Comparison of evidence on harms of medical interventions in randomized and nonrandomized studies

An analysis of published study designs in PubMed prisoner health abstracts from 1963 to 2023: a text mining study

BACKGROUND

The challenging nature of studies with incarcerated populations and other offender groups can impede the conduct of research, particularly that involving complex study designs such as randomised control trials and clinical interventions. Providing an overview of study designs employed in this area can offer insights into this issue and how research quality may impact on health and justice outcomes.

METHODS

We used a rule-based approach to extract study designs from a sample of 34,481 PubMed abstracts related to epidemiological criminology published between 1963 and 2023. The results were compared against an accepted hierarchy of scientific evidence.

RESULTS

We evaluated our method in a random sample of 100 PubMed abstracts. An F1-Score of 92.2% was returned. Of 34,481 study abstracts, almost 40.0% (13,671) had an extracted study design. The most common study design was observational (37.3%; 5101) while experimental research in the form of trials (randomised, non-randomised) was present in 16.9% (2319). Mapped against the current hierarchy of scientific evidence, 13.7% (1874) of extracted study designs could not be categorised. Among the remaining studies, most were observational (17.2%; 2343) followed by systematic reviews (10.5%; 1432) with randomised controlled trials accounting for 8.7% (1196) of studies and meta-analysis for 1.4% (190) of studies.

CONCLUSIONS

It is possible to extract epidemiological study designs from a large-scale PubMed sample computationally. However, the number of trials, systematic reviews, and meta-analysis is relatively small - just 1 in 5 articles. Despite an increase over time in the total number of articles, study design details in the abstracts were missing. Epidemiological criminology still lacks the experimental evidence needed to address the health needs of the marginalized and isolated population that is prisoners and offenders.

Pragmatic trial design to compare real-world effectiveness of different treatments for inflammatory bowel diseases: the PRACTICE-IBD European consensus

BACKGROUND AND AIMS

Pragmatic studies designed to test interventions in everyday clinical settings can successfully complement the evidence from registration and explanatory clinical trials. The European consensus project PRACTICE-IBD was developed to identify essential criteria and address key methodological issues needed to design valid comparative pragmatic studies in inflammatory bowel diseases (IBDs).

METHODS

Statements were issued by a panel of 11 European experts in IBD management and trial methodology on four main topics: (I) study design; (II) eligibility, recruitment and organization, flexibility; (III) outcomes; (IV) analysis. The consensus process followed a modified Delphi approach, involving two rounds of assessment and rating of the level of agreement (1 to 9; cut-off ≥7 for approval) with the statements by 18 additional European experts in IBD.

RESULTS

At the first voting round, 25 out of the 26 statements reached a mean score ≥7. Following the discussion that preceded the second round of voting, it was decided to eliminate two statements and to split one into two. At the second voting round, 25 final statements were approved: 7 for study design, 6 for eligibility, recruitment and organization, flexibility, 8 for outcomes, and 4 for analysis.

CONCLUSIONS

Pragmatic randomized clinical trials can address important questions in IBD clinical practice, and may provide complementary high-level evidence, as long as they follow a methodologically rigorous approach. These 25 statements intend to offer practical guidance in the design of high-quality pragmatic clinical trials that can aid decision making in choosing a management strategy for IBDs.

Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials: a meta-epidemiological study

BACKGROUND

Researchers and decision-makers often use evidence from randomised controlled trials (RCTs) to determine the efficacy or effectiveness of a treatment or intervention. Studies with observational designs are often used to measure the effectiveness of an intervention in 'real world' scenarios. Numerous study designs and their modifications (including both randomised and observational designs) are used for comparative effectiveness research in an attempt to give an unbiased estimate of whether one treatment is more effective or safer than another for a particular population. An up-to-date systematic analysis is needed to identify differences in effect estimates from RCTs and observational studies. This updated review summarises the results of methodological reviews that compared the effect estimates of observational studies with RCTs from evidence syntheses that addressed the same health research question.

OBJECTIVES

To assess and compare synthesised effect estimates by study type, contrasting RCTs with observational studies. To explore factors that might explain differences in synthesised effect estimates from RCTs versus observational studies (e.g. heterogeneity, type of observational study design, type of intervention, and use of propensity score adjustment). To identify gaps in the existing research comparing effect estimates across different study types.

SEARCH METHODS

We searched MEDLINE, the Cochrane Database of Systematic Reviews, Web of Science databases, and Epistemonikos to May 2022. We checked references, conducted citation searches, and contacted review authors to identify additional reviews.

SELECTION CRITERIA

We included systematic methodological reviews that compared quantitative effect estimates measuring the efficacy or effectiveness of interventions tested in RCTs versus in observational studies. The included reviews compared RCTs to observational studies (including retrospective and prospective cohort, case-control and cross-sectional designs). Reviews were not eligible if they compared RCTs with studies that had used some form of concurrent allocation.

DATA COLLECTION AND ANALYSIS

Using results from observational studies as the reference group, we examined the relative summary effect estimates (risk ratios (RRs), odds ratios (ORs), hazard ratios (HRs), mean differences (MDs), and standardised mean differences (SMDs)) to evaluate whether there was a relatively larger or smaller effect in the ratio of odds ratios (ROR) or ratio of risk ratios (RRR), ratio of hazard ratios (RHR), and difference in (standardised) mean differences (D(S)MD). If an included review did not provide an estimate comparing results from RCTs with observational studies, we generated one by pooling the estimates for observational studies and RCTs, respectively. Across all reviews, we synthesised these ratios to produce a pooled ratio of ratios comparing effect estimates from RCTs with those from observational studies. In overviews of reviews, we estimated the ROR or RRR for each overview using observational studies as the reference category. We appraised the risk of bias in the included reviews (using nine criteria in total). To receive an overall low risk of bias rating, an included review needed: explicit criteria for study selection, a complete sample of studies, and to have controlled for study methodological differences and study heterogeneity. We assessed reviews/overviews not meeting these four criteria as having an overall high risk of bias. We assessed the certainty of the evidence, consisting of multiple evidence syntheses, with the GRADE approach.

MAIN RESULTS

We included 39 systematic reviews and eight overviews of reviews, for a total of 47. Thirty-four of these contributed data to our primary analysis. Based on the available data, we found that the reviews/overviews included 2869 RCTs involving 3,882,115 participants, and 3924 observational studies with 19,499,970 participants. We rated 11 reviews/overviews as having an overall low risk of bias, and 36 as having an unclear or high risk of bias. Our main concerns with the included reviews/overviews were that some did not assess the quality of their included studies, and some failed to account appropriately for differences between study designs - for example, they conducted aggregate analyses of all observational studies rather than separate analyses of cohort and case-control studies. When pooling RORs and RRRs, the ratio of ratios indicated no difference or a very small difference between the effect estimates from RCTs versus from observational studies (ratio of ratios 1.08, 95% confidence interval (CI) 1.01 to 1.15). We rated the certainty of the evidence as low. Twenty-three of 34 reviews reported effect estimates of RCTs and observational studies that were on average in agreement. In a number of subgroup analyses, small differences in the effect estimates were detected: - pharmaceutical interventions only (ratio of ratios 1.12, 95% CI 1.04 to 1.21); - RCTs and observational studies with substantial or high heterogeneity; that is, I2 ≥ 50% (ratio of ratios 1.11, 95% CI 1.04 to 1.18); - no use (ratio of ratios 1.07, 95% CI 1.03 to 1.11) or unclear use (ratio of ratios 1.13, 95% CI 1.03 to 1.25) of propensity score adjustment in observational studies; and - observational studies without further specification of the study design (ratio of ratios 1.06, 95% CI 0.96 to 1.18). We detected no clear difference in other subgroup analyses.

