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Proceedings of the National Academy of... Aug 2020In randomized experiments, Fisher-exact values are available and should be used to help evaluate results rather than the more commonly reported asymptotic values. One...
In randomized experiments, Fisher-exact values are available and should be used to help evaluate results rather than the more commonly reported asymptotic values. One reason is that using the latter can effectively alter the question being addressed by including irrelevant distributional assumptions. The Fisherian statistical framework, proposed in 1925, calculates a value in a randomized experiment by using the actual randomization procedure that led to the observed data. Here, we illustrate this Fisherian framework in a crossover randomized experiment. First, we consider the first period of the experiment and analyze its data as a completely randomized experiment, ignoring the second period; then, we consider both periods. For each analysis, we focus on 10 outcomes that illustrate important differences between the asymptotic and Fisher tests for the null hypothesis of no ozone effect. For some outcomes, the traditional value based on the approximating asymptotic Student's distribution substantially subceeded the minimum attainable Fisher-exact value. For the other outcomes, the Fisher-exact null randomization distribution substantially differed from the bell-shaped one assumed by the asymptotic test. Our conclusions: When researchers choose to report values in randomized experiments, 1) Fisher-exact values should be used, especially in studies with small sample sizes, and 2) the shape of the actual null randomization distribution should be examined for the recondite scientific insights it may reveal.
Topics: Cross-Over Studies; Data Interpretation, Statistical; Humans; Models, Statistical; Random Allocation; Randomized Controlled Trials as Topic; Research Personnel; Sample Size
PubMed: 32703808
DOI: 10.1073/pnas.1915454117 -
Polish Journal of Radiology 2023The aetiology of free fluid detected in the abdomen can be investigated with magnetic resonance imaging (MRI). The aim of this study is to investigate the effectiveness...
PURPOSE
The aetiology of free fluid detected in the abdomen can be investigated with magnetic resonance imaging (MRI). The aim of this study is to investigate the effectiveness of diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values in the evaluation of abdominopelvic fluids.
MATERIAL AND METHODS
Patients with abdominopelvic fluid detected on MRI of the lower abdomen were included in this retrospective, single-centre study. Paracentesis and fluid analysis was performed in these patients. The average ADC values in fluids were measured by a radiologist. A cut-off value was determined, and the specificity, sensitivity, negative predictive value (NPV), and positive predictive values (PPV) were calculated. Intra-observer agreement was investigated.
RESULTS
The study comprised 41 (33 female) patients, and their mean age was 48 ± 4.02 years. The ADC values in infective fluids were significantly higher than in non-infective fluids ( < 0.001). The cut-off value used was 2.95 × 10 mm/s. According to this threshold value, sensitivity in distinguishing non-infective from infective fluids was 88%, specificity was 93.8%, PPV was 95.7%, and NPV was 83.3%. Intra-observer agreement was strong in ADC values (κ = 0.699) ( < 0.001).
CONCLUSIONS
We concluded that the ADC value is a non-invasive, reliable, reproducible imaging parameter that can be useful in the evaluation and characterization of abdominal fluids.
PubMed: 37057204
DOI: 10.5114/pjr.2023.126135 -
Scientific Reports Mar 2022Lung adenocarcinomas presenting as solid nodules are occasionally diagnosed as lepidic predominant lesions. The aim of this study was to clarify the histological...
Lung adenocarcinomas presenting as solid nodules are occasionally diagnosed as lepidic predominant lesions. The aim of this study was to clarify the histological structure and to identify factors predictive of lepidic predominant lesions. We retrospectively reviewed 38 patients that underwent lobectomy for small (≤ 2 cm) adenocarcinoma presenting as solid nodules. Resected tumor slides were reviewed and histological components were evaluated. Clinical and radiological data were analyzed to identify factors predictive of lepidic predominant lesions. Of 38 solid nodules, 9 (23.7%) nodules were lepidic predominant lesions. Five-year disease-free survival (DFS) rates were 100% for lepidic predominant lesions (n = 9) and 74.6% for non-lepidic predominant lesions (n = 29). Mean CT values (p = 0.039) and maximum CT values (p = 0.015) were significantly lower in lepidic predominant lesions compared with non-lepidic predominant lesions. For the prediction of lepidic predominant lesions, the sensitivity and specificity of mean CT value (cutoff, - 150 HU) were 77.8% and 82.8%, respectively, and those of maximum CT value (cutoff, 320 HU) were 77.8% and 72.4%, respectively. A combination of mean and maximum CT values (cutoffs of - 150 HU and 380 HU for mean CT value and maximum CT value, respectively) more accurately predicted lepidic predominant lesions, with a sensitivity and specificity of 77.8% and 86.2%, respectively. The prognosis of lepidic predominant lesions was excellent, even for solid nodules. The combined use of mean and maximum CT values was useful for predicting lepidic predominant lesions, and may help predict prognosis.
