Systolic Blood Pressure Response in SPRINT (Systolic Blood Pressure Intervention Trial) and ACCORD (Action to Control Cardiovascular Risk in Diabetes): A Possible Explanation for Discordant Trial Results

Background

SPRINT (Systolic Blood Pressure Intervention Trial) and the ACCORD (Action to Control Cardiovascular Risk in Diabetes) blood pressure trial used similar interventions but produced discordant results. We investigated whether differences in systolic blood pressure (SBP) response contributed to the discordant trial results.

Methods and Results

We evaluated the distributions of SBP response during the first year for the intensive and standard treatment groups of SPRINT and ACCORD using growth mixture models. We assessed whether significant differences existed between trials in the distributions of SBP achieved at 1 year and the treatment‐independent relationships of achieved SBP with risks of primary outcomes defined in each trial, heart failure, stroke, and all‐cause death. We examined whether visit‐to‐visit variability was associated with heterogeneous treatment effects. Among the included 9027 SPRINT and 4575 ACCORD participants, the difference in mean SBP achieved between treatment groups was 15.7 mm Hg in SPRINT and 14.2 mm Hg in ACCORD, but SPRINT had significantly less between‐group overlap in the achieved SBP (standard deviations of intensive and standard groups, respectively: 6.7 and 5.9 mm Hg in SPRINT versus 8.8 and 8.2 mm Hg in ACCORD; P<0.001). The relationship between achieved SBP and outcomes was consistent across trials except for stroke and all‐cause death. Higher visit‐to‐visit variability was more common in SPRINT but without treatment‐effect heterogeneity.

Conclusions

SPRINT and ACCORD had different degrees of separation in achieved SBP between treatment groups, even as they had similar mean differences. The greater between‐group overlap of achieved SBP may have contributed to the discordant trial results.

Coronary Computed Tomography Angiography vs Functional Stress Testing for Patients With Suspected Coronary Artery Disease: A Systematic Review and Meta-analysis

Importance

Coronary computed tomography angiography (CCTA) is a new approach for the diagnosis of anatomical coronary artery disease (CAD), but it is unclear how CCTA performs compared with the standard approach of functional stress testing.

Objective

To compare the clinical effectiveness of CCTA with that of functional stress testing for patients with suspected CAD.

Data Sources

A systematic literature search was conducted in PubMed and MEDLINE for English-language randomized clinical trials of CCTA published from January 1, 2000, to July 10, 2016.

Study Selection

Researchers selected randomized clinical trials that compared a primary strategy of CCTA with that of functional stress testing for patients with suspected CAD and reported data on patient clinical events and changes in therapy.

Data Extraction and Synthesis

Two reviewers independently extracted data from and assessed the quality of the trials. This analysis followed the PRISMA statement for reporting systematic reviews and meta-analyses and used the Cochrane Collaboration's tool for assessing risk of bias in randomized trials. The Mantel-Haenszel method was used to conduct the primary analysis. Summary relative risks were calculated with a random-effects model.

Main Outcomes and Measures

The outcomes of interest were all-cause mortality, cardiac hospitalization, myocardial infarction, invasive coronary angiography, coronary revascularization, new CAD diagnoses, and change in prescription for aspirin and statins.

Results

Thirteen trials were included, with 10 315 patients in the CCTA arm and 9777 patients in the functional stress testing arm who were followed up for a mean duration of 18 months. There were no statistically significant differences between CCTA and functional stress testing in death (1.0% vs 1.1%; risk ratio [RR], 0.93; 95% CI, 0.71-1.21) or cardiac hospitalization (2.7% vs 2.7%; RR, 0.98; 95% CI, 0.79-1.21), but CCTA was associated with a reduction in the incidence of myocardial infarction (0.7% vs 1.1%; RR, 0.71; 95% CI, 0.53-0.96). Patients undergoing CCTA were significantly more likely to undergo invasive coronary angiography (11.7% vs 9.1%; RR, 1.33; 95% CI, 1.12-1.59) and revascularization (7.2% vs 4.5%; RR, 1.86; 95% CI, 1.43-2.43). They were also more likely to receive a diagnosis of new CAD and to have initiated aspirin or statin therapy.