AUTHORS' CONCLUSIONS

We found no difference or a very small difference between effect estimates from RCTs and observational studies. These findings are largely consistent with findings from recently published research. Factors other than study design need to be considered when exploring reasons for a lack of agreement between results of RCTs and observational studies, such as differences in the population, intervention, comparator, and outcomes investigated in the respective studies. Our results underscore that it is important for review authors to consider not only study design, but the level of heterogeneity in meta-analyses of RCTs or observational studies. A better understanding is needed of how these factors might yield estimates reflective of true effectiveness.

Efficacy and Safety of Oral Anticoagulants in Older Adult Patients With Atrial Fibrillation: Pairwise and Network Meta-Analyses

OBJECTIVE

To evaluate the efficacy and safety of oral anticoagulants for older adult patients with atrial fibrillation (AF).

DESIGN

Pairwise and network meta-analyses.

SETTING AND PARTICIPANTS

Patients with AF aged ≥75 years.

METHODS

PubMed, Embase, and the Cochrane library were searched for published randomized controlled trials and adjusted observational studies evaluating the use of a non-vitamin K antagonist oral anticoagulants (NOACs), vitamin K antagonist, or antiplatelet drug for the prevention of stroke. The primary efficacy and safety outcomes were the composite of stroke and systemic embolism (SSE) and major bleedings.

RESULTS

This study included 38 studies enrolling 1,022,908 older adult patients with AF. Results from pairwise meta-analyses showed that NOACs were superior to warfarin for all outcomes, except that dabigatran increased the risk of gastrointestinal (GI) bleedings. Aspirin was associated with a higher risk of SSE and ischemic stroke than warfarin or NOACs. Results of network meta-analyses indicated that apixaban significantly reduced the risk of SSE, major bleedings, and GI bleedings than warfarin, rivaroxaban, and dabigatran. Apixaban, edoxaban, rivaroxaban, and dabigatran reduced the risk of ischemic stroke and intracranial bleeding compared to warfarin. Dabigatran showed lower risk of all-cause mortality than warfarin and of intracranial bleeding than rivaroxaban.

CONCLUSIONS AND IMPLICATIONS

NOACs are of at least equal efficacy, or even superior to warfarin. The safety profile of individual NOAC agents was significantly different, as apixaban performs better than the other oral anticoagulants in reducing major bleeding and GI bleeding, whereas dabigatran increased the risk of GI bleeding.

Impact of design characteristics among studies comparing coronary computed tomography angiography to noninvasive functional testing in chronic coronary syndromes

BACKGROUND

Coronary computed tomography angiography (CCTA) is widely adopted to detect obstructive coronary artery disease (CAD) in patients with chronic coronary syndromes (CCS). However, it is unknown to which extent study-specific characteristics yield different conclusions.

METHODS

We summarized non-randomized and randomized studies comparing CCTA and noninvasive functional testing for CCS with information on the outcome of myocardial infarction (MI). We evaluated the differential effect according to study characteristics using random-effect meta-analysis with Hartung-Knapp-Sidik-Jonkman adjustments.

RESULTS

Fifteen studies (8 non-randomized, 7 randomized) were included. CCTA was associated with decrease in relative (odds ratio (OR) 0.54, 95%CI 0.47 to 0.62, P < .001) and absolute MI risk (risk difference (RD) -0.4%, 95%CI -0.6 to -0.1, P = .005). The results remained consistent among the non-randomized (RD -0.4%, 95%CI -0.7 to -0.1, P=.029), but not among the randomized trials where there was no difference in the observed risk (RD 0.2%, 95%CI -0.6 to 0.1, P = .158). CCTA was not associated with MI reduction in studies with clinical outcome definition (OR 0.77, 95%CI 0.41 to 1.44, P = .212), research driven follow-up (OR 0.54, 95%CI 0.24 to 1.21, P = .090), central event assessment (OR 0.63, 95%CI 0.21 to 1.86, P = .207), outcome adjudication (OR 0.74, 95%CI 0.24 to 2.23, P = .178), or at low-risk of bias (OR 0.74, 95%CI 0.24 to 2.23, P = .178).

CONCLUSIONS

Among studies of any design, CCTA was associated with lower risk of MI in CCS compared to noninvasive functional testing. This benefit was diminished among studies with clinical outcome definition, central outcome assessment/adjudication or at low-risk of bias.

An empirical comparison of the harmful effects for randomized controlled trials and non-randomized studies of interventions

Introduction: Randomized controlled trials (RCTs) are the gold standard to evaluate the efficacy of interventions (e.g., drugs and vaccines), yet the sample size of RCTs is often limited for safety assessment. Non-randomized studies of interventions (NRSIs) had been proposed as an important alternative source for safety assessment. In this study, we aimed to investigate whether there is any difference between RCTs and NRSIs in the evaluation of adverse events. Methods: We used the dataset of systematic reviews with at least one meta-analysis including both RCTs and NRSIs and collected the 2 × 2 table information (i.e., numbers of cases and sample sizes in intervention and control groups) of each study in the meta-analysis. We matched RCTs and NRSIs by their sample sizes (ratio: 0.85/1 to 1/0.85) within a meta-analysis. We estimated the ratio of the odds ratios (RORs) of an NRSI against an RCT in each pair and used the inverse variance as the weight to combine the natural logarithm of ROR (lnROR). Results: We included systematic reviews with 178 meta analyses, from which we confirmed 119 pairs of RCTs and NRSIs. The pooled ROR of NRSIs compared to that of RCTs was estimated to be 0.96 (95% confidence interval: 0.87 and 1.07). Similar results were obtained with different sample size subgroups and treatment subgroups. With the increase in sample size, the difference in ROR between RCTs and NRSIs decreased, although not significantly. Discussion: There was no substantial difference in the effects between RCTs and NRSIs in safety assessment when they have similar sample sizes. Evidence from NRSIs might be considered a supplement to RCTs for safety assessment.

