Clinical cut scores for the Persian version of the personality inventory for DSM-5

BACKGROUND

The cut points of psychological tools to diagnose clinical conditions are not universal and depend on the region and prevalence of the disorder. Thus, we aimed to identify the cutoff points of the Persian original version of the personality inventory for DSM-5 (PID-5; 220 items) that would optimally distinguish nonclinical from clinical groups.

METHODS

Both nonclinical (N = 634, 73% female, 34.0 ± 10.8 years) and clinical (N = 454, 29% female, 29.5 ± 7.4 years) samples from the West of Iran participated in the study. Data were analyzed using receiver operating characteristic (ROC) and Youden's index was used to determine the cutoff scores across the PID-5 domains and facets. The means and standard deviations of both the clinical male and female were compared with the nonclinical group using Cohen's d and independent t-tests.

RESULTS

All the PID-5 algorithms and facets significantly distinguished clinical from nonclinical samples with some unique findings for male and female samples. The mean score of all the PID-5 algorithms and facets in the clinical male and female samples were respectively 1.0-2.0 SD and 0.5-1.0 SD above the mean for the nonclinical counterparts. A score higher than 1.5 on ranging from 0 to 3 in each domain or facet indicated clinical status.

CONCLUSION

Raw cutting scores throughout the PID-5 algorithms can be well used to diagnose any pathology of personality and the severity of the disorder in clinical patients. The cut scores provide a useful tool for the clinical use of the original version of PID-5 in Iran.

Immunogenicity of Cemiplimab: Low Incidence of Antidrug Antibodies and Cut-Point Suitability Across Tumor Types

The immunogenicity of cemiplimab, a fully human immunoglobulin G4 monoclonal antibody directed against programmed cell death 1, was assessed in patients across multiple tumor types. The development of antidrug antibodies (ADAs) against cemiplimab was monitored using a validated bridging immunoassay. To identify ADA-positive samples in the assay, statistically determined cut points were established by analyzing baseline clinical study samples from a mixed population of different tumor types, and this validation cut point was used to assess immunogenicity in all subsequent studies. Regulatory guidance requires that ADA assay cut points be verified for appropriateness in different patient populations. Thus, for the cemiplimab ADA assay, we evaluated whether each new oncology population was comparable with the validation population used to set the cut point. Assay responses from 2393 individual serum samples from 8 different tumor types were compared with the validation population, using established statistical methods for cut-point determination and comparison, with no significant differences observed. Across tumor types, the immunogenicity of cemiplimab was low, with an overall treatment-emergent ADA incidence rate of 1.9% and 2.5% at intravenous dose regimens of 3 mg/kg every 2 weeks and 350 mg every 3 weeks, respectively. Moreover, no neutralizing antibodies to cemiplimab were detected in patients with ADA-positive samples, and there was no observed impact of cemiplimab ADAs on pharmacokinetics. Study-specific cut points may be required in some diseases, such as immune and inflammatory diseases; however, based on this analysis, in-study cut points are not required for each new oncology disease indication for cemiplimab.

A consensus method for estimating physical activity levels in adults using accelerometry

Identifying the best analytical approach for capturing moderate-to-vigorous physical activity (MVPA) using accelerometry is complex but inconsistent approaches employed in research and surveillance limits comparability. We illustrate the use of a consensus method that pools estimates from multiple approaches for characterising MVPA using accelerometry. Participants (n = 30) wore an accelerometer on their right hip during two laboratory visits. Ten individual classification methods estimated minutes of MVPA, including cut-point, two-regression, and machine learning approaches, using open-source count and raw inputs and several epoch lengths. Results were averaged to derive the consensus estimate. Mean MVPA ranged from 33.9-50.4 min across individual methods, but only one (38.9 min) was statistically equivalent to the criterion of direct observation (38.2 min). The consensus estimate (39.2 min) was equivalent to the criterion (even after removal of the one individual method that was equivalent to the criterion), had a smaller mean absolute error (4.2 min) compared to individual methods (4.9-12.3 min), and enabled the estimation of participant-level variance (mean standard deviation: 7.7 min). The consensus method allows for addition/removal of methods depending on data availability or field progression and may improve accuracy and comparability of device-based MVPA estimates while limiting variability due to convergence between estimates.

