What is the best evidence for determining harms of medical treatment?

Effectiveness of zygomatic-implant fixed rehabilitation for the atrophic edentulous maxilla: protocol for a systematic review and network meta-analysis

BACKGROUND

Atrophic edentulous maxilla is a debilitating condition caused by the progressive and irreversible bone resorption following loss of teeth, that results in bone of inadequate volume and density. This makes conventional implant therapy extremely challenging without complex reconstructive procedures. Several techniques such as sinus augmentation, short implants, and tilted implants have been used for the rehabilitation of the atrophic maxilla. In recent years, zygomatic implants have emerged as a graftless rehabilitation technique. However, few studies compare zygomatic-implant fixed rehabilitation with other fixed rehabilitation techniques. The existing body of evidence on zygomatic implants is largely based on clinical and disease-oriented outcomes.

METHODS

A network meta-analysis (NMA) will be conducted in order to compare the effectiveness of zygomatic-implant fixed rehabilitation with the other rehabilitation techniques. Experimental and observational studies comparing different implant-assisted fixed rehabilitation in adults with atrophic maxilla will be included. The primary and secondary outcomes will be patient's satisfaction and quality of life respectively. Additional outcomes include the implant's survival/success, and biological and prosthetic complications. An electronic search will be performed through various databases for articles in English and French, without time limits. Risk of bias will be assessed using the Revised Cochrane Risk-of-Bias tool for randomized controlled trials, and ROBINS-I for non-randomized and observational studies. Two independent reviewers will screen the titles and abstracts and extract data. Any discrepancy between reviewers will be discussed and resolved through consensus or with the help of a third reviewer. Pairwise meta-analyses will be performed using a random effects model. I2, τ2, transitivity, subgroup/meta-regression analyses will assess and explain heterogeneity and distribution of effect modifiers. A network plot will be created to connect the different interventions directly and indirectly. Interventions will be ranked using the surface under cumulative ranking curve. Confidence in the results of the NMA will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

DISCUSSION

This study will be the first to assess the effectiveness of zygomatic-implant fixed rehabilitation for the atrophic maxilla using NMA. The evidence obtained will aid clinical decision-making and will advance the knowledge of the rehabilitation techniques for the atrophic maxilla.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023353303.

Evidence of mechanisms in evidence-based policy

Evidence-based policy has achieved great relevance in policy-making and social research. Nonetheless, over the past few years, several problematic aspects of this approach have been identified. This paper discusses whether, and to what extent, evidence of mechanisms could contribute to addressing certain difficulties faced by evidence-based policy. I argue that it could play a crucial role in the assessment of the efficacy of interventions, the extrapolation of interventions to target populations, and the identification of side effects. For analysing the potential contribution of evidence of mechanisms, the previous debate on the pluralist approach to evidence-based medicine is taken as reference.

From randomised controlled trials to real-world data: Clinical evidence to guide management of diabetic macular oedema

Randomised clinical trials (RCTs) are generally considered the gold-standard for providing scientific evidence for treatments' effectiveness and safety but their findings may not always be generalisable to the broader population treated in routine clinical practice. RCTs include highly selected patient populations that fit specific inclusion and exclusion criteria. Although they may have a lower level of certainty than RCTs on the evidence hierarchy, real-world data (RWD), such as observational studies, registries and databases, provide real-world evidence (RWE) that can complement RCTs. For example, RWE may help satisfy requirements for a new indication of an already approved drug and help us better understand long-term treatment effectiveness, safety and patterns of use in clinical practice. Many countries have set up registries, observational studies and databases containing information on patients with retinal diseases, such as diabetic macular oedema (DMO). These DMO RWD have produced significant clinical evidence in the past decade that has changed the management of DMO. RWD and medico-administrative databases are a useful resource to identify low frequency safety signals. They often have long-term follow-up with a large number of patients and minimal exclusion criteria. We will discuss improvements in healthcare information exchange technologies, such as blockchain technology and FHIR (Fast Healthcare Interoperability Resources), which will connect and extend databases already available. These registries can be linked with existing or emerging retinal imaging modalities using artificial intelligence to aid diagnosis, treatment decisions and provide prognostic information. The results of RCTs and RWE are combined to provide evidence-based guidelines.

Chan D, Y. Liu C. Effects of regional anaesthesia on mortality in patients undergoing lower extremity amputation: A retrospective pooled analysis

Background and Aims:

Lower extremity amputation (LEA) is a commonly performed surgery and is associated with significant mortality and morbidity. This review compares the impact of anaesthetic technique on 30-day mortality and other perioperative outcomes in patients undergoing LEA.

Methods:

A systematic search of databases including PubMed, Embase, Scopus and Cochrane Central Register of Controlled Trials, from January 2010 to March 2021, was performed. Studies were eligible if they compared 30-day mortality following either general anaesthesia (GA) or regional anaesthesia (RA), in adult patients undergoing LEA.

Results:

Ten retrospective observational studies were identified. Four of these studies utilised a propensity-score matching technique. Based on these four studies, RA when compared to GA, is not associated with a reduction in the 30-day mortality (Odds ratio 0.83, 95% confidence interval (CI): 0.65, 1.05, I² 20%, P = 0.12). Also there is a very low level of evidence that RA may result in a decrease in the hospital length-of-stay and intensive care unit admissions of patients undergoing LEA.

Conclusion:

RA does not decrease the 30-day postoperative mortality in patients undergoing LEA when compared to GA.

Umbrella review of 42 systematic reviews with meta-analyses: the safety of proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs) are widely used to treat and prevent acid-related disorders. Despite high efficacy, PPI safety has been increasingly scrutinised. However, no comprehensive review summarising investigations of various adverse events is available.

AIMS

To perform an umbrella review to comprehensively assess associations between adverse events and PPI use.

METHODS

In accordance with PRISMA, an umbrella review of systematic reviews with meta-analyses was conducted. PubMed and EMBASE were searched from 2015 to July 2019. AMSTAR 2 and GRADE were used to assess quality and certainty of evidence. Author-reported quality assessments were also reviewed.

RESULTS

Forty-two systematic reviews with meta-analyses, supported predominantly by observational evidence, were included. The most comprehensive studies reported statistically significant associations with PPI use for several outcomes, including: fractures (eg, hip; RR = 1.20; 95% CI = 1.14-1.28; n = 2 103 800), kidney disease (eg, acute kidney injury; RR = 1.61; 95% CI = 1.16-2.22; n = 2 396 640), infections (eg, Clostridioides difficile; OR = 1.99; 95% CI = 1.73-2.30; n = 356 683), gastric cancer (OR = 2.50; 95% CI = 1.74-3.85; n = 943 070) and gastrointestinal events (eg, fundic gland polyps; OR = 2.46; 95% CI = 1.42-4.27; n = 40 218). No associations with non-gastric cancers, or neurological disease were concluded, with conflicting evidence for cardiovascular outcomes. Certainty based on GRADE was very low for most outcomes.

CONCLUSIONS

This review identified several published associations between PPIs and adverse outcomes, however, further investigation is needed to understand their clinical significance and the likelihood of causal relationship. If higher quality evidence is generated substantiating the potential risks, it may be necessary for clinicians to consider alternative treatment strategies, especially when PPI efficacy is suboptimal.

Defining and measuring meditation-related adverse effects in mindfulness-based programs

BACKGROUND

Research on the adverse effects of mindfulness-based programs (MBPs) has been sparse and hindered by methodological imprecision.

