower SE than MI.     

Design,Analysis, and Reporting of Crossover Trials for Inclusion in a Meta-Analysis

Randomized crossover trials are clinical experiments in which participants are assigned randomly to a sequence of treatments and each participant serves as his/her own control in estimating treatment effect. We need a better understanding of the validity of their results to enable recommendations as to which crossover trials can be included in meta-analysis and for development of reporting guidelines.

Objective

To evaluate the characteristics of the design, analysis, and reporting of crossover trials for inclusion in a meta-analysis of treatment for primary open-angle glaucoma and to provide empirical evidence to inform the development of tools to assess the validity of the results from crossover trials and reporting guidelines.

Methods

We searched MEDLINE, EMBASE, and Cochrane’s CENTRAL register for randomized crossover trials for a systematic review and network meta-analysis we are conducting. Two individuals independently screened the search results for eligibility and abstracted data from each included report.

Results

We identified 83 crossover trials eligible for inclusion. Issues affecting the risk of bias in crossover trials, such as carryover, period effects and missing data, were often ignored. Some trials failed to accommodate the within-individual differences in the analysis. For a large proportion of the trials, the authors tabulated the results as if they arose from a parallel design. Precision estimates properly accounting for the paired nature of the design were often unavailable from the study reports; consequently, to include trial findings in a meta-analysis would require further manipulation and assumptions.

Conclusions

The high proportion of poorly reported analyses and results has the potential to affect whether crossover data should or can be included in a meta-analysis. There is pressing need for reporting guidelines for crossover trials.     

Risk of Cardiovascular Disease from Antiretroviral Therapy for HIV: A Systematic Review

Background

Recent studies suggest certain antiretroviral therapy (ART) drugs are associated with increases in cardiovascular disease.

Purpose

We performed a systematic review and meta-analysis to summarize the available evidence, with the goal of elucidating whether specific ART drugs are associated with an increased risk of myocardial infarction (MI).

Data Sources

We searched Medline, Web of Science, the Cochrane Library, and abstract archives from the Conference on Retroviruses and Opportunistic Infections and International AIDS Society up to June 2011 to identify published articles and abstracts.

Study Selection

Eligible studies were comparative and included MI, strokes, or other cardiovascular events as outcomes.

Data Extraction

Eligibility screening, data extraction, and quality assessment were performed independently by two investigators.

Data Synthesis

Random effects methods and Fisher’s combined probability test were used to summarize evidence.

Findings

Twenty-seven studies met inclusion criteria, with 8 contributing to a formal meta-analysis. Findings based on two observational studies indicated an increase in risk of MI for patients recently exposed (usually defined as within last 6 months) to abacavir (RR 1.92, 95% CI 1.51–2.42) and protease inhibitors (PI) (RR 2.13, 95% CI 1.06–4.28). Our analysis also suggested an increased risk associated with each additional year of exposure to indinavir (RR 1.11, 95% CI 1.05–1.17) and lopinavir (RR 1.22, 95% CI 1.01–1.47). Our findings of increased cardiovascular risk from abacavir and PIs were in contrast to four published meta-analyses based on secondary analyses of randomized controlled trials, which found no increased risk from cardiovascular disease.

Conclusion

Although observational studies implicated specific drugs, the evidence is mixed. Further, meta-analyses of randomized trials did not find increased risk from abacavir and PIs. Our findings that implicate specific ARTs in the observational setting provide sufficient evidence to warrant further investigation of this relationship in studies designed for that purpose.     

External Suction versus Water Seal after Selective Pulmonary Resection for Lung Neoplasm: A Systematic Review

Objective

To evaluate whether external suction is more advantageous than water seal in patients undergoing selective pulmonary resection (SPR) for lung neoplasm.

Summary of Background Data

Whether external suction should be routinely applied in postoperative chest drainage is still unclear, particularly for lung neoplasm patients. To most surgeons, the decision is based on their clinical experience.