Anabasine and Anatabine Exposure Attributable to Cigarette Smoking: National Health and Nutrition Examination Survey (NHANES) 2013-2014

Anabasine and anatabine are minor alkaloids in tobacco products and are precursors for tobacco-specific nitrosamines (TSNAs). The levels of these two compounds have been used to differentiate tobacco product sources, monitor compliance with smoking cessation programs, and for biomonitoring in TSNA-related studies. The concentrations of urinary anabasine and anatabine were measured in a representative sample of U.S. adults who smoked cigarettes (N = 770) during the 2013−2014 National Health and Nutrition Examination Survey (NHANES) study cycle, which was the first cycle where urinary anabasine and anatabine data became available. Weighted geometric means (GM) and geometric least squares means (LSM) with 95% confidence intervals were calculated for urinary anabasine and anatabine categorized by tobacco-use status [cigarettes per day (CPD) and smoking frequency] and demographic characteristics. Smoking ≥20 CPD was associated with 3.6× higher anabasine GM and 4.8× higher anatabine GM compared with smoking <10 CPD. Compared with non-daily smoking, daily smoking was associated with higher GMs for urinary anabasine (1.41 ng/mL vs. 6.28 ng/mL) and anatabine (1.62 ng/mL vs. 9.24 ng/mL). Urinary anabasine and anatabine concentrations exceeded the 2 ng/mL cut point in 86% and 91% of urine samples from people who smoke (PWS) daily, respectively; in comparison, 100% of them had serum cotinine concentrations greater than the established 10 ng/mL cut point. We compared these minor tobacco alkaloid levels to those of serum cotinine to assess their suitability as indicators of recent tobacco use at established cut points and found that their optimal cut point values would be lower than the established values. This is the first time that anabasine and anatabine are reported for urine collected from a U.S. population-representative sample of NHANES study participants, providing a snapshot of exposure levels for adults who smoked during 2013−2014. The results of this study serve as an initial reference point for future analysis of NHANES cycles, where changes in the national level of urinary anabasine and anatabine can be monitored among people who smoke to show the effect of changes in tobacco policy.

Endogenous Leptin Concentrations Poorly Predict Metreleptin Response in Patients With Partial Lipodystrophy

CONTEXT

Leptin replacement with metreleptin improves glycemia and hypertriglyceridemia in severely hypoleptinemic patients with generalized lipodystrophy (GLD), but its effects are variable in partially leptin-deficient patients with partial lipodystrophy (PLD).

OBJECTIVE

Compare 3 leptin assays (Study I); identify diagnostic performance of leptin assays to detect responders to metreleptin for each assay (Study II).

DESIGN

Study I: cross-sectional analysis of average bias between leptin assays. Study II: retrospective analysis of diagnostic accuracy of potential leptin cut points to detect clinical responders to metreleptin.

SETTING

National Institutes of Health; University of Michigan.

PARTICIPANTS AND INTERVENTIONS

Study I: Metreleptin-naïve patients with lipodystrophy (GLD, n = 33, PLD, n = 67) and healthy volunteers (n = 239). Study II: GLD (n = 66) and PLD (n = 84) patients treated with metreleptin for 12 months.

OUTCOME MEASURES

Leptin concentrations by Millipore radioimmunoassay (RIA), Millipore enzyme-linked immunosorbent assay (MELISA), and R&D Systems enzyme-linked immunosorbent assay (RDELISA). Response to metreleptin therapy was defined as either reduction ≥1.0% in A1c or ≥30% in serum triglycerides.

RESULTS

RDELISA measured 3.0 ± 9.5 ng/mL higher than RIA; MELISA measured 11.0 ± 17.8 and 14.0 ±19.2 less than RIA and RDELISA, respectively. Leptin by RIA, MELISA, and RDELISA modestly predicted metreleptin response in GLD + PLD [receiver operating characteristic (ROC) area under the curve (AUC) 0.74, 0.69, and 0.71, respectively; P < 0.01 for all] with lower predictive power in PLD (ROC AUC 0.63, 0.61 and 0.65, respectively; P > 0.05 for all). The only reproducible cut point identified on sensitivity analyses was RIA leptin 7.2 ng/mL (sensitivity 56%; specificity 78%).

CONCLUSIONS

Three common leptin assays are not interchangeable, and a reliable cut point to select responders to metreleptin was not identified.

An Alternative Data Transformation Approach for ADA Cut Point Determination: Why Not Use a Weibull Transformation?

The testing of protein drug candidates for inducing the generation of anti-drug antibodies (ADA) plays a fundamental role in drug development. The basis of the testing strategy includes a screening assay followed by a confirmatory test. Screening assay cut points (CP) are calculated mainly based on two approaches, either non-parametric, when the data set does not appear normally distributed, or parametric, in the case of a normal distribution. A normal distribution of data is preferred and may be achieved after outlier exclusion and, if necessary, transformation of the data. The authors present a Weibull transformation and a comparison with a decision tree-based approach that was tested on 10 data sets (healthy human volunteer matrix, different projects). Emphasis is placed on a transformation calculation that can be easily reproduced to make it accessible to non-mathematicians. The cut point value and the effect on the false positive rate as well as the number of excluded samples of both methods are compared.

