A systematic appraisal of allegiance effect in randomized controlled trials of psychotherapy Estimating the Horizon of Articles to Decide When to Stop Searching in Systematic Reviews: An Example Using a Systematic Review of RCTs Evaluating Osteoporosis Clinical Decision Support Tools Mineral Trioxide Aggregate vs. Calcium Hydroxide in Primary Molar Pulpotomy: A Systematic Review A systematic review of anxiety interventions in stroke and acquired brain injury: Efficacy and trial design A simplified search strategy for identifying randomised controlled trials for systematic reviews of health care interventions: a comparison with more exhaustive strategies Dietetic guidelines: diet in secondary prevention of cardiovascular disease. Comparative Effectiveness of Dipeptidylpeptidase-4 Inhibitors in Type 2 Diabetes: A Systematic Review and Mixed Treatment Comparison Effectiveness of workplace interventions in rehabilitating musculoskeletal disorders and preventing its consequences among workers with physical and sedentary employment: systematic review protocol Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Disease Risk in Adults: Synopsis of the 2013 American College of Cardiology/American Heart Association Cholesterol Guideline Statins for Primary Prevention: The Debate Is Intense, but the Data Are Weak.
Background Experimenter ’s allegiance ( EA ) refers to a personal confidence of the superiority of a specific psychotherapy treatment . This factor has been linked with larger treatment effects in favor of the preferred treatment . However , various studies have displayed contradictory results between EA and the pattern of treatment effects . Aims Using a systematic approach followed by meta- analysis , we aim ed to evaluate the impact of an allegiance effect on the results of psychotherapeutic studies . Method We considered the meta-analyses of r and omized controlled trials ( RCTs ) of different types of psychotherapies in the Cochrane Data base of Systematic Review s. Eligible articles included meta-analyses of RCTs with at least one study showing evidence of EA ( i.e. , allegiant study ) . Effect sizes in allegiant RCTs were compared with non-allegiant using r and om and fixed models and a summary relative odds ratio ( ROR ) were calculated . Heterogeneity was quantified with the I2 metric . Results A total of 30 meta-analyses including 240 RCTs were analyzed . The summary ROR was 1.31 [ ( 95 % confidence interval ( CI : 1.03–1.66 ) P = 0.30 , I2 = 53 % ] indicating larger effects when allegiance exists . The impact of allegiance did not differ significantly ( P > 0.05 ) when we compared psychiatric versus medical outcomes . Allegiance effect was significant for all forms of psychotherapy except for cognitive behavioral therapy . Moreover , the impact of allegiance was significant only when the treatment integrity of delivered psychotherapy was not assessed . Allegiance effect was even stronger where the experimenter was also both the developer of the preferred treatment and supervised or trained the therapists . No significant differences were found between allegiant and non-allegiant studies in terms of overall quality of studies . Conclusions Experimenter ’s allegiance influences the effect sizes of psychotherapy RCTs and can be considered non-financial conflict of interest introducing a form of optimism bias , especially since blinding is problematic in this kind of research . A clear reporting of EA in every single study should be given an opportunity to investigators of minimizing its overestimation effects Research ers conducting systematic review s need to search multiple bibliographic data bases such as MEDLINE and EMBASE . However , research ers have no rational search stopping rule when looking for potentially-relevant articles . We empirically tested a stopping rule based on the concept of  capture-mark-recapture ( CMR ) , which was first pioneered in ecology . The principles of CMR can be adapted to systematic review s and meta-analyses to estimate the Horizon of articles in the literature with its confidence interval . We retrospectively tested this Horizon Estimation using a systematic review of r and omized controlled trials ( RCTs ) that evaluated clinical decision support tools for osteoporosis disease management . The Horizon Estimation was calculated based on 4 bibliographic data bases that were included as the main data sources for the review in the following order : MEDLINE , EMBASE , CINAHL , and EBM Review s. The systematic review captured 68 % of known articles from the 4 data sources , which represented 592 articles that were estimated as missing from the Horizon Introduction : The aim of this quantitative systematic review /meta- analysis was to compare the treatment outcomes of mineral trioxide aggregate ( MTA ) and calcium hydroxide ( CH ) in pulpotomy of human primary molars . The focused PICO question was “ in case of pulp exposure in vital primary molars , how does MTA pulpotomy compare to CH in terms of clinical /radiographic success ? ” Methods and Material s : We retrieved published r and omized clinical trials ( RCTs ) of at least 6-month duration ; our search included articles published up to March 2013 in five following data bases : PubMed ( Medline ) , Cochrane data base of systematic review s , Science Citation Index , EMBASE , and Google Scholar . Mantel Haenszel and Inverse Variance-weighted methods were applied by STATA ; the relative risk ( RR ) was calculated with 95 % confidence intervals ( CI ) . Results : A total of 282 English articles were collected . Two authors independently screened the articles and five RCTs were selected ; data extraction and quality assessment were then carried out . Four RCTs were appropriate for meta- analysis according to their follow-up times by Mantel Haenszel method . Statistically significant difference was found between success rate of MTA compared to CH , with RR=0.08 ( 95 % CI , 0.02 - 0.39 ) , RR=0.19 ( 95 % CI , 0.08 - 0.46 ) , and RR=0.38 ( 95 % CI , 0.21 - 0.68 ) for 6- , 12- , and 24-month follow-ups , respectively . A significant difference was also observed for all included RCTs after analyses using the Inverse Variance-weighted method ( RR=0.44 ; 95 % CI , 0.27 - 0.72 ) . Conclusions : Systematic review /meta- analysis of included RCTs revealed that for pulpotomy of vital primary molars , MTA has better treatment outcomes compared to CH Objective There is little r and omized controlled trial ( RCT ) evidence to guide treatment for anxiety after stroke . We systematic ally review ed RCTs of anxiety interventions in acquired brain injury ( ABI ) conditions including stroke and traumatic brain injury ( TBI ) in order to summarize efficacy and key aspects of trial design to help guide future RCTs . Methods We search ed the Cochrane trial register , Medline , Embase , PsychInfo and CINAHL systematic ally up to August 2017 . Two independent review ers systematic ally selected studies and extracted data . We summarized the effect size , key study characteristics and sources of potential bias in trial design . Results 14 studies ( 12 stroke ; one stroke & TBI ; one TBI ) with 928 participants were included . Meta- analysis of five psychotherapy comparisons favoured intervention over control ( st and ardized mean difference ( SMD ) : − 0.41 [ − 0.79 , − 0.03 ] , I2 = 28 % ) ; Overall effect size of pharmacotherapy comparisons favoured intervention over control ( SMD : − 2.12 [ − 3.05 , − 1.18 ] , I2 = 89 % ) . One comparison of mixed pharmacotherapy and psychotherapy favoured intervention over usual care ( SMD : − 4.79 [ − 5.87 , − 3.71 ] ) . One comparison favoured  forest therapy versus urban control ( SMD : − 2.00 [ − 2.59 , − 1.41 ] ) . All positive studies carried high or unclear risk of bias . Sample sizes were small in all included studies . Conclusions There is low quality evidence to suggest that psychotherapy and pharmacotherapy may be effective interventions in the treatment of anxiety after stroke based on underpowered studies that carried high risk of bias . Large-scale well- design ed definitive trials are needed to establish whether pharmacological or psychotherapy works . Our review highlighted key considerations for investigators wishing to design high quality trials to evaluate treatments for anxiety after stroke Background It is generally believed that exhaustive search es of bibliographic data bases are needed for systematic review s of health care interventions . The CENTRAL data base of controlled trials ( RCTs ) has been built up by exhaustive search ing . The CONSORT statement aims to encourage better reporting , and hence indexing , of RCTs . Our aim was to assess whether developments in the CENTRAL data base , and the CONSORT statement , mean that a simplified RCT search strategy for identifying RCTs now suffices for systematic review s of health care interventions . Methods RCTs used in the Cochrane review s were identified . A brief RCT search strategy ( BRSS ) , consisting of a search of CENTRAL , and then for variants of the word r and om across all fields ( r and om$.af . ) in MEDLINE and EMBASE , was devised and run . Any trials included in the meta-analyses , but missed by the BRSS , were identified . The meta-analyses were then re-run , with and without the missed RCTs , and the differences quantified . The proportion of trials with variants of the word r and om in the title or abstract was calculated for each year . The number of RCTs retrieved by search ing with " r and om$.af . " was compared to the highly sensitive search strategy ( HSSS ) . Results The BRSS had a sensitivity of 94 % . It found all journal RCTs in 47 of the 57 review s. The missing RCTs made some significant differences to a small proportion of the total outcomes in only five review s , but no important differences in conclusions result ed . In the post-CONSORT years , 1997–2003 , the percentage of RCTs with r and om in the title or abstract was 85 % , a mean increase of 17 % compared to the seven years pre-CONSORT ( 95 % CI , 8.3 % to 25.9 % ) . The search using r and om$.af . reduced the MEDLINE retrieval by 84 % , compared to the HSSS , thereby reducing the workload of checking retrievals . Conclusion A brief RCT search strategy is now sufficient to locate RCTs for systematic review s in most cases . Exhaustive search ing is no longer cost-effective , because in effect it has already been done for CENTRAL AIM To produce dietetic guidelines summarizing the systematic review evidence on dietary advice for secondary prevention of cardiovascular disease . METHODS The Cochrane Library , MEDLINE and EMBASE were comprehensively search ed for systematic review s on aspects of diet and heart health . Review s were included if they search ed systematic ally for r and omised controlled trials relating to diet and secondary prevention of cardiovascular disease . Two members of the UK Heart Health and Thoracic Dietitians Group critically appraised each review . The quality and results of each review were discussed and summarized in a whole group meeting . The guidelines were trialled in seven dietetic departments and modified where necessary . RESULTS Providing evidence -based dietary information ( including increasing omega-3 fat plus fruit and vegetable intake ) to all people after myocardial infa rct ion will save more lives than concentrating dietary advice on those in need of weight loss or lipid lowering . The practice of prioritizing dietetic time to those with raised lipids is out of date since the advent of statin therapy . CONCLUSION There is good systematic review evidence that dietary advice to those with cardiovascular disease can reduce mortality and morbidity as well as modify risk factors .  Dietary advice that does this most effectively should be prioritized Objective To compare the safety and efficacy of the dipeptidylpeptidase-4 ( DPP-4 ) inhibitors in patients with type 2 diabetes and inadequate glycemic control . Design Systematic review of r and omized controlled trials ( RCTs ) , health economic evaluation studies , systematic review s , and meta-analyses , followed by primary Bayesian mixed treatment comparison meta-analyses ( MTCs ) , and secondary frequentist direct-comparison meta-analyses using a r and om-effects model . Outcomes were reported as weighted mean change from baseline , or odds ratio ( OR ) with 95 % credible interval . Data sources MEDLINE , MEDLINE In-Process , EMBASE , and BIOSIS via Dialog ProQuest ; Cochrane Central Register of Controlled Trials and Cochrane Data base of Systematic Review s via EBSCO ; four diabetes and two technical congress abstract s ; and health technology assessment organization websites . Eligibility criteria Patients with type 2 diabetes and inadequate glycemic control receiving any pharmacological anti-diabetic treatment . Data extraction and analysis Title/ abstract s were review ed for eligibility , followed by full-text review of publications remaining after first pass . A three-person team filtered articles and an independent review er checked a r and om selection ( 10 % ) of filtered articles . Data extraction and quality assessment of studies were also independently review ed . Five DPP-4 inhibitors ( alogliptin , linagliptin , saxagliptin , sitagliptin , and vildagliptin ) were compared via meta- analysis ( where data were available ) as monotherapy , dual therapy ( plus metformin , sulfonylurea , pioglitazone , or insulin ) , and triple therapy ( plus metformin/sulfonylurea ) . Results The review identified 6,601 articles ; 163 met inclusion criteria and 85 publications from 83 RCTs contained sufficient or appropriate data for analysis . MTCs demonstrated no differences between DPP-4 inhibitors in mean change from baseline in glycosylated hemoglobin ( HbA1c ) or body weight , or the proportions of patients achieving HbA1c < 7 % or experiencing a hypoglycemic event , apart from in patients on alogliptin plus metformin , who achieved HbA1c < 7 % more frequently than those treated with saxagliptin plus metformin [ OR 6.41 ( 95 % CI 3.15–11.98 ) versus 2.17 ( 95 % CI 1.56–2.95 ) ] . Conclusions This systematic review and MTC showed similar efficacy and safety for DPP-4 inhibitors as treatment for type 2 diabetes , either as monotherapy or combination therapy Background Musculoskeletal disorders ( MSDs ) are the leading cause of work disability