This paper aims to review the statistical methods that are widely used in medical and clinical research. Statistical analysis is crucial for ensuring the reliability of research results; therefore, methods should be carefully tailored to research interests and objectives, depending on the type and characteristics of the data. This paper explains various types of data, discusses how to confirm whether the data satisfy these methods’ specific assumptions, and elucidates the meaning and interpretation of univariable and multivariable analysis. Finally, it presents corresponding examples to help other researchers understand how these methods are applied in real-world studies and select appropriate methods that ensure both research quality and reliability.

Background: Acute eosinophilic pneumonia (AEP) is a rare and severe lung condition characterized by a rapid accumulation of eosinophils in the alveoli, leading to respiratory distress. This study analyzed the clinical characteristics of affected patients, aiming to shed light on the relationship between cigarette smoking and AEP. Methods: This retrospective study analyzed 17 cases of AEP, focusing on patients' smoking habits, clinical symptoms, diagnostic findings, and treatment outcomes. Data were collected from medical records, imaging studies, and bronchoalveolar lavage (BAL) findings. Results: The study cohort consisted primarily of male military personnel (94.1%), with a mean age of 20.8 years. Symptoms generally appeared approximately 2.82 days prior to hospitalization, with a mean body temperature at admission of 37.6 °C. The mean initial peripheral blood white blood cell count was 15.3×103/μL, with eosinophil percentages starting at 0.2%, peaking at a mean of 16.1%, and reaching as high as 32.4%. BAL fluid analysis showed a mean eosinophil level of 46.6%±15.1% (range, 17%–67%). In most cases, radiological examinations revealed bilateral ground-glass opacities, interlobular septal thickening, various degrees of airspace consolidation, and bilateral pleural effusions. Steroid treatment was administered to 70.5% of patients, lasting a mean of 8.3 days and resulting in significant improvements. Conclusions These cases reinforce the strong link between cigarette smoking and AEP. Additionally, these cases demonstrate the importance of obtaining a detailed smoking history and thorough diagnostic assessments, including BAL, in order to facilitate a more rapid diagnosis and early initiation of corticosteroid treatment.

An enlarged retrocrural mass was incidentally discovered in a 79-year-old male patient. Preoperative chest computed tomography and thoracolumbar junction spine magnetic resonance imaging indicated the possibility of a paraganglioma, Castleman disease, or neurogenic tumor. Due to the large size of the tumor, malignancy could not be ruled out, and we decided to perform surgery for diagnostic and therapeutic purposes. Video-assisted thoracoscopic surgery was safely performed, and histopathological examination revealed a capillary hemangioma.

This report presents radiologic changes after clinical improvement in a patient with acute interstitial nephritis (AIN). A 45-year-old female patient was referred for decreased renal function. Eight months prior, she had undergone hysterectomy and received chemotherapy. At the start of chemotherapy, her baseline creatinine level was 0.55 mg/dL, which rose to 1.46 mg/dL. Multiple imaging modalities performed when decreased renal function was observed revealed bilateral renal enlargement with increased cortical attenuation on computed tomography (CT), cortical hyperechogenicity on ultrasonography, and diffusion restriction in the renal cortices on magnetic resonance imaging. A renal biopsy was performed, and AIN was diagnosed. Follow-up laboratory tests showed that kidney function had improved to normal levels, and CT at that time showed a reduction in the size of both kidneys. Radiologic changes can serve as clues for the diagnosis of AIN. This is the first report to confirm radiological changes after the clinical improvement of AIN, thereby providing novel information about the course of AIN.