Methods

Randomized control trials were selected. The participants were patients undergoing SPR with lung neoplasm. Lung volume reduction surgery and pneumothorax were excluded. Suction versus non-suction for the intervention. The primary outcome was the incidence of persistent air leak (PAL). The definition of PAL was air leak for more than 3–7 days. The secondary outcomes included air leak duration, time of drainage, postoperative hospital stay and the incidence of postoperative pneumothorax. Studies were identified from literature collections through screening. Bias was analyzed and meta-analysis was used.

Results

From the 1824 potentially relevant trials, 6 randomized control trials involving 676 patients were included. There was no difference between external suction and water seal in decreasing the incidence of PAL [95% confidence interval (CI) 0.81−2.16; z = 1.10; P = 0.27]. Regarding secondary outcomes, there were no differences in time of drainage (95% CI−0.36−1.56, P = 0.22), postoperative hospital stay (95% CI -.31−.54, P = 0.87) or incidence of postoperative pneumothorax (95% CI 0.18−.02, P = 0.05) between external suction and water seal.

Conclusions

For participants, no differences are identified in terms of PAL incidence, drainage time, length of postoperative hospital stay or incidence of postoperative pneumothorax between external suction and water seal. The bias analysis should be emphasized. To the limitations of the bias and methodological differences among the included studies, we have no recommendation on whether external suction should be routinely applied after lung neoplasm SPR. More high-quality randomized controlled trials are needed.

Systematic Review Registration

None.     

Long-acting beta-agonists plus inhaled corticosteroids safety: a systematic review and meta-analysis of non-randomized studies

Background

Although several systematic reviews investigated the safety of long-acting beta–agonists (LABAs) in asthma, they mainly addressed randomized clinical trials while evidence from non-randomized studies has been mostly neglected. We aim to assess the risk of serious adverse events in adults and children with asthma treated with LABAs and Inhaled Corticosteroids (ICs), compared to patients treated only with ICs, from published non-randomized studies.

Methods

The protocol registration number was CRD42012003387 (http://www.crd.york.ac.uk/Prospero). Literature search for articles published since 1990 was performed in MEDLINE and EMBASE. Two authors selected studies independently for inclusion and extracted the data. A third reviewer resolved discrepancies. To assess the risk of serious adverse events, meta-analyses were performed calculating odds ratio summary estimators using random effect models when heterogeneity was found, and fixed effect models otherwise.

Results

Of 4,415 candidate articles, 1,759 abstracts were reviewed and 220 articles were fully read. Finally, 19 studies met the inclusion criteria. Most of them were retrospective observational cohorts. Sample sizes varied from 50 to 514,216. The meta-analyses performed (69,939-624,303 participants according to the outcome considered) showed that odds ratio of the LABAs and ICs combined treatment when compared with ICs alone was: 0.88 (95% CI 0.69-1.12) for asthma-related hospitalization; 0.75 (95% CI 0.66-0.84) for asthma-related emergency visits; 1.02 (95% CI 0.94-1.10) for systemic corticosteroids; and 0.95 (95% CI 0.9-1.0) for the combined outcome.

Conclusions

Evidence from observational studies shows that the combined treatment of LABAs and ICs is not associated with a higher risk of serious adverse events, compared to ICs alone. Major gaps identified were prospective design, paediatric population and inclusion of mortality as a primary outcome.     

Impact of Different Training Modalities on Anthropometric and Metabolic Characteristics in Overweight/Obese Subjects: A Systematic Review and Network Meta-Analysis

Background

The aim of this systematic review of randomized controlled trials was to compare the effects of aerobic training (AET), resistance training (RT), and combined aerobic and resistance training (CT) on anthropometric parameters, blood lipids, and cardiorespiratory fitness in overweight and obese subjects.

Methods

Electronic searches for randomized controlled trials were performed in MEDLINE, EMBASE and the Cochrane Trial Register. Inclusion criteria were: Body Mass Index: ≥25 kg/m², 19+ years of age, supervised exercise training, and a minimum intervention period of 8 weeks. Anthropometric outcomes, blood lipids, and cardiorespiratory fitness parameters were included. Pooled effects were calculated by inverse-variance random effect pairwise meta-analyses and Bayesian random effects network meta-analyses.

