Category: Statistics

Int J Biostat. 2020 Dec 2;17(2):331-348. doi: 10.1515/ijb-2020-0022.

ABSTRACT

We propose a nonparametric test of independence, termed optHSIC, between a covariate and a right-censored lifetime. Because the presence of censoring creates a challenge in applying the standard permutation-based testing approaches, we use optimal transport to transform the censored dataset into an uncensored one, while preserving the relevant dependencies. We then apply a permutation test using the kernel-based dependence measure as a statistic to the transformed dataset. The type 1 error is proven to be correct in the case where censoring is independent of the covariate. Experiments indicate that optHSIC has power against a much wider class of alternatives than Cox proportional hazards regression and that it has the correct type 1 control even in the challenging cases where censoring strongly depends on the covariate.

PMID:34826372 | DOI:10.1515/ijb-2020-0022

Cureus. 2021 Oct 20;13(10):e18918. doi: 10.7759/cureus.18918. eCollection 2021 Oct.

ABSTRACT

Aim and objective Diabetes mellitus is a chronic metabolic disorder that requires continuous self-management practices. The aim of our study is to assess the factors resulting in non-compliance with self-management practices in people with type 2 diabetes mellitus (T2DM). Methods This cross-sectional study was conducted at Baqai Institute of Diabetology and Endocrinology (BIDE), a tertiary care center in Karachi, Pakistan, from March 2019 to May 2019. People with T2DM diagnosed for at least six months were included. A predesigned questionnaire was used to assess various components of self-management such as the use of oral hypoglycemic agents (OHAs) and insulin, self-monitoring of blood glucose (SMBG), physical activity, and daily foot care. Certified diabetes educators conducted interviews on a one-to-one basis. Data were entered and analyzed by using SPSS (version 20; IBM Corp., Armonk, NY). Results Better glycated hemoglobin (HbA1c) levels were observed in compliant persons and a statistically significant difference was noted in those who were compliant with insulin use. Good compliance with self-management was observed in people who were given diabetes education previously. A total of 205 people with T2DM were included in the study, with a mean age of 52.66 ± 11.2 years and a mean duration of diabetes of 8.9 ± 7.5 years. There were 62.9% males and 37.1% females. Oral hypoglycemic agents (OHAs) were prescribed to 62.9% while 33.9 % were on both OHAs and insulin. Non-compliance with the intake of OHAs was 33.3%, insulin injection 21%, SMBG 25.7%, physical activity 69.5%, and foot care practice 34.3%. Various reasons identified for non-compliance included forgetfulness (negligence) (88%), fear of hypoglycemia (10.6%), time constraints (48%), and lack of foot care knowledge (84.8%). Conclusion Non-compliance with T2DM self-management is multifactorial and needs continuous reinforcement of structured diabetes education sessions. The study showed that the provision of diabetes education is directly proportional to self-management compliance levels.

PMID:34826318 | PMC:PMC8603089 | DOI:10.7759/cureus.18918

Disabil Rehabil. 2021 Nov 26:1-11. doi: 10.1080/09638288.2021.2003453. Online ahead of print.

ABSTRACT

PURPOSE: To study psychological distress and fatigue among persons with spina bifida (SB) 50 years or older and living in Norway.

METHODS: In 2017, cross-sectional data were collected (n = 30). The Hospital Anxiety and Depression Scale (HADS) and the Fatigue Severity Scale (FSS) were used. Descriptive statistics, non-parametric tests, and Spearman correlations were performed. Relevant information from previous studies on adults with chronic spinal cord injury (SCI) and the general population, were collected for comparison.

RESULTS: Participants were 18 women and 12 men, mean age 57.5 (SD 5.6), 26 with myelomeningocele, and six with hydrocephalus. Thirty percent scored above the HADS-A- and 20% above the HADS-D thresholds, thus in the same range as previous studies of SB, but higher compared to persons with SCI and norms. HADS-D correlated with pain and FSS scores. Forty percent reported fatigue symptoms (9/15 without hydrocephalus, 3/6 with hydrocephalus).