Proton Pump Inhibitors Use and the Risk of Pancreatic Cancer: Evidence from Eleven Epidemiological Studies, Comprising 1.5 Million Individuals

Previous epidemiological studies have shown that proton pump inhibitor (PPI) may modify the risk of pancreatic cancer. We conducted an updated systematic review and meta-analysis of observational studies assessing the effect of PPI on pancreatic cancer. PubMed, Embase, Scopus, and Web of Science were searched for studies published between 1 January 2000, and 1 May 2022. We only included studies that assessed exposure to PPI, reported pancreatic cancer outcomes, and provided effect sizes (hazard ratio or odds ratio) with 95% confidence intervals (CIs). We calculated an adjusted pooled risk ratio (RR) with 95%CIs using the random-effects model. Eleven studies (eight case-control and three cohorts) that reported 51,629 cases of pancreatic cancer were included. PPI was significantly associated with a 63% increased risk of pancreatic cancer (RRadj. 1.63, 95%CI: 1.19-2.22, p = 0.002). Subgroup analysis showed that the pooled RR for rabeprazole and lansoprazole was 4.08 (95%CI: 0.61-26.92) and 2.25 (95%CI: 0.83-6.07), respectively. Moreover, the risk of pancreatic cancer was established for both the Asian (RRadj. 1.37, 95%CI: 0.98-1.81) and Western populations (RRadj.2.76, 95%CI: 0.79-9.56). The findings of this updated meta-analysis demonstrate that the use of PPI was associated with an increased risk of pancreatic cancer. Future studies are needed to improve the quality of evidence through better verification of PPI status (e.g., patient selection, duration, and dosages), adjusting for possible confounders, and ensuring long-term follow-up.

Harms in Systematic Reviews Paper 2: Methods used to assess harms are neglected in systematic reviews of gabapentin

OBJECTIVE

We compared methods used with current recommendations for synthesizing harms in systematic reviews and meta-analyses (SRMAs) of gabapentin.

STUDY DESIGN & SETTING

We followed recommended systematic review practices. We selected reliable SRMAs of gabapentin (i.e., met a pre-defined list of methodological criteria) that assessed at least one harm. We extracted and compared methods in four areas: pre-specification, searching, analysis, and reporting. Whereas our focus in this paper is on the methods used, Part 2 examines the results for harms across reviews.

RESULTS

We screened 4320 records and identified 157 SRMAs of gabapentin, 70 of which were reliable. Most reliable reviews (51/70; 73%) reported following a general guideline for SRMA conduct or reporting, but none reported following recommendations specifically for synthesizing harms. Across all domains assessed, review methods were designed to address questions of benefit and rarely included the additional methods that are recommended for evaluating harms.

CONCLUSION

Approaches to assessing harms in SRMAs we examined are tokenistic and unlikely to produce valid summaries of harms to guide decisions. A paradigm shift is needed. At a minimal, reviewers should describe any limitations to their assessment of harms and provide clearer descriptions of methods for synthesizing harms.

Harms in Systematic Reviews Paper 1: An introduction to research on harms

OBJECTIVE

Most systematic reviews of interventions focus on potential benefits. Common methods and assumptions that are appropriate for assessing benefits can be inappropriate for harms. This paper provides a primer on researching harms, particularly in systematic reviews.

STUDY DESIGN AND SETTING

Commentary describing challenges with assessing harm.

RESULTS

Investigators should be familiar with various terminologies used to describe, classify, and group harms. Published reports of clinical trials include limited information about harms, so systematic reviewers should not depend on these studies and journal articles to reach conclusions about harms. Visualizations might improve communication of multiple dimensions of harms such as severity, relatedness, and timing.

CONCLUSION

The terminology, classification, detection, collection, and reporting of harms create unique challenges that take time, expertise, and resources to navigate in both primary studies and evidence syntheses. Systematic reviewers might reach incorrect conclusions if they focus on evidence about harms found in published reports of randomized trials of a particular health problem. Systematic reviews could be improved through better identification and reporting of harms in primary studies and through better training and uptake of appropriate methods for synthesizing evidence about harms.

Safety of Complementary and Alternative Medicine (CAM) treatment among children and young adults who suffer from adverse effects of conventional cancer treatment: A systematic review

Background:

Complementary and Alternative Medicine (CAM) is widely used around the world to treat adverse effects derived from cancer treatment among children and young adults. Parents often seek CAM to restore and maintain the child’s physical and emotional condition during and after cancer treatment.

Objectives:

The objectives of this review were (i) to identify literature that investigates CAM use for treating adverse effects of conventional cancer treatment, (ii) to investigate the safety of the included CAM modalities, and (iii) to evaluate the quality of included studies.

Methods:

Five scientific research databases were used to identify observational, quasi-experimental, and qualitative studies from January 1990 to May 2021. Included studies investigated the use of CAM to treat adverse effects of cancer treatment in childhood cancer.

Results:

Fifteen studies were included in this review. Ten quasi-experimental, 3 observational studies (longitudinal/prospective), 2 qualitative studies, and 1 study with a quasi-experimental and qualitative arm were identified. Less than half (n = 6; 40%) of the studies included reported adverse effects for the CAM modality being studied. Among the studies that reported adverse effects, they were mostly considered as direct risk, as 13% reported mainly bleeding and bruising upon acupuncture treatment, and dizziness with yoga treatment. All adverse effects were assessed as minor and transient. CAM modalities identified for treating adverse effects of cancer treatment were alternative medical systems, manipulative and body-based therapies, biologically-based therapies, and mind-body therapies. CAM modalities were used to alleviate anxiety, pain, toxicity, prevent trauma, and improve health-related quality of life, functional mobility, and physical activity levels. All studies assessed scored 70% or above according to the Joanna Briggs Institute critical appraisal for study quality checklists.

Conclusion:

Most of the studies (58.3%) included in this review did not report adverse effects from CAM modalities used to treat adverse effects of cancer treatment in children and young adults. This lack of safety information is of concern because parents need to know whether the modality represents an extra burden or harm to the child. To improve awareness about safety in the field, a universal and uniform reporting system for adverse effects in CAM research is needed.

Osteopathic Treatment of Infants in Their First Year of Life: A Prospective Multicenter Observational Study (OSTINF Study)

INTRODUCTION

In Germany in recent years, a growing number of parents are seeking help from osteopaths for the perceived health complaints of their infants and children. However, reliable evidence for the effectiveness of osteopathic interventions for this group of patients is largely lacking.

OBJECTIVE

To observe and document changes in the symptoms of certain health disturbances, as perceived by parents, during the course of an osteopathic treatment of their baby, and associated side effects.

METHODS

A single-arm, prospective, multicenter, observational study was chosen as the study design. Parents who contacted an osteopathic practice with any of the following 5 health disturbances were invited to include their baby into the study: idiopathic infant asymmetry (IA), deformational plagiocephaly (DP), feeding disorders (FD), excessive crying (EC), and sleep disorders (SD). Osteopaths performed osteopathic treatment as usual for these conditions, and the parents were asked to rate the perceived severity of symptoms on standardized forms including numerical rating scales (NRS 0-10). In DP, the head circumference of the child's skull was measured with a craniometer, and the cranial vault index (CVAI) was calculated.

