A basic introduction to fixed-effect and random-effects models for meta-analysis

Pooled individual patient data from five countries were used to derive a clinical prediction rule for coronary artery disease in primary care

OBJECTIVE

To construct a clinical prediction rule for coronary artery disease (CAD) presenting with chest pain in primary care.

STUDY DESIGN AND SETTING

Meta-Analysis using 3,099 patients from five studies. To identify candidate predictors, we used random forest trees, multiple imputation of missing values, and logistic regression within individual studies. To generate a prediction rule on the pooled data, we applied a regression model that took account of the differing standard data sets collected by the five studies.

RESULTS

The most parsimonious rule included six equally weighted predictors: age ≥55 (males) or ≥65 (females) (+1); attending physician suspected a serious diagnosis (+1); history of CAD (+1); pain brought on by exertion (+1); pain feels like "pressure" (+1); pain reproducible by palpation (-1). CAD was considered absent if the prediction score is <2. The area under the ROC curve was 0.84. We applied this rule to a study setting with a CAD prevalence of 13.2% using a prediction score cutoff of <2 (i.e., -1, 0, or +1). When the score was <2, the probability of CAD was 2.1% (95% CI: 1.1-3.9%); when the score was ≥ 2, it was 43.0% (95% CI: 35.8-50.4%).

CONCLUSIONS

Clinical prediction rules are a key strategy for individualizing care. Large data sets based on electronic health records from diverse sites create opportunities for improving their internal and external validity. Our patient-level meta-analysis from five primary care sites should improve external validity. Our strategy for addressing site-to-site systematic variation in missing data should improve internal validity. Using principles derived from decision theory, we also discuss the problem of setting the cutoff prediction score for taking action.

A systematic review and meta-analysis of the association between the apolipoprotein E genotype and delirium

The role of apolipoprotein E (APOE) in Alzheimer's disease and other dementias has been investigated intensively. However, the relationship between APOE and delirium has only recently been explored in studies that have included relatively small samples. A meta-analysis of the published pooled data is timely to explore the relationship between APOE and delirium and to inform further research in this topic. PubMed, EBSCOhost, Google Scholar, Scopus, all EBM Reviews (OVID) and the Cochrane Database of Systematic Reviews were searched with relevant keywords and from the references of relevant papers. Ten papers were found that examined the relationship between APOE and delirium. Data were extracted from eight of them and pooled for meta-analysis using random effects with R software. Data from 1762 participants, of whom 479 (27.2%) were diagnosed with delirium, showed low heterogeneity (Q=13.11, d.f.=7, P=0.07; I=44.86%). The possession of the APOE ε4 allele has a small (log odds ratio: 0.18, 95% confidence interval: 0.23-0.59), nonsignificant (P=0.38) effect on the presence of delirium. No publication bias was identified. The metapower of the pooled data was low (α=0.05, power=0.65). On analysing the studies to date, it seems that there is no association between APOE and the occurrence of delirium. We suggest that further studies are needed with greater number of patients to clarify any association as well as to examine for other patterns of association including relevance for subgroups of patients who develop delirium and for effects on the phenotype of delirium and the outcomes.

The prevalence of fatigue after stroke: A systematic review and meta-analysis

BACKGROUND

Fatigue is a common and debilitating symptom after stroke. The last decade has seen rapid expansion of the research literature on post-stroke fatigue, but prevalence remains unclear.

AIMS

To estimate post-stroke fatigue prevalence and to identify the contributing factors to fatigue, by conducting a systematic review and meta-analysis.

SUMMARY OF REVIEW

We included all studies of adult stroke survivors that used a recognized assessment scale for fatigue (search date September 2014). Two reviewers independently reviewed all full texts for inclusion. Data were extracted by one reviewer and independently cross-checked by a second. Risk of bias was evaluated using a critical appraisal tool. From an overall yield of 921 studies, 101 full text papers were screened, and 49 of these met inclusion criteria. The most widely used measure of fatigue was the Fatigue Severity Scale (n = 24 studies). Prevalence estimates at a cut-off score of > or ≥ 4 were available for 22 of these 24 studies (total n = 3491), and ranged from 25 to 85%. In random effects meta-analysis, the pooled prevalence estimate was 50% (95% CI 43-57%), with substantial heterogeneity (I² = 94%). Neither depression status nor time point post-stroke explained the heterogeneity between studies. In post-hoc analysis, fatigue prevalence was found to be lower in the four Asian studies (35%; 95% CI 20-50; I² = 96%).

CONCLUSIONS

Our results confirm that fatigue is a widespread issue for stroke survivors, although it may be less prevalent in Asia. Further research is needed to explain the wide variability in prevalence estimates between studies.

Dose-response effect of the lercanidipine/enalapril combination: a pooled analysis

OBJECTIVE

The dose-effect relationship of fixed-dose combinations of anti-hypertensive drugs has been only poorly explored. This pooled analysis investigates the dose-response relationship of fixed-dose lercanidipine + enalapril in patients with mild-to-moderate hypertension.

RESEARCH DESIGN AND METHODS

This was an individual patient data analysis of four randomized studies (n = 2340).

MAIN OUTCOME MEASURES

The primary efficacy variable was the change from baseline in sitting diastolic blood pressure (SDBP). Secondary variables were change from baseline in sitting systolic BP (SSBP), proportion of responder patients, and safety.

RESULTS

All fixed-dose combinations were superior to placebo in the reduction of SDBP. The greatest effect was observed with the market-available combination lercanidipine 20 mg/enalapril 20 mg (-15.3 mmHg vs. baseline; p < 0.05). The reduction in SDBP associated with the other two marketed fixed combinations of lercanidipine/enalapril were -10.7 mmHg for the 10 mg/20 mg combination and -9.8 mmHg for the 10 mg/10 mg combination (p < .05 for both comparisons). Similar findings were reported for SSBP reduction: the greatest effect was observed with lercanidipine 20 mg/enalapril 20 mg (-19.2 mmHg). The reduction in SSBP was -12.5 mmHg for the 10 mg/20 mg combination and -11.1 mmHg for the 10 mg/10 mg combination (p < .05 for all comparisons). The highest responder rate was reported with lercanidipine 20 mg/enalapril 20 mg (75.0%); this figure was 56.1% with the 10 mg/20 mg and 53.0% with the 10/10 mg combination. No safety concerns were reported.

CONCLUSION

This pooled analysis of four randomized studies shows evidence of a dose-response effect in BP reduction with different fixed combinations of lercanidipine + enalapril. To our knowledge, this is the first analysis investigating the dose-response effect of a specific fixed-dose combination of anti-hypertensive agents. Further studies on this intriguing topic are however necessary.

EUROmediCAT signal detection: an evaluation of selected congenital anomaly-medication associations

AIMS

To evaluate congenital anomaly (CA)-medication exposure associations produced by the new EUROmediCAT signal detection system and determine which require further investigation.

METHODS

Data from 15 EUROCAT registries (1995-2011) with medication exposures at the chemical substance (5th level of Anatomic Therapeutic Chemical classification) and chemical subgroup (4th level) were analysed using a 50% false detection rate. After excluding antiepileptics, antidiabetics, antiasthmatics and SSRIs/psycholeptics already under investigation, 27 associations were evaluated. If evidence for a signal persisted after data validation, a literature review was conducted for prior evidence of human teratogenicity.