CONCLUSIONS: The study revealed a high prevalence of fatigue symptomatology among middle-aged and older adults with SB. Symptoms of anxiety and depression were more common than among persons with chronic SCI and norms. SB follow-ups should include awareness of psychological distress and fatigue, and investigate pain and medication side effects among possible influencing factors.IMPLICATIONS FOR REHABILITATIONClinicians treating adult persons with SB should be aware of possible psychological distress and fatigue symptomatology among these patients.We suggest an initial screening for psychological distress and fatigue in persons with SB during follow-up visits and rehabilitation.Interventions to reduce pain may influence levels of psychological distress and/or fatigue in patients with SB.Clinicians should enquire about the effects of medication on fatigue when assessing and prescribing new medications; a thorough medication review helps to assess the benefits and risks.

PMID:34826231 | DOI:10.1080/09638288.2021.2003453

Br J Radiol. 2021 Nov 26:20210702. doi: 10.1259/bjr.20210702. Online ahead of print.

ABSTRACT

OBJECTIVES: The aim of this exploratory study was to evaluate whether three-dimensional texture analysis (3D-TA) features of non-contrast-enhanced T1-weighted MRI associate with traditional prognostic factors and disease-free survival (DFS) of breast cancer.

METHODS: 3D-T1-weighted images from 78 patients with 81 malignant histopathologically verified breast lesions were retrospectively analysed using standard-size volumes of interest. Grey-level co-occurrence matrix (GLCM) based features were selected for statistical analysis. In statistics the Mann-Whitney U and the Kruskal-Wallis tests, the Cox proportional hazards model and the Kaplan-Meier method were used.

RESULTS: Tumours with higher histological grade were significantly associated with higher contrast (1voxel: p = 0.033, two voxels: p = 0.036). All the entropy parameters showed significant correlation with tumour grade (p = 0.015-0.050) but there were no statistically significant associations between other TA parameters and tumour grade. The Nottingham Prognostic Index (NPI) was correlated with contrast and sum entropy parameters. A higher sum variance TA parameter was a significant predictor of shorter DFS.

CONCLUSION: Texture parameters, assessed by 3D-TA from non-enhanced T1-weighted images, indicate tumour heterogeneity but have limited independent prognostic value. However, they are associated with tumour grade, NPI, and DFS. These parameters could be used as an adjunct to contrast-enhanced TA parameters.

ADVANCES IN KNOWLEDGE: 3D texture analysis of non-contrast enhanced T1-weighted breast MRI associates with tumour grade, NPI, and DFS. The use of non-contrast 3D TA parameters in adjunct with contrast-enhanced 3D TA parameters warrants further research.

PMID:34826254 | DOI:10.1259/bjr.20210702

Integr Environ Assess Manag. 2021 Nov 26. doi: 10.1002/ieam.4560. Online ahead of print.

ABSTRACT

The pharmaceutical manufacturing industry, via the AMR Industry Alliance, has developed and implemented steps to help minimize the potential impact of pharmaceutical manufacturing on the spread of AMR. One of these steps was to publish Predicted No-Effect Concentrations (PNECs) to serve as targets for antibiotic manufacturing wastewater effluent risk assessments aimed to help protect environmental receptors and to mitigate against the spread of antibiotic resistance. Concentrations below which adverse effects in the environment are not expected to occur (predicted no effect concentrations, PNECs) were first published in 2018 and are updated annually. The current list now stands at 125 antibiotics; however, it is recognized that this list does not encompass all manufactured antibiotics. Therefore, a statistical evaluation of currently available data was conducted and a default PNEC of 0.05 µg/L for antibiotics in the absence of other data was derived. This article is protected by copyright. All rights reserved.