METHODS

The 44-item Meditation Experiences Interview (MedEx-I) was used by an independent assessor to measure meditation-related side effects (MRSE) following three variants of an 8-week program of mindfulness-based cognitive therapy (n = 96). Each item was queried for occurrence, causal link to mindfulness meditation practice, duration, valence, and impact on functioning.

RESULTS

Eighty-three percent of the MBP sample reported at least one MRSE. Meditation-related adverse effects (MRAEs) with negative valences or negative impacts on functioning occurred in 58% and 37% of the sample, respectively. Lasting bad effects occurred in 6-14% of the sample and were associated with signs of dysregulated arousal (hyperarousal and dissociation).

CONCLUSION

Meditation practice in MBPs is associated with transient distress and negative impacts at similar rates to other psychological treatments.

Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK

BACKGROUND

In adolescents with severe and persistent gender dysphoria (GD), gonadotropin releasing hormone analogues (GnRHa) are used from early/middle puberty with the aim of delaying irreversible and unwanted pubertal body changes. Evidence of outcomes of pubertal suppression in GD is limited.

METHODS

We undertook an uncontrolled prospective observational study of GnRHa as monotherapy in 44 12-15 year olds with persistent and severe GD. Prespecified analyses were limited to key outcomes: bone mineral content (BMC) and bone mineral density (BMD); Child Behaviour CheckList (CBCL) total t-score; Youth Self-Report (YSR) total t-score; CBCL and YSR self-harm indices; at 12, 24 and 36 months. Semistructured interviews were conducted on GnRHa.

RESULTS

44 patients had data at 12 months follow-up, 24 at 24 months and 14 at 36 months. All had normal karyotype and endocrinology consistent with birth-registered sex. All achieved suppression of gonadotropins by 6 months. At the end of the study one ceased GnRHa and 43 (98%) elected to start cross-sex hormones. There was no change from baseline in spine BMD at 12 months nor in hip BMD at 24 and 36 months, but at 24 months lumbar spine BMC and BMD were higher than at baseline (BMC +6.0 (95% CI: 4.0, 7.9); BMD +0.05 (0.03, 0.07)). There were no changes from baseline to 12 or 24 months in CBCL or YSR total t-scores or for CBCL or YSR self-harm indices, nor for CBCL total t-score or self-harm index at 36 months. Most participants reported positive or a mixture of positive and negative life changes on GnRHa. Anticipated adverse events were common.

CONCLUSIONS

Overall patient experience of changes on GnRHa treatment was positive. We identified no changes in psychological function. Changes in BMD were consistent with suppression of growth. Larger and longer-term prospective studies using a range of designs are needed to more fully quantify the benefits and harms of pubertal suppression in GD.

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.

Net benefit of statins for primary prevention of cardiovascular disease in people 75 years or older: a benefit-harm balance modeling study

BACKGROUND

We determined the risk thresholds above which statin use would be more likely to provide a net benefit for people over the age of 75 years without history of cardiovascular disease (CVD).

METHODS

An exponential model was used to estimate the differences in expected benefit and harms in people treated with statins over a 10-year horizon versus not treated. The analysis was repeated 100,000 times to consider the statistical uncertainty and produce a distribution of the benefit-harm balance index from which we determined the 10-year CVD risk threshold where benefits outweighed the harms. We considered treatment estimates from trials and observational studies, baseline risks, patient preferences, and competing risks of non-CVD death, and statistical uncertainty.

RESULTS

Based on average preferences, statins were more likely to provide a net benefit at a 10-year CVD risk of 24% and 25% for men aged 75-79 years and 80-84 years, respectively, and 21% for women in both age groups. However, these thresholds varied significantly depending on differences in individual patient preferences for the statin-related outcomes, with interquartile ranges of 21-33% and 23-36% for men aged 75-79 years and 80-84 years, respectively, as well as 20-32% and 21-32% for women aged 75-79 years and 80-84 years, respectively.

CONCLUSIONS

Statins would more likely provide a net benefit for primary prevention in older people taking the average preferences if their CVD risk is well above 20%. However, the thresholds could be much higher or lower depending on preferences of individual patients, which suggests more emphasis should be placed on individual-based decision-making, instead of recommending statins for everyone based on a single or a small number of thresholds.

Safety of psychotropic medicines: contribution from observational evidence

The risks associated with psychotropic drugs use should be accurately documented at the population level in view of the growing number of persons exposed to these drugs. The strengths of observational studies regarding the identification of drug-related harms mirror the limitations of randomised controlled trials and vice-versa. Observational studies can be carried out in large samples of unselected participants treated in real-life conditions and who may be followed up over long periods. Serious adverse effects undetected during pre-marketing clinical trials may be observed only in post-marketing use, such as metabolic effects of second-generation antipsychotics. Observational studies play a key role in the identification of teratogenic risks, such as those induced by prenatal exposure to anticonvulsants. These studies are the main source of information to investigate the long-term effects of drugs, such as the possible increased risk of dementia in benzodiazepine users. They may also contribute to the accurate assessment at population level of risks overestimated by studies carried out in non-representative samples, such as the risk of congenital heart diseases in babies prenatally exposed to lithium. Owing to the lack of random allocation of drugs, confounding by indication or by disease severity are the major sources of biases in observational studies exploring drug safety. An adverse outcome may be wrongly imputed to drug exposure while it is a symptom/outcome of the disease motivating the decision to prescribe. Such a bias may occur in studies investigating the link between exposure to antidepressants and suicidality. As several methods have been developed to lessen the impact of such biases, pharmaco-epidemiological studies based upon stringent methodological designs should be regarded as a valid approach for assessing psychotropic drug safety.

Side effects of corticosteroids in patients with advanced cancer: a systematic review

PURPOSE

Corticosteroids are commonly used in palliative care settings, but are associated with several side effects. Although adverse events (AEs) are highly distressing for patients, few data are available from prospective studies to look at incidence or predictors of such harms. The aim of this study is to identify AE reporting among studies of patients with advanced cancer receiving corticosteroids for any reason.

METHODS

A systematic review was conducted using the following data sources: PubMed, Medline, SCOPUS, Cochrane reviews, and CINAHL. Randomized controlled trials (RCTs) with patients with advanced cancer assessing the effect of corticosteroids were included. Consecutive cohort observational studies of corticosteroid toxicities in cancer patients were also included.

RESULTS

Twenty-seven RCTs and 12 consecutive cohort observational studies were identified. The most frequently reported primary outcome of RCTs was nausea and vomiting (8/27). Dexamethasone was prescribed in almost half of RCTs (13/27). In consecutive cohort studies, the primary outcomes were a wide variety of symptoms. Dexamethasone was also the most common glucocorticoid used (7/12). In terms of quality of AE reporting, two RCTs and one consecutive cohort study used a validated AE assessment tool in their studies.

CONCLUSIONS

Side effects of corticosteroids in advanced cancer patients were poorly reported with few data using validated tools. Researchers should be aware of the guideline of AE reporting to provide the best evidence of risk-benefit balance. Developing specific consensus guidelines about AE reporting in studies of glucocorticoids in studies of people with advanced cancer would be useful.

