In medical research, when independent variables are categorical (i.e., dividing groups), statistical analysis is often required. This situation mostly occurs on randomized controlled trials and observational studies that have multiple patient groups. Also, when analyzing continuous independent variables in a single patient group, breakpoints can be...

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, l...

The paper discussed the overall aspects of systematic review and meta-analysis and explored the main mathematical context of meta-analysis. This included various methods of analyzing the effect size and obtaining the average effect size depending on the variable type. In doing so, methods of obtaining effect sizes in continuous outcome variables, c...

Objective: To estimate global, regional, and national incidences and mortality of the coronavirus disease 2019 (COVID-19) in 237 countries and territories since the outbreak of the COVID-19 pandemic to 31 January, 2022. Methods: Comprehensive estimates were produced through global, regional, and national studies of cumulative severe acute respirato...

Objective: On September 2019, the United States Food and Drug Administration announced that some ranitidine products were contaminated with unacceptable levels of N-nitrosodimethylamine (NDMA). We aimed to determine whether the use of ranitidine that was potentially contaminated with NDMA, rather than another histamine H2-receptor antagonist (H2 bl...

Objective: To reduce the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, severe coronavirus disease 2019 (COVID-19) illness, and COVID-19 related death, all persons in South Korea should stay up to data with recommended COVID-19 vaccinations. This study investigated the rates and effectiveness of the COVID-19 vaccina...

Since the development of research methodology, there has always been keen interest in developing the accuracy of the research by comparing covariates. Propensity score is useful when the research covers many variables which are not intended to be included as independent variables, thus allowing the removal of certain covariates from the model. This...

The Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2), the cause of the pandemic of coronavirus disease 2019 (COVID-19), was first discovered in December 2019 in Wuhan, China, and was consequently transmitted across the world. Further, within a year of its initial discovery, vaccines against SARS-CoV-2 were developed using diverse t...

The Global Burden of Disease (GBD) is a compass that navigates researchers and clinicians in discovering the latest knowledge and the current status of health for populations and countries worldwide. The GBD helps to present various methods in evaluating health-related quality of life and assess the health burden, economic burden, years of life los...

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), induces coughing, vomiting, or fever. The occurrence, duration, and severity of these symptoms vary from person to person, which makes symptoms of the COVID-19 infection ranging from those of a mild cold to death in severe cases. The cau...

In medical research, analyzing the time it takes for a phenomenon to occur is sometimes crucial. However, various factors can contribute to the length of survival or observation periods, and removing specific data can lead to bias results. In this paper, we discuss the Kaplan-Meier analysis and Cox proportional hazards regression model, which are t...

Coronavirus disease 2019 (COVID-19) is caused by a coronavirus, also called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has caused urgent global health problems worldwide. The rapid spread of this pathogen, the development of its variants, and the escalating number of patients and their deaths prompted scientists to take up the...

Objective: We aimed to better understand the impact of the COVID-19 pandemic through analysis of disruptions in a global, regional, and national status of COVID-19 vaccination coverage compared by a global scale, World Health Organization regions, World Bank income groups, and each country. Methods: Global datasets of 237 countries and territories ...

The monkeypox is an unusual viral disease which, until recently, has rarely been detected outside of Africa. Approximately over 70,000 laboratory-verified or suspected cases of human monkeypox have been discovered in at least 107 countries in a matter of months. A total of 71,237 laboratory confirmed cases, 1,097 probable cases, and 26 related deat...

The monkeypox (MPX) is an unusual viral disease which, until recently, has rarely been detected outside of Africa. A total of 71,237 confirmed cases of MPX, as of October 6th, 2022, had been discovered in 109 countries in the matter of months. The risk factors of MPX are men who have sex with the same gender (prevalence 90.0%, 95% CI, 89.5 to 90.4)...

The study investigated age, ethnic, and sex disparities in body mass index (BMI) and waist circumference (WC) in South Korea and the United States. We conducted a bi-national large-scale study and analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES) and the National Health and Nutrition Examination Survey in the U...

Since its emergence on November 9, 2021, the Omicron variant has spread quickly across the globe as a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and became the variant of concern at an astonishingly rapid rate. This new variant was found to be a massively mutated virus from the original virus formation. The World Health Organi...

Objective: Measuring coronavirus disease 2019 (COVID-19) vaccination is crucial in improving global public health system during the pandemic. However, there is limited supporting data needed in order to identify the global, regional, and national status of the COVID-19 vaccination coverage. Given to such limitations, this study aimed at investigati...

In 2022, while the world has yet to be free from the aftermath of the long-term pandemic caused by COVID-19, the unusual epidemic of endemic diseases in Africa called mpox (monkeypox) was designated as the Public Health Emergency of International Concert by the World Health Organization, drawing world’s attention to whether new pandemic will occu...

Objective: The beneficial relationship of influenza vaccination rate on the COVID-19 pandemic is inconclusive and inconsistent. Thus, we aimed to investigate long-term trend changes in influenza vaccination rate among general population of South Korea before COVID-19 pandemic and during early/mid-pandemic period. Methods: We analyzed nationwide rep...