RESULTS

230 osteopaths agreed to participate, 151 osteopaths returned parental ratings. 1,136 infants were treated 2.8 ± 1.1 times (mean ± SD). IA was the most prevalent disturbance (48%), followed by EC (18%), FD (15%), DP (14%), and SD (4%). In IA, perceived asymmetry as rated on the NRS improved from 6.1 to 1.1, a mean improvement of 82%. In DP, the CVAI improved from 8.0 to 4.0%, a mean improvement of 51%. FD improved by 77%, EC by 70% (from 7.7 to 2.3 on the NRS) and SD by 56%. Adverse reactions with a timely association with osteopathic treatments were reported in 3.5% of all treatments, probably reflecting typical day-to-day variations in symptoms. In a total of 3,212 treatments, there was not a single serious adverse reaction affecting infant health.

CONCLUSIONS

This is one of the largest studies worldwide to date on the osteopathic treatment of infants. Osteopathic treatment was associated with major positive changes in the severity of perceived health complaints as assessed by parents, which in most cases were resolved as a matter of concern, and was proved to be a safe treatment modality among a large number of therapists. Based on these results, confirmatory intervention studies can and should be planned and conducted.

Improving Reporting of Clinical Studies Using the POSEIDON Criteria: POSORT Guidelines

The POSEIDON (Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number) criteria were developed to help clinicians identify and classify low-prognosis patients undergoing assisted reproductive technology (ART) and provide guidance for possible therapeutic strategies to overcome infertility. Since its introduction, the number of published studies using the POSEIDON criteria has increased steadily. However, a critical analysis of existing evidence indicates inconsistent and incomplete reporting of critical outcomes. Therefore, we developed guidelines to help researchers improve the quality of reporting in studies applying the POSEIDON criteria. We also discuss the advantages of using the POSEIDON criteria in ART clinical studies and elaborate on possible study designs and critical endpoints. Our ultimate goal is to advance the knowledge concerning the clinical use of the POSEIDON criteria to patients, clinicians, and the infertility community.

Ranking evidence in substance use and addiction

Evidence-based medicine has consistently prized the epistemological value of randomized-controlled trials (RCTs) owing to their methodological advantages over alternative designs such as observational studies. However, there are limitations to RCTs that hinder their ability to study chronic and dynamic conditions such as substance use and addiction. For these conditions, observational studies may provide superior evidence based on methodological and practical strengths. Assuming epistemic superiority of RCTs has led to an inappropriate devaluation of other study designs and the findings they support, including support for harm reduction services, especially needle exchange programs and supervised injection facilities. The value offered by observational studies should be reflected in evidence-based medicine by allowing more flexibility in evidence hierarchies that presume methodological superiority of RCTs. Despite the popularity of evidence ranking systems and hierarchies, nothing should replace critical appraisal of study methodology and examining the suitability of applying a given study design to a specific research question.

Is my patient ready for a safe transfer to a lower-intensity care setting? Nursing complexity as an independent predictor of adverse events risk after ICU discharge

BACKGROUND

Patients discharged from intensive care units (ICUs) are at risk for adverse events (AEs). Establishing safe discharge criteria is challenging. No available criteria consider nursing complexity among risk factors.

OBJECTIVES

To investigate whether nursing complexity upon ICU discharge is an independent predictor for AEs.

METHODS

Prospective observational study. The Patient Acuity and Complexity Score (PACS) was developed to measure nursing complexity. Its predictive power for AEs was tested using multivariate regression analysis.

RESULTS

The final regression model showed a very-good discrimination power (AUC 0.881; p<0.001) for identifying patients who experienced AEs. Age, ICU admission reason, PACS, cough strength, PaCO₂, serum creatinine and sodium, and transfer to Internal Medicine showed to be predictive of AEs. Exceeding the identified PACS threshold increased by 3.3 times the AEs risk.

CONCLUSIONS

The level of nursing complexity independently predicts AEs risk and should be considered in establishing patient's eligibility for a safe ICU discharge.

A Web-Based Clinical System for Cohort Surveillance of Specific Clinical Effectiveness and Safety Outcomes: A Cohort Study of Non-Vitamin K Antagonist Oral Anticoagulants and Warfarin

Background

Conventional systems of drug surveillance lack a seamless workflow, which makes it crucial to have an active drug surveillance system that proactively assesses adverse drug events.

Objective

The aim of this study was to develop a seamless, Web-based workflow for comparing the safety and effectiveness of drugs in a database of electronic medical records.

Methods

We proposed a comprehensive integration process for cohort surveillance using the National Taiwan University Hospital Clinical Surveillance System (NCSS). We studied a practical application of the NCSS that evaluates the drug safety and effectiveness of novel oral anticoagulants (NOACs) and warfarin by cohort tree analysis in an efficient and interoperable platform.

Results

We demonstrated a practical example of investigating the differences in effectiveness and safety between NOACs and warfarin in patients with nonvalvular atrial fibrillation (AF) using the NCSS. We efficiently identified 2357 patients with nonvalvular AF with newly prescribed oral anticoagulants between 2010 and 2015 and further developed 1 main cohort and 2 subcohorts for separately measuring ischemic stroke as the clinical effectiveness outcome and intracranial hemorrhage (ICH) as the safety outcome. In the subcohort of ischemic stroke, NOAC users exhibited a significantly lower risk of ischemic stroke than warfarin users after adjusting for age, sex, comorbidity, and comedication in an intention-to-treat (ITT) analysis (P=.01) but did not exhibit a significantly distinct risk in an as-treated (AT) analysis (P=.12) after the 2-year follow-up. In the subcohort of ICH, NOAC users did not exhibit a different risk of ICH both in ITT (P=.68) and AT analyses (P=.15).

Conclusions

With a seamless and Web-based workflow, the NCSS can serve the critical role of forming associations between evidence and the real world at a medical center in Taiwan.

Bowel surgery as a fertility-enhancing procedure in patients with colorectal endometriosis: methodological, pathogenic and ethical issues

Bowel surgery for colorectal endometriosis is being promoted to infertile women without severe sub-occlusive symptoms, with the objective of improving the likelihood of conception. Contrary to rectal shaving, bowel surgery involving full-thickness disk excision and segmental resection entails opening of the intestinal lumen thus increasing the risk of postoperative infectious complications. About 1 in 10 patients undergoing colorectal resection for intestinal endometriosis will experience severe sequelae, including anastomotic dehiscence, rectovaginal fistula formation, and bladder and bowel denervation. Similar to other surgical procedures aiming at enhancing fertility in women with endometriosis, bowel surgery has been introduced into clinical practice without adequate evaluation through randomized controlled trials. According to systematic literature reviews based mainly on case series, the incremental gain of adding bowel procedures to standard surgery appears uncertain in terms of pregnancy rate after both natural attempts and IVF. Considering the methodological drawbacks and the high risk of bias in the available observational studies, it is not possible to exclude the suggestion that the benefit of colorectal surgery has been overestimated. Given the risk of harms to women's health and the important ethical implications, less emphasis should be put on strict statistical significance and more emphasis should be placed on the magnitude of the effect size. In this regard, the published data may not be generalizable, as the surgeons publishing their results may not be representative of all surgeons. Until the results of adequately designed and conducted RCTs are available, colorectal surgery with the sole intent of improving the reproductive performance of infertile patients with intestinal endometriosis should be performed exclusively within research settings and by highly experienced surgeons. Women should be informed about the uncertainties regarding the harms and benefits of bowel surgery in different clinical conditions, and preoperative counselling must be conducted impartially with the objective of achieving a truly shared medical decision.