Findings

15 trials enrolling 741 participants were included in the meta-analysis. Compared to RT, AET resulted in a significantly more pronounced reduction of body weight [mean differences (MD): -1.15 kg, p = 0.04], waist circumference [MD: -1.10 cm, p = 0.004], and fat mass [MD: -1.15 kg, p = 0.001] respectively. RT was more effective than AET in improving lean body mass [MD: 1.26 kg, p<0.00001]. When comparing CT with RT, MD in change of body weight [MD: -2.03 kg, p<0.0001], waist circumference [MD: -1.57 cm, p = 0.0002], and fat mass [MD: -1.88 kg, p<0.00001] were all in favor of CT. Results from the network meta-analyses confirmed these findings.

Conclusion

Evidence from both pairwise and network meta-analyses suggests that CT is the most efficacious means to reduce anthropometric outcomes and should be recommended in the prevention and treatment of overweight, and obesity whenever possible.     

Outcome reporting bias in randomized trials funded by the Canadian Institutes of Health Research

Background

The reporting of outcomes within published randomized trials has previously been shown to be incomplete, biased and inconsistent with study protocols. We sought to determine whether outcome reporting bias would be present in a cohort of government-funded trials subjected to rigorous peer review.

Methods

We compared protocols for randomized trials approved for funding by the Canadian Institutes of Health Research (formerly the Medical Research Council of Canada) from 1990 to 1998 with subsequent reports of the trials identified in journal publications. Characteristics of reported and unreported outcomes were recorded from the protocols and publications. Incompletely reported outcomes were defined as those with insufficient data provided in publications for inclusion in meta-analyses. An overall odds ratio measuring the association between completeness of reporting and statistical significance was calculated stratified by trial. Finally, primary outcomes specified in trial protocols were compared with those reported in publications.

Results

We identified 48 trials with 68 publications and 1402 outcomes. The median number of participants per trial was 299, and 44% of the trials were published in general medical journals. A median of 31% (10th–90th percentile range 5%–67%) of outcomes measured to assess the efficacy of an intervention (efficacy outcomes) and 59% (0%–100%) of those measured to assess the harm of an intervention (harm outcomes) per trial were incompletely reported. Statistically significant efficacy outcomes had a higher odds than nonsignificant efficacy outcomes of being fully reported (odds ratio 2.7; 95% confidence interval 1.5–5.0). Primary outcomes differed between protocols and publications for 40% of the trials.

Interpretation

Selective reporting of outcomes frequently occurs in publications of high-quality government-funded trials.Selective reporting of results from randomized trials can occur either at the level of end points within published studies (outcome reporting bias)¹ or at the level of entire trials that are selectively published (study publication bias).² Outcome reporting bias has previously been demonstrated in a broad cohort of published trials approved by a regional ethics committee.¹ The Canadian Institutes of Health Research (CIHR) — the primary federal funding agency, known before 2000 as the Medical Research Council of Canada (MRC) — recognized the need to address this issue and conducted an internal review process in 2002 to evaluate the reporting of results from its funded trials. The primary objectives were to determine (a) the prevalence of incomplete outcome reporting in journal publications of randomized trials; (b) the degree of association between adequate outcome reporting and statistical significance; and (c) the consistency between primary outcomes specified in trial protocols and those specified in subsequent journal publications.     

Impact of Including Korean Randomized Controlled Trials in Cochrane Reviews of Acupuncture

Objective

Acupuncture is commonly practiced in Korea and is regularly evaluated in clinical trials. Although many Cochrane reviews of acupuncture include searches of both English and Chinese databases, there is no information on the value of searching Korean databases. This study aimed to investigate the impact of searching Korean databasesand journals for trials eligible for inclusion in existing Cochrane acupuncture reviews.

Methods

We searched 12 Korean databases and seven Korean journals to identify randomised trials meeting the inclusion criteria for acupuncture reviews in the Cochrane Database of Systematic Reviews. We compared risk of bias assessments of the Korean trials with the trials included in the Cochrane acupuncture reviews. Where possible, we added data from the Korean trials to the existing meta-analyses in the relevant Cochrane review and conducted sensitivity analyses to test the robustness of the results.

