Methods for testing statistical differences between groups in medical research: statistical standard and guideline of Life Cycle Committee

Lee, Seung Won

doi:10.54724/lc.2022.e1

Cited by 197 publications

(172 citation statements)

References 17 publications

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“…Comparisons between baseline and after AD or between after AD and after salbutamol were performed using the Wilcoxon rank paired test. Comparisons of the continuous variables between the two groups of children were performed using the Mann–Whitney U test [ 19 ]. Categorical variables were compared using a chi-square test with Fisher correction when needed.…”

Section: Methodsmentioning

confidence: 99%

Beneficial short-term effect of autogenic drainage on peripheral resistance in childhood cystic fibrosis disease

et al. 2022

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Background Airway clearance techniques are supposed to be a necessary adjunct for the enhancement of impaired peripheral clearance in cystic fibrosis (CF). The objective was to assess the effect of one physiotherapy session (autogenic drainage: AD) on mucus clearance (sputum wet weight) and impulse oscillometry system (IOS) indices, including those obtained from extended Resistance-Inertance-Compliance (eRIC) modelling, considering the degree of bronchial congestion. Methods Thirty children with CF (median age: 12.7 years) in a stable condition prospectively underwent IOS measurements at baseline and after AD. They were divided in two groups: with (visual analog scale of bronchial congestion by the physiotherapist ≥ 5/10) and without (scale < 5/10) bronchial congestion. Paired-comparison of the effects of AD on airway resistance measurements was done with Wilcoxon test. Results The congestion scale correlated with the wet weight of sputum production during the session (Pearson test: p < 0.0001, R = 0.66). Ten children had bronchial congestion and 20 were without congestion. In the whole group, R5–20 Hz significantly decreased after AD (P = 0.049), which was related to a decrease in the children with congestion (P = 0.025), whereas it was not significantly modified in the children without congestion (P = 0.327). The eRIC model allowed the calculation of the peripheral resistance of the respiratory system, which also decreased in the children with congestion (P = 0.037), however, not modified in the children without congestion (P = 0.390). Conclusion One session of autogenic drainage has the ability to decrease peripheral resistance obtained from IOS measurements, more specifically in children with CF with moderate to severe bronchial congestion. Trial registration ClinicalTrials.gov Identifier: NCT04094441.

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Section: Methodsmentioning

confidence: 99%

Beneficial short-term effect of autogenic drainage on peripheral resistance in childhood cystic fibrosis disease

et al. 2022

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“…Test methods for normality can be found in the previous paper. [5] The interpretation of the correlation coefficient can be done as the following: there is no linear correlation in the case of 0; the closer to 1, the stronger the linear proportional relationship between each other is; if it is a negative digit and closer to -1, the inverse linear relationship is stronger. The greater the absolute value itself is, the stronger the linearity.…”

Section: Correlation Coefficientmentioning

confidence: 99%

Regression analysis for continuous independent variables in medical research: statistical standard and guideline of Life Cycle Committee

Lee¹

2022

Life Cycle

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128

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Variables measured in medicine are usually continuous, such as blood pressure, serum glucose, and drug dosage. There are statistical methods to confirm whether these variables act as independent variables that cause an outcome. Most of these methods are types of regression analysis. In this article, starting with a simple correlation coefficient, linear regression, multifactor regression analysis, analysis of covariance (ANCOVA), logistic regression, and modified Poisson regression will be explained. This article shall also cover when and how to use these regression analysis techniques. The following explanations can be used as a statistical background of research using regression analysis. It can also promote the understanding of medical researchers who would like to conduct advanced regression analysis.

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“…Continuous variables are reported as means (standard error), and categorical variables are presented as weighted percentages (%). The demographic and biochemical characteristics of the study population with respect to obstructive lung pattern were compared using general linear model for continuous variables and the chi-square test for categorical variables [26]. Spirometry data according to TSH quartiles or fT4 quartiles were compared using general linear model or chi-square test [26].…”

Section: Discussionmentioning

confidence: 99%

“…The demographic and biochemical characteristics of the study population with respect to obstructive lung pattern were compared using general linear model for continuous variables and the chi-square test for categorical variables [26]. Spirometry data according to TSH quartiles or fT4 quartiles were compared using general linear model or chi-square test [26]. Complex samples logistic regression analyses were used to determine the risk of obstructive lung function patterns based on fT4 quartiles [27].…”

Section: Discussionmentioning

confidence: 99%

Association of free thyroxine with obstructive lung pattern in euthyroid middle-aged subjects: A population-based study

Kim

Park²,

Park³

et al. 2022

PLoS ONE

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Background The association between thyroid hormone levels and pulmonary function in euthyroid population is still unclear. We aimed to examine the relationship between thyroid function and lung function in a large cohort study of euthyroid subjects. Methods We analyzed biochemical and spirometry data from a nationwide, population-based, cross-sectional survey (KNHANES VI). A total of 1,261 middle-aged participants aged 45–65 years with spirometry tests and normal thyroid function were included in this study. The subjects were grouped according to free thyroxine (fT4) (ng/dL) quartiles (Q1, 0.89–1.09; Q2, 1.10–1.19; Q3, 1.20–1.30; Q4, 1.31–1.76). Obstructive lung pattern was defined as forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) <0.7. The probability of obstructive lung patterns according to fT4 quartiles was assessed using logistic regression models, adjusted for potential confounders. Results Overall, 10.9% of the subjects had an obstructive lung pattern. The mean fT4 levels were significantly higher in those with obstructive lung pattern than in those with normal lung function (1.26 vs. 1.20 ng/dL, p<0.001). The proportion of participants with obstructive lung pattern increased across the fT4 quartile categories (p<0.001). With the Q1 group as reference, the multivariate-adjusted odds ratios (95% confidence intervals) for obstructive lung pattern in the Q3 and Q4 groups were 2.875 (1.265–6.535) and 2.970 (1.287–6.854), respectively, even after adjusting for confounding variables. Conclusion High fT4 levels are an independent predictor of obstructive lung pattern in euthyroid middle-aged subjects. Further prospective studies are needed to confirm these findings.

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Methods for testing statistical differences between groups in medical research: statistical standard and guideline of Life Cycle Committee

Cited by 197 publications

References 17 publications

Beneficial short-term effect of autogenic drainage on peripheral resistance in childhood cystic fibrosis disease

Beneficial short-term effect of autogenic drainage on peripheral resistance in childhood cystic fibrosis disease

Regression analysis for continuous independent variables in medical research: statistical standard and guideline of Life Cycle Committee

Association of free thyroxine with obstructive lung pattern in euthyroid middle-aged subjects: A population-based study

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