Category: Statistics

Int J Periodontics Restorative Dent. 2023 Jul-Aug;43(4):e157-e163. doi: 10.11607/prd.5997.

ABSTRACT

This study aims to compare the incidence of biologic and mechanical complication rates and the survival rates after at least 5 years of implants and implant-supported fixed complete dental prostheses (IFCDPs) placed during second-stage surgery using four and six implants. A total of 77 patients (33 men, 44 women) with a mean age of 60.6 ± 8.8 years (range: 39 to 80 years) were included, and the total of 92 IFCDPs were classified into two groups: 51 received four implants, and 41 received six implants. No implant failed in the four-implant group (0/204), and one implant failed in the six-implant group (1/246), with no statistically significant differences (P > .05). One prosthetic failure occurred in the four-implant group (1/51), and one failure occurred in the six-implant group (1/41). Both groups experienced some technical and biologic complications, with no statistically significant differences between the groups (P > .05). For both groups, veneer or resin fracture was the most frequent mechanical complication, and mucositis was the most frequent biologic complication. The use of four or six implants may represent a predictable treatment option in the rehabilitation of completely edentulous patients with IFCDPs in the medium-term.

PMID:37552199 | DOI:10.11607/prd.5997

Statistics (Ber). 2018;52(5):1086-1095. doi: 10.1080/02331888.2018.1469023. Epub 2018 May 8.

ABSTRACT

In addition to point estimate for the probability of response in a two-stage design (e.g., Simon’s two-stage design for a Phase II clinical trial with binary endpoints), confidence limits should be Cute the confidence interval does not guarantee coverage probability in a two-stage setting. The existing exact approach to calculate one-sided limits is based on the overall number of responses to order the sample space. This approach could be conservative because many sample points have the same limits. We propose a new exact one-sided interval based on p-value for the sample space ordering. Exact intervals are computed by using binomial distributions directly, instead of a normal approximation. Both exact intervals preserve the nominal confidence level. The proposed exact interval based on the p-value generally performs better than the other exact interval with regard to expected length and simple average length of confidence intervals. Therefore, the new interval calculation based on p-value is recommended for use in practice.

PMID:30906095 | PMC:PMC6426334 | DOI:10.1080/02331888.2018.1469023

Statistics (Ber). 2018 May 8;52(5):1005-1024. doi: 10.1080/02331888.2018.1467420. eCollection 2018.

ABSTRACT

Reduced-rank regression is a dimensionality reduction method with many applications. The asymptotic theory for reduced rank estimators of parameter matrices in multivariate linear models has been studied extensively. In contrast, few theoretical results are available for reduced-rank multivariate generalized linear models. We develop M-estimation theory for concave criterion functions that are maximized over parameter spaces that are neither convex nor closed. These results are used to derive the consistency and asymptotic distribution of maximum likelihood estimators in reduced-rank multivariate generalized linear models, when the response and predictor vectors have a joint distribution. We illustrate our results in a real data classification problem with binary covariates.

PMID:30174379 | PMC:PMC6101205 | DOI:10.1080/02331888.2018.1467420

Statistics (Ber). 2016 Jul 3;50(4):917-929. doi: 10.1080/02331888.2015.1111892. Epub 2016 Jan 8.

ABSTRACT

Copula modelling has in the past decade become a standard tool in many areas of applied statistics. However, a largely neglected aspect concerns the design of related experiments. Particularly the issue of whether the estimation of copula parameters can be enhanced by optimizing experimental conditions and how robust all the parameter estimates for the model are with respect to the type of copula employed. In this paper an equivalence theorem for (bivariate) copula models is provided that allows formulation of efficient design algorithms and quick checks of whether designs are optimal or at least efficient. Some examples illustrate that in practical situations considerable gains in design efficiency can be achieved. A natural comparison between different copula models with respect to design efficiency is provided as well.

PMID:27453616 | PMC:PMC4936440 | DOI:10.1080/02331888.2015.1111892

Statistics (Ber). 2012 Jan 1;46(5):663-671. doi: 10.1080/02331888.2010.545408.

ABSTRACT

We extend the random permutation model to obtain the best linear unbiased estimator of a finite population mean accounting for auxiliary variables under simple random sampling without replacement (SRS) or stratified SRS. The proposed method provides a systematic design-based justification for well-known results involving common estimators derived under minimal assumptions that do not require specification of a functional relationship between the response and the auxiliary variables.

PMID:23645951 | PMC:PMC3640589 | DOI:10.1080/02331888.2010.545408

Statistics (Ber). 2010 Apr 1;44(2):145-153. doi: 10.1080/02331880902986984.

