Implications of variability on medical device chemical equivalence assessment.

Chemical equivalence testing can be used to assess the biocompatibility implications of a materials or manufacturing change for a medical device. This testing can provide a relatively facile means to evaluate whether the change may result in additional or different toxicological concerns. However, one of the major challenges in the interpretation of chemical equivalence data is the lack established criteria for determining if two sets of extractables data are effectively equivalent. To address this gap, we propose a two-part approach based upon a relatively simple statistical model. First, the probability of a false positive conclusion, wherein there is an incorrectly perceived increase for a given analyte in the comparator relative to the baseline device, can be reduced to a prescribed level by establishing an appropriate acceptance criterion for the ratio of the observed means. Second, the probability of a false negative conclusion, where an actual increase in a given analyte cannot be discerned from the test results, can be minimized by specifying a limiting value of applicability based on the margin of safety (MoS) of the analyte. This approach provides a quantitative, statistically motivated method to interpret chemical equivalence data, despite the relatively high intrinsic variability and small number of replicates typically associated with a chemical characterization evaluation.

Impact of benralizumab on asthma exacerbation-related medical healthcare resource utilization and medical costs: results from the ZEPHYR 2 study.

BACKGROUND AND AIM: Benralizumab is a biologic add-on treatment for severe eosinophilic asthma that can reduce the rate of asthma exacerbations, but data on the associated medical utilization are scarce. This retrospective study evaluated the economic value of benralizumab by analyzing healthcare resource utilization (HRU) and medical costs in a large patient population in the US. METHODS: Insurance claims data (11/2016-6/2020) were analyzed. A pre-post design was used to compare asthma exacerbation rates, medical HRU and medical costs in the 12 months pre vs. post index (day after benralizumab initiation). Patients were aged ≥12 years, with ≥2 records of benralizumab and ≥2 asthma exacerbations pre index, and constituted non-mutually exclusive cohorts: biologic-naïve, biologic-experienced (switched from omalizumab or mepolizumab to benralizumab), or with extended follow-up (18 or 24 months). RESULTS: In all cohorts (mean age 51-53 years; 67-70% female; biologic-naïve, N = 1,292; biologic-experienced, N = 349; 18-month follow-up, N = 419; 24-month follow-up, N = 156), benralizumab treatment reduced the rate of asthma exacerbation by 53-68% (p < .001). In the biologic-naïve cohort, inpatient admissions decreased by 58%, emergency department visits by 54%, and outpatient visits by 58% post index (all p < .001), with similar reductions in exacerbation-related medical HRU in other cohorts. Exacerbation-related mean total medical costs decreased by 51% in the biologic-naïve cohort ($4691 pre-index, $2289 post-index), with cost differences ranging from 16% to 64% across other cohorts (prior omalizumab: $2686 to $1600; prior mepolizumab: $5990 to $5008; 18-month: $3636 to $1667; 24-month: $4014 to $1449; all p < .001). Medical HRU and cost reductions were durable, decreasing by 64% in year 1 and 66% in year 2 in the 24 month follow-up cohort. CONCLUSION: Patients treated with benralizumab with prior exacerbations experienced reductions in asthma exacerbations and exacerbation-related medical HRU and medical costs regardless of prior biologic use, with the benefits observed for up to 24 months after treatment initiation.

Benralizumab is a biologic approved as an add-on treatment for severe eosinophilic asthma. Previous real-world studies and clinical trials have shown that benralizumab can reduce the rate of asthma exacerbations and systemic corticosteroid use. However, there is little information on the economic value of benralizumab in real-world patient populations. This study showed that patients with severe asthma in the United States had lower rates of asthma exacerbations after starting treatment with benralizumab. The patients also had fewer asthma exacerbation-related hospitalizations, emergency department visits, and outpatient visits as well as lower medical costs related to asthma exacerbations compared with before the treatment. These benefits were observed in patients who had never taken and those who had been previously treated with biologic therapies, and for up to 24 months after starting benralizumab treatment. These results show that the clinical value of benralizumab translates into reduced medical utilization for patients with severe asthma.