Conclusions and Relevance

Compared with functional stress testing, CCTA is associated with a reduced incidence of myocardial infarction but an increased incidence of invasive coronary angiography, revascularization, CAD diagnoses, and new prescriptions for aspirin and statins. Despite these differences, CCTA is not associated with a reduction in mortality or cardiac hospitalizations.

The FDA Unapproved Drugs Initiative: An Observational Study of the Consequences for Drug Prices and Shortages in the United States

BACKGROUND

Hundreds of drug products are currently marketed in the United States without approval from the FDA. The 2006 Unapproved Drugs Initiative (UDI) requires manufacturers to remove these drug products from the market or obtain FDA approval by demonstrating evidence of safety and efficacy. Once the FDA acts against an unapproved drug, fewer manufacturers remain in the market, potentially enabling drug price increases and greater susceptibility to drug shortages. There is a need for systematic study of the UDI's effect on prices and shortages of all targeted drugs.

OBJECTIVE

To examine the clinical evidence for approval and association with prices and shortages of previously unapproved prescription drugs after being addressed by the UDI.

METHODS

Previously unapproved prescription drugs that faced UDI regulatory action or with at least 1 product that received FDA approval through manufacturers' voluntary compliance with the UDI between 2006 and 2015 were identified. The clinical evidence was categorized as either newly conducted clinical trials or use of previously published literature and/or bioequivalence studies to demonstrate safety and efficacy. We determined the change in average wholesale price, presence of shortage, and duration of shortage for each drug during the 2 years before and after UDI regulatory action or approval through voluntary compliance.

RESULTS

Between 2006 and 2015, 34 previously unapproved prescription drugs were addressed by the UDI. Nearly 90% of those with a drug product that received FDA approval were supported by literature reviews or bioequivalence studies, not new clinical trial evidence. Among the 26 drugs with available pricing data, average wholesale price during the 2 years before and after voluntary approval or UDI action increased by a median of 37% (interquartile range [IQR] = 23%-204%; P < 0.001). The number of drugs in shortage increased from 17 (50.0%) to 25 (73.5%) during the 2 years before and after, respectively (P = 0.046). The median shortage duration in the 2 years before and after voluntary approval or UDI action increased from 31 days (IQR = 0-339) to 217 days (IQR = 0-406; P = 0.053).

CONCLUSIONS

The UDI was associated with higher drug prices and more frequent drug shortages when compared with the period before UDI action, while the approval process for these drugs did not necessarily require new clinical evidence to establish safety or efficacy.

DISCLOSURES

This project was not supported by any external grants or funds. Gupta was supported by the Yale University School of Medicine Office of Student Research at the time of this study. Dhruva is supported by the Department of Veterans Affairs as part of the Robert Wood Johnson Foundation Clinical Scholars program. Ross reports receiving research support through Yale University from Johnson and Johnson to develop methods of clinical trial data sharing; from Medtronic and the FDA to develop methods for postmarket surveillance of medical devices; from the FDA to establish the Yale-Mayo Clinic Center of Excellence in Regulatory Science and Innovation; from the Blue Cross Blue Shield Association to better understand medical technology evidence generation; from the Centers for Medicare & Medicaid Services to develop and maintain performance measures that are used for public reporting; and from the Laura and John Arnold Foundation to support the Collaboration on Research Integrity and Transparency at Yale. Fox reports travel support from Oklahoma Society of Health System Pharmacists, Premier Oncology Hematology Management Society, and SEHA-United Arab Emirates. Vizient provides some financial support to the University of Utah Drug Information Service to provide summaries of drug shortage information. Gupta and Ross were responsible for the conception and design of this work, drafted the manuscript, and conducted the statistical analysis. Gupta and Fox were responsible for acquisition of data. Ross provided supervision. All authors participated in the analysis and interpretation of the data and critically revised the manuscript for important intellectual content.

Abstract 148: Association of Socioeconomic Context With Blood Pressure Response and Cardiovascular Outcomes in ALLHAT

Introduction: Observational studies demonstrate that in low socioeconomic (SE) communities, where residents face social challenges and fewer opportunities for healthy lifestyle behaviors or quality care, blood pressure (BP) is higher and there are worse cardiovascular (CV) outcomes. Yet whether the effectiveness of antihypertensive therapy on BP control and CV outcomes varies by SE context in a randomized clinical trial (RCT) - where patients are treated under a standard protocol - is unknown.