Meta-Analysis and Trial Sequential Analysis Comparing Percutaneous Ventricular Assist Devices Versus Intra-Aortic Balloon Pump During High-Risk Percutaneous Coronary Intervention or Cardiogenic Shock

The intra-aortic balloon pump (IABP) and percutaneous ventricular assist devices (pVAD) are commonly used in different clinical scenarios. The goal of this study was to carry out a meta-analysis and Trial Sequential Analysis (TSA) comparing the IABP versus pVAD (TandemHeart and the Impella) during high-risk percutaneous coronary intervention (PCI) or cardiogenic shock (CS). Using PubMed, Cochrane Central Register of Controlled Trials, and EMBASE we searched for randomized clinical trials (RCTs) and nonrandomized studies that compared pVAD versus IABP in patients who underwent high-risk PCI or with CS. We included 5 RCTs and 1 nonrandomized study comparing pVAD versus IABP. Based on the RCTs, we demonstrated no difference in short-term (6 months) (risk ratio [RR] 1.09, 95% confidence interval [CI] 0.79 to 1.52; p = 0.59) or long-term (12 months) (RR 1.00, 95% CI 0.57 to 1.76; p = 1.00) all-cause mortality. The use of pVAD seemed associated with more adverse events (acute kidney injury, limb ischemia, infection, major bleeding, and vascular injury) compared with IABP (RR 1.65, 95% CI 1.14 to 2.39; p = 0.008) but this was not supported by TSA (random-effects RR 1.66, 95% CI 0.89 to 3.09; p = 0.11; TSA-adjusted CI 0.13 to 21.3). In conclusion there were no differences in short or long-term mortality when using IABP versus pVAD for high-risk PCI or CS. IABP showed superiority over pVAD in terms of risk of harm. However, further RCTs are needed to establish more conclusively the role of these modalities of mechanical circulatory support during high-risk PCI or CS.

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.

Methylphenidate for attention deficit hyperactivity disorder (ADHD) in children and adolescents - assessment of adverse events in non-randomised studies

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in childhood. The psychostimulant methylphenidate is the most frequently used medication to treat it. Several studies have investigated the benefits of methylphenidate, showing possible favourable effects on ADHD symptoms, but the true magnitude of the effect is unknown. Concerning adverse events associated with the treatment, our systematic review of randomised clinical trials (RCTs) demonstrated no increase in serious adverse events, but a high proportion of participants suffered a range of non-serious adverse events.

OBJECTIVES

To assess the adverse events associated with methylphenidate treatment for children and adolescents with ADHD in non-randomised studies.

SEARCH METHODS

In January 2016, we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 12 other databases and two trials registers. We also checked reference lists and contacted authors and pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included non-randomised study designs. These comprised comparative and non-comparative cohort studies, patient-control studies, patient reports/series and cross-sectional studies of methylphenidate administered at any dosage or formulation. We also included methylphenidate groups from RCTs assessing methylphenidate versus other interventions for ADHD as well as data from follow-up periods in RCTs. Participants had to have an ADHD diagnosis (from the 3rd to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders or the 9th or 10th edition of theInternational Classification of Diseases, with or without comorbid diagnoses. We required that at least 75% of participants had a normal intellectual capacity (intelligence quotient of more than 70 points) and were aged below 20 years. We excluded studies that used another ADHD drug as a co-intervention.

DATA COLLECTION AND ANALYSIS

Fourteen review authors selected studies independently. Two review authors assessed risk of bias independently using the ROBINS-I tool for assessing risk of bias in non-randomised studies of interventions. All review authors extracted data. We defined serious adverse events according to the International Committee of Harmonization as any lethal, life-threatening or life-changing event. We considered all other adverse events to be non-serious adverse events and conducted meta-analyses of data from comparative studies. We calculated meta-analytic estimates of prevalence from non-comparative cohorts studies and synthesised data from patient reports/series qualitatively. We investigated heterogeneity by conducting subgroup analyses, and we also conducted sensitivity analyses.

MAIN RESULTS

We included a total of 260 studies: 7 comparative cohort studies, 6 of which compared 968 patients who were exposed to methylphenidate to 166 controls, and 1 which assessed 1224 patients that were exposed or not exposed to methylphenidate during different time periods; 4 patient-control studies (53,192 exposed to methylphenidate and 19,906 controls); 177 non-comparative cohort studies (2,207,751 participants); 2 cross-sectional studies (96 participants) and 70 patient reports/series (206 participants). Participants' ages ranged from 3 years to 20 years. Risk of bias in the included comparative studies ranged from moderate to critical, with most studies showing critical risk of bias. We evaluated all non-comparative studies at critical risk of bias. The GRADE quality rating of the evidence was very low.Primary outcomesIn the comparative studies, methylphenidate increased the risk ratio (RR) of serious adverse events (RR 1.36, 95% confidence interval (CI) 1.17 to 1.57; 2 studies, 72,005 participants); any psychotic disorder (RR 1.36, 95% CI 1.17 to 1.57; 1 study, 71,771 participants); and arrhythmia (RR 1.61, 95% CI 1.48 to 1.74; 1 study, 1224 participants) compared to no intervention.In the non-comparative cohort studies, the proportion of participants on methylphenidate experiencing any serious adverse event was 1.20% (95% CI 0.70% to 2.00%; 50 studies, 162,422 participants). Withdrawal from methylphenidate due to any serious adverse events occurred in 1.20% (95% CI 0.60% to 2.30%; 7 studies, 1173 participants) and adverse events of unknown severity led to withdrawal in 7.30% of participants (95% CI 5.30% to 10.0%; 22 studies, 3708 participants).Secondary outcomesIn the comparative studies, methylphenidate, compared to no intervention, increased the RR of insomnia and sleep problems (RR 2.58, 95% CI 1.24 to 5.34; 3 studies, 425 participants) and decreased appetite (RR 15.06, 95% CI 2.12 to 106.83; 1 study, 335 participants).With non-comparative cohort studies, the proportion of participants on methylphenidate with any non-serious adverse events was 51.2% (95% CI 41.2% to 61.1%; 49 studies, 13,978 participants). These included difficulty falling asleep, 17.9% (95% CI 14.7% to 21.6%; 82 studies, 11,507 participants); headache, 14.4% (95% CI 11.3% to 18.3%; 90 studies, 13,469 participants); abdominal pain, 10.7% (95% CI 8.60% to 13.3%; 79 studies, 11,750 participants); and decreased appetite, 31.1% (95% CI 26.5% to 36.2%; 84 studies, 11,594 participants). Withdrawal of methylphenidate due to non-serious adverse events occurred in 6.20% (95% CI 4.80% to 7.90%; 37 studies, 7142 participants), and 16.2% were withdrawn for unknown reasons (95% CI 13.0% to 19.9%; 57 studies, 8340 participants).

AUTHORS' CONCLUSIONS

Our findings suggest that methylphenidate may be associated with a number of serious adverse events as well as a large number of non-serious adverse events in children and adolescents, which often lead to withdrawal of methylphenidate. Our certainty in the evidence is very low, and accordingly, it is not possible to accurately estimate the actual risk of adverse events. It might be higher than reported here.Given the possible association between methylphenidate and the adverse events identified, it may be important to identify people who are most susceptible to adverse events. To do this we must undertake large-scale, high-quality RCTs, along with studies aimed at identifying responders and non-responders.

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.

Intolerance of dolutegravir-containing combination antiretroviral therapy regimens in real-life clinical practice

OBJECTIVE

Dolutegravir (DGV) is one of the preferred antiretroviral agents in first-line combination antiretroviral therapy (cART). Though considered to be a well tolerated drug, we aimed to determine the actual rate, timing and detailed motivation of stopping DGV in a real-life clinical setting.

DESIGN

A cohort study including all patients who started DGV in two HIV treatment centers in The Netherlands.

METHODS

All cART-naïve and cART-experienced patients who had started DGV were identified from the institutional HIV databases. Clinical data, including motivation and timing of discontinuation of DGV, were extracted from the patient files. Factors that potentially influenced discontinuation of DGV were compared between patients who stopped or continued DGV by multivariate and Kaplan-Meier analyses.