Non-targeted analysis (NTA) and suspect screening analysis (SSA): a review of examining the chemical exposome.

Non-targeted analysis (NTA) and suspect screening analysis (SSA) are powerful techniques that rely on high-resolution mass spectrometry (HRMS) and computational tools to detect and identify unknown or suspected chemicals in the exposome. Fully understanding the chemical exposome requires characterization of both environmental media and human specimens. As such, we conducted a review to examine the use of different NTA and SSA methods in various exposure media and human samples, including the results and chemicals detected. The literature review was conducted by searching literature databases, such as PubMed and Web of Science, for keywords, such as "non-targeted analysis", "suspect screening analysis" and the exposure media. Sources of human exposure to environmental chemicals discussed in this review include water, air, soil/sediment, dust, and food and consumer products. The use of NTA for exposure discovery in human biospecimen is also reviewed. The chemical space that has been captured using NTA varies by media analyzed and analytical platform. In each media the chemicals that were frequently detected using NTA were: per- and polyfluoroalkyl substances (PFAS) and pharmaceuticals in water, pesticides and polyaromatic hydrocarbons (PAHs) in soil and sediment, volatile and semi-volatile organic compounds in air, flame retardants in dust, plasticizers in consumer products, and plasticizers, pesticides, and halogenated compounds in human samples. Some studies reviewed herein used both liquid chromatography (LC) and gas chromatography (GC) HRMS to increase the detected chemical space (16%); however, the majority (51%) only used LC-HRMS and fewer used GC-HRMS (32%). Finally, we identify knowledge and technology gaps that must be overcome to fully assess potential chemical exposures using NTA. Understanding the chemical space is essential to identifying and prioritizing gaps in our understanding of exposure sources and prior exposures. IMPACT STATEMENT: This review examines the results and chemicals detected by analyzing exposure media and human samples using high-resolution mass spectrometry based non-targeted analysis (NTA) and suspect screening analysis (SSA).

Real-World Effectiveness Study of Benralizumab for Severe Eosinophilic Asthma: ZEPHYR 2.

BACKGROUND: Benralizumab is an mAb therapy for severe eosinophilic asthma. Real-world data on its clinical impact in various patient populations such as patients with varying eosinophil levels, previous biologic use, and extended follow-up in the United States are limited. OBJECTIVE: To determine the effectiveness of benralizumab in different asthmatic patient cohorts and its long-term clinical impact. METHODS: Patients with asthma treated with benralizumab from November 2017 to June 2019 with 2 or more exacerbations in the 12 months before benralizumab initiation (index) were included in this pre-post cohort study that used medical, laboratory, and pharmacy US insurance claims. Asthma exacerbation rates in the 12 months pre and post index were compared. Nonmutually exclusive patient cohorts were defined by blood eosinophil counts (<150, ≥150, 150-<300, <300, and ≥300 cells/µL), a switch from another biologic, or follow-up for 18 or 24 months post index. RESULTS: There were 429 patients in the eosinophil cohort, 349 in the biologic-experienced cohort, and 419 in the extended follow-up cohort. In all eosinophil cohort subgroups, the asthma exacerbation rate decreased from 3.10-3.55 per patient-year (PPY) pre index to 1.11-1.72 PPY post index (52%-64% decrease; P < .001). Similar decreases were observed in patients switching from omalizumab (3.25 to 1.25 PPY [62%]) or mepolizumab (3.81 to 1.78 PPY [53%]) to benralizumab and those followed up for 18 months (3.38 to 1.18 PPY [65%]) or 24 months (3.38 to 1.08 PPY [68%]) (all P < .001). In the extended follow-up cohort, 39% and 49% had no exacerbations in the 0 to 12 months and the 12 to 24 months post index, respectively. CONCLUSIONS: Benralizumab achieved significantly improved asthma control in real-world patients with different blood eosinophil counts, including eosinophil counts ranging from less than 150 to greater than or equal to 300 cells/µL, switching from other biologics, or treated for up to 24 months.