ABSTRACT

Consider a set of order statistics that arise from sorting samples from two different populations, each with their own, possibly different distribution functions. The probability that these order statistics fall in disjoint, ordered intervals and that of the smallest statistics, a certain number come from the first populations is given in terms of the two distribution functions. The result is applied to computing the joint probability of the number of rejections and the number of false rejections for the Benjamini-Hochberg false discovery rate procedure.

PMID:21243084 | PMC:PMC3020799 | DOI:10.1080/02331880902986984

Neurol Neuroimmunol Neuroinflamm. 2023 Aug 7;10(5):e200145. doi: 10.1212/NXI.0000000000200145. Print 2023 Sep.

ABSTRACT

BACKGROUND AND OBJECTIVES: Neural antibodies are detected by tissue-based indirect immunofluorescence assay (IFA) in Mayo Clinic’s Neuroimmunology Laboratory practice, but the process of characterizing and validating novel antibodies is lengthy. We report our assessment of human protein arrays.

METHODS: Assessment of arrays (81% human proteome coverage) was undertaken using diverse known positive samples (17 serum and 14 CSF). Samples from patients with novel neural antibodies were reflexed from IFA to arrays. Confirmatory assays were cell-based (CBA) or line blot. Epitope mapping was undertaken using phage display immunoprecipitation sequencing (PhiPSeq).

RESULTS: Control positive samples known to be reactive with linear epitopes of intracellular antigens (e.g., ANNA-1 [anti-Hu]) were readily identified by arrays in 20 of 21 samples. By contrast, 10 positive controls known to be enriched with antibodies against cell surface protein conformational epitopes (e.g., GluN1 subunit of NMDA-R) were indistinguishable from background signal. Three antibodies, previously characterized by other investigators (but unclassified in our laboratory), were unmasked in 4 patients using arrays (July-December 2022): Neurexin-3α, 1 patient; regulator of gene protein signaling (RGS)8, 1 patient; and seizure-related homolog like 2 (SEZ6L2), 2 patients. All were accompanied by previously reported phenotypes (encephalitis, 1; cerebellar ataxia, 3). Patient 1 had subacute onset of seizures and encephalopathy. Neurexin-3α ranked high in CSF (second ranked neural protein) but low in serum (660th overall). Neurexin-3α CBA was positive in both samples. Patient 2 presented with rapidly progressive cerebellar ataxia. RGS8 ranked the highest neural protein in available CSF sample by array (third overall). RGS8-specific line blot was positive. Patients 3 and 4 had rapidly progressive cerebellar ataxia. SEZ6L2 was the highest ranked neural antigen by arrays in all samples (CSF, 1, serum, 2; Patient 3, ranked 9th overall in CSF, 11th in serum; Patient 4, 6th overall in serum]). By PhIPSeq, diverse neurexin-3α epitopes (including cell surface) were detected in CSF from patient 1, but no SEZ6L2 peptides were detected for serum or CSF samples from Patient 3.

DISCUSSION: Individualized autoimmune neurologic diagnoses may be accelerated using protein arrays. They are optimal for detection of intracellular antigen-reactive antibodies, though certain cell surface-directed antibodies (neurexin-3α and SEZ6L2) may also be detected.

PMID:37550073 | DOI:10.1212/NXI.0000000000200145

Heart. 2023 Aug 7:heartjnl-2023-322463. doi: 10.1136/heartjnl-2023-322463. Online ahead of print.

ABSTRACT

INTRODUCTION: Cardiac troponin (cTn) concentrations above the manufacturer recommended upper limit of normal (ULN) are frequently seen in hospital patients without a clinical presentation consistent with type 1 myocardial infarction, and the significance of this is uncertain. The aim of this study was to assess the relationship between medium-term mortality and cTn concentration in a large consecutive hospital population, regardless of whether there was a clinical indication for performing the test.

METHOD: This prospective observational study included 20 000 consecutive in-hospital and outpatient patients who had a blood test for any reason at a large teaching hospital, and in whom a hs-cTnI assay was measured, regardless of the original clinical indication. Mortality was obtained via NHS Digital.

RESULTS: A total of 20 000 patients were included in the analysis and 18 282 of these (91.4%) did not have a clinical indication for cardiac troponin I (cTnI) testing. Overall, 2825 (14.1%) patients died at a median of 809 days. The mortality was significantly higher if the cTnI concentration was above the ULN (45.3% vs 12.3% p<0.001 log rank). Multivariable Cox analysis demonstrated that the log₁₀ cTnI concentration was independently associated with mortality (HR 1.76 (95% CI 1.65 to 1.88)). Landmark analysis, excluding deaths within 30 days, showed the relationship between cTnI concentration and mortality persisted.