RESULTS

Thirteen out of 27 CA-medication exposure signals, based on 389 exposed cases, passed data validation. There was some prior evidence in the literature to support six signals (gastroschisis and levonorgestrel/ethinylestradiol (OR 4.10, 95% CI 1.70-8.53; congenital heart disease/pulmonary valve stenosis and nucleoside/tide reverse transcriptase inhibitors (OR 5.01, 95% CI 1.99-14.20/OR 28.20, 95% CI 4.63-122.24); complete absence of a limb and pregnen (4) derivatives (OR 6.60, 95% CI 1.70-22.93); hypospadias and pregnadien derivatives (OR 1.40, 95% CI 1.10-1.76); hypospadias and synthetic ovulation stimulants (OR 1.89, 95% CI 1.28-2.70). Antipropulsives produced a signal for syndactyly while the literature revealed a signal for hypospadias. There was no prior evidence to support the remaining six signals involving the ordinary salt combinations, propulsives, bulk-forming laxatives, hydrazinophthalazine derivatives, gonadotropin releasing hormone analogues and selective serotonin agonists.

CONCLUSION

Signals which strengthened prior evidence should be prioritized for further investigation, and independent evidence sought to confirm the remaining signals. Some chance associations are expected and confounding by indication is possible.

Physical activity and endometriosis risk in women with infertility or pain: Systematic review and meta-analysis

BACKGROUND

The potential association between endometriosis and physical activity (PA) has been suggested in several epidemiological studies.We aimed to establish whether PA influences endometriosis risk.

METHODS

MEDLINE and EMBASE were searched using "physical activity" OR "exercise" combined with "endometriosis," in Medical Subject Headings and free text. We selected original articles in English, published up to April 2016, evaluating the association between endometriosis and recent or past PA (case-control or cohort studies). References of retrieved papers were reviewed. We computed summary odds ratios (ORs) of endometriosis for recent and past PA.

RESULTS

Six case-control and 3 cohort studies included 3355 cases for recent PA and 4600 cases for past PA. The summary OR for endometriosis according to PA level, calculated by the random-effect model, was 0.85 [95% confidence interval (CI) 0.67-1.07] for any recent versus no PA. As compared to no recent PA, ORs for low and moderate/high PA were 1.00 (95% CI: 0.68-1.28) and 0.75 (95% CI: 0.53-1.07), respectively.

CONCLUSIONS

Though it suggests that PA may reduce the risk of endometriosis, this meta-analysis does not conclusively support the hypothesis. Whether our findings are really explained by the benefit of exercise at molecular and endocrine level, or related to confounding mechanisms, such as study design, choice of controls, and PA potentially improving pain, needs to be further investigated.

Meta-analysis identifies common and rare variants influencing blood pressure and overlapping with metabolic trait loci

Meta-analyses of association results for blood pressure using exome-centric single-variant and gene-based tests identified 31 new loci in a discovery stage among 146,562 individuals, with follow-up and meta-analysis in 180,726 additional individuals (total n = 327,288). These blood pressure-associated loci are enriched for known variants for cardiometabolic traits. Associations were also observed for the aggregation of rare and low-frequency missense variants in three genes, NPR1, DBH, and PTPMT1. In addition, blood pressure associations at 39 previously reported loci were confirmed. The identified variants implicate biological pathways related to cardiometabolic traits, vascular function, and development. Several new variants are inferred to have roles in transcription or as hubs in protein-protein interaction networks. Genetic risk scores constructed from the identified variants were strongly associated with coronary disease and myocardial infarction. This large collection of blood pressure-associated loci suggests new therapeutic strategies for hypertension, emphasizing a link with cardiometabolic risk.

Assessing the relationship between chronic pain and cardiovascular disease: A systematic review and meta-analysis

Background and Aims

Chronic pain is a potentially disabling condition affecting one in three people through impaired physical function and quality of life. While the psychosocial impact of chronic pain is already well established, little is known about the potential biological consequences. Chronic pain may be associated with an increased prevalence of cardiovascular disease, an effect that has been demonstrated across a spectrum of chronic pain conditions including low back pain, pelvic pain, neuropathic pain and fibromyalgia. The aim of this study was to review and summarize the evidence for a link between chronic pain and cardiovascular disease. We sought to clarify the nature of the relationship by examining the basis for a dose-response gradient (whereby increasing pain severity would result in greater cardiovascular disease), and by evaluating the extent to which potentially confounding variables may contribute to this association.

Methods

Major electronic databases MEDLINE, EMBASE, Psychinfo, Cochrane, ProQuest and Web of Science were searched for articles reporting strengths of association between chronic pain (pain in one or more body regions, present for three months or longer) and cardiovascular outcomes (cardiovascular mortality, cardiac disease, and cerebrovascular disease). Meta-analysis was used to pool data analysing the association between chronic pain and the three principal cardiovascular outcomes. The impact of pain severity, and the role of potentially confounding variables were explored narratively.

Results

The searches generated 11,141 studies, of which 25 matched our inclusion criteria and were included in the review. Meta-analysis (of unadjusted study outcomes) demonstrated statistically significant associations between chronic pain and mortality from cardiovascular diseases: pooled odds ratio 1.20, (95% confidence intervals 1.05–1.36); chronic pain and cardiac disease: pooled odds ratio 1.73 (95% confidence intervals 1.42–2.04); and chronic pain and cerebrovascular disease: pooled odds ratio 1.81 (95% confidence intervals 1.51–2.10). The systematic review also found evidence supporting a dose-response relationship, with greater pain intensity and distribution producing a stronger association with cardiovascular outcomes.

All of the included studies were based on observational data with considerable variation in chronic pain taxonomy, methodology and study populations. The studies took an inconsistent and incomplete approach in their adjustment for potentially confounding variables, making it impossible to pool data after adjustments for confounding variables, so it cannot be concluded that these associations are causal.

Conclusions

Our review supports a possible dose-response type of association between chronic pain and cardiovascular disease, supported by a range of observational studies originating from different countries. Such research has so far failed to satisfactorily rule out that the association is due to confounding variables. What is now needed are further population based longitudinal studies that are designed to allow more robust exploration of a cause and effect relationship.

Implications

Given the high prevalence of chronic pain in developed and developing countries our results highlight a significant, but underpublicized, public health concern. Greater acknowledgement of the potentially harmful biological consequences of chronic pain may help to support regional, national and global initiatives aimed at reducing the burden of chronic pain.

High-dose dexamethasone compared with prednisone for previously untreated primary immune thrombocytopenia: a systematic review and meta-analysis

BACKGROUND

Whether high-dose dexamethasone has long-term efficacy and safety in previously untreated patients with immune thrombocytopenia is unclear. We did a systematic review and a meta-analysis of randomised trials to establish the effect of high-dose dexamethasone compared with prednisone for long-term platelet count response.

METHODS

We searched MEDLINE, Embase, Cumulative Index of Nursing and Allied Health Literature, and the Cochrane Library Database for papers published from 1970 to July, 2016, and abstracts from American Society of Hematology annual meetings published from 2004 to 2015 for randomised trials comparing different corticosteroid regimens for patients with previously untreated immune thrombocytopenia who achieved a platelet count response. Trials that compared corticosteroids exclusively with other interventions were excluded. The primary endpoint was overall (platelets >30 × 109/L) and complete (platelets >100 × 109/L) platelet count response at 6 months with high-dose dexamethasone compared with standard-dose prednisone. Children and adults were analysed separately. Estimates of effect were pooled with a random-effects model.