Modeling extraction of medical device polymers for biocompatibility evaluation.

Extraction testing is critical for biocompatibility evaluation of medical devices, whether to generate samples for biological testing or form the basis for toxicological risk assessment. However, it is not always clear how to compare extraction testing between different extraction conditions and sample geometries. We employ a physics-based model to elucidate the theoretical impact of extraction conditions, sample geometry and material properties on extraction efficiency (M/M0) and extract concentration (C/C0) for single-step and iterative/exhaustive extraction test methods. The model is specified by three parameters: thermodynamic contributions (Ψ), kinetic contributions (τ), and number of extraction iterations (N). We find that over the range of typical parameters for single-step extractions, M/M0 only approaches one (complete exhaustion) for relatively large values of Ψ (≥10) and τ(≥1). Further, the model suggests that test article geometry and solvent volume can have a dramatic and sometimes opposing effect on M/M0 and C/C0. Our results imply that iterative extractions can be approximated as a single-step extraction with scaled parameters Ψ' = ΨN and τ' = τN. The model provides a framework to reduce the biocompatibility evaluation test burden by optimizing test article and extraction condition selection and guiding development of new test protocols.

Impact on hospitalizations of long-term versus short-term therapy with sodium zirconium cyclosilicate during routine outpatient care of patients with hyperkalemia: the recognize I study.

BACKGROUND: Hyperkalemia is associated with increased healthcare resource utilization (HRU). This study evaluated the impact of sodium zirconium cyclosilicate (SZC) use on HRU in outpatients with hyperkalemia. RESEARCH DESIGN AND METHODS: A retrospective noncomparative study using claims data from the HealthVerity warehouse, which included outpatients in the United States who initiated SZC between January and December 2019 (index date) with ≥6 months' continuous coverage before (baseline) and after (follow-up) the index date (total coverage of 12 months). The study aimed to describe HRU with long-term and short-term SZC (defined as >90 and ≤90 days' supply, respectively, during 180 days' follow-up) and identify characteristics associated with long-term versus short-term therapy. RESULTS: Of 1153 patients, 748 (64.9%) received short-term and 405 (35.1%) received long-term therapy. During follow-up, lower proportions of patients on long-term versus short-term therapy had hyperkalemia-related hospitalizations (10.1% vs 15.1%; P < 0.05) and all-cause hospitalizations (22.5% vs 29.3%; P < 0.05). Hyperkalemia-related and all-cause hospitalization proportions were 33.0% and 23.3% lower, respectively. Predictors of long-term therapy included stage 3 chronic kidney disease. CONCLUSIONS: Approximately one-third of patients with hyperkalemia received long-term SZC therapy. Hyperkalemia-related and all-cause hospitalization proportions were lower with long-term therapy, although further confirmatory studies are needed.

Association of Calcium and Phosphate Levels with Incident Chronic Kidney Disease in Patients with Hypoparathyroidism: A Retrospective Case-Control Study.

Objective: Reasons for the increased incidence of chronic kidney disease (CKD) in patients with chronic hypoparathyroidism are poorly understood. This study evaluated associations between levels of albumin-corrected serum calcium, serum phosphate, and calcium-phosphate product and the odds of CKD development in patients with chronic hypoparathyroidism. Design: A retrospective nested case-control study of adult patients with chronic hypoparathyroidism who had ≥1 prescription for calcitriol who developed CKD and matched controls who did not develop CKD were selected from the IBM® Explorys electronic medical record database. Patients. The study included a cohort of 300 patients for the albumin-corrected serum calcium analysis and 80 patients for the serum phosphate and calcium-phosphate product analyses. Measurements. We examined associations between albumin-corrected serum calcium, serum phosphate and calcium-phosphate product levels, and the risk of devloping CKD (defined as ≥2 outpatient estimated glomerular filtration values <60 mL/min/1.73 m2 occuring ≥3 months apart or ≥1 diagnostic code for CKD stages 3-5). Results: Individuals who had ≥67% of albumin-corrected serum calcium measurements outside, above, or below the study-defined range (2.00-2.25 mmol/L [8.0-9.0 mg/dL]) had 3.5-, 2.9-, and 2.7-fold higher odds of developing CKD (adjusted odds ratios [95% CI]: 3.46 [1.82-6.56], 2.85 [1.30-6.28], and 2.68 [1.16-6.15]), respectively, compared with patients who had <33% of albumin-corrected calcium measurements in those ranges. There was no association between developing CKD and having any serum phosphate measurements or any calcium-phosphate product measurements above normal population ranges. Conclusion: In adult patients with chronic hypoparathyroidism, a higher proportion of albumin-corrected calcium measurements outside of the 2.00-2.25 mmol/L (8.0-9.0 mg/dL) range was associated with higher odds of developing CKD.