and sickness absence worldwide . The prevalence of MSDs increases with age , consequently challenging sustainable employability among the growing ageing workforce . Knowledge of feasible and efficient workplace-based interventions to rehabilitate MSD or prevent its consequences is therefore warranted . This systematic review will evaluate the effectiveness of workplace-based interventions on MSDs and its consequences among adult workers with physical and sedentary work tasks , respectively . Methods We will search the following bibliographic data bases : PubMed ( including the data base ‘ MEDLINE ’ ) and Web of Science Core Collection ( including the data bases ‘ Science Citation Index Exp and ed ’ , ‘ Social Sciences Citation Index ’ and ‘ Arts & Humanities Citation Index ’ ) . Manual search es will also be performed . We will include r and omised controlled trials ( RCTs ) and non- RCTs reported in English in which ( 1 ) participants are adult workers with MSD , ( 2 ) interventions are aim ing at rehabilitating pain symptoms of MSD or preventing the consequences of MSD and ( 3 ) interventions are initiated and /or carried out at the workplace . The review will adhere to the ‘ Preferred Reporting Items for Systematic review s and Meta-Analyses ’ ( PRISMA ) guidelines for reporting systematic review s and the Institute for Work and Health ( IWH ) guidelines for workplace-based interventions . For the primary evaluation of the review , the quality assessment and evidence synthesis will conform to the IWH guidelines . Secondary evaluation will include a meta- analysis ( unless the included studies do not allow this due to heterogeneity ) and employ the risk of bias domains recommended by Cochrane along with the Grading of Recommendations , Assessment , Development and Evaluations ( GRADE ) approach on the studies with pain intensity as an outcome . Discussion This systematic review will provide knowledge on effective workplace-based interventions among physical and sedentary workers with MSD . RCTs are considered the most powerful experimental design in clinical trials , but solely including these may be too restrictive to underst and effective workplace-based interventions where r and omised and carefully controlled trials ( RCTs ) are not always possible . In order to maximize practical relevance , the selection process will , therefore , include both RCTs and non- RCTs and the quality assessment and evidence synthesis will conform to IWH guidelines focusing on developing practical guidelines for stakeholders . The result of this work will form the basis for industry-specific evidence -based recommendations on effective workplace-based interventions for rehabilitation of MSDs and its consequences that will later be operationalised into concrete and user-friendly practical tools for workplaces . Systematic review registration International Prospect i ve Register of Systematic Review s ( PROSPERO ) number CRD42018116752 Atherosclerotic cardiovascular disease ( ASCVD ) is the leading cause of death , decreased quality of life , and medical costs in the United States . Nearly 1 in 3 Americans die of heart disease and stroke ( 1 ) . Most ASCVD is preventable through a healthy lifestyle and effective treatment of cholesterol and blood pressure . The 2013 Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults from the American College of Cardiology and American Heart Association ( ACC/AHA ) provides an evidence -based approach to reducing ASCVD risk ( 2 ) . Guideline Development Process In 2008 , the National Heart , Lung , and Blood Institute ( NHLBI ) convened the Adult Treatment Panel ( ATP ) IV to up date the 2001 ATP-III cholesterol guidelines using a rigorous systematic process to identify and review r and omized , controlled trials ( RCTs ) with cardiovascular outcomes and meta-analyses of these RCTs . The panel comprised experts and clinicians from the fields of cardiology , epidemiology , primary care , and endocrinology ( 2 ) and received support from the Lifestyle Management and Risk Assessment Work Groups ( 3 , 4 ) . Systematic evidence review s conducted according to principles recommended by the Institute of Medicine ( 5 ) were performed to answer 3 questions relevant to clinical care . Two questions focused on the evidence supporting low-density lipoprotein cholesterol ( LDL-C ) and nonhigh-density lipoprotein cholesterol ( HDL-C ) levels as targets of treatment . One question examined the reduction in ASCVD events and adverse effects for each cholesterol-lowering drug class . The panel synthesized the evidence from these 3 review s as well as from Lifestyle Management and Risk Assessment Work Groups review s ( 3 , 4 ) that addressed 5 additional critical questions . Systematic electronic search es of relevant data bases of