RESULTS

In total, 556 patients were included, of whom 102 (18.4%) were cART-naïve at initiation of DGV. Median follow-up time was 225 days. Overall, in 85 patients (15.3%), DGV was stopped. In 76 patients (13.7%), this was due to intolerability. Insomnia and sleep disturbance (5.6%), gastrointestinal complaints (4.3%) and neuropsychiatric symptoms such as anxiety, psychosis and depression (4.3%) were the predominant reasons for switching DGV. In regimens that included abacavir, DGV was switched more frequently (adjusted relative risk 1.92, 95% confidence interval 1.09-3.38, P log-rank 0.01). No virologic failures were observed.

CONCLUSION

A relatively high rate of preliminary discontinuation of DGV due to intolerability was detected in our patient population. In particular, DGV was stopped more frequently if the regimen included abacavir. Multiple factors may explain these unexpected postmarketing observations, which warrant further investigation.

Clinical safety of insulin detemir in patients with Type 2 diabetes in the Gulf countries: The multicenter, noninterventional, open-label LevSafe study

AIM

To evaluate the safety profile of insulin detemir (IDet) in people with Type 2 diabetes mellitus (T2DM) in the Gulf countries in the 32-week, noninterventional LevSafe study.

METHODS

People with T2DM whose physicians had opted to start IDet therapy were included in the study. Safety parameters, including serious adverse drug reactions (SADRs) and hypoglycemia, and changes in body weight and glycemic control were evaluated at baseline, week 16 and week 32.

RESULTS

A total of 686 patients were exposed to IDet therapy with a mean (±standard deviation) age, body mass index, and diabetes duration of 51.3 ± 11.0 years, 31.3 ± 5.5 kg/m(2), and 10.2 ± 6.1 years, respectively. The mean total daily dose of IDet was 32.0 ± 32.8 U at baseline and 44.7 ± 60.7 U at week 32. No SADRs were reported during the study. Total hypoglycemia decreased from 435 events at baseline to 204 events at week 32 (mean change analyzed by Wilcoxon signed rank test: -0.34; P = 0.0115), and no major hypoglycemia was reported at week 32. Over the 32-week treatment period, the mean body weight decreased from 85.7 ± 15.2 kg to 85.4 ± 14.5 kg (P = 0.0203), glycated hemoglobin A1c from 9.9 ± 1.67% to 7.7 ± 1.36% (P < 0.0001), and fasting plasma glucose from 11.9 ± 3.27 mmol/L to 7.4 ± 1.85 mmol/L (P < 0.0001).

CONCLUSION

IDet therapy was well-tolerated and was associated with a decreased number of hypoglycemic events and improved glycemic control after 32 weeks in patients with T2DM in the Gulf countries.

Bayesian methods including nonrandomized study data increased the efficiency of postlaunch RCTs

OBJECTIVES

Findings from nonrandomized studies on safety or efficacy of treatment in patient subgroups may trigger postlaunch randomized clinical trials (RCTs). In the analysis of such RCTs, results from nonrandomized studies are typically ignored. This study explores the trade-off between bias and power of Bayesian RCT analysis incorporating information from nonrandomized studies.

STUDY DESIGN AND SETTING

A simulation study was conducted to compare frequentist with Bayesian analyses using noninformative and informative priors in their ability to detect interaction effects. In simulated subgroups, the effect of a hypothetical treatment differed between subgroups (odds ratio 1.00 vs. 2.33). Simulations varied in sample size, proportions of the subgroups, and specification of the priors.

RESULTS

As expected, the results for the informative Bayesian analyses were more biased than those from the noninformative Bayesian analysis or frequentist analysis. However, because of a reduction in posterior variance, informative Bayesian analyses were generally more powerful to detect an effect. In scenarios where the informative priors were in the opposite direction of the RCT data, type 1 error rates could be 100% and power 0%.

CONCLUSION

Bayesian methods incorporating data from nonrandomized studies can meaningfully increase power of interaction tests in postlaunch RCTs.

Utilization of inhaled corticosteroids for infants with bronchopulmonary dysplasia

OBJECTIVE

To determine demographic and clinical variables associated with inhaled corticosteroid administration and to evaluate between-hospital variation in inhaled steroid use for infants with bronchopulmonary dysplasia (BPD).

DESIGN

Retrospective Cohort Study.

SETTING

Neonatal units of 35 US children's hospitals; as recorded in the Pediatric Health Information System (PHIS) database.

PATIENTS

1429 infants with evolving BPD at 28 days who were born at <29 weeks gestation with birth weight <1500 grams, admitted within the first 7 postnatal days, and discharged between January 2007-June 2011.

RESULTS

Inhaled steroids were prescribed to 25% (n = 352) of the cohort with use steadily increasing during the first two months of hospitalization. The most frequently prescribed steroid was beclomethasone (n = 194, 14%), followed by budesonide (n = 125, 9%), and then fluticasone (n = 90, 6%). Birth gestation <24 weeks, birth weight 500-999 grams, and prolonged ventilation all increased the adjusted odds of ever receiving inhaled corticosteroids (p<0.05). Wide variations between hospitals in the frequency of infants ever receiving inhaled steroids (range: 0-60%) and the specific drug prescribed were noted. This variation persisted, even after controlling for observed confounders.

CONCLUSIONS

Inhaled corticosteroid administration to infants with BPD is common in neonatal units within U.S. Children's hospitals. However, its utilization varies markedly between centers from no treatment at some institutions to the majority of infants with BPD being treated at others. This supports the need for further research to identify the benefits and potential risks of inhaled steroid usage in infants with BPD.

Combined oral contraceptives: venous thrombosis

BACKGROUND

Combined oral contraceptive (COC) use has been associated with venous thrombosis (VT) (i.e., deep venous thrombosis and pulmonary embolism). The VT risk has been evaluated for many estrogen doses and progestagen types contained in COC but no comprehensive comparison involving commonly used COC is available.

OBJECTIVES

To provide a comprehensive overview of the risk of venous thrombosis in women using different combined oral contraceptives.

SEARCH METHODS

Electronic databases (Pubmed, Embase, Web of Science, Cochrane, CINAHL, Academic Search Premier and ScienceDirect) were searched in 22 April 2013 for eligible studies, without language restrictions.

SELECTION CRITERIA

We selected studies including healthy women taking COC with VT as outcome.

DATA COLLECTION AND ANALYSIS

The primary outcome of interest was a fatal or non-fatal first event of venous thrombosis with the main focus on deep venous thrombosis or pulmonary embolism. Publications with at least 10 events in total were eligible. The network meta-analysis was performed using an extension of frequentist random effects models for mixed multiple treatment comparisons. Unadjusted relative risks with 95% confidence intervals were reported.Two independent reviewers extracted data from selected studies.

MAIN RESULTS

3110 publications were retrieved through a search strategy; 25 publications reporting on 26 studies were included. Incidence of venous thrombosis in non-users from two included cohorts was 0.19 and 0.37 per 1 000 person years, in line with previously reported incidences of 0,16 per 1 000 person years. Use of combined oral contraceptives increased the risk of venous thrombosis compared with non-use (relative risk 3.5, 95% confidence interval 2.9 to 4.3). The relative risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate, or drospirenone were similar and about 50-80% higher than for combined oral contraceptives with levonorgestrel. A dose related effect of ethinylestradiol was observed for gestodene, desogestrel, and levonorgestrel, with higher doses being associated with higher thrombosis risk.

AUTHORS' CONCLUSIONS

All combined oral contraceptives investigated in this analysis were associated with an increased risk of venous thrombosis. The effect size depended both on the progestogen used and the dose of ethinylestradiol. Risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate and drospirenone were similar, and about 50-80% higher than with levonorgestrel. The combined oral contraceptive with the lowest possible dose of ethinylestradiol and good compliance should be prescribed-that is, 30 μg ethinylestradiol with levonorgestrel.

