Model-Based Assessment of the Reference Values of CAVI in Healthy Russian Population and Benchmarking With CAVI0

BACKGROUND

Cardio-ankle vascular index (CAVI) and its modified version (CAVI0) are promising non-invasive markers of arterial stiffness, extensively evaluated primarily in the Japanese population. In this work, we performed a model-based analysis of the association between different population characteristics and CAVI or CAVI0 values in healthy Russian subjects and propose a tool for calculating the range of reference values for both types of indices.

METHODS

The analysis was based on the data from 742 healthy volunteers (mean age 30.4 years; 73.45% men) collected from a multicenter observational study. Basic statistical analysis [analysis of variance, Pearson's correlation (r), significance tests] and multivariable linear regression were performed in R software (version 4.0.2). Tested covariates included age, sex, BMI, blood pressure, and heart rate (HR).

RESULTS

No statistically significant difference between healthy men and women were observed for CAVI and CAVI0. In contrast, both indices were positively associated with age (r = 0.49 and r = 0.43, P < 0.001), however, with no clear distinction between subjects of 20-30 and 30-40 years old. Heart rate and blood pressure were also identified as statistically significant predictors following multiple linear regression modeling, but with marginal clinical significance. Finally, the algorithm for the calculation of the expected ranges of CAVI in healthy population was proposed, for a given age category, HR and pulse pressure (PP) values.

CONCLUSIONS

We have evaluated the quantitative association between various population characteristics, CAVI, and CAVI0 values and established a method for estimating the subject-level reference CAVI and CAVI0 measurements.

Prediction of Specific Antibody- and Cell-Mediated Responses Using Baseline Immune Status Parameters of Individuals Received Measles-Mumps-Rubella Vaccine

A successful vaccination implies the induction of effective specific immune responses. We intend to find biomarkers among various immune cell subpopulations, cytokines and antibodies that could be used to predict the levels of specific antibody- and cell-mediated responses after measles-mumps-rubella vaccination. We measured 59 baseline immune status parameters (frequencies of 42 immune cell subsets, levels of 13 cytokines, immunoglobulins) before vaccination and 13 response variables (specific IgA and IgG, antigen-induced IFN-γ production, CD107a expression on CD8+ T lymphocytes, and cellular proliferation levels by CFSE dilution) 6 weeks after vaccination for 19 individuals. Statistically significant Spearman correlations between some baseline parameters and response variables were found for each response variable (p < 0.05). Because of the low number of observations relative to the number of baseline parameters and missing data for some observations, we used three feature selection strategies to select potential predictors of the post-vaccination responses among baseline variables: (a) screening of the variables based on correlation analysis; (b) supervised screening based on the information of changes of baseline variables at day 7; and (c) implicit feature selection using regularization-based sparse regression. We identified optimal multivariate linear regression models for predicting the effectiveness of vaccination against measles-mumps-rubella using the baseline immune status parameters. It turned out that the sufficient number of predictor variables ranges from one to five, depending on the response variable of interest.

Dose- and Intensity-Response Associations Between Leisure-Time Physical Activity and Markers of Inflammation and Oxidative Stress in Older Adults

This study aimed to investigate the dose- and intensity-response associations between leisure-time physical activity (LTPA) and markers of inflammation and oxidative stress in older adults. Multivariable linear regression was performed to evaluate the associations among 3,559 older adults in 2015-2018 National Health and Nutrition Examination Survey. LTPA was negatively associated with inflammatory markers including C-reactive protein, segmented neutrophil count and alkaline phosphatase, and positively associated with one marker of antioxidants albumin in older adults. Compared with vigorous LTPA, moderate LTPA could provide more benefits through further decreasing white blood cell count and alkaline phosphatase, and increasing serum bilirubin and albumin. The effects of LTPA on C-reactive protein and albumin were more significant in participants with chronic diseases including diabetes, hypertension, and cancer. In conclusion, this study demonstrates the dose- and intensity-response effects of LTPA on inflammation and oxidative stress and provides exercise prescription recommendations for older adults.

Predictors of radiation dose for uterine artery embolisation are angiography system-dependent

This study sought to achieve radiation dose reductions for patients receiving uterine artery embolisation (UAE) by evaluating radiation dose measurements for the preceding generation (Allura) and upgraded (Azurion) angiography system. Previous UAE regression models in the literature could not be applied to this centre's practice due to being based on different angiography systems and radiation dose predictor variables. The aims of this study were to establish whether radiation dose is reduced with the upgraded angiography system and to develop a regression model to determine predictors of radiation dose specific to the upgraded angiography system. A comparison between Group I (Allura,n= 95) and Group II (Azurion,n= 95) demonstrated a significant reduction in kerma-area product (KAP) and Ka, r (reference air kerma) by 63% (143.2 Gy cm²vs 52.9 Gy cm²;P< 0.001,d= 0.8) and 67% (0.6 Gy vs 0.2 Gy;P< 0.001,d= 0.8), respectively. The multivariable linear regression (MLR) model identified the UAE radiation dose predictors for KAP on the upgraded angiography system as total fluoroscopy dose, Ka, r, and total uterus volume. The predictive accuracy of the MLR model was assessed using a Bland-Altman plot. The mean difference was 0.39 Gy cm²and the limits of agreement were +28.49 and -27.71 Gy cm², and thus illustrated no proportional bias. The resultant MLR model was considered system-dependent and validated the upgraded angiography system and its advance capabilities to significantly reduce radiation dose. Interventional radiologist and interventional radiographer familiarisation of the system's features and the implementation of the newly established MLR model would further facilitate dose optimisation for all centres performing UAE procedures using the upgraded angiography system.