Topics: Adenocarcinoma; Adenocarcinoma of Lung; Humans; Lung Neoplasms; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 35361807
DOI: 10.1038/s41598-022-09173-1 -
European Review For Medical and... Mar 2023COVID-19 may cause thrombosis in both venous and arterial systems. Familiarity with the signs and symptoms of thrombosis and its treatment is essential in treating... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
COVID-19 may cause thrombosis in both venous and arterial systems. Familiarity with the signs and symptoms of thrombosis and its treatment is essential in treating COVID-19 infection and its complications. D-Dimer and mean platelet volume (MPV) are measurements related to the development of thrombosis. This study investigates whether MPV and D-Dimer values could be used to determine the risk of thrombosis and mortality in the COVID-19 early stages.
PATIENTS AND METHODS
424 patients who were COVID-19 positive, according to the World Health Organization (WHO) guidelines, were randomly and retrospectively included in the study. Demographic and clinical characteristics such as age, gender, and length of hospitalization were obtained from the digital records of participants. Participants were divided into living and deceased groups. The patients' biochemical, hormonal, and hematological parameters were analyzed retrospectively.
RESULTS
White blood cells (WBC), neutrophils, and monocytes were significantly different in the two groups (p-value <0.001), and their values were lower in the living group than in the deceased group. MPV median values did not differ according to prognosis (p-value = 0.994). While the median value was 9.9 in the survivors, it was 10 in the deceased. Creatinine, procalcitonin, ferritin, and the number of hospitalization days in living patients were significantly lower than in patients who died (p-value <0.001). Median values of D-dimer (mg/L) differ according to prognosis (p-value <0.001). While the median value was 0.63 in the survivors, it was found as 438 in the deceased.
CONCLUSIONS
Our results did not show any significant relationship between the mortality of COVID-19 patients and their MPV levels. However, a significant association between D-Dimer and mortality in COVID-19 patients was observed.
Topics: Humans; COVID-19; Mean Platelet Volume; Prognosis; Retrospective Studies; Thrombosis
PubMed: 37013789
DOI: 10.26355/eurrev_202303_31808 -
Journal of Clinical Medicine Jul 2022COVID-19 patients may manifest thrombocytopenia and some of these patients succumb to infection due to coagulopathy. The aim of our study was to examine platelet count...
COVID-19 patients may manifest thrombocytopenia and some of these patients succumb to infection due to coagulopathy. The aim of our study was to examine platelet count values in patients infected with SARS-CoV-2, comparing them to a control group consisting of non-COVID-19 patients. Moreover, we evaluated the correlation between the platelet value and the respiratory alteration parameters and the outcome (hospitalization and mortality) in COVID-19 patients. The mean platelet values (×109/L) differed between patients with positive or negative SARS-CoV-2 swabs (242.1 ± 92.1 in SARS-CoV-2 negative vs. 215.2 ± 82.8 in COVID-19 patients, p < 0.001). In COVID-19 patients, the platelet count correlated with the A-aO2 gradient (p = 0.001, rho = −0.149), with its increase over the expected (p = 0.013; rho = −0.115), with the PaO2 values (p = 0.036; rho = 0.093), with the PCO2 values (p = 0.003; rho = 0.134) and with the pH values (p = 0.016; rho = −0.108). In COVID-19 negative patients, the platelet values correlated only with the A-aO2 gradient: (p = 0.028; rho = −0.101). Patients discharged from emergency department had a mean platelet value of 234.3 ± 68.7, those hospitalized in ordinary wards had a mean value of 204.3 ± 82.5 and in patients admitted to sub-intensive/intensive care, the mean value was 201.7 ± 75.1. In COVID-19 patients, the survivors had an average platelet value at entry to the emergency department of 220.1 ± 81.4, while that of those who died was 206.4 ± 87.7. Our data confirm that SARS-CoV-2 infection may induce thrombocytopenia, and that the reduction in platelet counts could be correlated with the main blood gas parameters and with clinical outcome; as a consequence, platelet count could be an important prognostic factor to evaluate and stratify COVID-19 patients.