Risk of Nephrolithiasis and Nephrocalcinosis in Patients with Chronic Hypoparathyroidism: A Retrospective Cohort Study.

INTRODUCTION: Chronic hypoparathyroidism managed with conventional treatment, comprising oral administration of calcium and active vitamin D, has been associated with renal complications, including nephrolithiasis and nephrocalcinosis. Further larger-scale studies are needed to examine these risks. This study evaluated the risk of nephrolithiasis and nephrocalcinosis in patients with chronic hypoparathyroidism. METHODS: A retrospective cohort study using a managed care claims database in the United States from January 2007 to June 2017. Included patients were those with chronic hypoparathyroidism (excluding those receiving parathyroid hormone) and randomly selected patients without hypoparathyroidism over a maximum of 5-year follow-up. The main outcome measures were nephrolithiasis, identified by diagnosis codes or procedure codes for removing kidney stones, and nephrocalcinosis, identified by diagnosis codes. RESULTS: The nephrolithiasis analyses included 8097 adult patients with hypoparathyroidism and 40,485 adult patients without hypoparathyroidism. After excluding patients with a diagnosis of nephrocalcinosis at baseline, nephrocalcinosis analyses included 8051 patients with hypoparathyroidism and 40,466 patients without hypoparathyroidism. During 5 years of follow-up, patients with chronic hypoparathyroidism had significantly increased risk of nephrolithiasis and nephrocalcinosis in Kaplan-Meier analysis compared with patients without hypoparathyroidism (both P < 0.001). In the adjusted analyses, chronic hypoparathyroidism was associated with higher risks of nephrolithiasis (hazard ratio [HR], 1.81; 95% confidence interval [CI] 1.60-2.04) and nephrocalcinosis (HR, 6.94; 95% CI 4.41-10.92). A sensitivity analysis restricted to patients with at least one kidney imaging examination showed that 2.6% of patients (n = 59) with hypoparathyroidism and 0.5% of patients (n = 20) without hypoparathyroidism (ratio, 5.5; P < 0.001) developed nephrocalcinosis. CONCLUSIONS: This large retrospective cohort study showed a statistically significant and clinically meaningful increased risk of nephrolithiasis and nephrocalcinosis in patients who have chronic hypoparathyroidism compared with those who do not have chronic hypoparathyroidism.

Predicting Refractive Outcome of Small Incision Lenticule Extraction for Myopia Using Corneal Properties.

