Tag: pubmed

Stat Med. 2021 Jun 10. doi: 10.1002/sim.9104. Online ahead of print.

ABSTRACT

Response adaptive randomization (RAR) is appealing from methodological, ethical, and pragmatic perspectives in the sense that subjects are more likely to be randomized to better performing treatment groups based on accumulating data. However, applications of RAR in confirmatory drug clinical trials with multiple active arms are limited largely due to its complexity, and lack of control of randomization ratios to different treatment groups. To address the aforementioned issues, we propose a Response Adaptive Block Randomization (RABR) design allowing arbitrarily prespecified randomization ratios for the control and high-performing groups to meet clinical trial objectives. We show the validity of the conventional unweighted test in RABR with a controlled type I error rate based on the weighted combination test for sample size adaptive design invoking no large sample approximation. The advantages of the proposed RABR in terms of robustly reaching target final sample size to meet regulatory requirements and increasing statistical power as compared with the popular Doubly Adaptive Biased Coin Design are demonstrated by statistical simulations and a practical clinical trial design example.

PMID:34111902 | DOI:10.1002/sim.9104

Rofo. 2021 Jun 10. doi: 10.1055/a-1382-8482. Online ahead of print.

ABSTRACT

PURPOSE: To investigate whether a humanoid robot in a clinical radiological setting is accepted as a source of information in conversations before MRI examinations of patients. In addition, the usability and the information transfer were compared with a tablet.

METHODS: Patients were randomly assigned to a robot or tablet group with their consent prior to MRI. The usability of both devices was compared with the extended System Usability Scale (SUS) and the information transfer with a knowledge query. Reasons for refusal were collected by a non-responder questionnaire.

RESULTS: At the University Hospital Halle 117 patients were included for participation. There was no statistically significant difference in gender and age. Of 18 non-responders, 4 refused to participate partly because of the robot; for another 3 the reason could not be clarified. The usability according to SUS score was different with statistical significance between the groups in the mean comparison and was one step higher for the tablet on the adjective scale. There was no statistically significant difference in knowledge transfer. On average, 8.41 of 9 questions were answered correctly.

CONCLUSION: This study is the first application, in a clinical radiological setting, of a humanoid robot interacting with patients. Tablet and robot are suitable for information transfer in the context of MRI. In comparison to studies in which the willingness to interact with a robot in the health care sector was investigated, the willingness is significantly higher in the present study. This could be explained by the fact that it was a concrete use case that was understandable to the participants and not a hypothetical scenario. Thus, potentially high acceptance for further specific areas of application of robots in radiology can be assumed. The higher level of usability perceived in the tablet group can be explained by the fact that here the interface represents a form of operation that has been established for years in all population groups. More frequent exposure to robots could also improve the response in the future.

KEY POINTS: · patients accept humanoid robots in clinical radiologic situations. · at present they can only convey information as well as an inexpensive tablet. · future systems can relieve the burden on personnel..

CITATION FORMAT: · Stoevesandt D, Jahn P, Watzke S et al. Comparison of Acceptance and Knowledge Transfer in Patient Information Before an MRI Exam Administered by Humanoid Robot Versus a Tablet Computer: A Randomized Controlled Study. Fortschr Röntgenstr 2021; DOI: 10.1055/a-1382-8482.

PMID:34111898 | DOI:10.1055/a-1382-8482

Stat Med. 2021 Jun 10. doi: 10.1002/sim.9008. Online ahead of print.

ABSTRACT

In medical research, the development of mediation analysis with a survival outcome has facilitated investigation into causal mechanisms. However, studies have not discussed the death-truncation problem for mediators, the problem being that conventional mediation parameters cannot be well defined in the presence of a truncated mediator. In the present study, we systematically defined the completeness of causal effects to uncover the gap, in conventional causal definitions, between the survival and nonsurvival settings. We propose a novel approach to redefining natural direct and indirect effects, which are generalized forms of conventional causal effects for survival outcomes. Furthermore, we developed three statistical methods for the binary outcome of survival status and formulated a Cox model for survival time. We performed simulations to demonstrate that the proposed methods are unbiased and robust. We also applied the proposed method to explore the effect of hepatitis C virus infection on mortality, as mediated through hepatitis B viral load.