Results

Sixteen Korean trials (742 participants) met the inclusion criteria for eight Cochrane acupuncture reviews (125 trials; 13,041 participants). Inclusion of the Korean trials provided data for 20% of existing meta-analyses (24 out of 120). Inclusion of the Korean trials did not change the direction of effect in any of the existing meta-analyses. The effect size and heterogeneity remained mostly unchanged. In only one meta-analysis did the significance change. Compared to the studies included in the Cochrane acupuncture reviews, the risk of bias in the Korean trials was higher in terms of outcome assessor blinding and allocation concealment.

Conclusions

Many Korean studies contributed additional data to the existing meta-analyses in Cochrane acupuncture reviews. Although inclusion of these studies did not alter the results of the meta-analyses, comprehensive searches of the literature are important to avoid potential language bias. The identification and inclusion of eligible Korean trials should be considered for reviews of acupuncture.     

Inconsistent Definitions for Intention-To-Treat in Relation to Missing Outcome Data: Systematic Review of the Methods Literature

Background

Authors of randomized trial reports seem to hold a variety of views regarding the relationship between missing outcome data (MOD) and intention to treat (ITT). The objectives of this study were to systematically investigate how authors of methodology articles define ITT in the presence of MOD, how they recommend handling MOD under ITT, and to make a proposal for potential improvement in the definition and use of ITT in relation to MOD.

Methods and Findings

We systematically searched MEDLINE in February 2009 for methodological articles written in English that devoted at least one paragraph to ITT and two other paragraphs to either ITT or MOD. We excluded original trial reports, observational studies, and clinical systematic reviews. Working in teams of two, we independently extracted relevant information from each eligible article. Of 1007 titles and abstracts reviewed, 66 articles met eligibility criteria. Five (8%) did not provide a definition of ITT; 25 (38%) mentioned MOD but did not discuss its relationship to ITT; and 36 (55%) discussed the relationship of MOD with ITT. These 36 articles described one or more of three statements: complete follow-up is required for ITT (58%); ITT and MOD are separate issues (17%); and ITT requires a specific strategy for handling MOD (78%); 17 (47%) endorsed more than one relationship. The most frequently mentioned strategies for handling MOD within ITT were: using the last outcome carried forward (50%); sensitivity analysis (50%); and use of available data to impute missing data (46%).

Conclusion

We found that there is no consensus on the definition of ITT in relation to MOD. For conceptual clarity, we suggest that both reports of randomized trials and systematic reviews separately consider and describe how they deal with participants with complete data and those with MOD.     

Efficacy of Muscle Exercise in Patients with Muscular Dystrophy: A Systematic Review Showing a Missed Opportunity to Improve Outcomes

Background

Although muscular dystrophy causes muscle weakness and muscle loss, the role of exercise in the management of this disease remains controversial.

Objective

The purpose of this systematic review is to evaluate the role of exercise interventions on muscle strength in patients with muscular dystrophy.

Methods

We performed systematic electronic searches in Medline, Embase, Web of Science, Scopus and Pedro as well as a list of reference literature. We included trials assessing muscle exercise in patients with muscular dystrophy. Two reviewers independently abstracted data and appraised risk of bias.

Results

We identified five small (two controlled and three randomized clinical) trials comprising 242 patients and two ongoing randomized controlled trials. We were able to perform two meta-analyses. We found an absence of evidence for a difference in muscle strength (MD 4.18, 95% CIs - 2.03 to 10.39; p = 0.91) and in endurance (MD −0.53, 95% CIs –1.11 to 0.05; p = 0.26). In both, the direction of effects favored muscle exercise.

Conclusions

The first included trial about the efficacy of muscular exercise was published in 1978. Even though some benefits of muscle exercise were consistently reported across studies, the benefits might be due to the small size of studies and other biases. Detrimental effects are still possible. After several decades of research, doctors cannot give advice and patients are, thus, denied basic information. A multi-center randomized trial investigating the strength of muscles, fatigue, and functional limitations is needed.     