Detection of Alzheimer's disease amyloid beta 1-42, p-tau, and t-tau assays

Introduction

We aimed to provide cut points for the automated Elecsys Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers.

Methods

Cut points for Elecsys amyloid beta 42 (Aβ42), total tau (t‐tau), hyperphosphorylated tau (p‐tau), and t‐tau/Aβ42 and p‐tau/Aβ42 ratios were evaluated in Mayo Clinic Study of Aging (n = 804) and Mayo Clinic Alzheimer's Disease Research Center (n = 70) participants.

Results

The t‐tau/Aβ42 and p‐tau/Aβ42 ratios had a higher percent agreement with normal/abnormal amyloid positron emission tomography (PET) than the individual CSF markers. Reciever Operating Characteristic (ROC)‐based cut points were 0.26 (0.24–0.27) for t‐tau/Aβ42 and 0.023 (0.020–0.025) for p‐tau/Aβ42. Ratio cut points derived from other cohorts performed as well in our cohort as our own did. Individual biomarkers had worse diagnostic properties and more variable results in terms of positive and negative percent agreement (PPA and NPA).

Conclusion

CSF t‐tau/Aβ42 and p‐tau/Aβ42 ratios are very robust indicators of AD. For individual biomarkers, the intended use should determine which cut point is chosen.

Determination of Cut Point in the Age of Colorectal Cancer Diagnosis Using a Survival Cure Model

Background and Objectives:

Colorectal Cancer (CRC) is the fourth cancer-related cause of death worldwide. CRC is a multi-stage cancer, which is curable during the early stages of the disease. Therefore, determining the time of cut-point existence could improve treatment planning and help directly allocate resources. This study aims to determine the cut point in the age of CRC diagnosis.

Methods:

This study, covering the course 1985 to 2012, consisted of 345 colorectal cancer patients registered in Taleghani Hospital, Tehran, Iran and followed up to 2013. The cut-point in the age of CRC diagnosis was obtained using a mixture cure model. The data were analyzed using SPSS and R, V. 20 and 2.15.0, respectively.

Results:

The results showed that the cut point in the age of CRC diagnosis was 50 years. Based on our estimation, 65% of the patients diagnosed with CRC at or younger than 50 were cured, while 31% of them diagnosed older than 50 were cured, and the younger group had a better survival over the older group.

Conclusion:

Since access to a cut-point and analysis of created prognostic groups are important in screening and treatment planning, our results suggested that it is better to estimate the cut-point in the age of curable cancers in early stages via survival cure models, and the cure rate would increase by CRC timely screening.

Prognostic value of urinary 11-dehydro-thromboxane B2 for mortality: A cohort study of stable coronary artery disease patients treated with aspirin

AIM

There is a variable cardiovascular risk reduction attributable to aspirin because of individual differences in the suppression of thromboxane A₂ and its downstream metabolite 11-dehydro-thromboxane B₂ (11dhTxB₂ ). The aim of this study is to evaluate the optimal cut point of urinary 11dhTxB₂ for the risk of mortality in aspirin-treated coronary artery disease (CAD) patients.

METHODS AND RESULTS

This was a prospective cohort study including stable CAD patients who visited the Baylor Heart and Vascular Hospital in Dallas or the Texas Heart Hospital Baylor Plano, TX between 2010 and 2013. The outcome of all-cause mortality was ascertained from chart review and automated sources. The 449 patients included in this analysis had a mean age of 66.1 ± 10.1 years. 67 (14.9%) patients died within 5 years; 56 (87.5%) of the 64 patients with known cause of death suffered a cardiovascular related mortality. Baseline ln(urinary 11dhTxB₂ /creatinine) ranged between 5.8 and 11.1 (median = 7.2) with the higher concentrations among those who died (median: 7.6) than those who survived (median = 7.2, P < 0.001). Using baseline ln(11dhTxB₂ ) to predict all-cause mortality, the area under the curve was 0.70 (95% CI: 0.64-0.76). The optimal cut point was found to be ln(7.38) = 1597.8 pg/mg, which had the following decision statistics: sensitivity = 0.67, specificity = 0.62, positive predictive value = 0.24, negative predictive value = 0.92, and accuracy = 0.63.

CONCLUSION

Our data indicate the optimal cut point for urine 11dhTxB2 is 1597.8 (pg/mg) for the risk prediction of mortality over five years in stable patients with CAD patients treated with aspirin.