FINDINGS

Nine randomised trials (n=1138) were included. Of those, five (n=533) compared one to three cycles of dexamethasone (40 mg per day for 4 days) with prednisone (1 mg per kg) for 14-28 days followed by dose tapering in adults. We found no difference in overall platelet count response at 6 months (pooled proportions 54% vs 43%, relative risk [RR] 1·16, 95% CI 0·79-1·71; p=0·44). At 14 days, overall platelet count response was higher with dexamethasone (79% vs 59%, RR 1·22, 95% CI 1·00-1·49; p=0·048). The dexamethasone group had fewer reported toxicities. Long-term response rates were similar when the data were analysed by cumulative corticosteroid dose over the course of treatment. No difference in initial platelet count response was observed with different high-dose corticosteroid regimens in children.

INTERPRETATION

In adults with previously untreated immune thrombocytopenia, high-dose dexamethasone did not improve durable platelet count responses compared with standard-dose prednisone. High-dose dexamethasone might be preferred over prednisone for patients with severe immune thrombocytopenia who require a rapid rise in platelet count.

FUNDING

Canadian Institutes of Health Research, and Canadian Blood Services, and Health Canada.

Do pharmacist-led medication reviews in hospitals help reduce hospital readmissions? A systematic review and meta-analysis

AIMS

The aim of this meta-analysis is to examine the impact of in-hospital pharmacist-led medication reviews in paediatric and adult patients.

METHODS

Relevant studies were identified from the Medline and Cochrane Library databases. Studies were included if they met the following criteria (without any language or date restrictions): design: randomized controlled trial; intervention: in-hospital pharmacist-led medication review (experimental group) vs. usual care (control group); participants: paediatric or adult population. The primary outcome was all-cause readmissions and/or emergency department (ED) visits at different time points. The secondary outcomes were all-cause readmissions, all-cause ED visits, drug-related readmissions, mortality, length of hospital stay, adherence and quality of life. We calculated the relative risk (RR) or mean differences (MD) with 95% confidence intervals (CIs) for each study. We used fixed and/or random effects models. Heterogeneity was assessed using the I² statistic.

RESULTS

We systematically reviewed 19 randomized controlled trials (4805 participants). The readmission rates did not differ between the experimental group and the control group (RR = 0.97, 95% CI 0.89; 1.05, p = 0.470). The secondary outcomes did not differ between the two groups, except for in drug-related readmissions, which were lower in the experimental group (RR = 0.25, 95% CI 0.14; 0.45, p < 0.001), and all-cause ED visits (RR = 0.70, 95% CI 0.59; 0.85 p = 0.001).

CONCLUSION

The low-quality evidence in this analysis suggests an impact of pharmacist-led medication reviews on drug-related readmissions and all-cause ED visits. Few studies reported on adherence and quality of life. More high-quality randomized clinical trials are needed to assess the impact of pharmacist-led medication reviews on patient-relevant outcomes, including adherence and quality of life.

Motor control exercise for symptomatic lumbar disc herniation: protocol for a systematic review and meta-analysis

INTRODUCTION

Lumbar disc herniation (LDH) is a common condition in adults and can impose a heavy burden on both the individual and society. It is defined as displacement of disc components beyond the intervertebral disc space. Various conservative treatments have been recommended for the treatment of LDH and physical therapy plays a major role in the management of patients. Therapeutic exercise is effective for relieving pain and improving function in individuals with symptomatic LDH. The aim of this systematic review is to evaluate the effectiveness of motor control exercise (MCE) for symptomatic LDH.

METHODS AND ANALYSIS

We will include all clinical trial studies with a concurrent control group which evaluated the effect of MCEs in patients with symptomatic LDH. We will search PubMed, SCOPUS, PEDro, SPORTDiscus, CINAHL, CENTRAL and EMBASE with no restriction of language. Primary outcomes of this systematic review are pain intensity and functional disability and secondary outcomes are functional tests, muscle thickness, quality of life, return to work, muscle endurance and adverse events. Study selection and data extraction will be performed by two independent reviewers. The assessment of risk of bias will be implemented using the PEDro scale. Publication bias will be assessed by funnel plots, Begg's and Egger's tests. Heterogeneity will be evaluated using the I2 statistic and the χ2 test. In addition, subgroup analyses will be conducted for population and the secondary outcomes. All meta-analyses will be performed using Stata V.12 software.

ETHICS AND DISSEMINATION

No ethical concerns are predicted. The systematic review findings will be published in a peer-reviewed journal and will also be presented at national/international academic and clinical conferences.

TRIAL REGISTRATION NUMBER

CRD42016038166.

FTO genotype and weight loss: systematic review and meta-analysis of 9563 individual participant data from eight randomised controlled trials

OBJECTIVE

 To assess the effect of the FTO genotype on weight loss after dietary, physical activity, or drug based interventions in randomised controlled trials.

DESIGN

 Systematic review and random effects meta-analysis of individual participant data from randomised controlled trials.

DATA SOURCES

 Ovid Medline, Scopus, Embase, and Cochrane from inception to November 2015.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

 Randomised controlled trials in overweight or obese adults reporting reduction in body mass index, body weight, or waist circumference by FTO genotype (rs9939609 or a proxy) after dietary, physical activity, or drug based interventions. Gene by treatment interaction models were fitted to individual participant data from all studies included in this review, using allele dose coding for genetic effects and a common set of covariates. Study level interactions were combined using random effect models. Metaregression and subgroup analysis were used to assess sources of study heterogeneity.

RESULTS

 We identified eight eligible randomised controlled trials for the systematic review and meta-analysis (n=9563). Overall, differential changes in body mass index, body weight, and waist circumference in response to weight loss intervention were not significantly different between FTO genotypes. Sensitivity analyses indicated that differential changes in body mass index, body weight, and waist circumference by FTO genotype did not differ by intervention type, intervention length, ethnicity, sample size, sex, and baseline body mass index and age category.

CONCLUSIONS

 We have observed that carriage of the FTO minor allele was not associated with differential change in adiposity after weight loss interventions. These findings show that individuals carrying the minor allele respond equally well to dietary, physical activity, or drug based weight loss interventions and thus genetic predisposition to obesity associated with the FTO minor allele can be at least partly counteracted through such interventions.

SYSTEMATIC REVIEW REGISTRATION

 PROSPERO CRD42015015969.

Diabetes and mortality in patients with prostate cancer: a meta-analysis

BACKGROUND

There are conflicting results as to the association between pre-existing diabetes and the risk of mortality in patients with prostate cancer. The purpose of this study is to estimate the influence of pre-existing diabetes on prostate cancer-specific mortality and all-cause mortality.

METHODS

We searched PubMed and Embase to identify studies that investigated the association between pre-existing diabetes and risk of death among men with prostate cancer. Pooled risk estimates and 95 % confidence intervals were calculated using fixed-effects models or random-effects models. Heterogeneity tests were conducted between studies. Publication bias was analyzed by using the Egger's test, Begg's test, and the trim and fill method.