A Case Study of Discordant Overlapping Meta-Analyses: Vitamin D Supplements and Fracture

Background

Overlapping meta-analyses on the same topic are now very common, and discordant results often occur. To explore why discordant results arise, we examined a common topic for overlapping meta-analyses- vitamin D supplements and fracture.

Methods and Findings

We identified 24 meta-analyses of vitamin D (with or without calcium) and fracture in a PubMed search in October 2013, and analysed a sample of 7 meta-analyses in the highest ranking general medicine journals. We used the AMSTAR tool to assess the quality of the meta-analyses, and compared their methodologies, analytic techniques and results. Applying the AMSTAR tool suggested the meta-analyses were generally of high quality. Despite this, there were important differences in trial selection, data extraction, and analytical methods that were only apparent after detailed assessment. 25 trials were included in at least one meta-analysis. Four meta-analyses included all eligible trials according to the stated inclusion and exclusion criteria, but the other 3 meta-analyses “missed” between 3 and 8 trials, and 2 meta-analyses included apparently ineligible trials. The relative risks used for individual trials differed between meta-analyses for total fracture in 10 of 15 trials, and for hip fracture in 6 of 12 trials, because of different outcome definitions and analytic approaches. The majority of differences (11/16) led to more favourable estimates of vitamin D efficacy compared to estimates derived from unadjusted intention-to-treat analyses using all randomised participants. The conclusions of the meta-analyses were discordant, ranging from strong statements that vitamin D prevents fractures to equally strong statements that vitamin D without calcium does not prevent fractures.

Conclusions

Substantial differences in trial selection, outcome definition and analytic methods between overlapping meta-analyses led to discordant estimates of the efficacy of vitamin D for fracture prevention. Strategies for conducting and reporting overlapping meta-analyses are required, to improve their accuracy and transparency.     

Carvedilol for Prevention of Atrial Fibrillation after Cardiac Surgery: A Meta-Analysis

Background

Postoperative atrial fibrillation (POAF) remains the most common complication after cardiac surgery. Current guidelines recommend β-blockers to prevent POAF. Carvedilol is a non-selective β-adrenergic blocker with anti-inflammatory, antioxidant, and multiple cationic channel blocking properties. These unique properties of carvedilol have generated interest in its use as a prophylaxis for POAF.

Objective

To investigate the efficacy of carvedilol in preventing POAF.

Methods

PubMed from the inception to September 2013 was searched for studies assessing the effect of carvedilol on POAF occurrence. Pooled relative risk (RR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models when appropriate. Six comparative trials (three randomized controlled trials and three nonrandomized controlled trials) including 765 participants met the inclusion criteria.

Results

Carvedilol was associated with a significant reduction in POAF (relative risk [RR] 0.49, 95% confidence interval [CI] 0.37 to 0.64, p<0.001). Subgroup analyses yielded similar results. In a subgroup analysis, carvedilol appeared to be superior to metoprolol for the prevention of POAF (RR 0.51, 95% CI 0.37 to 0.70, p<0.001). No evidence of heterogeneity was observed.

Conclusions

In conclusion, carvedilol may effectively reduce the incidence of POAF in patients undergoing cardiac surgery. It appeared to be superior to metoprolol. A large-scale, well-designed randomized controlled trial is needed to conclusively answer the question regarding the utility of carvedilol in the prevention of POAF.     

Stereotactic Aspiration versus Craniotomy for Primary Intracerebral Hemorrhage: A Meta-Analysis of Randomized Controlled Trials

Background

A wealth of evidence based on the randomized controlled trials (RCTs) has indicated that surgery may be a better choice in the management of primary intracerebral hemorrhage (ICH) compared to conservative treatment. However, there is considerable controversy over selecting appropriate surgical procedures for ICH. Thus, this meta-analysis was performed to assess the effects of stereotactic aspiration compared to craniotomy in patients with ICH.