Recommendations for the Reporting of Harms in Manuscripts on Clinical Trials Assessing Osteoarthritis Drugs: A Consensus Statement from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)

BACKGROUND

There is strong evidence of under-reporting of harms in manuscripts on randomized controlled trials (RCTs) compared with the volume of raw data retrieved from these trials. Many guidelines have been developed to tackle this, but they have failed to address some important issues that would allow for standardization and transparency. As a consequence, harms reporting in manuscripts remains suboptimal.

OBJECTIVE

The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) aimed to deliver accurate recommendations for better reporting of harms in clinical trials manuscripts on anti-osteoarthritis (OA) drugs. These could help to better inform clinicians on harms recorded in RCTs and further help researchers conducting meta-analyses.

METHODS

Using the outcomes of several systematic reviews on the safety of anti-OA drugs, we summarized the ways in which harms have been reported in OA RCT manuscripts to date. Next, we drafted some recommendations and initiated a modified Delphi process that involved a panel of clinicians and clinical researchers to build an expert consensus on recommendations from the ESCEO for the reporting of harms in future manuscripts on RCTs assessing anti-OA drugs.

RESULTS

These recommendations emphasize that all treatment-emergent adverse events (AEs) should always be taken into account for harms reporting, with no frequency threshold, and describe how specific AEs should be reported; they also provide a list of the most relevant organ systems to be considered according to each class of drug for reporting of harms within the results section of a manuscript. Irrespective of the drug, the ESCEO recommends that total, severe and serious AEs and withdrawals due to AEs should always be reported; guidance on the reporting of specific events pertaining to each category is provided. The ESCEO also recommends the reporting of information on drug effect on biological parameters, with specific guidance.

CONCLUSIONS

These recommendations may contribute to improve transparency in the field of safety of anti-OA medications. Pharmaceutical companies developing drugs for OA, and researchers conducting clinical trials, are encouraged to comply with them when reporting harms-related results in manuscripts on RCTs. The ESCEO also encourages journals to refer to the ESCEO recommendations in their instructions to authors for the publication of manuscripts on trials of anti-OA medications.

Real-World Costs of Continuous Insulin Pump Therapy and Multiple Daily Injections for Type 1 Diabetes: A Population-Based and Propensity-Matched Cohort From the Swedish National Diabetes Register

OBJECTIVE

To investigate real-world costs of continuous insulin pump therapy compared with multiple daily injection (MDI) therapy for type 1 diabetes.

RESEARCH DESIGN AND METHODS

Individuals with type 1 diabetes and pump therapy in the Swedish National Diabetes Register (NDR) since 2002 were eligible. Control subjects on MDI were matched 2:1 using time-varying propensity scores. Longitudinal data on health care resource use, antidiabetes treatment, sickness absence, and early retirement were taken from national registers for 2005-2013. Mean annual costs were analyzed using univariate analysis. Regression analyses explored the role of sociodemographic factors. Subgroup and sensitivity analyses were performed.

RESULTS

A total of 14,238 individuals with type 1 diabetes entered in the NDR between 2005 and 2013 (insulin pump n = 4,991, MDI n = 9,247, with switches allowed during the study) were included. Mean age at baseline was 34 years, with 21 years of diabetes duration and a mean HbA_1c of 8.1% (65 mmol/mol). We had 73,920 person-years of observation with a mean follow-up of 5 years per participant. Mean annual costs were higher for pump therapy than for MDI therapy ($12,928 vs. $9,005, respectively; P < 0.001; mean difference $3,923 [95% CI $3,703-$4,143]). Health care costs, including medications and disposables, accounted for 73% of the costs for pump therapy and 63% of the costs for MDI therapy. Regression analyses showed higher costs for low education, low disposable income, women, and older age.

CONCLUSIONS

Nine years of real-world data on all measurable diabetes-related resource use show robust results for additional costs of insulin pump therapy in adults by subgroup and alternative propensity score specifications. Identification of tangible and intangible benefits of pump therapy over time remain important to support resource allocation decisions.

The role of meta-analyses and umbrella reviews in assessing the harms of psychotropic medications: beyond qualitative synthesis

ὠφελέειν, ἢ μὴ βλάπτειν (Primum non nocere) - Hιppocrates' principle should still guide daily medical prescribing. Therefore, assessing evidence of psychopharmacologic agents' safety and harms is essential. Randomised controlled trials (RCTs) and observational studies may provide complementary information about harms of psychopharmacologic medications from both experimental and real-world settings. It is considered that RCTs provide a better control of confounding variables, while observational studies provide evidence from larger samples, longer follow-ups, in more representative samples, which may be more reflective of real-life clinical scenarios. However, this may not always hold true. Moreover, in observational studies, safety data are poorly or inconsistently reported, precluding reliable quantitative synthesis in meta-analyses. Beyond individual studies, meta-analyses, which represent the highest level of 'evidence', can be misleading, redundant and of low methodological quality. Overlapping meta-analyses sometimes even reach different conclusions on the same topic. Meta-analyses should be assessed systematically. Descriptive reviews of reviews can be poorly informative. Conversely, 'umbrella reviews' can use a quantitative approach to grade evidence. In this editorial, we present the main factors involved in the assessment of psychopharmacologic agents' harms from individual studies, meta-analyses and umbrella reviews. Study design features, sample size, number of the events of interest, summary effect sizes, p-values, heterogeneity, 95% prediction intervals, confounding factor adjustment and tests of bias (e.g., small-study effects and excess significance) can be combined with other assessment tools, such as AMSTAR and GRADE to create a framework for assessing the credibility of evidence.

Adverse effects of psychotherapy: protocol for a systematic review and meta-analysis

BACKGROUND

While it is well known that psychotherapy is efficacious in the treatment of mental disorders, much less is known about the adverse effects of psychotherapeutic interventions. The aim of this systematic review is to examine the definition, frequency, nature, and severity of adverse effects occurring parallel to or following psychotherapeutic treatment and to compare it against control groups.

METHODS

All registered randomised controlled trials published since 2004 (publication year of harm-reporting extension of the CONSORT statement) with adult patients fulfilling clinical criteria of defined mental disorders, which compare individual or group psychotherapy against a control group, will be included. First, a search through international trial registers as well as a search in literature databases (e.g. MEDLINE) and in relevant journals (e.g. Trials) for study protocols will be conducted to identify eligible trials. In a second step, we will search for respective publications of the results of the eligible studies. Publications will be retrieved and screened for eligibility. Two previously trained, independent raters will extract the data in duplicate. Reporting of adverse effects will be descriptively analysed regarding frequency, heterogeneity, and longitudinal course. We will further compare the adverse effects of psychotherapeutic interventions against various control groups. For each categorical outcome, we will calculate relative risks (RR) together with 95% confidence intervals. For continuous outcomes, standardised mean differences (Hedges' g) with a 95% confidence interval will be computed. Between-study heterogeneity will be tested with the Q statistic and quantified using I2.

