Chapter 8: Meta-analysis of Test Performance When There is a “Gold Standard”

Synthesizing information on test performance metrics such as sensitivity, specificity, predictive values and likelihood ratios is often an important part of a systematic review of a medical test. Because many metrics of test performance are of interest, the meta-analysis of medical tests is more complex than the meta-analysis of interventions or associations. Sometimes, a helpful way to summarize medical test studies is to provide a “summary point”, a summary sensitivity and a summary specificity. Other times, when the sensitivity or specificity estimates vary widely or when the test threshold varies, it is more helpful to synthesize data using a “summary line” that describes how the average sensitivity changes with the average specificity. Choosing the most helpful summary is subjective, and in some cases both summaries provide meaningful and complementary information. Because sensitivity and specificity are not independent across studies, the meta-analysis of medical tests is fundamentaly a multivariate problem, and should be addressed with multivariate methods. More complex analyses are needed if studies report results at multiple thresholds for positive tests. At the same time, quantitative analyses are used to explore and explain any observed dissimilarity (heterogeneity) in the results of the examined studies. This can be performed in the context of proper (multivariate) meta-regressions

Cutaneous Adverse Events in the Randomized, Double-Blind, Active-Comparator DECIDE Study of Daclizumab High-Yield Process Versus Intramuscular Interferon Beta-1a in Relapsing-Remitting Multiple Sclerosis

INTRODUCTION: Cutaneous adverse events (AEs) have been observed in clinical studies of daclizumab high-yield process (HYP) in relapsing-remitting multiple sclerosis (RRMS). Here, we report cutaneous AEs observed in the randomized, double-blind, active-comparator DECIDE study (ClinicalTrials.gov identifier, NCT01064401). METHODS: DECIDE was a randomized, double-blind, active-controlled phase 3 study of daclizumab HYP 150 mg subcutaneous every 4 weeks versus interferon (IFN) beta-1a 30 mcg intramuscular (IM) once weekly in RRMS. Treatment-emergent AEs were classified and recorded by investigators. Investigators also assessed the severity of each AE, and whether it met the criteria for a serious AE. Cutaneous AEs were defined as AEs coded to the Medical Dictionary for Regulatory Activities System Organ Class of skin and subcutaneous tissue disorders. The incidence, severity, onset, resolution, and management of AEs were analyzed by treatment group. RESULTS: Cutaneous AEs were reported in 37% of daclizumab HYP-treated patients and 19% of IFN beta-1a-treated patients. The most common investigator-reported cutaneous AEs with daclizumab HYP were rash (7%) and eczema (4%). Most patients with cutaneous AEs remained on treatment (daclizumab HYP, 81%; IM IFN beta-1a, 90%) and had events that were mild or moderate (94% and 98%) and subsequently resolved (78% and 82%). Most patients with cutaneous AEs did not require treatment with corticosteroids or were treated with topical corticosteroids (daclizumab HYP, 73%; IM IFN beta-1a, 81%). Serious cutaneous AEs were reported in 14 (2%) daclizumab HYP patients and one (<1%) IM IFN beta-1a patient. CONCLUSION: There was an increased risk of cutaneous AEs with daclizumab HYP. While physicians should be aware of the potential for serious cutaneous AEs, the typical cutaneous AEs were mild-to-moderate in severity, manageable, and resolved over time. FUNDING: Biogen and AbbVie Biotherapeutics Inc. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01064401. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12325-016-0353-2) contains supplementary material, which is available to authorized users

Perioperative morbidity and complications in minimal access surgery techniques in obese patients with degenerative lumbar disease

The medical profession is increasingly confronted with the epidemic phenomenon of obesity. Its impact on spine surgery is not quite clear. Published data concerning the use of minimally invasive surgery (MIS) in the spine among obese patients is scarce. The purpose of the present retrospective study was to evaluate perioperative as well as postoperative complication rates in MIS fusion of the lumbar spine in obese, overweight and normal patients classified according to their body mass index. Lumbar MIS fusion was performed by means of TLIF procedures and/or posterolateral fusion alone. A laminotomy was performed in patients with spinal stenosis. Of 72 patients, 39 underwent additional laminotomy for spinal stenosis. No differences were registered in respect of the numbers of fused segments or cages. Any harmful event occurring peri- or postoperatively was noted and included in the statistical analysis. No infection at the site of surgery or severe wound healing disorder was encountered. We registered no difference in blood loss, drainage, or the length of the hospital stay between the three BMI groups. We also observed no difference in complication rates between the three groups. This study confirms the low soft tissue damage of minimal access surgery techniques, which is an important type of surgery in obese patients. The smaller approach helps to minimize infections and wound healing disorders. Moreover, deeper regions of wounds are clearly visualized with the aid of tubular retractors