Clinical experience with insulin detemir in patients with type 2 diabetes from the near East countries

INTRODUCTION

This study aimed at determining the clinical safety and efficacy of insulin detemir (IDet) in combination with oral anti-diabetic drugs (OADs) in type 2 diabetes (T2D) patients from four Near East Countries (Israel, Jordan, Pakistan and Lebanon).

METHODS

This prospective observational study included T2D patients previously on OADs and newly diagnosed patients initiating IDet with or without OADs, at the discretion of physicians. Safety objectives included evaluation of hypoglycemia and adverse drug reactions (ADRs) from baseline to Week 24. Efficacy outcomes included baseline to Week 24 changes in glucose control parameters (glycated hemoglobin [HbA1c], fasting plasma glucose [FPG] and post-breakfast post-prandial plasma glucose [PPPG]). Change in body weight during this period was also assessed.

RESULTS

A total of 2,155 patients (mean ± SD: age 57.1 ± 11.0 years, BMI 29.4 ± 5.1 kg/m(2), average diabetes duration 9.2 ± 5.4 years) were included. IDet dose at baseline was 0.20 ± 0.09 U/kg titrated up to 0.34 ± 0.14 U/kg by Week 24. From baseline to Week 24, the total number of hypoglycemic episodes increased from 1.30 to 1.37 events/patient-year, while major hypoglycemic episodes decreased from 0.15 to 0.02 events/patient-year. A total of 9 ADRs were reported, of which one event was a serious ADR. Statistically significant improvements in glucose control were reported from baseline to Week 24 (HbA1c: 9.6 ± 1.6% vs. 7.6 ± 1.1%; FPG: 201.5 ± 59.5 mg/dL vs. 124.9 ± 31.6 mg/dL; PPPG: 264.2 ± 65.7 mg/dL vs. 167.2 ± 36.8 mg/dL; all p < 0.0001). Body weight did not change significantly after 24 weeks of IDet therapy.

CONCLUSION

IDet therapy in combination with OADs improved glycemic control without increasing the risk of hypoglycemia or weight gain.

Comparison of pooled risk estimates for adverse effects from different observational study designs: methodological overview

BACKGROUND

A diverse range of study designs (e.g. case-control or cohort) are used in the evaluation of adverse effects. We aimed to ascertain whether the risk estimates from meta-analyses of case-control studies differ from that of other study designs.

METHODS

Searches were carried out in 10 databases in addition to reference checking, contacting experts, and handsearching key journals and conference proceedings. Studies were included where a pooled relative measure of an adverse effect (odds ratio or risk ratio) from case-control studies could be directly compared with the pooled estimate for the same adverse effect arising from other types of observational studies.

RESULTS

We included 82 meta-analyses. Pooled estimates of harm from the different study designs had 95% confidence intervals that overlapped in 78/82 instances (95%). Of the 23 cases of discrepant findings (significant harm identified in meta-analysis of one type of study design, but not with the other study design), 16 (70%) stemmed from significantly elevated pooled estimates from case-control studies. There was associated evidence of funnel plot asymmetry consistent with higher risk estimates from case-control studies. On average, cohort or cross-sectional studies yielded pooled odds ratios 0.94 (95% CI 0.88-1.00) times lower than that from case-control studies.

INTERPRETATION

Empirical evidence from this overview indicates that meta-analysis of case-control studies tend to give slightly higher estimates of harm as compared to meta-analyses of other observational studies. However it is impossible to rule out potential confounding from differences in drug dose, duration and populations when comparing between study designs.

Until RCT proven? On the asymmetry of evidence requirements for risk assessment

The problem of collecting, analysing and evaluating evidence on adverse drug reactions is an example of the more general class of epistemological problems related to scientific inference and prediction, as well as a central problem of health care practice. Philosophical discussions have analysed critically the methodological pitfalls and epistemological implications of evidence assessment in medicine; however, they have focused predominantly on evidence of treatment efficacy. Most of this work is devoted to statistical methods of causal inference with a special focus on the privileged role assigned to randomized controlled trials (RCTs) in evidence-based medicine. Regardless of whether the RCT's privilege holds for efficacy assessment, it is nevertheless important to make a distinction between causal inference in relation to intended and unintended effects, in that the unknowns at stake are heterogeneous in the two contexts. This point has been emphasized by epidemiologists in the last decade. Their primary focus is methodological and regards the fact that bias and confounding factors do not affect studies on intended and unintended effects in the same way. However, deeper concerns ground the intuition for such a distinction; these are related to the constraints we impose on evidence and their epistemological justification. My thesis is that such constraints ought to be understood as being different in evidence for risk versus for efficacy. I present the recent debate on the causal association between acetaminophen and asthma in order to illustrate the point at issue. The upshot of my analysis is that different epistemologies confer different methodological choices, which in turn bring about relevant practical implications such as the decision to restrict or suspend drug use rather than leaving it on the market. Thus, it is worth considering the criteria underlying our evidence constraints because they may be ill suited to the purpose for which they are used.

Safety and effectiveness of insulin detemir in type 2 diabetes: results from the ASEAN cohort of the A₁chieve study

AIM

To determine the safety and effectiveness of insulin detemir (IDet) in type 2 diabetes patients from the ASEAN cohort of the A1chieve study.

METHODS

Patients from Indonesia, Malaysia, Philippines and Singapore prescribed IDet at the discretion of their physicians were included. The primary outcome was the incidence of serious adverse drug reactions including major hypoglycaemia over 24 weeks. Secondary endpoints included changes in the frequency of hypoglycaemia, serious adverse events and effectiveness assessments.

RESULTS

This sub-analysis included 1540 patients (insulin-naive, 1239; insulin-experienced, 301) with mean age ± SD 56.4 ± 10.9 years, BMI 25.4 ± 4.6 kg/m(2) and diabetes duration 6.9 ± 5.3 years. Insulin-naive patients received a baseline IDet dose of 0.24 ± 0.11 U/kg titrated up to 0.37 ± 0.21 U/kg by Week 24. The pre-study insulin dose in insulin-experienced patients was 0.41 ± 0.25 U/kg and baseline IDet dose was 0.31 ± 0.24 U/kg titrated up to 0.40 ± 0.20 U/kg by Week 24. Overall hypoglycaemia decreased from 1.73 to 0.46 events/patient-year from baseline to Week 24 (change in proportion of patients affected, p < 0.0001). At Week 24, 1 major hypoglycaemic event was reported in 1 insulin-experienced patient. IDet significantly improved glucose control (p < 0.001) at Week 24. The lipid profile and systolic blood pressure improved (p < 0.001) and body weight did not change significantly. Quality of life was positively impacted (p < 0.001).

CONCLUSION

IDet was well-tolerated and improved glycaemic control without increasing the risk of hypoglycaemia or weight gain.

Safety and effectiveness of biphasic insulin aspart 30 in type 2 diabetes patients switched from biphasic human insulin 30: results from the Filipino cohort of the A₁chieve study

AIM

To evaluate the safety and effectiveness of biphasic insulin aspart 30 (BIAsp 30) in Filipino patients with type 2 diabetes previously treated with biphasic human insulin 30 (BHI 30).

METHODS

Safety and effectiveness outcomes were measured in all patients switching from BHI 30 to BIAsp 30 in the Filipino cohort of the 24-week, multinational, prospective, non-interventional A₁chieve study.

