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General medical journals such as the

It has been encouraging to see the growing number of outstanding article submissions and publications in the

General methods of presenting easy-to-read results can be found in the previous article [^{1)}

Various types of tables are used to clearly present various forms of research results. Even if presented independently, tables must contain the essential elements needed to convey the necessary information. For instance, the title must contain sufficient description of the content, while the body and footnotes of the table must describe in detail the statistical method and results of the analysis.

The following are the examples of typical tabular results commonly submitted to this journal. The data used in the examples were generated randomly, unless otherwise indicated, and do not reflect results of a specific study, i.e., the presented results have no clinical significance.

Statistic provided in all the tables follow the guidelines on the representation of significant figures and statistics in the Instructions for authors provided by the KJA. There must be no blank spaces in the table and estimate, sample size (n), and the statistical method used must be appropriately included when presenting results using statistical analysis. Quantitative data can be expressed as a representative value and its distribution, such as ‘mean ± standard deviation’ or ‘median (first quartile, third quartile). Qualitative data can be expressed as ‘frequency (percent, %)’, et al. For statistical analyses involving variable transformation that changes the shape of the distribution (i.e., log transformation), statistic reflective of the original value should be used. An inverse statistic may also be expressed if needed. Description of the transformation method and transformed values must accompany variable transformation. For more information on data transformation, refer to Lee's article [

Based on the statistic derived from the sample data of the study, the population parameters are estimated. It is recommended to display a confidence interval (i.e., 95% CI) that is an interval estimator along with point estimators such as mean, median, proportion, coefficient, et al. The previously derived estimates are described together with the hypothesis test results. P value must be described in three decimal places, and a test statistic should be presented in detail so that statistical inference can be made. Presenting the effect size, if possible, can aid the interpretation of statistical results.

An explanation of the abbreviations must be included in the footnote even if an explanation is provided in the text so that the table can be interpreted independently. The unit of measure of each variable must be accurately described, and the number of samples should be presented in the title or alongside the variable.

In one sample comparisons, the data of the experimental sample are compared to a specific reference value. The example in

In the case of categorical data, proportions, etc. can be compared. One sample proportion test can be performed to compare the response rate with the reference value, and when the response rate is close to 0% or 100%, an exact binomial test is sometimes performed. The comparison results are described in

^{2}. The number of patients in each sample has been presented and the mean or median blood pressure was used as the representative value according to the distribution of measurements. A paired t-test was used to perform a paired comparison using the difference in pre- and post-treatment values for each patient. The statistically estimated differences are presented alongside the its 95% CI. The statistical method and P value is also clearly presented.

Results from a study on pain control following a Cesarean section are presented in

The dependent variable is a nominal scale. This analysis method is widely used when selecting a meaningful variable among various explanatory variables and results are presented in terms of odds ratio, etc. Parts of results of a study published in the KJA is presented in

This article examined the principles of presenting the statistical results in clinical studies as a table. We hope to see manuscript submissions with standardized tables reflective of the provided framework. Such standardized format will help facilitate the submission and review process for both authors and reviewers.

All authors are Statistical Round Board Members in KJA.

Sang Gyu Kwak (Conceptualization; Supervision; Writing – original draft; Writing – review & editing)

Hyun Kang (Validation; Writing – review & editing)

Jong Hae Kim (Validation; Writing – review & editing)

Tae Kyun Kim (Validation; Writing – review & editing)

EunJin Ahn (Validation; Writing – review & editing)

Dong Kyu Lee (Validation; Writing – original draft; Writing – review & editing)

Sangseok Lee (Project administration; Validation; Writing – review & editing)

Jae Hong Park (Validation; Writing – review & editing)

Francis Sahngun Nahm (Validation; Writing – review & editing)

Junyong In (Conceptualization; Supervision; Writing – original draft; Writing – review & editing)

Example of One Sample Comparison with Reference Value

Variables | Results | Reference value | Difference (95% CI) | P value |
---|---|---|---|---|

MBP (mmHg, n = 30)^{*} |
70.0 ± 5.0 | 60 | 10.0 (8.0, 12.0) | < 0.001^{†} |

MBP (mmHg, n = 28)^{‡} |
70 (64.0, 75.0) | 60 | 10.0 (8.0, 12.0) | < 0.001^{†} |

Values are presented as mean ± SD or median (Q1, Q3). MBP: mean blood pressure.

^{*}One-sample t-test,

^{†}Two-sided P value < 0.05,

^{‡}Wilcoxon’s signed rank test. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point.