Characterization of Physicians That Might Be Reluctant to Propose HIV Cure-Related Clinical Trials with Treatment Interruption to Their Patients? The ANRS-APSEC Study

HIV cure-related clinical trials (HCRCT) with analytical antiretroviral treatment interruptions (ATIs) have become unavoidable. However, the limited benefits for participants and the risk of HIV transmission during ATI might negatively impact physicians’ motivations to propose HCRCT to patients. Between October 2016 and March 2017, 164 French HIV physicians were asked about their level of agreement with four viewpoints regarding HCRCT. A reluctance score was derived from their answers and factors associated with reluctance identified. Results showed the highest reluctance to propose HCRCT was among physicians with a less research-orientated professional activity, those not informing themselves about cure trials through scientific literature, and those who participated in trials because their department head asked them. Physicians’ perceptions of the impact of HIV on their patients’ lives were also associated with their motivation to propose HCRCT: those who considered that living with HIV means living with a secret were more motivated, while those worrying about the negative impact on person living with HIV’s professional lives were more reluctant. Our study highlighted the need to design a HCRCT that minimizes constraints for participants and for continuous training programs to help physicians keep up-to-date with recent advances in HIV cure research.

Health-related quality of life in patients with esophageal cancer or precancerous lesions assessed by EQ-5D: A multicenter cross-sectional study

Background

We aimed to obtain a set of health state utility scores of patients with esophageal cancer (EC) and precancerous lesions in China, and to explore the influencing factors of health‐related quality of life (HRQoL).

Methods

A hospital‐based multicenter cross‐sectional study was conducted. From 2013 to 2014, patients with EC or precancerous lesions were enrolled. HRQoL was assessed using a European quality of life‐5 dimension (EQ‐5D‐3L) instrument. Multivariable linear regression analysis was performed to explore the influencing factors of the EQ‐5D utility scores.

Results

A total of 2090 EC patients and 156 precancer patients were included in the study. The dimension of pain/discomfort had the highest rate of self‐reported problems, 60.5% in EC and 51.3% in precancer patients. The mean visual analog scale (VAS) score for EC and precancer patients were 68.4 ± 0.7 and 64.5 ± 3.1, respectively. The EQ‐5D utility scores for EC and precancer patients were estimated as 0.748 ± 0.009 and 0.852 ± 0.022, and the scores of EC at stage I, stage II, stage III, and stage IV were 0.693 ± 0.031, 0.747 ± 0.014, 0.762 ± 0.015, and 0.750 ± 0.023, respectively. According to the multivariable analyses, the factors of region, occupation, household income in 2012, health care insurance type, pathological type, type of therapy, and time points of the survey were statistically associated with the EQ‐5D utility scores of EC patients.

Conclusions

There were remarkable decrements of utility scores among esophageal cancer patients, compared with precancer patients. The specific utility scores of EC would support further cost‐utility analysis in populations in China.

Propensity score methods and regression adjustment for analysis of nonrandomized studies with health-related quality of life outcomes

PURPOSE

The aim of this study was to investigate the potential added value of combining propensity score (PS) methods with multivariable linear regression (MLR) in estimating the average treatment effect on the treated (ATT) in nonrandomized studies with health-related quality of life (HRQoL) outcomes.

METHODS

We first used simulations to compare the performances of different PS-based methods, either alone or in combination with further MLR adjustment, in estimating ATT. PS methods were, respectively, optimal pair (OPM) and full (OFM) PS matching, subclassification on the PS (SBC), and the inverse probability of treatment weighting (IPTW). We simulated several scenarios, according to different sample sizes, proportions of treated vs untreated subjects, and types of HRQoL outcomes. We also applied the same methods to a real clinical data set.

RESULTS

OPM and IPTW provided the closest Type I error to the nominal threshold α = 0.05 across all scenarios. Overall, both methods showed also lower variability in estimates than SBC and OFM. SBC performed worst, generally providing the highest levels of bias. Further MLR adjustment lessened bias for all methods, however providing higher Type I error for SBC and OFM. In the real case, all methods provided similar ATT estimates except for one outcome.

CONCLUSIONS

Our findings suggest that for sample sizes up to n = 200, OPM and IPTW are to be preferred to OFM and SBC in estimating ATT on HRQoL outcomes. Specifically, OPM performed best in sample sizes of n ≥ 80, IPTW for smaller sample sizes. Additional MLR adjustment can further improve ATT estimates.

An epidemiological analysis of the level of biosecurity and animal welfare on pig farms in Japan and their effect on the use of veterinary antimicrobials

In Japan the highest use of veterinary antimicrobials is in pig production. To obtain useful information to achieve the best approach to reducing this use, we analyzed the association between the level of on-farm biosecurity and animal welfare with the level of antimicrobial use as recorded on prescriptions on 38 pig farms under contract to veterinarians of the Japanese Association of Swine Veterinarians. To determine the level of welfare we recorded the risk of pre- and post-weaning deaths and the floor space available per fattening pig (m²/head). Multivariable linear regression analysis was performed, using biosecurity scores and animal welfare indicators as independent variables and the amount of antimicrobial usage as dependent variables. The results showed that the higher scores for the site condition (location) and external biosecurity scores of the sub-categories ‘farm contractors’ were strongly associated with the lower use of oral antimicrobials (P<0.05). This suggests that in order to reduce the usage of antimicrobials for herd treatments, farmers should consider the location when building a new farm or pig house and strengthen the entrance requirements for high risk visitors. Regression analysis for the respective antimicrobials showed that the site condition, the biosecurity scores of the sub-categories ‘farm contractors’, ‘pen layouts’ (e.g. independence of pens and sites), ‘pig flows’ (e.g. the completeness of all-in/ all-out system) and an animal welfare indicator (i.e. post-weaning mortality risk) were significantly associated with the use of one or more antimicrobials (P<0.05).