RESULTS

A total of 111 Filipino patients (mean age ± SD, 57.4 ± 12.8 years; BMI, 25.8 ± 5.6 kg/m(2)) with mean diabetes duration of 9.9 ± 7.1 years switched therapy from BHI 30 to BIAsp 30. The mean pre-study BHI 30 dose was 0.65 ± 0.28 IU/kg and the baseline BIAsp 30 dose was 0.65 ± 0.26 U/kg titrated up to 0.70 ± 0.26 U/kg by Week 24. No serious adverse drug reactions were reported. Overall hypoglycaemia was reduced from 5.62 to 1.98 events/patient-year. Minor and nocturnal hypoglycaemia decreased and no major hypoglycaemia was reported at Week 24. Glucose control improved from baseline to Week 24 (HbA1c, -2.2 ± 2.1% [24 ± 23 mmol/mol]; FPG, -72.0 ± 71.8 mg/dL; PPPG, -145.5 ± 125.4 mg/dL). A total of 24 patients achieved HbA1c levels <7.0% at Week 24 compared to 6 patients reporting this target at baseline. Quality of life was positively impacted at Week 24 (change in visual analogue scores, 15.3 ± 16.9 points).

CONCLUSION

Switching from BHI 30 to BIAsp 30 improved glycaemic control without increasing the risk of hypoglycaemia.

Clinical safety and effectiveness of biphasic insulin aspart 30 in type 2 diabetes patients switched from biphasic human insulin 30: results from the Indonesian cohort of the A₁chieve study

AIM

To evaluate the safety and effectiveness of biphasic insulin aspart 30 (BIAsp 30) in Indonesian type 2 diabetes patients switched from biphasic human insulin 30 (BHI 30) as a sub-analysis of the A₁chieve study.

METHODS

Clinical safety and effectiveness over 24 weeks was evaluated in Indonesian patients who switched from BHI 30 to BIAsp 30 at the discretion of their physician.

RESULTS

A total of 244 patients with mean age ± SD 55.6 ± 9.5 years, BMI 24.6 ± 3.8 kg/m(2), and mean diabetes duration 7.8 ± 5.7 years were included. The mean pre-study BHI 30 dose was 0.56 ± 0.25 IU/kg and the baseline BIAsp 30 dose was 0.60 ± 0.26 U/kg titrated up to 0.65 ± 0.25 U/kg by Week 24. No serious adverse drug reactions were reported throughout the study. Overall hypoglycaemia decreased from 2.18 to 0.06 events/patient-year with a significant decrease in the proportion of patients affected (p < 0.0001). No nocturnal or major hypoglycaemia was reported at Week 24. HbA1c improved from 8.8 ± 1.2% at baseline to 7.3 ± 0.8% at Week 24. A total of 45 patients achieved HbA1c <7.0% as compared to 5 patients with HbA1c <7.0% at baseline. FPG and PPPG improved significantly after 24 weeks (p < 0.001). Quality of life was positively impacted (change in visual analogue scores, 3.0 ± 11.6 points, p < 0.001).

CONCLUSION

Switching from BHI 30 to BIAsp 30 in this Indonesian cohort was well-tolerated and improved glycaemic control with a decreased risk of hypoglycaemia.

Some improvements are apparent in identifying adverse effects in systematic reviews from 1994 to 2011

OBJECTIVE

An increasing amount of research and guidelines has been published on search methodology and the reporting of search strategies in systematic reviews. This research assessed whether this has lead to any improvements in the reporting and quality of searching in systematic reviews of adverse effects.

STUDY DESIGN AND SETTING

All records within Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects were scanned for systematic reviews of adverse effects. Data were then extracted on the methods used for information retrieval in these reviews and a descriptive analysis conducted by publication year.

RESULTS

A total of 849 reviews published from 1994 to 2011 met the inclusion criteria. There has been a significant increase (P<0.001) in the number of adverse effects reviews per year from 1994 (n=5) to 2010 (n=104). Some improvements were apparent, such as an increase in the number of databases searched and fewer date and language restrictions applied. However, there has been an increase in reviews limited to data from randomized controlled trials, whereas the reporting of search strategies could still be improved further, with only 9% (74/849) of the reviews reporting reproducible searches.

CONCLUSION

Some improvements in searching systematic reviews of adverse effects are apparent; however, poor reporting of search strategies remains a great obstacle to readers.

Pharmacological treatment of neonatal seizures: a systematic review

Pharmacologic treatment options for neonatal seizures have expanded over the past 2 decades, and there is no consensus on optimal treatment strategy. We systematically reviewed the published literature to determine which medication(s) are most effective for treating neonatal seizures, by retrieving trials and observational investigations via PubMed (through August 2011) that focused on pharmacological seizure treatment of neonates (≤ 28 days old) and utilized continuous or amplitude-integrated EEG to confirm seizure diagnosis and cessation. Our search identified 557 initial articles and 14 additional studies after reference reviews, with 16 meeting inclusion criteria. Of these, 2 were randomized trials and only 3 additional investigations included comparison groups. We found limited evidence regarding the best pharmacologic treatment for neonatal seizures, but were able to devise a treatment algorithm from available data. These findings have the potential to serve as a clinical reference and to inform the design of comparative effectiveness investigations for neonatal antiepileptics.

What intervention is best practice for vestibular schwannomas? A systematic review of controlled studies

OBJECTIVE

Largely, watchful waiting is the initial policy for patients with small-sized or medium-sized vestibular schwannoma, because of slow growth and relatively minor complaints, that do not improve by an intervention. If intervention (microsurgery, radiosurgery or fractionated radiotherapy) becomes necessary, the choice of intervention appears to be driven by the patient's or clinician's preference rather than by evidence based. This study addresses the existing evidence based on controlled studies of these interventions.

DESIGN

A systematic Boolean search was performed focused on controlled intervention studies. The quality of the retrieved studies was assessed based on the Sign-50 criteria on cohort studies.

DATA SOURCES

Pubmed/Medline, Embase, Cochrane Central Register of Controlled Trials and reference lists.

STUDY SELECTION

Six eligibility criteria included a controlled intervention study on a newly diagnosed solitary, vestibular schwannoma reporting on clinical outcomes. Two prospective and four retrospective observational, controlled studies published before November 2011 were selected.

DATA ANALYSIS

Two reviewers independently assessed the methodological quality of the studies and extracted the outcome data using predefined formats.

RESULTS

Neither randomised studies, nor controlled studies on fractionated radiotherapy were retrieved. Six studies compared radiosurgery and microsurgery in a controlled way. All but one were confined to solitary tumours less than 30 mm in diameter and had no earlier interventions. Four studies qualified for trustworthy conclusions. Among all four, radiosurgery showed the best outcomes: there were no direct mortality, no surgical or anaesthesiological complications, but better facial nerve outcome, better preservation of useful hearing and better quality of life.

CONCLUSIONS

The available evidence indicates radiosurgery to be the best practice for solitary vestibular schwannomas up to 30 mm in cisternal diameter.