PMID:34111901 | DOI:10.1002/sim.9008

Gynecol Obstet Invest. 2021 Jun 10:1-6. doi: 10.1159/000515894. Online ahead of print.

ABSTRACT

OBJECTIVE: Our main objective was to assess the association between the markers p16 and Ki-67 and recurrence of disease in patients previously treated for cervical high-grade squamous intraepithelial lesion (HSIL).

DESIGN: This is a case-control study at the National Cancer Institute conducted between 2005 and 2015. Of the patients with a pathologically confirmed diagnosis of HSIL, 107 cases were selected. They were divided into 2 groups: 28 cases with recurrence after treatment and a control group of 79 patients without recurrence. We identified clinical, pathological, and treatment variables.

METHODS: Two experienced pathologists performed immunohistochemical analysis of biomarkers; they agreed on their interpretation, and we calculated the odds ratios (ORs) associated with recurrence. For group comparisons, we used the Wilcoxon signed-rank, χ2, or Fisher’s exact test, depending on the type of variable. We conducted logistic regression models to estimate ORs and determine the factors associated with recurrence. The recurrence-free period was defined as the time frame between conization and either recurrence of disease or the last date the patient was seen. We used Kaplan-Meier plots to visualize survival curves and log-rank tests to compare the curves. We established a p value <0.05 as statistically significant.

RESULTS: After pathologists performed immunohistochemical analysis, they achieved an agreement level of 83.7% for p16 and 60% for Ki-67. We did not find an association between recurrence and either p16 expression (p = 0.69) or the percentage of Ki-67 expression (p = 0.71). The recurrence-free period analysis did not reveal a difference in p16 expression (p = 0.57) nor in the percentage of Ki-67 expression in the 3-tiered scale (p = 0.56).

LIMITATIONS: Our main limitation was a reduced sample size.

CONCLUSION: We found no association between p16 and Ki-67 positivity and the risk of recurrence in previously treated HSIL.

PMID:34111875 | DOI:10.1159/000515894

Retina. 2021 Jun 8. doi: 10.1097/IAE.0000000000003233. Online ahead of print.

ABSTRACT

PURPOSE: To identify the incidence of, risk factors for, and outcomes of posterior segment complications (PSC) after Boston type 1 keratoprosthesis (KPro) implantation.

METHODS: Retrospective, consecutive case series of KPro procedures at the Stein Eye Institute. Data regarding ocular history, intraoperative details, postoperative management, and outcomes were collected. Eyes with at least one PSC (PSC Group) were compared with eyes without PSC (No PSC Group) and risk factors for PSC were determined.

RESULTS: 95 PSC occurred in 69/169 eyes (40.8%), at a mean of 20.1 months after KPro implantation (0.01 complications/eye-month). The median follow-up after KPro implantation was 44.0 months (range 3.0 – 174.4). The most common PSC were epiretinal membrane (ERM, 16.6%), cystoid macular edema (CME, 12.4%), vitritis (11.2%) and retinal detachment (RD, 9.5%). Previous RD repair, concomitant intraocular lens removal, postoperative aphakia and vitritis were risk factors for RD. Postoperative infectious keratitis was a risk factor for ERM, CME and vitritis. PSC Group had a significantly higher rate of eyes failing to maintain visual acuity ≥ 20/200 (HR = 2.28; 95%CI = 1.35 – 3.85) and KPro retention failure rate (HR = 1.66; 95%CI = 0.95 – 2.91).

CONCLUSION: PSC occur in approximately 40% of eyes after KPro implantation, resulting in reduced visual outcomes and KPro retention.

PMID:34111883 | DOI:10.1097/IAE.0000000000003233

Retina. 2021 Jun 7. doi: 10.1097/IAE.0000000000003234. Online ahead of print.