RESULTS

Of the 733 articles identified, 17 cohort studies that had 274,677 male patients were included in this meta-analysis. Pre-existing diabetes was associated with a 29 % increase in prostate cancer-specific mortality [relative risk (RR) 1.29, 95 % CI 1.22-1.38, I(2) = 66.68 %], and with a 37 % increase in all-cause mortality (RR 1.37, 95 % CI 1.29-1.45, p < 0.01, I(2) = 90.26 %). Additionally, in a subgroup analysis that was a type specific analysis focusing on type 2 diabetes and was conducted only with three cohort studies, pre-existing type 2 diabetes was associated with all-cause mortality (RR 2.01, 95 % CI 1.37-2.96, I(2) = 95.55 %) and no significant association with prostate cancer-specific mortality was detected (RR 1.17, 95 % CI 0.96-1.42, I(2) = 75.59 %). There was significant heterogeneity between studies and no publication bias was found.

CONCLUSIONS

This meta-analysis suggests diabetes may result in a worse prognosis for men with prostate cancer. Considering heterogeneity between studies, additional studies should be conducted to confirm these findings, and to allow generalization regarding the influence that each type of diabetes has on prostate cancer mortality.

Association of genetic variants in the receptor for advanced glycation end products gene with diabetic retinopathy: A meta-analysis

BACKGROUND

Diabetic retinopathy (DR) is a major sight-threatening diabetic complication. Previous studies have examined the association of DR with multiple genetic variants in the receptor for advanced glycation end products (RAGE) gene, with inconsistent results.

OBJECTIVE

To perform a systematic literature search and conduct meta-analyses to examine the association of genetic variants in RAGE with DR.

DATA SOURCES

PubMed, Cochrane Library, Embase, Google Scholar, and HuGE.

STUDY ELIGIBILITY CRITERIA AND PARTICIPANTS

Studies were on human subjects; the studies were case-control ones and included subjects who had DR and those who did not have DR; and the studies provided genotype data for genetic variants in RAGE, separately for subjects who had and did not have DR, or provided odds ratios (ORs) and the 95% confidence intervals (CIs), or provided sufficient data for the calculation of OR and the 95% CI.

STUDY APPRAISAL AND SYNTHESIS METHODS

We used OR as a measure of association, and used random-effects model in all the meta-analyses. Between-study heterogeneity was assessed using I, and publication bias was evaluated using Egger test.

RESULTS

A total of 13 studies met the eligibility criteria and were included in our analyses. We found that Gly82Ser was significantly associated with DR (OR = 2.40, 95% CI: 1.46-3.97; P = 0.001) using a recessive model. -374T/A also showed significant association with DR under a dominant model (OR = 1.21, 95% CI: 1.03-1.43; P = 0.023). We did not find a significant association of DR with other genetic variants in RAGE.

LIMITATIONS

The number of included studies is small for some genetic variants; duration of diabetes varied across studies; most studies were conducted in Asia; and it is not clear whether the observed association can be generalized to other ethnicities; and we could not control for other potential confounding factors.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

We found that Gly82Ser in RAGE showed significant association with DR. More studies with larger sample sizes that control for important risk factors, such as duration of diabetes, are needed to validate our findings.

Scapholunate Interosseous Ligament Tears: Diagnostic Performance of 1.5 T, 3 T MRI, and MR Arthrography-A Systematic Review and Meta-analysis

RATIONALE AND OBJECTIVES

The study aimed to perform a systematic review and meta-analysis for evaluating the diagnostic accuracy of 1.5 Tesla and 3.0 Tesla magnetic resonance imaging (MRI), and magnetic resonance arthrography (MRA), in the detection of scapholunate interosseous ligament (SLIL) injury.

MATERIALS AND METHODS

A literature search was performed (until July 2015) using the PubMed (MEDLINE), Embase, ISI Web of Science, Scopus, and conference proceedings. Original studies evaluating the diagnostic accuracy of MRI or MRA in the detection of SLIL injuries using arthroscopy or open surgery as the reference standard were included.

RESULTS

Of the initial 930 published records and 103 conference proceedings, 24 studies (1902 MRI examinations) were included (median SLIL injury prevalence: 33% [interquartile range: 25-42]). Heterogeneity was detected for 1.5 T MRI (chi-square: 47.93, P < 0.001) but not for 3.0 T MRI (chi-square: 8.00, P value: 0.09) and MRA (chi-square: 14.54, P value: 0.34) studies. The sensitivities of 1.5 T MRI, 3.0 T MRI, and MRA for detection of SLIL injury were 45.7% (95% confidence interval: 40.1-51.4), 75.7% (66.8-83.2), and 82.1% (76.1-87.2), respectively. The specificities of 1.5 T MRI, 3.0 T MRI, and MRA for detection of SLIL injury were 80.5% (77.3-83.4), 97.1% (89.8-99.6), and 92.8% (90.2-94.9), respectively. The diagnostic odds ratios of 1.5 T MRI, 3.0 T MRI, and MRA for detection of SLIL injury were 5.56 (2.71-11.39), 23.23 (3.16-171.00), and 65.04 (32.89-128.62) (P value < 0.001), respectively. The results were consistent after addressing publication bias and sensitivity analyses.

CONCLUSIONS

MRA is superior to 3.0 T MRI, and 3.0 T MRI is superior to 1.5 T MRI in terms of diagnostic performance. 3.0 T MRI has the highest specificity for the detection of SLIL injuries.

Genetic variants in ANCA-associated vasculitis: a meta-analysis

BACKGROUND

Genetic factors may influence the pathogenic pathways leading to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We performed a meta-analysis to determine the genetic variants most likely associated with AAV and investigated whether diagnostic and serological subtypes within AAV have distinct genetic backgrounds.

METHODS

Studies investigating the association between genetic variants and AAV in humans were searched in PubMed, EMBASE and Web of Science. All variants investigated in at least two studies were selected. Subsequently, all studies assessing these variants were included in this meta-analysis. Additionally, data on these variants from the largest genome-wide association studies in AAV were included to increase the validity of this meta-analysis.

RESULTS

The literature search yielded 5180 articles. 62 articles investigating 140 genetic variants were included, 33 of which were associated with AAV in a meta-analysis. These genetic variants were in or near the following genes: CD226, CTLA-4, FCGR2A, HLA-B, HLA-DP, HLA-DQ, HLA-DR, HSD17B8, IRF5, PTPN22, RING1/RXRB, RXRB, STAT4, SERPINA1 and TLR9. Moreover, we identified genetic distinctions between granulomatosis with polyangiitis and microscopic polyangiitis and between proteinase 3 ANCA vasculitis and myeloperoxidase ANCA vasculitis. In 76% of the genetic variants, subdivision based on ANCA serotype resulted in higher ORs than subdivision based on clinical diagnosis.

CONCLUSIONS

This meta-analysis identified 33 genetic variants associated with AAV, supporting a role for alpha-1-antitrypsin, the major histocompatibility complex system, and several distinct inflammatory processes in AAV pathogenesis. Our results indicate that subdivision of AAV based on ANCA serotype has a stronger genetic basis than subdivision based on clinical diagnosis.

Investigating the epidemiology of medication errors and error-related adverse drug events (ADEs) in primary care, ambulatory care and home settings: a systematic review protocol

INTRODUCTION

There is a need to better understand the epidemiology of medication errors and error-related adverse events in community care contexts.