Example of One Sample Test of Proportions

Variables | Positive response | Reference probability | Response rate (95% CI) | P value |
---|---|---|---|---|

PONV (n = 25)^{*} |
9 | 0.20 | 0.36 (0.18, 0.57) | 0.080 |

Itching sense (n=64)^{†} |
5 | 0.02 | 0.08 (0.03, 0.17) | 0.009^{‡} |

PONV: postoperative nausea and vomiting,

^{*}One sample proportion test with continuity correction,

^{†}Exact binomial test,

^{‡}Two-sided P value < 0.05. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point.

Example of Independent Two Sample Comparison

Variables | Group S (n = 49) | Group P (n = 53) | Difference (95% CI) | P value |
---|---|---|---|---|

MBP (mmHg)^{*} |
72.3 ± 14.3 | 73.1 ± 14.9 | −0.8 (−6.5, 4.9) | 0.781 |

Heart rate^{†} |
89.0 (75.0, 103.0) | 82.0 (72.0, 93.0) | 7.0 (0, 14.0) | 0.062 |

Values are presented as mean ± SD or median (Q1, Q3). MBP: mean blood pressure.

^{*}Independent two sample t-test,

^{†}Mann-Whitney U test. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point.

Example of Dependent Two Samples Comparison

Underlying factors | MBP |
Mean difference (95% CI) | P value | |
---|---|---|---|---|

Pre-treatment | Post-treatment | |||

Hypertension (n = 20)^{*} |
74.0 ± 13.9 | 70.9 ± 13.6 | 3.1 (0.4, 5.8) | 0.026^{†} |

BMI > 30 kg/m^{2} (n = 25)^{‡} |
75.4 (66.8, 81.5) | 73.9 (65.0, 84.5) | 1.5 (-1.0, 4.0) | 0.228 |

Values are presented as mean ± SD or median (Q1, Q3). BMI: body mass index, MBP: mean blood pressure.

^{*}Paired t-test,

^{†}Two-sided P value < 0.05,

^{‡}Wilcoxon’s signed rank test. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point.

Example of Three Independent Samples Comparison

Variables | Control group (n = 30) | ITM group (n = 30) | QLB group (n = 30) | P value |
---|---|---|---|---|

Morphine requirement (mg)^{*} |
61.0 ± 12.9 | 42.8 ± 10.4 | 18.2 ± 9.6 | <0.001^{†} |

Time to first morphine dose (h)^{‡} |
2 (0.5, 4) | 8 (3, 24) | 17 (6, 36) | 0.002^{†} |

Values are presented as mean ± SD or median (Q1, Q3). ITM: intrathecal morphine, QLB: quadratus lumborum block. P values indicate the statistical inference result of overall comparisons.

^{*}One-way analysis of variance with Tukey’s method,

^{†}Two-sided P value < 0.05,

^{‡}Kruskal-Wallis H test with Dunn’s procedure. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point. Excerpt from Salama ER [

Example of Categorical Data Comparison

Variables | Group N (n = 49) | Group C (n = 53) | P value |
---|---|---|---|

Successful tracheal intubation^{*} |
44 (89.8) | 32 (60.4) | 0.001^{†} |

Sore throat at 1 h^{‡} |
11 (22.4) | 20 (37.8) | 0.144 |

Vocal cord paralysis^{‡} |
1 (2.0) | 2 (3.8) | >0.999 |

Values are presented as frequency (%).

^{*}Chi-squared test,

^{†}Two-sided P value < 0.05,

^{‡}Fisher’s exact test. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point.

Risk Factors of Emergence Agitation in the PACU (n = 158) [

Variables | Odds ratio (95% CI) | P value^{*} |
---|---|---|

Marital status | ||

Divorced | Reference | |

Single | 0.16 (0.04, 0.64) | 0.009^{†} |

Married | 0.16 (0.04, 0.62) | 0.008^{†} |

Pre-existing ND | 6.78 (1.36, 33.80) | 0.020^{†} |

Gynecological surgery | 0.29 (0.12, 0.71) | 0.007^{†} |

Thoracic surgery | 0.23 (0.07, 0.80) | 0.021^{†} |

IO bleeding | 1.00 (1.00, 1.00) | 0.047^{†} |

IO morphine administration | 1.15 (1.03, 1.28) | 0.015^{†} |

Analgesic drugs in PACU | 2.99 (1.56, 5.73) | 0.001^{†} |

The odds ratio of Marital status is estimated with non-weighted dummified variables. IO: intraoperative, ND: neurologic disorders, PACU: post-anesthesia care unit,

^{*}Backward binary stepwise logistic regression,

^{†}Two-sided P value < 0.05. These values, including P values, are presented according to the Instructions for Authors of Korean Journal of Anesthesiology for notation below the decimal point.