Methods

According to the study strategy, we searched PUBMED, EMBASE and Cochrane Central Register of Controlled Trials. Other sources such as the internet-based clinical trial registries, relevant journals and the lists of references were also searched. After literature searching, two investigators independently performed literature screening, assessment of quality of the included trials and data extraction. The outcome measures included death or dependence, total risk of complication, and the risk of rebleeding, gastrointestinal hemorrhage and systematic infection.

Results

Four RCTs with 2996 participants were included. The quality of the included trials was acceptable. Stereotactic aspiration significantly decreased the odds of death or dependence at the final follow-up (odds ratio (OR): 0.80, 95% confidence interval (CI): 0.69–0.93; P = 0.004) and the risk of intracerebral rebleeding (OR: 0.44, 95% CI: 0.26–0.74; P = 0.002) compared to craniotomy with no significant heterogeneity among the study results.

Conclusions

The present meta-analysis provides evidence that the stereotactic aspiration may be associated with a reduction in the odds of being dead or dependent in primary ICH, which should be interpreted with caution. Further trials are needed to identify those patients most likely to benefit from the stereotactic aspiration.     

Prevention of Chronic Kidney Disease and Subsequent Effect on Mortality: A Systematic Review and Meta-Analysis

Objectives

To perform a systematic review of randomized controlled trials to determine whether prevention or slowing of progression of chronic kidney disease would translate into improved mortality, and if so, the attributable risk due to CKD itself on mortality.

Background

CKD is associated with increased mortality. This association is largely based on evidence from the observational studies and evidence from randomized controlled trials is lacking.

Methods

We searched Ovid, Medline and Embase for RCTs in which an intervention was given to prevent or slow the progression of CKD and mortality was reported as primary, secondary or adverse outcomes were eligible and selected. For the first phase, pooled relative risks for renal endpoints were assessed. For the second phase, we assessed the effect on mortality in trials of interventions that definitively reduced CKD endpoints.

Results

Among 52 studies selected in first phase, only renin-angiotensin-aldosterone-system blockade vs. placebo (n = 18 trials, 32,557 participants) met the efficacy criteria for further analysis in the second phase by reducing renal endpoints 15 to 27% compared to placebo. There was no difference in all-cause mortality (RR 0.99, 95% CI 0.92 to 1.08) or CV death (RR 0.97, 95% CI 0.78 to 1.21) between the treatment and control groups in these trials. There was sufficient statistical power to detect a 9% relative risk reduction in all-cause mortality and a 14% relative risk reduction in cardiovascular mortality.

Conclusions

Firm evidence is lacking that prevention of CKD translates into reductions in mortality. Larger trials with longer follow-up time are needed to determine the benefit of CKD prevention on survival.     

Self-guided psychological treatment for depressive symptoms: a meta-analysis

Background

A number of trials have examined the effects of self-guided psychological intervention, without any contact between the participants and a therapist or coach. The results and sizes of these trials have been mixed. This is the first quantitative meta-analysis, aimed at organizing and evaluating the literature, and estimating effect size.

Method

We conducted systematic literature searches in PubMed, PsycINFO and Embase up to January 2010, and identified additional studies through earlier meta-analyses, and the references of included studies. We identified seven randomized controlled trials that met our inclusion criteria, with a total of 1,362 respondents. The overall quality of the studies was high. A post-hoc power calculation showed that the studies had sufficient statistical power to detect an effect size of d = 0.19.

Results

The overall mean effect size indicating the difference between self-guided psychological treatment and control groups at post-test was d = 0.28 (p<0.001), which corresponds to a NNT of 6.41. At 4 to 12 months follow-up the effect size was d = 0.23. There was no indication for significant publication bias.

Conclusions

We found evidence that self-guided psychological treatment has a small but significant effect on participants with increased levels of depressive symptomatology.     

Effects of Intra-Aortic Balloon Counterpulsation Pump on Mortality of Acute Myocardial Infarction

Background

Several randomized controlled trials (RCTs) have evaluated the effect of intra-aortic balloon counterpulsation pump(IABP) on the mortality of acute myocardial infarction (AMI).