PMID:34826209 | DOI:10.1002/ieam.4560

Mol Genet Genomic Med. 2021 Nov 26:e1844. doi: 10.1002/mgg3.1844. Online ahead of print.

ABSTRACT

BACKGROUND: Variants in the ATP binding cassette protein subfamily D member 1 (ABCD1) gene are known to cause X-linked adrenoleukodystrophy (X-ALD). This study focused on the characteristics of ABCD1 variants in Chinese X-ALD families and elucidated the value of genetic approaches for X-ALD.

METHODS: 68 male probands diagnosed as X-ALD were screened for ABCD1 variants by the Sanger sequencing of polymerase chain reaction (PCR) products and multiplex ligation-dependent probe amplification (MLPA) combined with long-range PCR. Prenatal diagnosis was performed in 20 foetuses of 17 probands’ mothers. Descriptive statistics were used to summarise the gene variants and prenatal diagnosis characteristics and outcomes.

RESULTS: This study allowed the identification of 61 variants occurring in 68 families, including 58 single nucleotide variants or small deletion/insertion variants and 3 large deletions. Three probands with no variants detected by next-generation sequencing were found to have variants by PCR-sequencing. Prenatal diagnosis found that 10 of the 20 foetuses had no variants in ABCD1.

CONCLUSION: PCR primers that do not amplify the pseudogenes must be used for PCR-sequencing. MLPA combined with long-range PCR can detect large deletions and insertions, which are usually undetectable by PCR-sequencing. Prenatal diagnosis could help to prevent the birth of infants with X-ALD.

PMID:34826210 | DOI:10.1002/mgg3.1844

Physiol Rep. 2021 Nov;9(22):e15067. doi: 10.14814/phy2.15067.

ABSTRACT

Postural control is often quantified by recording the trajectory of the center of pressure (COP)-also called stabilogram-during human quiet standing. This quantification has many important applications, such as the early detection of balance degradation to prevent falls, a crucial task whose relevance increases with the aging of the population. Due to the complexity of the quantification process, the analyses of sway patterns have been performed empirically using a number of variables, such as ellipse confidence area or mean velocity. This study reviews and compares a wide range of state-of-the-art variables that are used to assess the risk of fall in elderly from a stabilogram. When appropriate, we discuss the hypothesis and mathematical assumptions that underlie these variables, and we propose a reproducible method to compute each of them. Additionally, we provide a statistical description of their behavior on two datasets recorded in two elderly populations and with different protocols, to hint at typical values of these variables. First, the balance of 133 elderly individuals, including 32 fallers, was measured on a relatively inexpensive, portable force platform (Wii Balance Board, Nintendo) with a 25-s open-eyes protocol. Second, the recordings of 76 elderly individuals, from an open access database commonly used to test static balance analyses, were used to compute the values of the variables on 60-s eyes-open recordings with a research laboratory standard force platform.

PMID:34826208 | DOI:10.14814/phy2.15067

Autism Res. 2021 Nov 26. doi: 10.1002/aur.2645. Online ahead of print.

ABSTRACT

This study was performed to determine (a) the age at which autism spectrum disorder (ASD) is first diagnosed in Ugandan children receiving mental health services, (b) whether age at diagnosis varies by sex and clinical presentation, and (c) the average age of ASD diagnosis in children manifesting comorbid conditions. A retrospective chart review was performed and demographic as well as clinical data were collected from children with ASD diagnoses who attended two mental health clinics in Uganda between 2014 and 2019. Descriptive statistics such as percentages, means, and standard deviations were used to summarize the data. Independent t-test was also performed to determine differences in the mean age of diagnosis between males and females. Two hundred and thirty-seven (156 males, 81 females) children with ASD were identified. The average age of ASD diagnosis was (6.9 ± 4.0) years. A statistically significant difference in age of ASD diagnosis was found between males and females (t = -2.106, p = 0.036), such that on average females received a diagnosis at least 1 year later than males. Of the 237 participants, 53.6% were identified with ASD only, 16.0% had ASD and ADHD, 10.5% were diagnosed with ASD and epilepsy, and 7.2% had a diagnosis of complex ASD. The results confirm delays in access to ASD diagnosis and suggest that females are more likely to receive a ASD diagnosis later than males within the Ugandan context. ASD awareness should be intensified to improve public or professional knowledge about ASD to enhance early identification in Uganda.