Methods: We used data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), which randomized 42,418 people with hypertension (HTN) to chlorthalidone, lisinopril, amlodipine or doxazosin. After excluding non-continental US sites and the doxazosin arm (terminated early), our study included 27,862 participants. We defined SE context by mapping study site ZIP codes to counties and stratifying these into income quintiles based on the national distribution of cost-of-living adjusted county median household income (2000 US Census). We compared characteristics and outcomes between participants in the lowest and highest SE quintiles using multivariable regression models. We replicated the analysis with black participants (n = 10532).

Results: Participants enrolled in low SE sites (n = 2169, 7.8%) were more likely to be female, black, Hispanic, less educated, live in the South, and have fewer CV risk factors than participants in high SE sites (n = 10458, 37.6%). Participants in low SE sites were less likely to achieve BP control (<140/90 mmHg) at 6 years (OR 0.48, 95% CI [0.37, 0.63]). They had higher all-cause mortality (HR 1.25, 95% CI [1.10, 1.41]) and heart failure hospitalization/mortality (HR 1.26, 95% CI [1.03, 1.55]), though lower angina hospitalization (HR 0.70, 95% CI [0.59, 0.83]) and coronary revascularization (HR 0.71, 95% CI [0.57, 0.89]) and no differences in stroke or MI. Results were similar among black participants.

Conclusion: Despite having access to extra resources afforded by an RCT, ALLHAT participants in low SE sites had poorer BP control, higher mortality and greater heart failure morbidity. Our findings suggest a need to address the SE context beyond the medical environment to attain equity in HTN outcomes.

Inclusion of Demographic-Specific Information in Studies Supporting US Food & Drug Administration Approval of High-Risk Medical Devices

This analysis characterizes the studies used to support US Food & Drug Administration 2015 premarket approval of devices, particularly findings of device safety and effectiveness for women, the elderly, and minorities.

Association between FDA black box warnings and Medicare formulary coverage changes

OBJECTIVES

To assess whether Medicare formularies restrict access to drugs receiving new FDA black box warnings for which safer drug alternatives are available.

STUDY DESIGN

A retrospective analysis using Medicare Prescription Drug Plan Formulary files to determine formulary changes for drugs receiving FDA black box warnings between 2007 and 2013.

METHODS

We identified all FDA-approved medications available in tablet or capsule formulation that received a black box warning between 2007 and 2013 related to death and/or cardiovascular risk. We then determined formulary coverage of these drugs pre-black box warning, 1 year after, and 2 years after. For each formulary, we identified formulary restrictiveness, defined as: unrestrictive coverage (no prior authorization or step therapy), restrictive coverage (prior authorization or step therapy required), or no coverage.

RESULTS

Nine drugs with at least 1 FDA-approved safer drug alternative received 10 new black box warnings for death and/or cardiovascular risk between 2007 and 2013. In response to FDA black box warnings, overall formulary restrictiveness increased for 40% (n = 4) of drugs at 1 year, and for 50% (n = 5) at 2 years. However, for the majority of drugs (n = 7), most formularies remained unrestrictive 2 years after a new black box warning.

CONCLUSIONS

Medicare formularies became more restrictive for half of the drugs that recently received new FDA black box warnings for death and/or cardiovascular risk and for which safer drug alternatives are available. However, a substantial proportion of formularies remained unrestrictive, suggesting inconsistent responses to new safety information to curtail the use of these medications.

Characteristics of Clinical Studies Used for US Food and Drug Administration Approval of High-Risk Medical Device Supplements

IMPORTANCE

High-risk medical devices often undergo modifications, which are approved by the US Food and Drug Administration (FDA) through various kinds of premarket approval (PMA) supplements. There have been multiple high-profile recalls of devices approved as PMA supplements.

OBJECTIVE

To characterize the quality of the clinical studies and data (strength of evidence) used to support FDA approval of panel-track supplements (a type of PMA supplement pathway that is used for significant changes in a device or indication for use and always requires clinical data).

DESIGN AND SETTING

Descriptive study of clinical studies supporting panel-track supplements approved by the FDA between April 19, 2006, and October 9, 2015.

EXPOSURE

Panel-track supplement approval.

MAIN OUTCOMES AND MEASURES

Methodological quality of studies including randomization, blinding, type of controls, clinical vs surrogate primary end points, use of post hoc analyses, and reporting of age and sex.