A pathway to improved prospective observational post-authorization safety studies

Randomized controlled trials (RCTs) are the gold standard for assessing the efficacy of drugs but not necessarily so for drug safety where inadequate power to detect either multiple or rare adverse events is a major handicap. Furthermore, the conditions under which drugs are approved for market use are often different from the settings in actual use. Indeed, with their control mechanisms, trials are by design largely inadequate for the identification of potential safety signals, especially of the rare type, hence the value of postmarketing surveillance and risk management plan-based activities. Today, clinical trials constitute only a part of the research that goes into assessing the safety of drugs. Observational studies, where the investigators merely collect data on treatments received by patients and their health status in routine clinical practice are increasing in uptake because they reflect the real-life utility of drugs, despite the absence of random treatment assignment. Although such studies generally provide less compelling evidence than RCTs, they can be far more useful to drug safety assessment activities than generally acknowledged. An increasing number of post-authorization safety studies (PASS) within the European Medicines Agency's jurisdiction are of the observational type - considered perhaps as more appropriate vehicles for exploring and documenting how products perform in the real world. A similar trend is emerging in the US following the FDA Amendments Act of 2007; since early 2010, an increasing number of post-approval commitments mandated by the FDA include observational studies. However, despite this pattern, not much is known about ongoing efforts to address many of the recognized inadequacies associated with existing methodologies and practices currently adopted in observational PASS. This current opinion presents an overview of some of the main challenges we face in prospective observational PASS, mainly from practical experience, and proposes certain steps for improvement.

Caring for the older person with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a common disease in elderly patients, is characterized by high symptom burden, health care utilization, mortality, and unmet needs of patients and caregivers. Respiratory failure and dyspnea may be exacerbated by heart failure, pulmonary embolism, and anxiety; by medication effects; and by other conditions, including deconditioning and malnutrition. Randomized controlled trials, which provide the strongest evidence for guideline recommendations, may underestimate the risk of adverse effects of interventions for older patients with COPD. The focus of guidelines on disease-modifying therapies may not address the full spectrum of patient and caregiver needs, particularly the high rates of bothersome symptoms, risk of functional and cognitive decline, and need for end-of-life care planning. Meeting the many needs of older patients with COPD and their families requires that clinicians supplement guideline-recommended care with treatment decision making that takes into account older persons' comorbid conditions, recognizes the trade-offs engendered by the increased risk of adverse events, focuses on symptom relief and function, and prepares patients and their loved ones for further declines in the patient's health and their end-of-life care. A case of COPD in an 81-year-old man hospitalized with severe dyspnea and respiratory failure highlights both the challenges in managing COPD in the elderly and the limitations in applying guidelines to geriatric patients.

Vascular-endothelial-growth-factor (VEGF) targeting therapies for endocrine refractory or resistant metastatic breast cancer

BACKGROUND

Vascular-endothelial-growth-factor (VEGF) is a key mediator of angiogenesis. VEGF-targeting therapies have shown significant benefits and been successfully integrated in routine clinical practice for other types of cancer, such as metastatic colorectal cancer. By contrast, individual trial results in metastatic breast cancer (MBC) are highly variable and their value is controversial.

OBJECTIVES

To evaluate the benefits (in progression-free survival (PFS) and overall survival (OS)) and harms (toxicity) of VEGF-targeting therapies in patients with hormone-refractory or hormone-receptor negative metastatic breast cancer.

SEARCH METHODS

Searches of CENTRAL, MEDLINE, EMBASE, the Cochrane Breast Cancer Group's Specialised Register, registers of ongoing trials and proceedings of conferences were conducted in January and September 2011, starting in 2000. Reference lists were scanned and members of the Cochrane Breast Cancer Group, experts and manufacturers of relevant drug were contacted to obtain further information. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) to evaluate treatment benefit and non-randomised studies in the routine oncology practice setting to evaluate treatment harms.

DATA COLLECTION AND ANALYSIS

We performed data collection and analysis according to the published protocol. Individual patient data was sought but not provided. Therefore, the meta-analysis had to be based on published data. Summary statistics for the primary endpoint (PFS) were hazard ratios (HRs).

MAIN RESULTS

We identified seven RCTs, one register, and five ongoing trials from a total of 347 references. The published trials for VEGF-targeting drugs in MBC were limited to bevacizumab. Four trials, including a total of 2886 patients, were available for the comparison of first-line chemotherapy, with versus without bevacizumab. PFS (HR 0.67; 95% confidence interval (CI) 0.61 to 0.73) and response rate were significantly better for patients treated with bevacizumab, with moderate heterogeneity regarding the magnitude of the effect on PFS. For second-line chemotherapy, a smaller, but still significant benefit in terms of PFS could be demonstrated for patients treated with bevacizumab (HR 0.85; 95% CI 0.73 to 0.98), as well as a benefit in tumour response. However, OS did not differ significantly, neither in first- (HR 0.93; 95% CI 0.84 to 1.04), nor second-line therapy (HR 0.98; 95% CI 0.83 to 1.16). Quality of life (QoL) was evaluated in four trials but results were published for only two of these with no relevant impact. Subgroup analysis stated a significant greater benefit for patients with previous (taxane) chemotherapy and patients with hormone-receptor negative status. Regarding toxicity, data from RCTs and registry data were consistent and in line with the known toxicity profile of bevacizumab. While significantly higher rates of adverse events (AEs) grade III/IV (odds ratio (OR) 1.77; 95% CI 1.44 to 2.18) and serious adverse events (SAEs) (OR 1.41; 95% CI 1.13 to 1.75) were observed in patients treated with bevacizumab, rates of treatment-related deaths were lower in patients treated with bevacizumab (OR 0.60; 95% CI 0.36 to 0.99).

AUTHORS' CONCLUSIONS

The overall patient benefit from adding bevacizumab to first- and second-line chemotherapy in metastatic breast cancer can at best be considered as modest. It is dependent on the type of chemotherapy used and limited to a prolongation of PFS and response rates in both first- and second-line therapy, both surrogate parameters. In contrast, bevacizumab has no significant impact on the patient-related secondary outcomes of OS or QoL, which indicate a direct patient benefit. For this reason, the clinical value of bevacizumab for metastatic breast cancer remains controversial.

Patterns of care in the management of seminoma stage I: results from a European survey

Study Type - Therapy (practise pattern survey). Level of Evidence 3b. What's known on the subject? and What does the study add? The uncertainties about differences in relapse and rates of other late events such as second malignancy and cardiovascular events for the three post-orchidectomy strategies in seminoma stage I patients has led to debates about whether the three strategies are equally effective and safe. The differences in interpretation of the data as well as the debates are likely to result in differences in treatment after orchidectomy in seminoma stage I patient management. Current care patterns after orchidectomy are, however, unknown. We assessed patterns of care for seminoma stage I patients after orchidectomy by distributing a survey among doctors treating such patients across Europe. The 969 respondents showed large differences in care strategies between specialties and countries that indicate the need for research into long-term relapse rates and long-term adverse effects to standardize and optimize care for seminoma stage I patients.

OBJECTIVE

• To assess precise patterns of care after orchidectomy in Europe for stage I seminoma patients, we aimed to perform a survey among doctors in the various European countries.

PATIENTS AND METHODS

• We distributed a survey in 2009 and 2010 among American Society of Clinical Oncology and European Association of Urology members.

RESULTS

• In total, 969 questionnaires were included in the analysis. More than half of the 969 physicians (58%) currently offer only one post-surgical treatment: 18% only surveillance, 19% only radiotherapy and 21% only chemotherapy. Thirteen percent of the 969 physicians currently offer all three strategies, 25% offer surveillance and adjuvant radiotherapy or chemotherapy, and 5% offer either adjuvant radiotherapy or chemotherapy without surveillance. • We found large differences in care patterns between specialties and countries. Even within countries, care after orchidectomy was not standardized. • Before 2005, 73% of the physicians offered only one treatment and of those 51% gave adjuvant radiotherapy.

CONCLUSIONS

• Large differences in pattern of care after orchidectomy for stage I seminoma patients exist between specialties and countries within Europe. • More information on long-term relapse rates and long-term adverse effects of the three strategies is needed to standardize and optimize care after orchidectomy.