PURPOSE: To investigate whether preoperative corneal topographic and biomechanical parameters (CTBPs) predict postoperative residual refractive error (RRE). METHODS: We retrospectively included 151 eyes from 151 patients of small-incision lenticule extraction (SMILE) with target RRE of plano and 3-month measurements of refractive error from Tianjin Eye Hospital. Multivariate linear/logistic regressions were performed to associate age, gender, preoperative refractive error, lenticule thickness, and CTBPs with postoperative RRE/the occurrence of myopic RRE ≤ -0.25 diopter (D). Stepwise regression was used for feature selection. Leave-one-cross-validation was used for model evaluation by the area under the receiver operating characteristic curve (AUC). RESULTS: From linear regression, more myopic RRE was associated with higher preoperative myopia, intraocular pressure (IOP), flattest curvature of anterior cornea (AC), and highest concavity deformation (HCD), and was associated with lower anterior elevation, anterior asphericity, steepest curvature of AC, and second applanation velocity. The occurrence of ≤ -0.25 D RRE was associated with higher myopia, IOP, posterior elevation and asphericity, flattest curvature of AC, first applanation velocity and HCD, and was associated with lower first applanation stiffness parameter, central corneal thickness, anterior elevation and asphericity, steepest curvature of AC, and second applanation velocity as well as thinner lenticule thickness. Compared to the baseline model using age, gender, and preoperative refractive error, adding CTBPs significantly (P < 0.001) improved the AUC performance to 0.771 from 0.615. CONCLUSIONS: Postoperative outcomes of SMILE can be predicted by individual CTBPs. TRANSLATIONAL RELEVANCE: Our findings could be used to customize a refractive nomogram based on individual corneal properties improving outcomes and patient satisfaction.

VALUE OF FRACTAL ANALYSIS OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN VARIOUS STAGES OF DIABETIC RETINOPATHY.

PURPOSE: To use fractal dimensional analysis to investigate retinal vascular disease patterns in patients with diabetic retinopathy using spectral domain optical coherence tomography angiography. METHODS: A retrospective study was conducted which included 49 eyes from 26 control subjects and 58 eyes from 35 patients known to have diabetic retinopathy. Of the 58 eyes with known retinopathy, 31 were categorized as nonproliferative diabetic retinopathy (13 mild, 9 moderate, and 9 severe) and 27 were categorized as proliferative diabetic retinopathy. Optical coherence tomography angiography images were acquired using the RTVue XR Avanti (Optovue, Inc). Automated segmentation was obtained through both the superficial and deep capillary plexuses for each eye. Grayscale optical coherence tomography angiography images were standardized and binarized using ImageJ (National Institutes of Health). Fractal box-counting analyses were conducted using Fractalyse (ThéMA). Fractal dimensions (FDs) and correlation coefficient of the superficial and deep capillary plexuses were compared between control eyes and those in various stages of diabetic retinopathy. RESULTS: The superficial and deep capillary plexuses from diabetic and control eyes were analyzed. The average FD for diabetic eyes was significantly lower than in control eyes in the superficial plexus (P = 2.4 × 10) and in the deep capillary plexus (P = 1.87 × 10 ) with a more statistically significant difference noted in the deep capillary plexus. When analyzing diabetic patients without edema noted on optical coherence tomography, the FD was significantly reduced in the superficial (P = 0.001) and deep (P = 1.49 × 10) plexuses. When analyzing diabetic patients with edema noted on optical coherence tomography, the FD was significantly reduced in the superficial (P = 2.0 × 10) and deep (P = 1.85 × 10) plexuses. CONCLUSION: The optical coherence tomography angiography FD is significantly lower in both superficial and deep capillary plexuses in eyes with all stages studied of diabetic retinopathy. The results were more often significant for the deep capillary plexus. The use of fractal analysis provides an objective criterion to assess microvascular disease burden in diabetic retinopathy.

Electropolymerized Pyrrole-Based Conductive Polymeric Ionic Liquids and Their Application for Solid-Phase Microextraction.