ABSTRACT

PURPOSE: Retinal vascular abnormalities (RVA) have been recently described in patients with neurofibromatosis type 1 (NF1) as vascular tortuosity, best visible on infrared imaging. This study assessed clinical RVA’s characteristics in a large series of children with NF1.

METHODS: This retrospective observational study was conducted in children (0 – 18 years old) with an NF1 diagnosis. Using near infrared imaging, RVAs were classified according to the nature of vessels involvement and their degree of tortuosity.

RESULTS: Retinal imaging from 140 children, with a median age of 8.8 [1.5 – 18] years, were included; 52 (37.1%) patients (81 eyes) exhibited RVAs. These RVAs comprised 96% (50/52) of simple vascular tortuosity and 17% (9/52) of cork-screw pattern. Cork-screw pattern involved only small veins, while simple vascular tortuosity could affect both arteries and veins. No statistically significant age correlation was observed, but evolution of RVAs from simple vascular tortuosity to cork-screw pattern was observed in 5 cases.

CONCLUSION: Retinal vascular abnormalities occurred in 37.1% of children with NF1. These abnormalities may result from NF1 promoting localised tortuosity in both small arteries and veins, while only small second or tertiary order venules evolve to highly tortuous pattern.

PMID:34111884 | DOI:10.1097/IAE.0000000000003234

Neonatology. 2021 Jun 10:1-9. doi: 10.1159/000516372. Online ahead of print.

ABSTRACT

INTRODUCTION: Neonatal tracheal intubation (TI) outcomes have been assessed by role, but training level may impact TI success and safety. Effect of physician training level (PTL) on the first-attempt success, adverse TI-associated events (TIAEs), and oxygen desaturation was assessed.

METHODS: Prospective cohort study in 11 international NEAR4NEOS sites between October 2014 and December 2017. Primary TIs performed by pediatric/neonatal physicians were included. Univariable analysis evaluated association between PTL, patient/practice characteristics, and outcomes. Multivariable analysis with generalized estimating equation assessed for independent association between PTL and outcomes (first-attempt success, TIAEs, and oxygen desaturation ≥20%; attending as reference).

RESULTS: Of 2,608 primary TIs, 1,298 were first attempted by pediatric/neonatal physicians. PTL was associated with patient age, weight, comorbidities, TI indication, difficult airway history, premedication, and device. First-attempt success rate differed across PTL (resident 23%, fellow 53%, and attending 60%; p < 0.001). There was no statistically significant difference in TIAEs (resident 22%, fellow 20%, and attending 25%; p = 0.34). Desaturation occurred more frequently with residents (60%), compared to fellows and attendings (46 and 53%; p < 0.001). In multivariable analysis, adjusted odds ratio of the first-attempt success was 0.18 (95% CI: 0.11-0.30) for residents and 0.80 (95% CI: 0.51-1.24) for fellows. PTL was not independently associated with adjusted odds of TIAEs or severe oxygen desaturation.

CONCLUSION: Higher PTL was associated with increased first-attempt success but not TIAE/oxygen desaturation. Identifying strategies to decrease adverse events during neonatal TI remains critical.

PMID:34111869 | DOI:10.1159/000516372

Blood Purif. 2021 Jun 10:1-7. doi: 10.1159/000514059. Online ahead of print.

ABSTRACT

BACKGROUND: Arteriovenous fistula (AVF) is considered to be the best choice of vascular access, but the maturation rate and patency rate of AVF are not satisfactory. Many studies have explored the influencing factors of AVF failure but do not involve the direct relationship between monocyte count and AVF failure. This study aims to explore the relationship between monocyte count and AVF dysfunction related to stenosis.

METHODS: From September 2017 to September 2018, basic clinical data and laboratory parameters of patients were collected. All included patients were followed up to September 2019. The stenosis-related AVF failure events that occurred after the patient included in the study and the time of their occurrence were recorded. All patients were divided into 3 groups based on the tertile of monocyte count. Kaplan-Meier method was used to compare the patency rate of AVF in each group. The effects of variables on AVF failure were analyzed. A multivariate Cox regression model with p < 0.05 was included in the univariate Cox regression analysis.