METHODS AND ANALYSIS

We will systematically search the following databases: Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Eastern Mediterranean Regional Office of the WHO (EMRO), MEDLINE, PsycINFO and Web of Science. In addition, we will search Google Scholar and contact an international panel of experts to search for unpublished and in progress work. The searches will cover the time period January 1990-December 2015 and will yield data on the incidence or prevalence of and risk factors for medication errors and error-related adverse drug events in adults living in community settings (ie, primary care, ambulatory and home). Study quality will be assessed using the Critical Appraisal Skills Program quality assessment tool for cohort and case-control studies, and cross-sectional studies will be assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Descriptive Studies. Meta-analyses will be undertaken using random-effects modelling using STATA (V.14) statistical software.

ETHICS AND DISSEMINATION

This protocol will be registered with PROSPERO, an international prospective register of systematic reviews, and the systematic review will be reported in the peer-reviewed literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Illness representations, coping, and illness outcomes in people with cancer: a systematic review and meta-analysis

OBJECTIVE

Cancer is associated with negative health and emotional outcomes in those affected by it, suggesting the need to better understand the psychosocial determinants of illness outcomes and coping. The common sense model is the leading psychological model of self-regulation in the face of illness and assumes that subjective illness representations explain how people attempt to cope with illness. This systematic review and meta-analysis examines the associations of the common sense model's illness representation dimensions with health and coping outcomes in people with cancer.

METHODS

A systematic literature search located 54 studies fulfilling the inclusion criteria, with 38 providing sufficient data for meta-analysis. A narrative review of the remaining studies was also conducted.

RESULTS

Random-effects models revealed small to moderate effect sizes (Fisher Z) for the relations between illness representations and coping behaviors (in particular between control perceptions, problem-focused coping, and cognitive reappraisal) and moderate to large effect sizes between illness representations and illness outcomes (in particular between identity, consequences, emotional representations, and psychological distress). The narrative review of studies with insufficient data provided similar results.

CONCLUSIONS

The results indicate how illness representations relate to illness outcomes in people with cancer. However, more high-quality studies are needed to examine causal effects of illness representations on coping and outcomes. High heterogeneity indicates potential moderators of the relationships between illness representations and health and coping outcomes, including diagnostic, prognostic, and treatment-related variables. This review can inform the design of interventions to improve coping strategies and mental health outcomes in people with cancer.

Resistin as potential biomarker for chronic periodontitis: A systematic review and meta-analysis

OBJECTIVES

To determine the serum and gingival crevicular fluid (GCF) levels of resistin between individuals with chronic periodontitis (CP) and those without CP, and to evaluate the role of resistin in CP.

MATERIALS AND METHODS

The addressed focused question was "Is there a difference in the resistin levels between individuals with CP and those without CP?" four electronic databases: Medline, PubMed (National Institutes of Health, Bethesda), EMBASE, and Science direct databases from 1977 up to March 2016 for appropriate articles addressing the focused question. EMBASE and Medline were accessed using OVID interface which facilitated simultaneous search of text words, MeSH or Emtree. Unpublished studies (gray literature) were identified by searching the Open-GRAY database and references of the included studies (cross referencing) were performed to obtain new studies. In-vitro studies, animal studies, studies that reported levels of other cytokines but not resistin, letters to the editor and review papers were excluded.

RESULTS

Ten studies were included. Nine studies compared resistin levels between CP and periodontally healthy (H) individuals and reported higher mean serum and GCF levels of resistin in CP patients than the H controls. Two studies showed comparable resistin levels from GCF and serum between diabetes mellitus with CP (DMCP) and CP groups. Three studies included obese subjects and showed comparable serum and GCF resistin levels between obese subjects with CP (OBCP) and CP subjects.

CONCLUSIONS

CP patients were presented with elevated levels of GCF or serum resistin as compared with H individuals. Resistin modulates inflammation in chronic periodontal disease and may be used as surrogate measure to identify subjects at risk for periodontitis. Resistin levels in patients with CP and systemic inflammatory disorders such as diabetes, obesity, or rheumatoid arthritis was not significantly higher than the levels in patients with only CP.

Ocular motor disturbances in autism spectrum disorders: Systematic review and comprehensive meta-analysis

There has been considerable focus placed on how individuals with autism spectrum disorder (ASD) visually perceive and attend to social information, such as facial expressions or social gaze. The role of eye movements is inextricable from visual perception, however this aspect is often overlooked. We performed a series of meta-analyses based on data from 28 studies of eye movements in ASD to determine whether there is evidence for ocular motor dysfunction in ASD. Tasks assessed included visually-guided saccade tasks, gap/overlap, anti-saccade, pursuit tasks and ocular fixation. These analyses revealed evidence for ocular motor dysfunction in ASD, specifically relating to saccade dysmetria, difficulty inhibiting saccades and impaired tracking of moving targets. However there was no evidence for deficits relating to initiating eye movements, or engaging and disengaging from simple visual targets. Characterizing ocular motor abnormalities in ASD may provide insight into the functional integrity of brain networks in ASD across development, and assist our understanding of visual and social attention in ASD.

Association between microRNA-27a rs895819 polymorphism and risk of colorectal cancer: A meta-analysis

Colorectal cancer (CRC) is the most common malignancy in the human digestive system. Previous results regarding the association between microRNA-27a rs895819 polymorphisms and CRC risk are controversial. We therefore performed a meta-analysis of seven studies totaling 2230 cases and 2775 controls to systematically evaluate this association. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using a fixed-effects model. A moderate evidence for the association between mir-27a polymorphism and CRC risk was found under multiple genetic models (dominant model: OR = 1.15, 95% CI: 1.02-1.29, p = 0.02; recessive model: OR = 1.49, 95% CI: 1.27-1.76, p <0.001; homozygote model: OR = 1.53, 95% CI: 1.28-1.83, p <0.001; allele model: OR = 1.21, 95% CI: 1.11-1.31, p <0.001). Subgroup analysis showed a significant association between mir-27a rs895819 polymorphism and CRC risk among Chinese populations. On the contrary, we found no evidence of association among Caucasian populations due to small samples (p > 0.05). In conclusion, this meta-analysis suggested that rs895819 polymorphism in mir-27a may be a potential genetic risk factor for CRC, particularly in Chinese populations.

Reporting of financial and non-financial conflicts of interest by authors of systematic reviews: a methodological survey

BACKGROUND

Conflicts of interest may bias the findings of systematic reviews. The objective of this methodological survey was to assess the frequency and different types of conflicts of interest that authors of Cochrane and non-Cochrane systematic reviews report.

METHODS

We searched for systematic reviews using the Cochrane Database of Systematic Reviews and Ovid MEDLINE (limited to the 119 Core Clinical Journals and the year 2015). We defined a conflict of interest disclosure as the reporting of whether a conflict of interest exists or not, and used a framework to classify conflicts of interest into individual (financial, professional and intellectual) and institutional (financial and advocatory) conflicts of interest. We conducted descriptive and regression analyses.