Objectives

To analyze the relevant RCT data on the effect of IABP on mortality and the occurrence of bleeding in AMI.

Data Sources

Published RCTs on the treatment of AMI by IABP were retrieved in searches of Medline, EMBASE, Cochrane and other related databases. The last search was conducted on July 20, 2014.

Study Eligibility Criteria

Randomized clinical trials comparing IABP to controls as treatment for AMI.

Participants

Patients with AMI.

Synthesis Methods

The primary endpoint was mortality, and the secondary endpoint was bleeding events. To account for to heterogeneity, a random-effects model was used to analyze the study data.

Results

Ten trials with a total population of 973 patients that were included in the analysis showed no significant difference in 2-month mortality between the IABP and the control groups. The 6-month mortality in the IABP group was not significantly lower than in the control group in the four RCTs that enrolled 59 AMI patients with CS. But in the four that enrolled AMI 66 patients without CS, the data showed opposite conclusion.

Conclusions

IABP cannot reduce within 2 months and 6–12 months mortality of AMI patients with CS as well as within 2 months mortality of AMI patients without CS, but can reduce 6–12 months mortality of AMI patients without CS. In addition, IABP can increase the risk of bleeding.     

Can Team-Based Care Improve Patient Satisfaction? A Systematic Review of Randomized Controlled Trials

Background

Team-based approaches to patient care are a relatively recent innovation in health care delivery. The effectiveness of these approaches on patient outcomes has not been well documented. This paper reports a systematic review of the relationship between team-based care and patient satisfaction.

Methods

We searched MEDLINE, EMBASE, Cochrane Library, CINAHL, and PSYCHOINFO for eligible studies dating from inception to October 8, 2012. Eligible studies reported (1) a randomized controlled trial, (2) interventions including both team-based care and non-team-based care (or usual care), and (3) outcomes including an assessment of patient satisfaction. Articles with different settings between intervention and control were excluded, as were trial protocols. The reference lists of retrieved papers were also evaluated for inclusion.

Results

The literature search yielded 319 citations, of which 77 were screened for further full-text evaluation. Of these, 27 articles were included in the systematic review. The 26 trials with a total of 15,526 participants were included in this systematic review. The pooling result of dichotomous data (number of studies: 10) showed that team-based care had a positive effect on patient satisfaction compared with usual care (odds ratio, 2.09; 95% confidence interval, 1.54 to 2.84); however, combined continuous data (number of studies: 7) demonstrated that there was no significant difference in patient satisfaction between team-based care and usual care (standardized mean difference, −0.02; 95% confidence interval, −0.40 to 0.36).

Conclusions

Some evidence showed that team-based care is better than usual care in improving patient satisfaction. However, considering the pooling result of continuous data, along with the suboptimal quality of included trials, further large-scale and high-quality randomized controlled trials comparing team-based care and usual care are needed.     

Albumin versus Other Fluids for Fluid Resuscitation in Patients with Sepsis: A Meta-Analysis

Background

Early fluid resuscitation is vital to patients with sepsis. However, the choice of fluid has been a hot topic of discussion. The objective of this study was to evaluate whether the use of albumin-containing fluids for resuscitation in patients with sepsis was associated with a decreased mortality rate.

Methods

We systematically searched PubMed, EMBASE and Cochrane library for eligible randomized controlled trials (RCTs) up to March 2014. The selection of eligible studies, assessment of methodological quality, and extraction of all relevant data were conducted by two authors independently.

Results

In total, 15 RCTs were eligible for analysis. After pooling the data, we found there was no significant effect of albumin-containing fluids on mortality in patients with sepsis of any severity (RR: 0.94, 95% CI: 0.87, 1.02 and RD: –0.01, 95% CI: –0.03, 0.01). The results were robust to subgroup analyses, sensitivity analyses and trial sequential analyses.

Conclusion

The present meta-analysis did not demonstrate significant advantage of using albumin-containing fluids for resuscitation in patients with sepsis of any severity. Given the cost-effectiveness of using albumin, crystalloids should be the first choice for fluid resuscitation in septic patients.