PMID:34826197 | DOI:10.1002/aur.2645

Liver Transpl. 2021 Nov 26. doi: 10.1002/lt.26375. Online ahead of print.

ABSTRACT

BACKGROUND & AIMS: Burnout among transplant hepatologists has not been well-characterized. The goal of this study was to describe the prevalence and predictors of burnout among practicing transplant hepatologists in the United States.

METHODS: We designed a 69-item survey, including the Maslach Burnout Inventory – Human Services Survey (MBI-HSS) and questions on provider demographics, practice characteristics, and psychological factors. The survey was administered to practicing U.S. transplant hepatologists between October and December 2019. We described burnout using MBI subscales [emotional exhaustion (EE), depersonalization (DP), personal accomplishment (PA)] and determined significant predictors of burnout, which we defined as high EE, using univariate and multivariate analyses.

RESULTS: A total of 185 transplant hepatologists completed the survey (response rate= 25% of 738 practicing transplant hepatologists in the US). Forty percent reported high EE, while 17% and 16% reported high DP and low PA, respectively. On multivariate analysis, respondents with more than five colleagues (odds ratio [OR], 95% confidence interval [CI]: 0.44 (0.23-0.84)), reporting adequate time for outpatient visits (OR 0.42 [0.22-0.80]), reporting greater comfort with their clinical caseload (OR 0.58 [0.37-0.91]) and reporting higher confidence in their prior training (OR 0.59 [0.29-0.86]) had a lower likelihood of high EE. Working six or more hours from home outside of work per week (OR 2.04, [1.07-3.89]) predicted a higher likelihood of burnout. Compensation, age, gender, career phase, caregiver status, and transplant center volume did not predict burnout.

CONCLUSION: Forty percent of transplant hepatologists experienced burnout, predicted mostly by factors related to work-time distribution, peer support, and affect. These findings should prompt development of system-level initiatives.

PMID:34826182 | DOI:10.1002/lt.26375

Mol Ecol Resour. 2021 Nov 26. doi: 10.1111/1755-0998.13558. Online ahead of print.

ABSTRACT

Polyploidy plays an important role in the evolution of eukaryotes, especially for flowering plants. Many of ecologically or agronomically important plant or crop species are polyploids, including sycamore maple (tetraploid), the world 2^nd and 3^rd largest food crops wheat (hexaploid) and potato (tetraploid) as well as economically important aquaculture animals such as Atlantic salmon and trout. The next generation sequencing data enables to allocate genotype at a sequence variant site, known as genotyping by sequencing (GBS). GBS has stimulated enormous interests in population based genomics studies in almost all diploid and many polyploid organisms. DNA sequence polymorphisms are codominant and thus fully informative about the underlying genotype at the polymorphic site, making GBS a straightforward task in diploids. However, sequence data may usually be uninformative in polyploid species, making GBS a far more challenging task in polyploids. This paper presents novel and rigorous statistical methods for predicting the number of sequence reads needed to ensure accurate GBS at a polymorphic site bared by the reads in polyploids and shows that a dozen of reads can ensure a probability of 95% to recover all constituent alleles of any tetraploid genotype but several hundreds of reads are needed to accurately uncover the genotype with probability confidence of 90%, subverting the proposition of GBS using low coverage sequence data in the literature. The theoretical prediction was tested by use of RAD-seq data from tetraploid potato cultivars. The paper provides polyploid experimentalists with theoretical guides and methods for designing and conducting their sequence-based studies.

PMID:34826191 | DOI:10.1111/1755-0998.13558