RESULTS

Of the 200 systematic reviews, 194 (97%) reported authors' conflicts of interest disclosures, typically in the main document, and in a few cases either online (2%) or on request (5%). Of the 194 Cochrane and non-Cochrane reviews, 49% and 33%, respectively, had at least one author reporting any type of conflict of interest (p=0.023). Institutional conflicts of interest were less frequently reported than individual conflicts of interest, and Cochrane reviews were more likely to report individual intellectual conflicts of interest compared with non-Cochrane reviews (19% and 5%, respectively, p=0.004). Regression analyses showed a positive association between reporting of conflicts of interest (at least one type of conflict of interest, individual financial conflict of interest, institutional financial conflict of interest) and journal impact factor and between reporting individual financial conflicts of interest and pharmacological versus non-pharmacological intervention.

CONCLUSIONS

Although close to half of the published systematic reviews report that authors (typically many) have conflicts of interest, more than half report that they do not. Authors reported individual conflicts of interest more frequently than institutional and non-financial conflicts of interest.

Timing of initiation of renal replacement therapy for acute kidney injury: a systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

The effects of early renal replacement therapy (RRT) on mortality and renal recovery in patients with acute kidney injury (AKI) remain controversial. A systematic review and meta-analysis of randomized-controlled trials (RCTs) was performed.

METHODS

MEDLINE, EMBASE and the Cochrane Library database (Cochrane Central Register of Controlled Trials) were searched to identify RCTs, investigating the effects of early RRT on patients with AKI.

RESULTS

Six studies with a total of 1257 participants were included in this meta-analysis. Compared to late RRT, early RRT did not reduce the risk of mortality (RR 0.93, 95 % CI 0.68-1.26) or affect renal recovery (RR 0.88, 95 % CI 0.48-1.62) or composite endpoint (death or dialysis dependence) (RR 0.91, 95 % CI 0.71-1.17). There was no significant difference in adverse events in the analysis, between the early RRT and late RRT arms.

CONCLUSIONS

Early initiation of RRT for patients with AKI is not associated with decreased overall mortality or a delayed renal recovery rate. The optimal time to initiate RRT remains uncertain. Large scale and adequately powered RCTs are needed to detect the effects of early initiation of RRT in AKI patients.

The treatment of chronic depression with cognitive behavioral analysis system of psychotherapy: a systematic review and meta-analysis of randomized-controlled clinical trials

BACKGROUND

Chronic depression is a severe and disabling condition. Compared to an episodic course, chronic depression has been shown to be less responsive to psychopharmacological and psychological treatments. The cognitive behavioral analysis system of psychotherapy (CBASP) has been developed as a specific psychotherapy for chronic depression. However, conflicting results concerning its efficacy have been reported in randomized-controlled trials (RCT). Therefore, we aimed at examining the efficacy of CBASP using meta-analytical methods.

METHODS

Randomized-controlled trials assessing the efficacy of CBASP in chronic depression were identified by searching electronic databases (PsycINFO, PubMed, Scopus, Cochrane Central Register of Controlled Trials) and by manual searches (citation search, contacting experts). Searching period was restricted from the first available entry to October 2015. Identified studies were systematically reviewed. The standardized mean difference Hedges' g was calculated from posttreatment and mean change scores. The random-effects model was used to compute combined overall effect sizes. A risk of publication bias was addressed using fail-safe N calculations and trim-and-fill analysis.

RESULTS

Six studies comprising 1.510 patients met our inclusion criteria. The combined overall effect sizes of CBASP versus other treatments or treatment as usual (TAU) pointed to a significant effect of small magnitude (g = 0.34-0.44, P < 0.01). In particular, CBASP revealed moderate-to-high effect sizes when compared to TAU and interpersonal psychotherapy (g = 0.64-0.75, P < 0.05), and showed similar effects when compared to antidepressant medication (ADM) (g = -0.29 to 0.02, ns). The combination of CBASP and ADM yielded benefits over antidepressant monotherapy (g = 0.49-0.59, P < 0.05).

LIMITATIONS

The small number of included studies, a certain degree of heterogeneity among the study designs and comparison conditions, and insufficient data evaluating long-term effects of CBASP restrict generalizability yet.

CONCLUSIONS

We conclude that there is supporting evidence that CBASP is effective in the treatment of chronic depression.

Association of SLC30A8 gene polymorphism with type 2 diabetes, evidence from 46 studies: a meta-analysis

The solute carrier family 30 member 8 (SLC30A8) gene may be involved in the development of type 2 diabetes mellitus (T2DM) through disrupting β-cell function. The aim of this study was to assess the association between SLC30A8 rs13266634 polymorphism and susceptibility to T2DM. We searched all reports regarding the association between SLC30A8 rs13266634 polymorphism and T2DM risk through Pubmed, Embase, and the Cochrane Library for English language reports and Chongqing VIP database, Wanfang data, CBMDisc, and CNKI for Chinese language studies. Allelic and genotype comparisons between cases and controls were evaluated, and odds ratios with 95 % confidence intervals were used to assess the strength of their association. A random effects model was selected. Publication bias was estimated using Begg's test. Forty-six studies were included in the analysis with a total of 71,890 cases and 96,753 controls. This meta-analysis suggests that SLC30A8 (rs13266634) polymorphism was associated with T2DM risk. Although previous meta-analyses have shown that this association was only found in Asian and European groups, and not in African populations, our analysis revealed the deleterious effect of SLC30A8 rs13266634 on T2DM in an African population when stratified by ethnicity under additive model even with a small number of studies.

Comparative effectiveness of exercise and drug interventions on mortality outcomes: metaepidemiological study

Objective

To determine the comparative effectiveness of exercise versus drug interventions on mortality outcomes.

Design

Metaepidemiological study.

Eligibility criteria

Meta-analyses of randomised controlled trials with mortality outcomes comparing the effectiveness of exercise and drug interventions with each other or with control (placebo or usual care).

Data sources

Medline and Cochrane Database of Systematic Reviews, May 2013.

Main outcome measure

Mortality.

Data synthesis

We combined study level death outcomes from exercise and drug trials using random effects network meta-analysis.

Results

We included 16 (four exercise and 12 drug) meta-analyses. Incorporating an additional three recent exercise trials, our review collectively included 305 randomised controlled trials with 339 274 participants. Across all four conditions with evidence on the effectiveness of exercise on mortality outcomes (secondary prevention of coronary heart disease, rehabilitation of stroke, treatment of heart failure, prevention of diabetes), 14 716 participants were randomised to physical activity interventions in 57 trials. No statistically detectable differences were evident between exercise and drug interventions in the secondary prevention of coronary heart disease and prediabetes. Physical activity interventions were more effective than drug treatment among patients with stroke (odds ratios, exercise vanticoagulants 0.09, 95% credible intervals 0.01 to 0.70 and exercise v antiplatelets 0.10, 0.01 to 0.62). Diuretics were more effective than exercise in heart failure (exercise v diuretics 4.11,1.17to 24.76). Inconsistency between direct and indirect comparisons was not significant.

Conclusions

Although limited in quantity, existing randomised trial evidence on exercise interventions suggests that exercise and many drug interventions are often potentially similar in terms of their mortality benefits in the secondary prevention of coronary heart disease, rehabilitation after stroke, treatment of heart failure, and prevention of diabetes.