DISCUSSION

Preselecting studies with regard to randomised controlled trials might induce bias due to dropout before the beginning of treatment or end of treatment. However, we will thoroughly assess the negative effects of randomisation, e.g. reasons for non-randomisation, if reported. Even if delayed adverse effects might be overlooked in randomised controlled trials, these are the only sources of causal evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews 2017: CRD42017055507 (17 January 2017).

A Pharmacoepidemiology Database System for Monitoring Risk Due to the Use of Medicines by New Zealand Primary Care Patients

INTRODUCTION

The use of large record-linked healthcare databases for drug safety research and surveillance is now accepted practice. New Zealand's standardized national healthcare datasets provide the potential to automate the conduct of pharmacoepidemiological studies to provide rapid validation of medicine safety signals.

OBJECTIVES

Our objectives were to describe the methodology undertaken by a semi-automated computer system developed to rapidly assess risk due to drug exposure in New Zealand's population of primary care patients and to compare results from three studies with previously published findings.

METHODS

Data from three national databases were linked at the patient level in the automated studies. A retrospective nested case-control design was used to evaluate risk for upper gastrointestinal bleeding (UGIB), acute kidney failure (AKF), and serious arrhythmia associated with individual medicines, therapeutic classes of medicines, and concurrent use of medicines from multiple therapeutic classes.

RESULTS

The patient cohort available for each study included 5,194,256 patients registered between 2007 and 2014, with a total of 34,630,673 patient-years at risk. An increased risk for UGIB was associated with non-steroidal anti-inflammatory drugs (NSAIDs) (adjusted odds ratio [AOR] 4.16, 95% confidence interval [CI] 3.90-4.43, p < 0.001) and selective serotonin reuptake inhibitors (AOR 1.39, 95% CI 1.20-1.62, p < 0.001); an increased risk for AKF was associated with NSAIDs (AOR 1.78, 95% CI 1.73-1.83, p < 0.001) and proton pump inhibitors (AOR 1.78, 95% CI 1.72-1.83, p < 0.001); and an increased risk for serious arrhythmia was associated with fluoroquinolones (AOR 1.38, 95% CI 1.26-151, p < 0.001) and penicillins (AOR 1.69, 95% CI 1.61-1.77, p < 0.001).

CONCLUSIONS

Automated case-control studies using New Zealand's healthcare datasets can replicate associations of risk with drug exposure consistent with previous findings. Their speed of conduct enables systematic monitoring of risk for adverse events associated with a wide range of medicines.

Acid-suppressive drugs and risk of kidney disease: A systematic review and meta-analysis

BACKGROUND AND AIM

More concerns had been raised about the risk of kidney disease (KD) associated with acid-suppressive drugs. But whether they could directly increase such risk remained unclear. Meta-analysis was conducted to comprehensively investigate this relationship.

METHODS

PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and three Chinese databases were searched until April 2017 for observational studies investigating the associations between acid-suppressive drugs and KD. Pooled log (odds ratios [ORs]) or log (hazard ratios [HRs]) with standard errors for KD risk were calculated using the generic inverse variance method and random-effect model.

RESULTS

Ten studies involving 128 020 KD patients were included. Proton pump inhibitor (PPI) therapy was associated with higher risks of acute interstitial nephritis (OR, 2.78; 95% confidence interval [CI], 1.25-6.17), acute kidney injury (AKI) (HR, 1.85; 95% CI, 1.33-2.59), chronic kidney disease (CKD) (HR, 1.47; 95% CI, 1.03-2.09), and end-stage renal disease (ESRD) (HR, 1.61; 95% CI, 1.26-2.04) than non-PPI therapy. Additionally, PPI significantly increased the risks of AKI (HR, 1.32; 95% CI, 1.16-1.51), CKD (HR, 1.28; 95% CI, 1.24-1.33), and ESRD (HR, 1.96; 95% CI, 1.21-3.17) compared with histamine 2 receptor antagonist (H2 RA). Relationship between H2 RA therapy and AKI (OR, 0.98; 95% CI, 0.90-1.07) or CKD (OR, 1.00; 95% CI, 0.89-1.11) was not found.

CONCLUSIONS

Proton pump inhibitor therapy significantly increased the risks of acute interstitial nephritis, AKI, CKD, and ESRD. Similar risks were not identified for H2 RA therapy. More clinical trials are needed to confirm our findings.

Summarising the Evidence for Drug Safety: A Methodological Discussion of Different Meta-Analysis Approaches

Evidence on drug safety obtained from randomised clinical trials is very limited due to, among other reasons, their relatively small sample size. Hence, combining the results of available studies can prove particularly useful. This paper reviews the different data sources for summarising drug safety outcomes, according to study design, publication of data, and origin of the information. It then discusses the various types of overviews that can be used in the study of treatment harms, focusing on meta-analyses of aggregate data and meta-analyses of individual patient data, with their advantages and drawbacks, such as publication bias and heterogeneity. Although the different approaches available for combining the results are of great utility in assessing treatment harms, none of them is free from limitations. Therefore, it might be appropriate to perform an analysis of sensitivity to assess whether the results are sensitive to the technique that has been used.

Early Recurrence and Major Bleeding in Patients With Acute Ischemic Stroke and Atrial Fibrillation Treated With Non-Vitamin-K Oral Anticoagulants (RAF-NOACs) Study

BACKGROUND

The optimal timing to administer non-vitamin K oral anticoagulants (NOACs) in patients with acute ischemic stroke and atrial fibrillation is unclear. This prospective observational multicenter study evaluated the rates of early recurrence and major bleeding (within 90 days) and their timing in patients with acute ischemic stroke and atrial fibrillation who received NOACs for secondary prevention.

METHODS AND RESULTS

Recurrence was defined as the composite of ischemic stroke, transient ischemic attack, and symptomatic systemic embolism, and major bleeding was defined as symptomatic cerebral and major extracranial bleeding. For the analysis, 1127 patients were eligible: 381 (33.8%) were treated with dabigatran, 366 (32.5%) with rivaroxaban, and 380 (33.7%) with apixaban. Patients who received dabigatran were younger and had lower admission National Institutes of Health Stroke Scale score and less commonly had a CHA₂DS₂-VASc score >4 and less reduced renal function. Thirty-two patients (2.8%) had early recurrence, and 27 (2.4%) had major bleeding. The rates of early recurrence and major bleeding were, respectively, 1.8% and 0.5% in patients receiving dabigatran, 1.6% and 2.5% in those receiving rivaroxaban, and 4.0% and 2.9% in those receiving apixaban. Patients who initiated NOACs within 2 days after acute stroke had a composite rate of recurrence and major bleeding of 12.4%; composite rates were 2.1% for those who initiated NOACs between 3 and 14 days and 9.1% for those who initiated >14 days after acute stroke.