Pyrrole was covalently bonded to 1-methyl and 1-benzylimidazolium ionic liquids (ILs) via an N-substituted alkyl linkage to prepare electropolymerizable IL monomers with excellent thermal stability. The methylimidazolium IL, [pyrrole-C6MIm]+, was then electropolymerized on macro- and microelectrode materials to form conductive polymeric IL (CPIL)-modified surfaces. Electrochemical characterization of a 1.6 mm diameter Pt disk electrode modified with poly[pyrrole-C6MIm]+ demonstrated a selective uptake for an anionic redox probe while rejecting a cationic redox probe. Furthermore, electropolymerization of [pyrrole-C6MIm]+ doped with single-walled carbon nanotubes (SWNT) on 125 µm platinum wires produced 42 µm thick poly[pyrrole-C6MIm]+/SWNT films compared to 17 µm in the absence of SWNT and 5 µm for the previously reported poly[thiophene-C6MIm]+ coatings. The poly[pyrrole-C6MIm]+/SWNT films were prepared with reproducible thicknesses as well as thermal properties sufficient for high-temperature applications, such as solid-phase microextraction (SPME) with gas chromatographic analysis. The utilization of the CPIL sorbent materials in SPME experiments provided excellent extraction efficiencies and selectivity toward organic aromatic analytes. The CPIL sorbent coatings also yielded outstanding fiber-to-fiber reproducibility on the basis of extraction efficiencies and improved response for a range of analytes relative to commercial 100 µm poly(dimethylsiloxane) fibers when normalized for differences in film thickness. Poly[pyrrole-C6MIm]+ CPIL coatings doped with SWNT are therefore promising new sorbent materials for SPME analyses.

Fractal Dimensional Analysis of Optical Coherence Tomography Angiography in Eyes With Diabetic Retinopathy.

PURPOSE: We used fractal dimensional analysis to analyze retinal vascular disease burden in eyes with diabetic retinopathy using spectral-domain optical coherence tomography angiography (OCTA). METHODS: A retrospective study was performed of 13 eyes with diabetic retinopathy without diabetic macular edema and 56 control eyes. Optical coherence tomography angiography images were acquired using the RTVue XR Avanti. Automated segmentation was obtained through the superficial and deep capillary plexuses for each eye. Grayscale OCTA images were standardized and binarized using ImageJ. Fractal box-counting analyses were performed using Fractalyse. Fractal dimensions (FD) as well as software-generated vascular density analyses of the superficial and deep capillary plexuses were compared between diabetic and control eyes using 2-tailed t-tests and 1-way multivariate ANOVA (MANOVA) analyses. RESULTS: The superficial and deep plexuses from diabetic and control eyes were analyzed. The average FD for diabetic eyes was significantly lower than control eyes for the superficial (P = 4.513 × 10-3) and deep (P = 2.653 × 10-3) capillary plexuses. In diabetic eyes, the vascular density also was significantly reduced in the superficial (P = 8.068 × 10-5) and deep (P = 3.120 × 10-6) capillary plexuses. One-way MANOVA showed a significant difference between diabetic and control eyes. CONCLUSIONS: The OCTA FD is significantly reduced in the superficial and deep capillary plexuses in eyes with diabetic retinopathy. Applying fractal analysis to OCTA imaging holds the potential to establish quantitative parameters for microvascular pathology.

Conductive polymeric ionic liquids for electroanalysis and solid-phase microextraction.

Three novel electropolymerizable thiophene-based ionic liquids (ILs) were synthesized and characterized as potential candidates for developing selective extraction media for chemical analysis. Electropolymerization of the bis[(trifluoromethyl)sulfonyl]imide ([NTf2](-)) analogs successfully produced uniform polymeric thin-films on macro- and microelectrode substrates from both vinyl and methylimidazolium IL monomer derivatives. The resultant conducting polymer IL (CPIL) films were characterized by electrochemical methods and found to exhibit attractive behavior towards anionic species while simultaneously providing an exclusion barrier toward cationic species. Thermogravimetric analysis of the thiophene-based IL monomers established a high thermal stability, particularly for the methylimidazolium IL, which was stable until temperatures above 350 °C. Subsequently, the methylimidazolium IL was polymerized on 125 µm platinum wires and utilized for the first time as a sorbent coating for headspace solid-phase microextraction (HS-SPME). The sorbent coating was easily prepared in a reproducible manner, provided high thermal stability, and allowed for the gas chromatographic analysis of polar analytes. The normalized response of the poly[thioph-C6MIm][NTf2]-based sorbent coating exhibited higher extraction efficiency compared to an 85 µm polyacrylate fiber and excellent fiber-to-fiber reproducibility. Therefore, the electropolymerizable thiophene-based ILs were found to be viable new materials for the preparation of sorbent coatings for HS-SPME.