Implicit memory in schizophrenia: a meta-analysis

OBJECTIVE

Previous studies examining implicit memory in schizophrenia yielded inconsistent results. The present meta-analysis aimed at determining whether, compared to healthy controls, schizophrenic patients: (a) exhibited reduced priming in the whole set of studies; (b) were differentially impaired in conceptual/perceptual and production/identification tests; and (c) were less efficient in the use of semantic encoding processes.

METHOD

A systematic search in PsycINFO and PubMed led to the selection of 22 critical studies (31 effect sizes), comparing repetition priming in 836 schizophrenic patients and 760 healthy controls. Moderators were assessed by classifying implicit tasks into the perceptual/conceptual and identification/production categories, and by distinguishing between perceptual and conceptual encoding instructions.

RESULTS

Overall, implicit memory was slightly, but significantly, impaired in schizophrenia (d=0.179). Patients exhibited reduced priming in conceptually-driven tasks (d=0.447), but intact priming in perceptually-driven tasks (d=0.080). No significant difference was observed between identification and production priming (d=0.064 vs. d=0.243). Finally, priming in schizophrenic patients was significantly lower than that of controls when the encoding task required the analysis of the conceptual properties of the stimuli (d=0.261).

CONCLUSION

Results suggest that schizophrenia is associated with a specific deficit in the use of conceptual processes, both at encoding and at retrieval. In contrast with theoretical expectations, high levels of response competition did not disproportionately impair the patients' performance.

Introducing Meta-Partition, a Useful Methodology to Explore Factors That Influence Ecological Effect Sizes

The study of the heterogeneity of effect sizes is a key aspect of ecological meta-analyses. Here we propose a meta-analytic methodology to study the influence of moderators in effect sizes by splitting heterogeneity: meta-partition. To introduce this methodology, we performed a meta-partition of published data about the traits that influence species sensitivity to habitat loss, that have been previously analyzed through meta-regression. Thus, here we aim to introduce meta-partition and to make an initial comparison with meta-regression. Meta-partition algorithm consists of three steps. Step 1 is to study the heterogeneity of effect sizes under the assumption of fixed effect model. If heterogeneity is found, we perform step 2, that is, to partition the heterogeneity by the moderator that minimizes heterogeneity within a subset while maximizing heterogeneity between subsets. Then, if effect sizes of the subset are still heterogeneous, we repeat step 1 and 2 until we reach final subsets. Finally, step 3 is to integrate effect sizes of final subsets, with fixed effect model if there is homogeneity, and with random effects model if there is heterogeneity. Results show that meta-partition is valuable to assess the importance of moderators in explaining heterogeneity of effect sizes, as well as to assess the directions of these relations and to detect possible interactions between moderators. With meta-partition we have been able to evaluate the importance of moderators in a more objective way than with meta-regression, and to visualize the complex relations that may exist between them. As ecological issues are often influenced by several factors interacting in complex ways, ranking the importance of possible moderators and detecting possible interactions would make meta-partition a useful exploration tool for ecological meta-analyses.

A systematic review and meta-analysis of psychiatric treatments for excoriation (skin-picking) disorder

OBJECTIVE

While individual trials suggest benefit of interventions for excoriation (skin-picking) disorder (ExD), limited systematic evaluation of treatments, or their collective benefit, exists.

METHODS

The present study examined the current state of treatments for ExD in a systematic review and meta-analysis and explored potential treatment moderators. Twelve trials were identified for review, including five with a control condition. Of these, nine were eligible to be included in the meta-analysis (three with a control).

RESULTS

A fixed-effects meta-analysis found a large overall treatment effect size (g=1.13), comprised of large effects for behavioral treatments (g=1.19), lamotrigine (g=0.98) and selective serotonin reuptake inhibitors (g=1.09). Clinician-rated measures did not significantly differ from self-rated measures; however, larger effects were observed on self-rated measures of severity, as compared to impairment [Q(1)=4.63, P=.03]. Treatment type, trial length and trial methodological quality were not significant moderators. For controlled trials, the comparative efficacy of treatments for ExD was in the moderate range (g=0.47).

CONCLUSION

Findings suggest that treatment for ExD has benefit; however, the meta-analysis did not provide strong evidence to support any specific treatment or to suggest its unique clinical benefit over control conditions. Overall, there is a lack of study on treatments for ExD and additional randomized controlled trials with inclusion of multiple informants in assessment is needed.

Gingival crevicular fluid levels of cytokines/chemokines in chronic periodontitis: a meta-analysis

AIMS

To compare gingival crevicular fluid (GCF) cytokines/chemokines levels between periodontally healthy subjects and subjects diagnosed with chronic periodontitis (ChP), before and after non-surgical periodontal treatment, and to establish their predictive value for periodontal disease progression.

METHODS

Studies indexed in MEDLINE and EMBASE published in English, Portuguese and Spanish were eligible for this review. Database searches up to December 2015, and manual search of the reference list from reviews and selected articles was performed. Only studies providing data on GCF cytokines/chemokines levels in subjects diagnosed with ChP and periodontally healthy controls were included. Cross-sectional, case series, single-arm clinical studies, randomized controlled trials and prospective/retrospective cohort studies were included. Meta-analyses were conducted for those cytokines/chemokines with at least three available studies.

RESULTS

GCF levels of IL-1β, IL-6, IFN-γ and MCP-1/CCL2 were significantly higher in subjects diagnosed with ChP than periodontally healthy subjects. A significant decrease in GCF levels of IL-1β and IL-17 was observed after non-surgical periodontal treatment, whereas a significant increase was observed for IL-4.

CONCLUSION

Evidence for significant differences between periodontal health and ChP was observed for a few cytokines and one chemokine. No conclusions could be drawn with regards to increased risk of disease progression.

Re-Paying Attention to Visitor Behavior: A Re-Analysis using Meta-Analytic Techniques

The present study describes a meta-analytic review of museum visitors' behavior. Although there is a large number of visitor studies available, their cumulative importance has not been determined due to the lack of rigorous methods to determine common causes of visitors' behaviors. We analyzed Serrell's (1998) database of 110 studies, defining a number of variables that measure visitors' behaviors in exhibition spaces which exceeded the most typical and obvious ones. We defined four indexes of effect size and obtained their combined estimates: average time per feature [ATF● = 0.43 (0.49; 0.37)], percentage of diligent visitors [dv● = 30% (0.39; 0.23)], inverse of velocity [Iv● = 4.07 min/100m2 (4.55; 3.59)], and stops per feature [SF● = 0.35 (0.38; 0.33)], and we analyzed the role of relevant moderating variables. Key findings indicate, for example, that the visiting time for each display element relates to the size of the exhibition and its newness, and visitor walking speed is higher in large exhibit areas. The indexes obtained in this study can be understood as references to be used for comparison with new evaluations. They may help to predict people's behavior and appreciation of new exhibitions, identifying important problems in museum designs, and providing new research tools for this field.

A comparative evaluation of data-merging and meta-analysis methods for reconstructing gene-gene interactions

BACKGROUND

We address the problem of integratively analyzing multiple gene expression, microarray datasets in order to reconstruct gene-gene interaction networks. Integrating multiple datasets is generally believed to provide increased statistical power and to lead to a better characterization of the system under study. However, the presence of systematic variation across different studies makes network reverse-engineering tasks particularly challenging. We contrast two approaches that have been frequently used in the literature for addressing systematic biases: meta-analysis methods, which first calculate opportune statistics on single datasets and successively summarize them, and data-merging methods, which directly analyze the pooled data after removing eventual biases. This comparative evaluation is performed on both synthetic and real data, the latter consisting of two manually curated microarray compendia comprising several E. coli and Yeast studies, respectively. Furthermore, the reconstruction of the regulatory network of the transcription factor Ikaros in human Peripheral Blood Mononuclear Cells (PBMCs) is presented as a case-study.