CONCLUSIONS

In patients with acute ischemic stroke and atrial fibrillation, treatment with NOACs was associated with a combined 5% rate of ischemic embolic recurrence and severe bleeding within 90 days.

Alcohol consumption and the risk of postoperative mortality and morbidity after primary hip or knee arthroplasty - A register-based cohort study

Objective

To investigate the implications of low and moderate preoperative alcohol consumption on postoperative mortality and morbidity after primary hip and knee arthroplasty.

Methods

A total of 30,799 patients who underwent primary hip or knee arthroplasty between January 1^st, 2005 and October 8^th, 2011 with information on preoperative alcohol consumption (0 grams of pure alcohol/week, >0–168 g/week, >168–252 g/week, and >252 g/week) were identified through the Danish Anesthesia Database. The 90-day and 1-year risks of mortality (primary outcomes), 1-year risk of prosthetic infection, and 30-day risks of cardiovascular disease and deep venous thrombosis (secondary outcomes) were estimated by Cox regression analysis.

Results

We identified 285 (0.9%) deaths within the first 90 days and 694 (2.3%) within the first year. Within the first 30 days, 209 (0.7%) and 270 (0.9%) patients had acquired cardiovascular disease and deep venous thrombosis, respectively, and 514 (1.7%) patients developed prosthetic infection within the first year. The adjusted mortality models yielded hazard ratios of 0.55 (95% confidence interval [CI] 0.41 to 0.74) at 90 days and 0.61 (95% CI 0.51 to 0.73) at 1 year for the group consuming >0–168 g/week when compared to abstainers. Adjusted hazard ratios showed that the group consuming >0–168 g/week had a 0.91 (95% CI 0.75 to 1.11) risk of prosthetic infection, 0.68 (95% CI 0.50 to 0.92) risk of cardiovascular disease and 0.88 (95% CI 0.67 to 1.15) risk of deep venous thrombosis when compared to abstainers.

Conclusions

This study demonstrates that low-to-moderate alcohol consumption prior to primary hip or knee arthroplasty is associated with lower risks of mortality at both 90 days and 1 year after surgery and of cardiovascular disease after 30 days. More research from longitudinal studies is needed to identify specific causal relations and explanations.

Using the Comprehensive Complication Index to Assess the Impact of Neoadjuvant Chemoradiotherapy on Complication Severity After Esophagectomy for Cancer

Background

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery for patients with esophageal or junctional cancer has become a standard of care. The comprehensive complication index (CCI) has recently been developed and accounts for all postoperative complications. Hence, CCI better reflects the burden of all combined postoperative complications in surgical patients than the Clavien–Dindo score alone, which incorporates only the most severe complication. This study was designed to evaluate the severity of complications in patients treated with nCRT followed by esophagectomy versus in patients who underwent esophagectomy alone using the comprehensive complication index.

Study-design

All patients included in the CROSS trial—a randomized, clinical trial on the value of nCRT followed by esophagectomy—were included. Complications were assessed and graded using the Clavien–Dindo classification. CCI was derived from these scores, using the CCI calculator available online (www.assessurgery.com). CCI of patients who underwent nCRT followed by surgery was compared with the CCI of patients who underwent surgery alone.

Results

In both groups 161 patients were included. The median (and interquartile range) CCI of patients with nCRT and surgery was 26.22 (17.28–42.43) versus 25.74 (8.66–43.01) in patients who underwent surgery alone (p = 0.58). There also was no difference in CCI between subgroups of patients with anastomotic leakage, pulmonary complications, cardiac complications, thromboembolic events, chyle leakage, and wound infections.

Conclusions

Neoadjuvant chemoradiotherapy according to CROSS did not have a negative impact on postoperative complication severity expressed by CCI compared with patients who underwent surgery alone for potentially curable esophageal or junctional cancer.

Antiepileptic drugs' tolerability and safety--a systematic review and meta-analysis of adverse effects in dogs

Background

The safety profile of anti-epileptic drugs (AEDs) is an important consideration for the regulatory bodies, owners and prescribing clinicians. Information on their adverse effects still remains limited. A systematic review including a meta-analytic approach was designed to evaluate existing evidence for the safety profile of AEDs in canine patients. Electronic searches of PubMed, CAB Direct and Google scholar were carried out without date or language restrictions. Conference proceedings were also searched. Peer-reviewed full-length studies reporting adverse effects of AEDs in epileptic and healthy non-epileptic dogs were included. Studies were allocated to three groups based on their design. Individual studies were evaluated based on the quality of evidence (study design, study group sizes, subject enrolment quality and overall risk of bias) and the outcome measures reported (proportion of specific adverse effects for each AED, prevalence and 95 % confidence interval of the affected population in each study and comparative odds ratio of adverse effects for AEDs).

Results

Ninety studies, including six conference proceedings, reporting clinical outcomes of AEDs’ adverse effects were identified. Few studies were designed as blinded randomised controlled clinical trials. Many studies included low canine populations with unclear criteria of subject enrolment and short treatment periods. Direct comparisons suggested that imepitoin and levetiracetam might have a better safety profile than phenobarbital, whilst the latter might have a better safety profile than potassium bromide. However, none of these comparisons showed a statistically significant difference. Comparisons between other AEDs were not possible as a considerable amount of studies lacked power calculations or adequate data to allow further statistical analysis. Individual AED assessments indicated that levetiracetam might be one of the safest AEDs, followed by imepitoin and then phenobarbital and potassium bromide; these findings were all supported by a strong level of evidence. The safety profile in other AEDs was variable, but weak evidence was found to permit firm conclusions or to compare their safety to other AEDs.

Conclusions

This systematic review provides objective evaluation of the most commonly used AEDs’ adverse effects. Adverse effects usually appeared mild in all AEDs and subsided once doses and/or serum levels were monitored or after the AED was withdrawn. Although phenobarbital might be less safe than imepitoin and levetiracetam, there was insufficient evidence to classify it as an AED with a high risk of major adverse effects. It is important for clinicians to evaluate both AEDs’ effectiveness and safety on an individual basis before the selection of the appropriate monotherapy or adjunctive AED therapy.

Diverse criteria and methods are used to compare treatment effect estimates: a scoping review

OBJECTIVES

To determine what criteria researchers use to assess whether the estimates of effect of an intervention on a dichotomous outcome are different when obtained using different study designs.

STUDY DESIGN AND SETTING

Scoping review of the literature. We included studies of dichotomous outcomes in which authors compared the estimates of effects from different study designs. We performed searches in electronic databases and in the list of references of relevant studies. Two reviewers independently selected studies and abstracted data. We created a list of the criteria used to compare estimates of effects between study designs, described their main features, and classified them using a clinical perspective.

RESULTS

We included 26 studies, from which we identified 24 criteria. Most of the studies focused on comparing estimates from observational studies and randomized controlled trials (n = 19). The most common criteria aimed to determine whether there was a difference or not (n = 18), provided guidance for such a judgment (n = 16), and were based on the point estimates (n = 11). We judged 14 criteria to be appropriate and classified them as either statistically related or clinically related.

