Publications

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.

BACKGROUND

A low proportion of CD28CD8 T cells that express CD57 is associated with increased mortality in HIV infection. The effect of increasing body mass index (BMI) changes in the proportion of CD57CD28CD8 T cells among HIV-infected individuals on antiretroviral therapy is unknown.

SETTING

In a US cohort of HIV-infected women, we evaluated associations of BMI and waist circumference with 3 distinct CD8 T cell phenotypes: % CD28CD57CD8 T cells, % CD57 of CD28CD8 T cells, and % CD28 of all CD8 T cells.

METHODS

Multivariable linear regression analysis was used to estimate beta coefficients for each of 3 T-cell phenotypes. Covariates included HIV parameters (current and nadir CD4, current viral load), demographics (age, race, income, and study site), and lifestyle (tobacco and alcohol use) factors.

RESULTS

Of 225 participants, the median age was 46 years and 50% were obese (BMI >30 m/kg). Greater BMI and waist circumference were both associated with higher % CD28CD57CD8 T cells and % CD57 of all CD28CD8 T cells in multivariable analysis, including adjustment for HIV viral load (all P < 0.05). The association between greater BMI and the overall proportion of CD28 CD8 cells in fully adjusted models (0.078, 95% confidence interval: -0.053 to 0.209) was not significant.

CONCLUSIONS

In this analysis, greater BMI and waist circumference are associated with greater expression of CD57 on CD28CD8 T cells and a greater proportion of CD57CD28 CD8 T cells. These findings may indicate that increasing BMI is immunologically protective in HIV-infected women. Future research is needed to understand the prognostic importance of these associations on clinical outcomes.

BACKGROUND AND AIMS

Varying recommendations regarding the detection and management of dysplasia can lead to uncertainty and may impede the uptake of strategies that could improve surveillance in patients with inflammatory bowel disease (IBD). An educational event was held to assist in disseminating the recently published Surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease Patients: International Consensus Recommendations (SCENIC).

METHODS

Specialists in IBD and endoscopy led the Optimizing Quality of Endoscopy in IBD course. The American Society for Gastrointestinal Endoscopy (ASGE) organized the course, and the Crohn's and Colitis Foundation of America (CCFA) provided endorsement. One was held in March 2015 at the ASGE Institute for Training and Technology in Chicago, Illinois, and the second in September 2016 preceding the ASGE Endofest in Chandler, Arizona. The program included interactive case-based discussions and didactic presentations on topics including the rationale and current approach of surveillance in IBD; endoscopic characterization and nomenclature of active and quiescent disease; detection of dysplasia during IBD surveillance; role of image-enhanced endoscopy in IBD surveillance, with a focus on chromoendoscopy technique; and management of dysplasia in IBD. Participants were surveyed before and after the course to assess their perspectives and practice.

RESULTS

Eighteen presenters or panel members and approximately 92 IBD and endoscopist physician leaders attended the meeting. Most attendees were aged 30 to 49 years (88.1%), had been in practice less than 10 years (89.7%), were from academic medical centers (90.7%), and spent >50% of their time caring for patients with IBD (59.7%). Recommended quality improvements for endoscopy in IBD included the use of endoscopic scoring systems to describe disease activity, the use of a modified Paris classification to characterize visible dysplastic lesions (polypoid, nonpolypoid with description of presence of ulcer and distinct or indistinct borders), the use of chromoendoscopy for dysplasia detection, and the endoscopic removal of visible dysplastic lesions. In the follow-up survey, participants were asked to indicate whether they had changed their practice as a result of attending the course. Ninety-three percent (93%) indicated they had changed their practice. For dysplasia detection, the use of chromoendoscopy increased: 51.7% of respondents reported using chromoendoscopy in most surveillance colonoscopies compared with 34.3% before the course. For dysplasia management, the use of EMR increased for polypoid and nonpolypoid lesions 10 to 20 mm in size; and the referral of dysplastic lesions 20 mm or larger that appeared endoscopically resectable shifted toward removal by an experienced endoscopist.