RESULTS

Eighty-three clinical studies supported the approval of 78 panel-track supplements, with 71 panel-track supplements (91%) supported by a single study. Of the 83 studies, 37 (45%) were randomized clinical trials and 25 (30%) were blinded. The median number of patients per study was 185 (interquartile range, 75-305), and the median follow-up duration was 180 days (interquartile range, 84-270 days). There were a total of 150 primary end points (mean [SD], 1.8 [1.2] per study), and 57 primary end points (38%) were compared with controls. Of primary end points with controls, 6 (11%) were retrospective controls and 51 (89%) were active controls. One hundred twenty-one primary end points (81%) were surrogate end points. Thirty-three studies (40%) did not report age and 25 (30%) did not report sex for all enrolled patients. The FDA required postapproval studies for 29 of 78 (37%) panel-track supplements.

CONCLUSIONS AND RELEVANCE

Among clinical studies used to support FDA approval of high-risk medical device modifications, fewer than half were randomized, blinded, or controlled, and most primary outcomes were based on surrogate end points. These findings suggest that the quality of studies and data evaluated to support approval by the FDA of modifications of high-risk devices should be improved.

Heterogeneity in Early Responses in ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial)

Randomized trials of hypertension have seldom examined heterogeneity in response to treatments over time and the implications for cardiovascular outcomes. Understanding this heterogeneity, however, is a necessary step toward personalizing antihypertensive therapy. We applied trajectory-based modeling to data on 39 763 study participants of the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) to identify distinct patterns of systolic blood pressure (SBP) response to randomized medications during the first 6 months of the trial. Two trajectory patterns were identified: immediate responders (85.5%), on average, had a decreasing SBP, whereas nonimmediate responders (14.5%), on average, had an initially increasing SBP followed by a decrease. Compared with those randomized to chlorthalidone, participants randomized to amlodipine (odds ratio, 1.20; 95% confidence interval [CI], 1.10-1.31), lisinopril (odds ratio, 1.88; 95% CI, 1.73-2.03), and doxazosin (odds ratio, 1.65; 95% CI, 1.52-1.78) had higher adjusted odds ratios associated with being a nonimmediate responder (versus immediate responder). After multivariable adjustment, nonimmediate responders had a higher hazard ratio of stroke (hazard ratio, 1.49; 95% CI, 1.21-1.84), combined cardiovascular disease (hazard ratio, 1.21; 95% CI, 1.11-1.31), and heart failure (hazard ratio, 1.48; 95% CI, 1.24-1.78) during follow-up between 6 months and 2 years. The SBP response trajectories provided superior discrimination for predicting downstream adverse cardiovascular events than classification based on difference in SBP between the first 2 measurements, SBP at 6 months, and average SBP during the first 6 months. Our findings demonstrate heterogeneity in response to antihypertensive therapies and show that chlorthalidone is associated with more favorable initial response than the other medications.

Update on Pediatric Overuse

As concerns over health care-related harms and costs continue to mount, efforts to identify and combat medical overuse are needed. Although much of the recent attention has focused on health care for adults, children are also harmed by overuse. Using a structured PubMed search and manual tables of contents review, we identified important articles on pediatric overuse published in 2015. These articles were evaluated according to the quality of the methods, the magnitude of clinical effect, and the number of patients potentially affected and were categorized into overdiagnosis, overtreatment, and overutilization. Overdiagnosis: Findings included evidence for overdiagnosis of hypoxemia in children with bronchiolitis and skull fractures in children suffering minor head injuries. Overtreatment: Findings included evidence that up to 85% of hospitalized children with radiographic pneumonia may not have a bacterial etiology; many children are receiving prolonged intravenous antibiotic therapy for osteomyelitis although oral therapy is equally effective; antidepressant medication for adolescents and nebulized hypertonic saline for bronchiolitis appear to be ineffective; and thresholds for treatment of hyperbilirubinemia may be too low. Overutilization: Findings suggested that the frequency of head circumference screening could be relaxed; large reductions in abdominal computed tomography testing for appendicitis appear to have been safe and effective; and overreliance on C-reactive protein levels in neonatal early onset sepsis appears to extend hospital length-of-stay.

2016 Update on Medical Overuse: A Systematic Review

IMPORTANCE

Overuse of medical care is an increasingly recognized problem in clinical medicine.