PubMed: 35887877
DOI: 10.3390/jcm11144112 -
Educational and Psychological... Jun 2017Bayesian and classical statistical approaches are based on different types of logical principles. In order to avoid mistaken inferences and misguided interpretations,...
Bayesian and classical statistical approaches are based on different types of logical principles. In order to avoid mistaken inferences and misguided interpretations, the practitioner must respect the inference rules embedded into each statistical method. Ignoring these principles leads to the paradoxical conclusions that the hypothesis [Formula: see text] could be less supported by the data than a more restrictive hypothesis such as [Formula: see text], where [Formula: see text] and [Formula: see text] are two population means. This article intends to discuss and explicit some important assumptions inherent to classical statistical models and null statistical hypotheses. Furthermore, the definition of the -value and its limitations are analyzed. An alternative measure of evidence, the -value, is discussed. This article presents the steps to compute -values and, in order to illustrate the methods, some standard examples are analyzed and compared with -values. The examples denunciate that -values, as opposed to -values, fail to hold some logical relations.
PubMed: 29795926
DOI: 10.1177/0013164416667979 -
PloS One 2018Although determining the quality of life among glaucoma patients has important clinical and public health implications, the utility value of glaucoma patients has not...
OBJECTIVES
Although determining the quality of life among glaucoma patients has important clinical and public health implications, the utility value of glaucoma patients has not yet been determined in Korea.
METHODS
The Korean National Health and Nutrition Examination Survey database was used to identify 833 glaucoma patients based on ophthalmologic examinations. The adjusted mean utility values, calculated by EuroQol-5D (EQ-5D-3L), of glaucoma patients according to patient demographics and measures of glaucoma severity were determined using multivariate linear regression analysis.
RESULTS
The mean utility value of glaucoma patients was 0.8968. Patients aged 70 years or more had significantly lower utility value (0.86, p value 0.005) compared to those aged less than 50 years (0.96). Patients within the lowest quartile of income had a utility value of 0.87, compared to a utility value of 0.96 for those within the highest quartile (p value 0.001). Patients who were not married had lower utility value (0.87) compared to married patients (0.93). Patients within the lowest quartile of worse eye frequency doubling technology (FDT) score had lower utility value (0.88) compared to those within the highest quartile (0.94). Finally, bilateral vision loss patients had significantly lower utility value (0.83, p value 0.013) compared to patients without vision loss (0.92).
CONCLUSION
The present study assessed utility values of Korean glaucoma patients. The quality of life determined by EQ-5D-3L in Korean glaucoma patients was higher compared to those in other countries. Patient demographics as well as measures of disease severity were important factors in determining the quality of life within glaucoma patients.
Topics: Adult; Aged; Aged, 80 and over; Female; Glaucoma; Humans; Male; Middle Aged; Nutrition Surveys; Quality of Life; Republic of Korea; Severity of Illness Index; Vision Disorders
PubMed: 29847608
DOI: 10.1371/journal.pone.0197581 -
Journal of Pathology Informatics 2020To improve communication between clinical providers and the laboratory, we recently implemented secure text messaging for our critical value notifications. This was done...
BACKGROUND
To improve communication between clinical providers and the laboratory, we recently implemented secure text messaging for our critical value notifications. This was done to communicate laboratory critical values (CV) to providers faster so changes to patient care could be done faster. Our previous method of communicating CV to providers was paging and relied on a call back to receive the critical value.
METHODS
We implemented delivery of CV through a secure texting application in which the CV was directly communicated to the provider on their smart phone device.
RESULTS
The mean pre-implementation turnaround time (TAT) was 11.3 minutes (median: 7 minutes, range: 0 - 210 minutes). The mean post- secure text messaging implementation TAT was 3.03 minutes (median: 0.89 minutes, range: < 1 - 95 minutes).When comparing pre- and post-implementation, there was a significant reduction in the TAT from using secure text messaging (p < 0.001). Of the 234 surveys sent out, 81 providers responded (35%). Of these responses, 85% reported that critical value notification by secure text messaging has increased their efficiency and 95% reported that critical value notification is more effective than a pager-phone-call based system. 83% of providers reported that they were able to provide better, faster care to their patients.