CONCLUSIONS

Evidence-based advances in endoscopy have occurred in the characterization and nomenclature of active and quiescent disease, polypoid and nonpolypoid dysplasia in IBD, and in the detection and management of dysplasia in colonic IBD. Implementation of updated guidelines and recommendations into clinical practice may be facilitated by interactive image- and video-based courses on the topic.

Bone marrow fat is a unique fat depot that may regulate bone metabolism. Marrow fat is increased in states of low bone mass, severe underweight, and diabetes. However, longitudinal effects of weight loss and improved glucose homeostasis on marrow fat are unclear, as is the relationship between marrow fat and bone mineral density (BMD) changes. We hypothesized that after Roux-en-Y gastric bypass (RYGB) surgery, marrow fat changes are associated with BMD loss. We enrolled 30 obese women, stratified by diabetes status. Before and 6 months after RYGB, we measured BMD by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and vertebral marrow fat content by magnetic resonance spectroscopy. At baseline, those with higher marrow fat had lower BMD. Postoperatively, total body fat declined dramatically in all participants. Effects of RYGB on marrow fat differed by diabetes status (p = 0.03). Nondiabetic women showed no significant mean change in marrow fat (+1.8%, 95% confidence interval [CI] -1.8% to +5.4%, p = 0.29), although those who lost more total body fat were more likely to have marrow fat increases (r = -0.70, p = 0.01). In contrast, diabetic women demonstrated a mean marrow fat change of -6.5% (95% CI -13.1% to 0%, p = 0.05). Overall, those with greater improvements in hemoglobin A1c had decreases in marrow fat (r = 0.50, p = 0.01). Increases in IGF-1, a potential mediator of the marrow fat-bone relationship, were associated with marrow fat declines (r = -0.40, p = 0.05). Spinal volumetric BMD decreased by 6.4% ± 5.9% (p < 0.01), and femoral neck areal BMD decreased by 4.3% ± 4.1% (p < 0.01). Marrow fat and BMD changes were negatively associated, such that those with marrow fat increases had more BMD loss at both spine (r = -0.58, p < 0.01) and femoral neck (r = -0.49, p = 0.01), independent of age and menopause. Our findings suggest that glucose metabolism and weight loss may influence marrow fat behavior, and marrow fat may be a determinant of bone metabolism. © 2017 American Society for Bone and Mineral Research.

BACKGROUND

Models that predict the risk of estrogen receptor (ER)-positive breast cancers may improve our ability to target chemoprevention. We investigated the contributions of sex hormones to the discrimination of the Breast Cancer Surveillance Consortium (BCSC) risk model and a polygenic risk score comprised of 83 single nucleotide polymorphisms.

METHODS

We conducted a nested case-control study of 110 women with ER-positive breast cancers and 214 matched controls within a mammography screening cohort. Participants were postmenopausal and not on hormonal therapy. The associations of estradiol, estrone, testosterone, and sex hormone binding globulin with ER-positive breast cancer were evaluated using conditional logistic regression. We assessed the individual and combined discrimination of estradiol, the BCSC risk score, and polygenic risk score using the area under the receiver operating characteristic curve (AUROC).

RESULTS

Of the sex hormones assessed, estradiol (OR 3.64, 95% CI 1.64-8.06 for top vs bottom quartile), and to a lesser degree estrone, was most strongly associated with ER-positive breast cancer in unadjusted analysis. The BCSC risk score (OR 1.32, 95% CI 1.00-1.75 per 1% increase) and polygenic risk score (OR 1.58, 95% CI 1.06-2.36 per standard deviation) were also associated with ER-positive cancers. A model containing the BCSC risk score, polygenic risk score, and estradiol levels showed good discrimination for ER-positive cancers (AUROC 0.72, 95% CI 0.65-0.79), representing a significant improvement over the BCSC risk score (AUROC 0.58, 95% CI 0.50-0.65).

CONCLUSION

Adding estradiol and a polygenic risk score to a clinical risk model improves discrimination for postmenopausal ER-positive breast cancers.