OBJECTIVE

To identify and highlight original research articles published in 2015 that are most likely to reduce overuse of medical care, organized into 3 categories: overuse of testing, overtreatment, and questionable use of services. The articles were reviewed and interpreted for their importance to clinical medicine.

EVIDENCE REVIEW

A structured review of English-language articles on PubMed published in 2015 and review of tables of contents of relevant journals to identify potential articles that related to medical overuse in adults.

FINDINGS

Between January 1, 2015, and December 31, 2015, we reviewed 1445 articles, of which 821 addressed overuse of medical care. Of these, 112 were deemed most relevant based on their originality, methodologic quality, and number of patients potentially affected. The 10 most influential articles were selected by consensus using the same criteria. Findings included a doubling of specialty referrals and advanced imaging for simple headache (from 6.7% in 2000 to 13.9% in 2010); unnecessary hospital admission for low-risk syncope, often leading to adverse events; and overly frequent colonoscopy screening for 34% of patients. Overtreatment was common in the following areas: 1 in 4 patients with atrial fibrillation at low risk for thromboembolism received anticoagulation; 94% of testosterone replacement therapy was administered off guideline recommendations; 91% of patients resumed taking opioids after overdose; and 61% of patients with diabetes were treated to potentially harmfully low hemoglobin A1c levels (<7%). Findings also identified medical practices to question, including questionable use of treatment of acute low-back pain with cyclobenzaprine and oxycodone/acetaminophen; of testing for Clostridium difficile with molecular assays; and serial follow-up of benign thyroid nodules.

CONCLUSIONS AND RELEVANCE

The number of articles on overuse of medical care nearly doubled from 2014 to 2015. The present review promotes reflection on the top 10 articles and may lead to questioning other non-evidence-based practices.

Update on Medical Practices That Should Be Questioned in 2015

IMPORTANCE

Overuse of medical care, consisting primarily of overdiagnosis and overtreatment, is a common clinical problem.

OBJECTIVES

To identify and highlight articles published in 2014 that are most likely to influence medical overuse, organized into the categories of overdiagnosis, overtreatment, and methods to avoid overuse, and to review these articles and interpret them for their importance to clinical medicine.

EVIDENCE REVIEW

A structured review of English-language articles in PubMed published in 2014 and a review of tables of contents of relevant journals to identify potential articles that related to medical overuse in adults.

FINDINGS

We reviewed 910 articles, of which 440 addressed medical overuse. Of these, 104 were deemed most relevant based on the presentation of original data, quality of methods, magnitude of clinical effect, and number of patients potentially affected. The 10 most influential articles were selected by author consensus using the same criteria. Findings included lack of benefit for screening pelvic examinations (positive predictive value <5%), carotid artery screening (no reduction in stroke), and thyroid ultrasonography (15-fold increase in thyroid cancer). The harms of cancer screening included unnecessary surgery and complications. Head computed tomography was an overused diagnostic test (clinically significant findings in 4% [7 of 172] of head computed tomographic scans). Overtreatment included acetaminophen for low back pain, perioperative aspirin use, medications to increase high-density lipoprotein cholesterol level, stenting for renal artery stenosis, and prolonged opioid use after surgery (use >90 days in 3% [1229 of 39,140] of patients).

CONCLUSIONS AND RELEVANCE

Many common medical practices should be reconsidered. It is anticipated that our review will promote reflection on these 10 articles and lead to questioning of other non-evidence-based practices.

Selective reporting in trials of high risk cardiovascular devices: cross sectional comparison between premarket approval summaries and published reports

OBJECTIVE

To investigate characteristics of clinical trials and results on safety and effectiveness reported in US Food and Drug Administration (FDA) documents for recently approved high risk cardiovascular devices compared with the characteristics and results reported in peer reviewed publications.

DESIGN

A search of the publicly available FDA database was performed for all cardiovascular devices that received premarket approval from 1 January 2000 to 31 December 2010. For each study listed in the premarket approval documents, a Medline search was conducted to obtain the corresponding publication.

MAIN OUTCOME MEASURES

Clinical trial characteristics, primary endpoints, and safety and efficacy results in the FDA documents and corresponding publications.