CONCLUSIONS
Using secure text messaging (STM) to deliver critical values significantly reduces the CV TAT. Furthermore, providers noted they preferred to receive CV notifications through STM and reported that they were able to provide more effective care to their patients.
PubMed: 33042600
DOI: 10.4103/jpi.jpi_19_20 -
Journal of Human Kinetics Jan 2021The aim of this study was to compare heart rate variability indices before and after a table tennis match. Sixteen males (21.86 ± 8.34 yr, 1.73 ± 0.08 m, 64.09 ±...
The aim of this study was to compare heart rate variability indices before and after a table tennis match. Sixteen males (21.86 ± 8.34 yr, 1.73 ± 0.08 m, 64.09 ± 13.39 kg and 21.46 ± 4.38 kg·m) were evaluated in 21 matches, before and after the match. We observed that in time domain analysis, Mean RR, SDNN, LnRMSSD and pNN50 after match values were significantly lower than before match values (p < 0.01 or p < 0.05), while Mean HR, Min HR and Max HR values were higher (p < 0.01) after than before the match, with no significant differences (p > 0.05) in STD HR. Meanwhile, frequency domain analysis showed LF Power (log), HF Power (log) and HF Power (in normalized units) after match values significantly lower than before match values (p < 0.01 or p < 0.05), while LF/HF value was higher after the match (p < 0.01), with no significant differences (p > 0.05) in LF Power (ms), LF Power (in normalized units) and HF Power (ms) values. Non-linear analysis showed SD1 and SD2 POST values significantly lower than PRE values (p < 0.05), while no significant differences were observed in SD2/SD1 value between POST and PRE analysis. As conclusion, due to the physiological strain of the table tennis match, changes were observed in heart rate variability values, suggesting an increase of sympathetic influence and a reduction of the parasympathetic influence.
PubMed: 34168696
DOI: 10.2478/hukin-2021-0015 -
Translational Vision Science &... Jun 2021The purpose of this study was to investigate the relationship between perfusion of the choriocapillaris (CC) and retinal sensitivity in eyes with intermediate...
PURPOSE
The purpose of this study was to investigate the relationship between perfusion of the choriocapillaris (CC) and retinal sensitivity in eyes with intermediate age-related macular degeneration (iAMD).
METHODS
This prospective study included patients with iAMD and healthy controls. All enrolled subjects underwent optical coherence tomography angiography (OCT-A) in order to compute the percent perfused choriocapillaris area (PPCA). In patients with iAMD, microperimetry (MP) testing was performed in order to quantify: mean retinal sensitivity (MRS), over an area of 10 degrees; mean macular sensitivity (MMS), over the macular area scanned with OCT-A; and retinal sensitivity (RS) in each macular point.
RESULTS
Eighteen eyes of 13 patients were included in the analysis. In addition, 18 eyes of 12 healthy subjects were enrolled as controls. No statistically significant difference (P value > 0.2) was observed in age between patients (73.9 ± 2.0 years) and controls (70.1 ± 2.8 years). We observed significantly lower values of PPCA between patients with iAMD and healthy controls (42.0% ± 3.8% vs. 66.4% ± 3.0%; -β = 23.8%; P value < 0.001). Among iAMD eyes, higher values of PPCA were significantly associated with higher values of MRS (P value = 0.002) and MMS (P value = 0.013). Finally, higher values of RS in each macular point analyzed with MP were significantly (P value < 0.001) associated with higher values of PPCA computed in circular regions of interest (ROIs) centered in each analyzed MP point with radii of 0.5 degrees and 1.0 degree.
CONCLUSIONS
Using OCT-A, we demonstrated a significant association between CC impairment and macular dysfunction, quantified by MP, in iAMD eyes.
TRANSLATIONAL RELEVANCE
OCT-A could be a useful tool for detecting CC alterations and to monitor disease progression.
Topics: Aged; Choroid; Fluorescein Angiography; Humans; Macular Degeneration; Prospective Studies; Retina
PubMed: 34061948
DOI: 10.1167/tvst.10.7.2