CONCLUSION

We found that diverse criteria are used to compare effect estimates between study designs. Familiarity with these would aid in the interpretation of results from different studies regarding the same question.

Instrumental variable analysis as a complementary analysis in studies of adverse effects: venous thromboembolism and second-generation versus third-generation oral contraceptives

PURPOSE

A potentially useful role for instrumental variable (IV) analysis may be as a complementary analysis to assess the presence of confounding when studying adverse drug effects. There has been discussion on whether the observed increased risk of venous thromboembolism (VTE) for third-generation oral contraceptives versus second-generation oral contraceptives could be (partially) attributed to confounding. We investigated how prescribing preference IV estimates compare with conventional estimates.

METHODS

Women in the Clinical Practice Research Database who started a second-generation or third-generation oral contraceptive from 1989 to 2013 were included. Ordinary least squares and two-stage least squares regression were used to estimate risk differences in VTE. Cox regression and IV for Cox proportional hazards regression were used to calculate hazard ratios (HR). The instrument used was the proportion of prescriptions for third-generation oral contraceptives by the general practitioner in the year preceding the current prescription.

RESULTS

All analyses pointed in the direction of an increased VTE risk for third-generation oral contraceptives. The adjusted HR from the conventional Cox regression was 1.62 (95% confidence interval 1.16-2.27) and the fully adjusted HR from the IV Cox regression was 3.45 (95% confidence interval; 0.97-11.7), showing a larger risk and wider confidence intervals in the IV analysis.

CONCLUSIONS

The similarity in direction of results from the IV analyses and conventional analyses suggests that major confounding is unlikely. IV analysis can be a useful complementary analysis to assess the presence of confounding in studies of adverse drug effects in very large databases.

A 'reluctant' critical review: 'Manual for evidence-based clinical practice (2015)'

BACKGROUND

The Users' Guides to the Medical Literature Manual has been a major influence on the teaching and practice of health care globally.

METHODS

The 3rd edition of the multi-authored Manual was reviewed using the principles outlined in Evidence-based Medicine (EBM) texts. One 'clinical scenario' was selected for critical appraisal, as were several chapters; objectivity was enhanced by citing references to support opinions. RESULTS (SUMMARY OF THE APPRAISAL): (1) Strengths: Clinical pearls, too numerous to list.

EXAMPLES

(i) evidence is never enough to drive clinical decision making; (ii) do not rush to adopt new interventions; and (iii) question efficacy data based only on surrogate markers. (2) Weaknesses: The Manual shares shortcomings of textbooks discussed by Straus et al.: (i) references may not be current, important ones may be excluded and citations may be selective; (ii) often, opinion-based; and (iii) delays between revisions. (3) Notable omissions: Little or no discussion of: (i) important segments of the population: those <18 years of age, >65 years of age and those with multimorbidity; (ii) surgical disciplines; (iii) Greenhalgh et al.'s essay on EBM; (iv) alternate views on the hierarchy of evidence; and (vi) critical thinking. (4) Additional issues: (i) Omission of important references on dabigatran (clinical scenario: chapter 13.1); (ii) authors' advice (Chapter 13.3) to 'bypass the discussion section of published research'; and (iii) the advocacy of pre-appraised sources of evidence and network meta-analysis without warnings about limitations, are critiqued.

CONCLUSION

The Manual has several clinical pearls but readers should also be aware of shortcomings.

Clinical and Safety Outcomes of Oral Antithrombotics for Stroke Prevention in Atrial Fibrillation: A Systematic Review and Network Meta-analysis

INTRODUCTION

Novel oral anticoagulants (NOACs) expanded the options for stroke prevention in atrial fibrillation (AF). Earlier studies comparing their relative effectiveness and safety typically do not incorporate age-related differences or postmarketing studies. This study aimed to summarize and compare clinical and safety outcomes of oral antithrombotics for stroke prevention in AF in younger (65-74 years) and older (≥75 years) elderly.

METHODS

We searched PubMed, Embase, and The Cochrane Library from inception through May 1, 2015, for randomized and nonrandomized studies comparing NOACs, warfarin, and aspirin in elderly with AF. Stroke and systemic embolism (SSE) and major bleeding (MB) are the main outcomes. We also studied secondary outcomes of ischemic stroke, all-cause mortality, intracranial bleeding, and gastrointestinal bleeding.

RESULTS

Of 5255 publications identified, 25 randomized controlled trials and 24 nonrandomized studies of 897,748 patients were included. NOACs reduced the risk of SSE compared with warfarin (rate ratios [RRs] range from 0.78-0.82). Relative to SSE, NOACs demonstrated a smaller benefit for ischemic stroke (dabigatran 110 mg, RR 1.08; edoxaban, 1.00; apixaban, 0.99). On the contrary, aspirin was associated with a significantly higher risk of SSE, ischemic stroke, and mortality than warfarin or NOACs (RR > 1), particularly in older elderly. Regarding safety, medium-dose aspirin (100-300 mg daily) and aspirin/clopidogrel combination showed an increased risk of MB compared with warfarin (RR 1.17 and 1.15, respectively), as per dabigatran 150 mg and rivaroxaban in older elderly (RR 1.17 and 1.12, respectively). Among the NOACs, dabigatran 150 mg conferred greater gastrointestinal bleeding risk compared with warfarin (RR 1.51), whereas rivaroxaban (RR 0.73) demonstrated less benefit of reduced intracranial bleeding than other NOACs (RRs range 0.39-0.46).

CONCLUSIONS

Lower rates of SSE and intracranial bleeding were observed with the NOACs compared with warfarin. Dabigatran 150 mg and rivaroxaban were associated with higher rates of MB in older elderly.

Causal assessment of pharmaceutical treatments: why standards of evidence should not be the same for benefits and harms?

It is increasingly acknowledged both among epidemiologists and regulators that the assessment of pharmaceutical harm requires specific methodological approaches that cannot simply duplicate those developed for testing efficacy. However, this intuition lacks sound epistemic bases and delivers ad hoc advice. This paper explains why the same methods of scientific inference do not fare equally well for efficacy and safety assessment by tracing them back to their epistemic foundations. To illustrate this, Cartwright's distinction into clinching and vouching methods is adopted and a series of reasons is provided for preferring the latter to the former: (1) the need to take into account all available knowledge and integrate it with incoming data; (2) the awareness that a latent unknown risk may always change the safety profile of a given drug (precautionary principle); (3) cumulative learning over time; (4) requirement of probabilistic causal assessment to allow decision under uncertainty; (5) impartiality; and (6) limited and local information provided by randomised controlled trials. Subsequently, the clinchers/vouchers distinction is applied to a case study concerning the debated causal association between paracetamol and asthma. This study illustrates the tension between implicit epistemologies adopted in evaluating evidence and causality; furthermore, it also shows that discounting causal evidence may be a result of unacknowledged low priors or lack of valid alternative options. We conclude with a presentation of the changing landscape in pharmacology and the trend towards an increased use of Bayesian tools for assessment of harms.