RESULTS

106 cardiovascular devices received premarket approval from 1 January 2000 to 31 December 2010. FDA premarket approval documents for these devices contained 177 studies, of which 86 (49%) had been published by 1 January 2013. These 86 publications corresponded to 60 distinct devices. The mean time from FDA approval to publication in a peer reviewed journal was 6.5 months (range -4.8-7.5 years). In 22 (26%) of the 86 compared studies the number of participants enrolled in the study differed in the FDA summary and the corresponding publications. Of 152 primary endpoints identified in the FDA documents, in the corresponding publications three (2%) were labeled as secondary, 43 (28%) were unlabeled, and 15 (10%) were not found. Among the primary results, 69 (45%) were identical, 35 (23%) were similar, 17 (11%) were substantially different, and 31 (20%) could not be compared.

CONCLUSIONS

Many clinical trials for high risk cardiovascular devices approved by the FDA remain unpublished. Even when trials are published, the study population, primary endpoints, and results can differ substantially from data submitted to the FDA.

Abstract 140: Majority of High-Risk Cardiovascular Device Studies Do Not Include Comparative Efficacy Data at the Time of FDA Approval

Introduction Comparative effectiveness data is important in informing regulatory and treatment decisions with information on the clinical significance of the measured outcomes. There is increasing utilization and significance of cardiovascular devices in the United States, thus it is important to know the comparative efficacy of novel cardiovascular devices at the time they receive Food and Drug Administration (FDA) approval.

Hypothesis We assessed the hypothesis that clinical trials results submitted to the FDA for approval of novel, high-risk cardiovascular devices often provide comparative efficacy data.

Methods Comparative efficacy was defined as the presence of an active control. For all high-risk cardiovascular devices approved by the FDA from 2000 through 2011, we extracted information on comparative efficacy data from Summaries of Safety and Effectiveness Data (Summary) which include study data used to justify FDA approval. All identified studies were examined to determine if they relied upon active controls, historical controls, objective performance criteria, or if they had no control. The proportion of studies containing comparative efficacy data was calculated and cross-tabulated by approval year and device class. A multivariate logistic model was used to assess trends over time and the Kruskal-Wallis test was used to examine differences between device sub-types.

Results We examined 114 Summaries which contained 340 cardiovascular device studies. Of these studies, 140 (41%) contained an active control. Historical controls 48 (14%) and objective performance 83 (24%) criteria were commonly used. Sixty-nine (20%) of the studies were single-arm studies without controls. In our Summary-level analysis, 74 (65%) devices had an active control in at least one supporting study. Approval year was not significantly associated with type of control arm after controlling for device type in our multivariate logistic analysis. Use of comparative efficacy data was significantly associated with device type. Use ranged from 15/19 (79%) of hemostasis devices to 0/3 (0%) of ventricular assist devices.

Conclusions A minority of studies for the highest risk cardiovascular devices approved by the FDA since 2000 included comparative efficacy data through the use of an active comparator arm. Increasing use of active controls would help to better inform regulatory and treatment decisions at the point of FDA approval.

Medical device regulation: time to improve performance

Sanket Dhruva and Rita Redberg comment on a research study evaluating the evidence regarding the performance of device regulatory systems. They argue that adequate funding and increased transparency are vital to future reform.

Gender bias in studies for Food and Drug Administration premarket approval of cardiovascular devices

BACKGROUND

Cardiovascular devices can have different safety and effectiveness profiles in men and women. The type and quality of sex-specific data reviewed by the Food and Drug Administration (FDA) before approval of these devices are unknown.

METHODS AND RESULTS

We performed a systematic review of the demographics, comments on gender bias, and analysis of results by sex for 78 high-risk cardiovascular devices that received premarket approval by the FDA between 2000 and 2007. FDA summaries of evidence did not report sex of enrollees in 34 (28%) of 123 studies. For studies reporting sex distribution, the study populations were, on average, 67% men. There was no increase in the enrollment of women over time. Explanations for the relatively low percentage of women often stated that the trials reflected either underlying disease distribution or referral rates for similar procedures or that the sex distribution reflected similar or previous trials. Forty-one percent of studies included a gender bias comment or analysis, and 12 (26%) of 47 of these analyses identified some difference in device safety or effectiveness by sex.

CONCLUSIONS

There is a lack of sex-specific safety and effectiveness data for high-risk cardiovascular devices before FDA approval. The justifications for this lack of evidence may perpetuate the status quo. More rigorous FDA requirements for sex-specific data before device approval could present an opportunity to improve cardiovascular outcomes.