RESULTS

The meta-analysis and data-merging methods included in our experimentations provided comparable performances on both synthetic and real data. Furthermore, both approaches outperformed (a) the naïve solution of merging data together ignoring possible biases, and (b) the results that are expected when only one dataset out of the available ones is analyzed in isolation. Using correlation statistics proved to be more effective than using p-values for correctly ranking candidate interactions. The results from the PBMC case-study indicate that the findings of the present study generalize to different types of network reconstruction algorithms.

CONCLUSIONS

Ignoring the systematic variations that differentiate heterogeneous studies can produce results that are statistically indistinguishable from random guessing. Meta-analysis and data merging methods have proved equally effective in addressing this issue, and thus researchers may safely select the approach that best suit their specific application.

Does telemedicine improve treatment outcomes for diabetes? A meta-analysis of results from 55 randomized controlled trials

AIMS

To assess the overall effect of telemedicine on diabetes management and to identify features of telemedicine interventions that are associated with better diabetes management outcomes.

METHODS

Hedges's g was estimated as the summary measure of mean difference in HbA1c between patients with diabetes who went through telemedicine care and those who went through conventional, non-telemedicine care using a random-effects model. Q statistics were calculated to assess if the effect of telemedicine on diabetes management differs by types of diabetes, age groups of patients, duration of intervention, and primary telemedicine approaches used.

RESULTS

The analysis included 55 randomized controlled trials with a total of 9258 patients with diabetes, out of which 4607 were randomized to telemedicine groups and 4651 to conventional, non-telemedicine care groups. The results favored telemedicine over conventional care (Hedges's g=-0.48, p<0.001) in diabetes management. The beneficial effect of telemedicine were more pronounced among patients with type 2 diabetes (Hedges's g=-0.63, p<0.001) than among those with type 1 diabetes (Hedges's g=-0.27, p=0.027) (Q=4.25, p=0.04).

CONCLUSIONS

Compared to conventional care, telemedicine is more effective in improving treatment outcomes for diabetes patients, especially for those with type 2 diabetes.

Do Model-Based Studies in Chronic Obstructive Pulmonary Disease Measure Correct Values of Utility? A Meta-Analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a progressive chronic disease that has considerable impact on utility-based health-related quality of life. Utility is a key input of many decision analytic models used for economic evaluations.

OBJECTIVE

To systematically review COPD-related utilities and to compare these with alternative values used in decision models.

METHODS

The literature review comprised studies that generated utilities for COPD-related stages based on EuroQol five-dimensional questionnaire surveys of patients and of decision models of COPD progression that have been used for economic evaluations. The utility values used in modeling studies and those from the meta-analysis of actual patient-level studies were compared and differences quantified.

RESULTS

Twenty decision modeling studies that used utility value as an input parameter were found. Within the same span of publication period, 13 studies involving patient-level utility data were identified and included in the meta-analysis. The estimated mean utility values ranged from 0.806 (95% confidence interval [CI] 0.747-0.866) for stage I to 0.616 (95% CI 0.556-0.676) for stage IV. The utility scores for comparable stages in modeling studies were different (significant difference 0.045 [95% CI 0.041-0.052] for stage III). Modeling studies consistently used higher utility values than the average reported patient-level data.

CONCLUSIONS

COPD decision analytic models are based on a limited range of utility values that are systematically different from average values estimated using a meta-analysis. A more systematic approach in the application of utility measures in economic evaluation is required to appropriately reflect current literature.

FOLFIRINOX for locally advanced pancreatic cancer: a systematic review and patient-level meta-analysis

BACKGROUND

35% of patients with pancreatic cancer have unresectable locally advanced disease at diagnosis. Several studies have examined systemic chemotherapy with FOLFIRINOX (leucovorin and fluorouracil plus irinotecan and oxaliplatin) in patients with locally advanced pancreatic cancer. We aimed to assess the effectiveness of FOLFIRINOX as first-line treatment in this patient population.

METHODS

We systematically searched Embase, MEDLINE (OvidSP), Web of Science, Scopus, PubMed Publisher, Cochrane, and Google Scholar from July 1, 1994, to July 2, 2015, for studies of treatment-naive patients of any age who received FOLFIRINOX as first-line treatment of locally advanced pancreatic cancer. Our primary outcome was overall survival. Secondary outcomes were progression-free survival; rates of grade 3 or 4 adverse events; and the proportion of patients who underwent radiotherapy or chemoradiotherapy, surgical resection after FOLFIRINOX, and R0 resection. We evaluated survival outcomes with the Kaplan-Meier method with patient-level data. Grade 3 or 4 adverse events, and the proportion of patients who underwent subsequent radiotherapy or chemoradiotherapy or resection, were pooled in a random-effects model.

FINDINGS

We included 13 studies comprising 689 patients, of whom 355 (52%) patients had locally advanced pancreatic cancer. 11 studies, comprising 315 patients with locally advanced disease, reported survival outcomes and were eligible for patient-level meta-analysis. Median overall survival from the start of FOLFIRINOX ranged from 10·0 months (95% CI 4·0-16·0) to 32·7 months (23·1-42·3) across studies with a pooled patient-level median overall survival of 24·2 months (95% CI 21·7-26·8). Median progression-free survival ranged from 3·0 months (95% CI not calculable) to 20·4 months (6·5-34·3) across studies with a patient-level median progression-free survival of 15·0 months (95% 13·8-16·2). In ten studies comprising 490 patients, 296 grade 3 or 4 adverse events were reported (60·4 events per 100 patients). No deaths were attributed to FOLFIRINOX toxicity. The proportion of patients who underwent radiotherapy or chemoradiotherapy ranged from 31% to 100% across studies. In eight studies, 154 (57%) of 271 patients received radiotherapy or chemoradiotherapy after FOLFIRINOX. The pooled proportion of patients who received any radiotherapy treatment was 63·5% (95% CI 43·3-81·6, I(2) 90%). The proportion of patients who underwent surgical resection for locally advanced pancreatic cancer ranged from 0% to 43%. The proportion of patients who had R0 resection of those who underwent resection ranged from 50% to 100% across studies. In 12 studies, 91 (28%) of 325 patients underwent resection after FOLFIRINOX. The pooled proportion of patients who had resection was 25·9% (95% CI 20·2-31·9, I(2) 24%). R0 resection was reported in 60 (74%) of 81 patients. The pooled proportion of patients who had R0 resection was 78·4% (95% CI 60·2-92·2, I(2) 64%).

INTERPRETATION

Patients with locally advanced pancreatic cancer treated with FOLFIRINOX had a median overall survival of 24·2 months-longer than that reported with gemcitabine (6-13 months). Future research should assess these promising results in a randomised controlled trial, and should establish which patients might benefit from radiotherapy or chemoradiotherapy or resection after FOLFIRINOX.

FUNDING

None.