the peer- review ed English- language literature published from 1 January 1995 through 1 December 2009 for each critical question were conducted by an NHLBI-selected independent contractor and focused on RCTs and systematic review s and meta-analyses of RCTs assessed as fair to good quality . In addition , RCTs with ASCVD outcomes that included coronary heart disease , stroke , and cardiovascular deaths published after that date were eligible for consideration through July 2013 . Evidence tables were constructed , and the strength of evidence was rated according to the NHLBI ( Table 1 of the Supplement ) . Recommendations were grade d according to criteria from the NHLBI ( Table 2 of the Supplement ) and ACC/AHA ( Table 3 of the Supplement ) . Because of the inherent differences in grading systems and the clinical questions driving the recommendations , alignment between the NHLBI and ACC/AHA formats was imperfect . A complete description of the methods used and results of the evidence review are provided in the guideline ( 2 ) and the NHLBI evidence report ( www.nhlbi.nih.gov/ guidelines /cholesterol/ser/index.htm ) . Supplement . NHLBI and ACC/AHA Criteria for Rating Strength of Evidence To help clinicians estimate ASCVD risk , the risk assessment working group developed the Pooled Cohort Equations using data from 5 NHLBI-sponsored longitudinal , population -based cohorts of African American and non-Hispanic white men and women to estimate risk for a first myocardial infa rct ion , coronary heart disease death , or fatal or nonfatal stroke on the basis of age , sex , race , smoking status , total cholesterol level , HDL-C level , systolic blood pressure , antihypertensive therapy , and diabetes ( 4 , 6 ) . These equations significantly advance ASCVD risk estimation by providing sex- and race-specific estimates and including stroke as an outcome . The earlier Framingham equations calculated only coronary heart disease risk for non-Hispanic whites . The draft recommendations were review ed by 23 experts and representatives of federal agencies identified by the NHLBI . In September 2013 , the recommendations developed by the panel were transitioned to the ACC/AHA and had additional review by 4 experts nominated by the ACC Foundation and the AHA . The governing bodies of the ACC and AHA approved the guideline , which also received endorsement from the American Association of Cardiovascular and Pulmonary Rehabilitation , American Pharmacists Association , American Society for Preventive Cardiology , Association of Black Cardiologists , Preventive Cardiovascular Nurses Association , and WomenHeart : The National Coalition for Women with Heart Disease . Recommendations The guideline focuses on treatment of blood cholesterol to reduce ASCVD risk in adults . Major recommendations are summarized here and in Table 1 . The guideline report provides a complete listing of recommendations and supporting evidence behind each recommendation ( 2 ) . Table 1 . Major Recommendations for the Treatment of Blood Cholesterol to Reduce ASCVD Risk in Adults * 1 . Encourage Adherence to a Healthy Lifestyle A healthy lifestyle is the foundation for cardiovascular health . The panel endorsed the 2013 ACC/AHA Lifestyle Management Guideline ( 3 ) for a diet that is low in saturated fat , trans fat , and sodium ; emphasizes vegetables , fruits , whole grains , low-fat dairy products , poultry , fish , legumes , nontropical vegetable oils , and nuts ; and limits sweets , sugar-sweetened beverages , and red meats and engage in regular aerobic physical activity . Adults also should maintain a healthy body weight , avoid smoking , and control hypertension and diabetes when present . 2 . Statin Therapy Is Recommended for Adults in Groups Demonstrated to Benefit Strong RCT evidence shows that reduction in ASCVD events from statin therapy exceeds adverse events for 4 patient groups : those with clinical ASCVD ( acute coronary syndromes , myocardial infa rct ion , stable angina , coronary or other arterial revascularization , stroke , transient ischemic attack , or peripheral arterial disease of atherosclerotic origin ) when  statins are used for secondary prevention , and those with LDL-C levels 190 mg/dL ; those aged 40 to 75 years with diabetes and LDL-C levels 70 to 189 mg/dL ; and those aged 40 to 75 years without diabetes and with a 10-year ASCVD risk 7.5 % when statins are used for primary prevention . Moderate evidence supports consideration of statin therapy for primary prevention in individuals with a 10-year ASCVD risk of 5 % to < 7.5 % . Routine initiation of statin therapy is not recommended in adults with New York Heart Association heart failure class II to IV or those receiving maintenance hemodialysis . R and omized , controlled trials in these groups showed no reduction in ASCVD . 