Inclusion of training patients in US Food and Drug Administration premarket approval cardiovascular device studies

BACKGROUND

Training patients are the first individuals in whom a physician uses an investigational device. There is great variability in the use of data from training patients in the absence of guidelines. The prevalence and extent of data reporting from training patients in cardiovascular device studies submitted for US Food and Drug Administration (FDA) approval has not been characterized.

METHODS

Information on training patients was abstracted from the Summary of Safety and Effectiveness Data summarizing cardiovascular device premarket applications approved by the FDA from 2000 through 2007. We examined the numbers and characteristics of training patients and the inclusion of their results in end-point analyses.

RESULTS

There were 78 cardiovascular device summaries in this 8-year period, of which 17 (22%) involved training patients. Of the 123 studies in the summaries, 20 (16%) used training patients. All studies excluded training patients from efficacy analyses and 19 of 20 (95%) excluded them from safety analyses. Sixteen of 20 (80%) did not provide any outcome data, and 15 of 20 (75%) did not check for outcome differences between training and nontraining treatment patients. Eighteen of 20 (90%) did not provide demographic information on training patients, and 14 of 20 (70%) did not prespecify guidelines for their enrollment.

CONCLUSIONS

Training patients comprise a considerable proportion of patients receiving investigational cardiovascular devices, but their results are excluded from FDA submissions. Their exclusion from analyses means that safety and efficacy outcomes may look better than actual results. Guidelines on the use and inclusion of results for training patients would improve accuracy on results reporting.

Strength of study evidence examined by the FDA in premarket approval of cardiovascular devices

CONTEXT

Medical devices are common in clinical practice and have important effects on morbidity and mortality, yet there has not been a systematic examination of evidence used by the US Food and Drug Administration (FDA) for device approval.

OBJECTIVES

To study premarket approval (PMA)--the most stringent FDA review process--of cardiovascular devices and to characterize the type and strength of evidence on which it is based.

DATA SOURCES AND STUDY SELECTION

Systematic review of 78 summaries of safety and effectiveness data for 78 PMAs for high risk cardiovascular devices that received PMA between January 2000 and December 2007 [corrected].

DATA EXTRACTION

Examination of the methodological characteristics considered essential to minimize confounding and bias, as well as the primary end points of the 123 studies supporting the PMAs.

RESULTS

Thirty-three of 123 studies (27%) used to support recent FDA approval of cardiovascular devices were randomized and 17 of 123 (14%) were blinded. Fifty-one of 78 PMAs (65%) were based on a single study. One hundred eleven of 213 primary end points (52%) were compared with controls and 34 of 111 controls (31%) were retrospective. One hundred eighty-seven of 213 primary end points (88%) were surrogate measures and 122 of 157 (78%) had a discrepancy between the number of patients enrolled in the study and the number analyzed.

CONCLUSION

Premarket approval of cardiovascular devices by the FDA is often based on studies that lack adequate strength and may be prone to bias.

Variations between clinical trial participants and Medicare beneficiaries in evidence used for Medicare national coverage decisions

BACKGROUND

There is a paucity of data on the adequacy of the resources and tools used by the Centers for Medicaid and Medicare Services (CMS) in making national coverage determinations about services for beneficiaries. The objective of this study was to determine the extent to which clinical trials relied on by the CMS are applicable to Medicare beneficiaries.

METHODS

We performed a meta-analysis of data on 40 009 individuals from all 141 trials included in the technology assessments for the 6 cardiovascular disease meetings of the CMS advisory panel and compared them with the demographics of the Medicare population.

RESULTS

Medicare beneficiaries differ significantly from the cardiovascular clinical trial participants used to inform Medicare coverage decisions. Clinical trial participants, compared with beneficiaries, are more likely to be younger (60.1 vs 74.7 years), male (75.4% vs 41.8%), and non-US residents (60% vs 0%). The clinical trials, moreover, rarely included outcome stratification by age, sex, and race.

CONCLUSIONS

Participants in cardiovascular studies relied on by the CMS for coverage determinations differ substantially from the Medicare population. Data frequently are not available on relevant subgroup populations. Suggestions are made that address the need for data more relevant to Medicare beneficiaries by increasing enrollment of, and reporting on, women and elderly individuals in clinical trials and use of relevant data for coverage decisions.