Safety and diagnostic image quality of iopromide: results of a large non-interventional observational study of European and Asian patients (IMAGE)

BACKGROUND

Iodine-based contrast agents such as iopromide play a central role in improving the diagnostic quality of imaging modalities using ionizing radiation.

PURPOSE

To investigate the safety and diagnostic image quality of iopromide in the routine clinical setting.

MATERIAL AND METHODS

This was an international, multicenter, prospective, single-arm, non-interventional study (NIS). The study was performed in out- and inpatients in 738 study centers in 21 countries in Europe and Asia. Iopromide was administered in a routine manner, in compliance with the local package insert. The use of premedication was at the discretion of the attending physician. Case report forms for 44,835 patients were analyzed (57.4% men). The median age of the patients was 55 years.

RESULTS

For the vast majority of patients (94.8%), the contrast quality was rated as 'good' (55.8%) or 'excellent' (39.0%). For 1265 (2.8%) patients, there were reports of adverse drug reactions (ADRs) excluding tolerance indicators (TIs) (i.e. injection site warmth, feeling hot, or injection site pain of mild intensity). At least one ADR including TIs was reported in 2415 (5.4%) patients. There were 11 (0.02%) patients with serious ADRs, and no drug-related deaths. Events of injection site warmth and/or feeling hot were reported by 3.5%, nausea and/or vomiting by 0.96%, and urticaria, erythema, and/or rash by 0.54% of patients. Patients at risk for an acute idiosyncratic reaction (i.e. patients with a history of bronchial asthma, allergies, and/or contrast media reaction) had a higher incidence of ADRs compared with the overall study population. At-risk patients who did not receive premedication reported distinctly more ADRs compared with those who received premedication (12.0% versus 5.9%).

CONCLUSION

Iopromide was shown to be a well-tolerated contrast agent whose usage resulted in high image quality. No unknown ADRs were observed. Premedication with antiallergy drugs should be considered in at-risk patients.

Improved glycemic control with weight loss and a low risk of hypoglycemia with insulin detemir: insights from the Italian cohort of the PREDICTIVE study after 6-month observation in type 2 diabetic subjects

OBJECTIVE

PREDICTIVE (Predictable Results and Experience in Diabetes through Intensification and Control to Target: an International Variability Evaluation) is a large, multinational, open-label, prospective, observational study addressed to assess the efficacy and safety of insulin detemir in clinical practice. This paper reports 26 weeks of follow-up data, from 1298 type 2 diabetes patients from Italy.

RESEARCH DESIGN AND METHODS

In this observational study, the primary end point was the incidence of serious adverse drug reactions (SADRs), including major hypoglycemia. Secondary end points were: hemoglobin A1c (HbA1c), mean self-monitored fasting glucose, within-patient fasting glucose variability and body weight change.

RESULTS

Insulin detemir significantly improved glycemic control, with a decrease in mean HbA1c, fasting glucose and within-patient fasting glucose variability. Interestingly, the improvements in glycemic control occurred in association with a small, but significant reduction in weight. The safety results of this study showed that 26 weeks of treatment with insulin detemir was associated with a very low rate of SADRs (only 14 events), which mainly consisted of hypoglycemia (78%, of which 42% were major hypoglycemia).

CONCLUSIONS

Insulin detemir improves glycemic control, with low risk of hypoglycemia, no weight gain and an excellent safety profile; these data support the overall findings of PREDICTIVE.

Prioritizing comparative effectiveness research: are drug and implementation trials equally worth funding?

Comparative effectiveness research (CER) is the generation and synthesis of evidence that compares the benefits and harms of alternative methods to prevent, diagnose, treat and monitor a clinical condition, or to improve the delivery of care. The purpose of this article is to compare--within the scope of CER--the value of implementation and drug trials. Implementation trials have limitations similar to drug trials in terms of generalizability of results outside the trial setting and ability to identify best practice. However, in contrast to drug trials, implementation trials do not provide value in terms of ruling out harm, as implementation strategies are unlikely to cause harm in the first place. Still, implementation trials may provide good value when there is a high error probability in deciding whether implementation will be cost effective or if costs associated with making an erroneous decision are high. Yet the low risk of implementation programmes to cause harm may also allow for alternative approaches to identify best implementation practice, perhaps outside the scope of rigorous trials and testing. One such approach that requires further investigation is a competitive market for quality of care, where implementation programmes may be introduced without prior evaluation.

Meta-analyses of adverse effects data derived from randomised controlled trials as compared to observational studies: methodological overview

BACKGROUND

There is considerable debate as to the relative merits of using randomised controlled trial (RCT) data as opposed to observational data in systematic reviews of adverse effects. This meta-analysis of meta-analyses aimed to assess the level of agreement or disagreement in the estimates of harm derived from meta-analysis of RCTs as compared to meta-analysis of observational studies.

METHODS AND FINDINGS

Searches were carried out in ten databases in addition to reference checking, contacting experts, citation searches, and hand-searching key journals, conference proceedings, and Web sites. Studies were included where a pooled relative measure of an adverse effect (odds ratio or risk ratio) from RCTs could be directly compared, using the ratio of odds ratios, with the pooled estimate for the same adverse effect arising from observational studies. Nineteen studies, yielding 58 meta-analyses, were identified for inclusion. The pooled ratio of odds ratios of RCTs compared to observational studies was estimated to be 1.03 (95% confidence interval 0.93-1.15). There was less discrepancy with larger studies. The symmetric funnel plot suggests that there is no consistent difference between risk estimates from meta-analysis of RCT data and those from meta-analysis of observational studies. In almost all instances, the estimates of harm from meta-analyses of the different study designs had 95% confidence intervals that overlapped (54/58, 93%). In terms of statistical significance, in nearly two-thirds (37/58, 64%), the results agreed (both studies showing a significant increase or significant decrease or both showing no significant difference). In only one meta-analysis about one adverse effect was there opposing statistical significance.

CONCLUSIONS

Empirical evidence from this overview indicates that there is no difference on average in the risk estimate of adverse effects of an intervention derived from meta-analyses of RCTs and meta-analyses of observational studies. This suggests that systematic reviews of adverse effects should not be restricted to specific study types. Please see later in the article for the Editors' Summary.

Data mining on electronic health record databases for signal detection in pharmacovigilance: which events to monitor?

PURPOSE

Data mining on electronic health records (EHRs) has emerged as a promising complementary method for post-marketing drug safety surveillance. The EU-ADR project, funded by the European Commission, is developing techniques that allow mining of EHRs for adverse drug events across different countries in Europe. Since mining on all possible events was considered to unduly increase the number of spurious signals, we wanted to create a ranked list of high-priority events.

METHODS

Scientific literature, medical textbooks, and websites of regulatory agencies were reviewed to create a preliminary list of events that are deemed important in pharmacovigilance. Two teams of pharmacovigilance experts independently rated each event on five criteria: 'trigger for drug withdrawal', 'trigger for black box warning', 'leading to emergency department visit or hospital admission', 'probability of event to be drug-related', and 'likelihood of death'. In case of disagreement, a consensus score was obtained. Ordinal scales between 0 and 3 were used for rating the criteria, and an overall score was computed to rank the events.

RESULTS

An initial list comprising 23 adverse events was identified. After rating all the events and calculation of overall scores, a ranked list was established. The top-ranking events were: cutaneous bullous eruptions, acute renal failure, anaphylactic shock, acute myocardial infarction, and rhabdomyolysis.

CONCLUSIONS

A ranked list of 23 adverse drug events judged as important in pharmacovigilance was created to permit focused data mining. The list will need to be updated periodically as knowledge on drug safety evolves and new issues in drug safety arise.