3 . Statins have an Acceptable Margin of Safety When Used in Properly Selected Individuals and Appropriately Monitored Strong RCT evidence supports safety of statins when they are used as directed in conjunction with regular follow-up assessment s in properly selected patients . Adjustment of statin intensity is recommended in individuals older than 75 years with a history of statin intolerance or other characteristics ( 2 ) or those receiving drug therapy that may increase statin adverse events . Routine monitoring of hepatic aminotransferase level or creatine kinase level is not recommended unless clinical ly indicated by symptoms suggesting hepatotoxicity or myopathy . Given the potential for decreasing ASCVD events and death , the relationship of muscle and other symptoms to statin treatment must be confirmed . Therefore , eliciting a history of muscle symptoms before statin initiation and carefully monitoring symptoms during statin discontinuation and rechallenge is recommended . Severe myopathy , rhabdomyolysis , and possibly hemorrhagic stroke are rare complications of statin therapy . Although statin therapy modestly increases the risk for type 2 diabetes , ASCVD risk reduction outweighs the excess risk for diabetes for high-intensity statins in secondary prevention or for 10-year ASCVD risk 7.5 % . Similarly , ASCVD risk reduction outweighs the excess risk for diabetes for moderate-intensity statin therapy in adults with a 10-year ASCVD risk 5 % . 4 . Engage in a ClinicianPatient Discussion Before Initiating Statin Therapy , Especially for Primary Prevention in Patients With Lower ASCVD Risk Decisions to initiate statin therapy in primary prevention should be based on clinical judgment and preferences of informed patients . In adults without clinical ASCVD or diabetes whose LDL-C level is < 190 mg/dL , calculating the estimated 10-year ASCVD risk should be the start of the clinicianpatient discussion and should not automatically lead to statin initiation . As the absolute risk for ASCVD events decreases , so does the net benefit of the intervention . Therefore , discussion of the potential for ASCVD event reduction , adverse effects , drugdrug interactions , and patient preferences is especially important for lower-risk primary prevention . The discussion provides the opportunity to encourage healthy lifestyle habits and control other risk factors . Additional factors may be considered when a risk-based decision is uncertain , including LDL-C levels 160 mg/dL , family history of premature ASCVD , elevated  lifetime ASCVD risk  , high-sensitivity C-reactive protein level 2.0 mg/L ,  coronary artery calcification score  > 300 Agatston units , and anklebrachial index < 0.9 . After age 75 years , comorbid conditions , anticipated longevity , safety considerations , and patient preferences should play a large role in decision making . 5 . Use the Newly Developed Pooled Cohort Equations for Estimating 10-Year ASCVD Risk The Pooled Cohort Equations are currently the best available method for estimating 10-year ASCVD risk to guide statin initiation ( 4 , 6 ) . Application of the inclusion and exclusion criteria from RCTs is cumbersome and results in underidentifying high-risk and overidentifying low-risk individuals for statin treatment . The Pooled Cohort Equations were developed using recent data from 5 NHLBI-sponsored , longitudinal , population -based cohorts of African American and white men and women ( ARIC [ This issue of JAMA contains the latest US Preventive Services Task Force ( USPSTF ) recommendation statement on statins for prevention of cardiovascular disease in adults,1 along with the accompanying evidence report and systematic review 2 on which the recommendations are based . The evidence report summarized data from 19 trials including a total of 71 344 patients and concluded that statin therapy was associated with reduced risk of all-cause and cardiovascular mortality and cardiovascular disease ( CVD ) events . Thus , the task force recommended “ initiating use of lowto moderate-dose statins in adults aged 40 to 75 years without a history of CVD who have 1 or more CVD risk factors and a calculated 10-year CVD event risk of 10 % or greater ( B recommendation ) ” or “ 7.5 % to 10 % ( C recommendation ) .”1 Although the task force did their usual careful job of review ing the evidence , the evidence for treating asymptomatic persons with statins does not appear to merit a grade B or even a grade C recommendation . The task force evidence report estimated an absolute benefit for use of statins of 0.40 % for all-cause mortality and 0.43 % for cardiovascular mortality and indicated that the absolute benefit was greater for patients at greater baseline risk.2 Notably , the evidence report did not