CONCLUSION: In a large, unselected hospital population, in 91.4% of whom there was no clinical indication for testing, cTnI concentration was independently associated with medium-term cardiovascular and non-cardiovascular mortality in the statistical model tested.

PMID:37550072 | DOI:10.1136/heartjnl-2023-322463

Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2023 Aug 8;58:741-746. doi: 10.3760/cma.j.cn115330-20230120-00035. Online ahead of print.

ABSTRACT

Objective: To investigate the value of aspirin challenge tests in the diagnosis of non-steroidal anti-inflammatory drugs-exacerbated respiratory disease (NERD). Methods: Fifty patients (28 females; age, 16-61 years) who were diagnosed with chronic rhinosinusitis with nasal polyps (CRSwNP) with/without asthma, and underwent NERD standardized diagnosis in the Allergy Centre of West China Hospital, Sichuan University from December 2021 to November 2022 were included in the study. The first step was asking about the history of exacerbation respiratory symptoms after intake of any non-steroidal anti-inflammatory drug, including aspirin; the second step was performing intranasal aspirin challenge (IAC); the third step was performing oral aspirin challenge (OAC). The diagnosis of NERD was made if any of the above steps was positive, and the subsequent steps were not performed, otherwise the diagnosis was made to OAC. If OAC was negative, the diagnosis was non-NERD. All patients completed the sino-nasal outcome test 22 (SNOT 22) score, Lund-Kennedy score by nasal endoscopic, allergen skin prick test, blood routine and serum total IgE test. SPSS version 20.0 was used for statistical analysis. Results: The diagnosis of NRED was confirmed in 27 patients (27/50, 54%). Seven (7/50, 14%) of them were diagnosed by clinical history and 20 (20/50, 40%) were diagnosed by aspirin challenge tests, of which 17 (17/20, 85%) were positive to IAC and 3 (3/20, 15%) to OAC. Of the 43 patients who underwent IAC testing, only 2 (2/43, 5%) developed asthma attacks during challenge. Comparing the clinical characteristics of patients in NERD and non-NERD group, there were significant differences between the two groups in gender (P=0.001), hyposmia (P=0.003), history of repeated CRSwNP surgeries (P=0.028), comorbid asthma (P=0.013), SNOT-22 score (P=0.004) and the percentage of peripheral blood eosinophil (P=0.043). Conclusions: Patients may be underdiagnosed if the diagnosis of NERD is made only by medical history, and it is necessary to carry out aspirin challenge tests. IAC is an important means to diagnose NERD with high accuracy and good safety. However, If IAC is negative, further OAC is required.

PMID:37550033 | DOI:10.3760/cma.j.cn115330-20230120-00035

BMJ Open. 2023 Aug 7;13(8):e069208. doi: 10.1136/bmjopen-2022-069208.

ABSTRACT

OBJECTIVES: The emergency department (ED) represents a place and moment of opportunity to provide interventions to improve long-term asthma outcomes, but feasibility, effectiveness and mechanisms of impact are poorly understood. We aimed to review the existing literature on interventions that are delivered in the ED for adults and adolescents, targeting asthma outcomes beyond the ED, and to code the interventions according to theory used, and to understand the barriers and facilitators to their implementation.

METHODS: We systematically searched seven electronic databases and research registers, and manually searched reference lists of included studies and relevant reviews. Both quantitative and qualitative studies that reported on interventions delivered in the ED which aimed to improve asthma outcomes beyond management of the acute exacerbation, for adolescents or adults were included. Methodological quality was assessed using the Mixed Methods Appraisal Tool and informed study interpretation. Theory was coded using the Theoretical Domains Framework. Findings were summarised by narrative synthesis.

RESULTS: 12 articles were included, representing 10 unique interventions, including educational and medication-based changes (6 randomised controlled trials and 4 non-randomised studies). Six trials reported statistically significant improvements in one or more outcome measures relating to long-term asthma control, including unscheduled healthcare, asthma control, asthma knowledge or quality of life. We identified limited use of theory in the intervention designs with only one intervention explicitly underpinned by theory. There was little reporting on facilitators or barriers, although brief interventions appeared more feasible.

CONCLUSION: The results of this review suggest that ED-based asthma interventions may be capable of improving long-term outcomes. However, there was significant variation in the range of interventions, reported outcomes and duration of follow-up. Future interventions would benefit from using behaviour change theory, such as constructs from the Theoretical Domains Framework.

PROSPERO REGISTRATION NUMBER: CRD 42020223058.

PMID:37550032 | DOI:10.1136/bmjopen-2022-069208