RESULTS: A total of 120 patients were included in this study. According to the recorded baseline monocyte count levels, they were divided into 3 groups according to their tertiles, 34 cases in the T1 group (T1 < 0.32 × 109/L), 44 cases in the T2 group (0.32 ≤ T2 < 0.51 × 109/L), and 42 cases in T3 group (T3 ≥0.51 × 109/L). After a median follow-up of 20 months, a total of 31 AVF failure events occurred. Kaplan-Meier survival curves showed that patients with a baseline monocyte count ≥0.51 × 109/L had the lowest patency rate of AVF (log-rank test χ2 = 7.525, p = 0.023). After adjusting to basic clinical data and biochemical indicators, there were statistically significant differences in patency rates of the 3 groups (hazard ratio = 2.774, 95% CI = 1.092-7.043).

CONCLUSION: Monocyte count ≥0.51 × 109/L is an independent risk factor for AVF failure, and AVF failure caused by monocytes may be driven by inflammation.

PMID:34111871 | DOI:10.1159/000514059

Nanotechnology. 2021 Jun 10. doi: 10.1088/1361-6528/ac0a13. Online ahead of print.

ABSTRACT

In this work, we studied the impact of magnetic nanoparticles (MNPs) interactions with HeLa cells when they are exposed to high frequency alternating magnetic field (AMF). Specifically, we measured the nanobiomechanical properties of cell interfaces by using Atomic Force Microscopy (AFM). The Magnetite (Fe₃O₄) MNPs were synthesized by coprecipitation and encapsulated with silica (SiO₂): Fe₃O₄@SiO₂and functionalized with amino groups (-NH₂): Fe₃O₄@SiO₂-NH₂, by sonochemical processing. HeLa cells were incubated or not with MNPs, then exposed or not to AMF at 37 °C. A biomechanical analysis was then performed through AFM, providing the Young’s modulus and stiffness of the cells. The statistical analysis (p < 0.001) showed that AMF application or MNPs interaction modify the biomechanical behavior of the cell interfaces. Interestingly, the most significant difference was found for HeLa cells incubated with Fe₃O₄@SiO₂-NH₂and exposed to AMF, showing that local heat of these MNPs modify elasticity and stiffness.

PMID:34111853 | DOI:10.1088/1361-6528/ac0a13

Physiol Meas. 2021 Jun 10. doi: 10.1088/1361-6579/ac0a34. Online ahead of print.

ABSTRACT

OBJECTIVE: Filtering can change the timing of pulse feature points on photoplethysmography (PPG) signals. We aim to quantitatively investigate the effect of measurement site and type of pulse feature on the filtering-induced time shift (TS).

APPROACH: 60-second PPG signals were measured from six body sites [finger, wrist under (volar), wrist upper (dorsal), earlobe, and forehead] of 36 healthy adults. Using infinite impulse response digital filters, PPG signals were prefiltered (band-pass, pass and stop bands: >0.5Hz and <0.2Hz for high-pass filter, <20Hz and >30Hz for low-pass filter) then filtered (low-pass, pass and stop bands: <3Hz and >5Hz). Four pulse features (peak, valley, maximal first derivative, and maximal second derivative) were extracted. For each subject, overall TS and intra-subject TS variability in feature points were calculated as the mean and standard deviation of TS between prefiltered and filtered PPG signals in 50 cardiac cycles. Statistical test was performed to investigate the effect of measurement site and type of pulse feature on overall TS and intra-subject TS variability.

RESULTS: Measurement site, type of pulse feature, and their interaction had significant impacts on the overall TS and intra-subject TS variability (p<0.001 for all). Valley and maximal second derivative showed higher overall TS than peak and maximal first derivative. Finger has higher overall TS and lower intra-subject TS variability than other measurement sites.

SIGNIFICANCE: Measurement site and type of pulse feature can significantly influence the timing of feature point on filtered PPG signals. Filtering parameters should be quoted to support the reproducibility of PPG-related studies.

PMID:34111855 | DOI:10.1088/1361-6579/ac0a34