exclude studies that included patients taking statins for secondary prevention , who have a higher baseline risk of cardiac events and death and thus are more likely to benefit from therapy that inflates the benefit attributed to a primary prevention population . The task force did perform a sensitivity analysis that excluded 3 trials with persons for whom there were prior “ hard ” cardiovascular events and obtained similar results of benefits ( eTable 5 in the article by Chou et al2 ) . This sensitivity analysis did not exclude WOSCOPS , which included patients receiving statins for secondary prevention—5 % had angina and 3 % had intermittent claudication,3 accounting for 15 % of the total weight in the meta- analysis . In contrast , a meta- analysis of 11 studies and 65 229 patients receiving statins for primary prevention , in which patients receiving statins for secondary prevention were excluded , found no benefit of statins for reducing all-cause mortality.4 The confidence intervals of these 2 analyses overlap , and the difference between these findings likely reflects differences in studies included . The USPSTF and authors of the evidence report did not have access to the primary data ( clinical study reports and anonymized patient-level data ) from the statin clinical trials . Rather , they had to rely on peer- review ed published reports as the basis for these recommendations . Exacerbating the potential bias , all of the trials included in the task force evidence report2 were industry-sponsored except 1 trial,5 and that trial contributed 0.2 % of the weight to the mortality calculation . Industry-sponsored studies have been shown to report greater benefit and lesser adverse effects than noncommercially sponsored trials of the same drugs.6 Whether this is true for statins and primary prevention of CVD is unknown . Among the 19 r and omized clinical trials of statins vs placebo or no statin included in the evidence report for the task force recommendations , only 15 reported all-cause mortality , 10 reported cardiovascular mortality , 12 reported fatal and nonfatal myocardial infa rct ion  , and 13 reported fatal and nonfatal stroke.2,7  Reliance on selective reporting of the most important outcomes , which are likely included in the clinical trial data , makes reporting bias possible . Furthermore , after allcause mortality , the comparative incidence of serious adverse events between treatment and control groups is arguably the second most important measure of the effect of active therapy in r and omized clinical trials . Underst and ing the evidence base in evaluating harms of statin therapy is also critically important . Although the benefits of any preventive therapy accrue according to risk of disease ( greater benefit in higher-risk patients ) , the harms of therapy usually distribute equally over all risk levels . Thus , persons at low risk have little chance of benefit but equal chance of harms and thus are more likely to have a net harm . The evidence base for harms of statins , despite the introduction of these drugs more than 20 years ago , is incomplete . Many of the trials did not ask about commonly reported statin effects , such as muscle pains and weakness , and only recorded myopathy , for which an increase in creatine kinase levels was required . Because most muscle problems do not involve an increase in creatine kinase levels , this leads to a significant underestimate of muscle problems . Other studies have estimated that closer to 20 % of statin users have muscle problems.8 Additionally , the actual trial data are largely held by the Cholesterol Treatment Trialists ’ Collaboration on behalf of the industry sponsor and have not been made available to other research ers , despite multiple requests over many years.9 Although reported rates of adverse events in clinical trials are low , this does not reflect the experience of clinicians who see patients who are taking statins . For instance , the experience of an NPR reporter with a calculated 2.9 % risk of heart disease over 10 years using the recommended American College of Cardiology/American Heart Association ( ACC/AHA ) risk calculator,10 but still prescribed a statin , and experiencing adverse effects from the medication , is typical of what many Related articles at jama.com
In the meta-regression analysis , changes in plasma cortisol concentrations following statin therapy were found to be independent of treatment duration .
Results of this meta- analysis of RCTs suggest a significant elevation in plasma cortisol levels following statin therapy
This study aim ed to perform a systematic review and meta- analysis of r and omized controlled trials ( RCTs ) in order to calculate the effect size of statin therapy in changing plasma cortisol concentrations .