Background: This study analyzed the impact of the coronavirus disease 2019 (COVID-19) pandemic on acute appendicitis (AA) treatment in Korea, a country that did not implement lockdown measures. Methods: A retrospective analysis was conducted during two discretionary time periods: a pre COVID-19 period, and a COVID-19 period. This study included adult and pediatric patients diagnosed with AA who underwent surgical treatment. Clinical and laboratory parameters, changes in surgery timing, disease severity, and postoperative outcomes were compared between the pre and post pandemic periods. Results: The study included a total of 221 patients, with 139 receiving appendectomy in the COVID-19 cohort and 82 in the control cohort. In patients without fever, operative time was significantly longer during the COVID-19 period (p<0.01). Among patients presenting with fever, the rate of complicated AA was higher during the COVID-19 period than in the control period (p<0.01). During the COVID-19 period, the diagnostic and preoperative delay times, as well as postoperative hospital stays, were longer (p<0.05), and the incidence of postoperative complications and other hospital diagnoses was higher (p<0.01) during the COVID-19 period than in the control period. Multivariate analysis showed that age (p=0.03) and the presence of fever (p<0.01) were independent risk factors for complicated AA. Conclusions Older patients and those with fever were at greater risk of severe AA. During outbreaks of infectious diseases like COVID-19, careful consideration is needed regarding surgical interventions in older patients with fever. Understanding vulnerabilities is crucial for disease management in the future.

Background: The significance of risk modification in patients with acute coronary syndrome (ACS) is well recognized; however, the optimal timing for adminstering PCSK9 inhibitors remains unclear. Additionally, the lipid-lowering efficacy of evolocumab and alirocumab has not been fully established. This study evaluated the lipid-lowering effects of these two PCSK9 inhibitors. Methods: Patients diagnosed with ACS, including unstable angina, ST-segment elevation myocardial infarction, and non-ST-segment elevation myocardial infarction, who were treated with a PCSK9 inhibitor (evolocumab or alirocumab) during hospitalization for ACS between 2021 and 2023 were retrospectively analyzed. Baseline low-density lipoprotein cholesterol (LDL-C) levels were assessed, and changes in LDL-C levels during the acute and subacute phases after PCSK9 inhibitor administration were compared between the evolocumab and alirocumab groups. Results: Among 80 patients diagnosed with ACS, 36 received evolocumab, while 44 were treated with alirocumab. The mean baseline LDL-C level was 123 mg/dL in the evolocumab group and 128 mg/dL in the alirocumab group (p=0.456). In the subacute phase, the mean follow-up LDL-C levels were 47.05 mg/dL in the evolocumab group and 49.5 mg/dL in the alirocumab group (p=0.585). The mean percentage reduction in LDL-C levels during the subacute phase was 60.41% in the evolocumab group and 58.51% in the alirocumab group (p=0.431). These differences were not statistically significant. Conclusions No significant differences were observed between evolocumab and alirocumab. LDL-C levels exhibited a similar trend, characterized by a rapid decline in the acute phase, followed by a slight rebound in the subacute phase.

Background: Aerobic exercise training and drug therapy are well-established interventions for the prevention and treatment of hypertension and dyslipidemia. We investigated the synergistic effects of aerobic exercise and olmesartan/rosuvastatin on epicardial fat thickness (EFT) and endothelial function in patients with hypertension and dyslipidemia. Methods: A sample of 75 participants with hypertension and dyslipidemia was evaluated for multifactorial cardiovascular risk at baseline and at 6 months of intervention according to anthropometric and hemodynamic components, lipid profile, glycemia, brachial artery flow-mediated dilation (FMD), and EFT. After 3 months of drug therapy only, participants were allocated to one of three conditions: treadmill (n=22), exergame (n=29), or control (n=24). Results: After 12 weeks of drug therapy only, systolic and diastolic blood pressure (3% and 2%, both p<0.05), total cholesterol (6.3%, p<0.01), low-density lipoprotein cholesterol (4.9%, p<0.05), triglycerides (11.1%, p<0.05), fasting blood glucose (10.2%, p<0.01), and glycosylated hemoglobin (3%, p<0.01) were significantly reduced. After 12 weeks of combined aerobic exercise and drug therapy, both the treadmill and exergame groups showed a significant improvement in FMD (both p<0.001) and reduction in EFT (both p<0.001). Systolic and diastolic blood pressures decreased in the treadmill group only (1.9% and 2.7%, respectively, p<0.05). Conclusions Incorporating aerobic exercise into drug therapy regimens can yield synergistic effects, particularly in improving endothelial function and reducing EFT, providing a comprehensive approach to managing cardiovascular risk in patients with hypertension and dyslipidemia.

Olfactory receptors (ORs), which are primarily responsible for olfactory sensation in the nasal epithelium, constitute the largest family of genes in the human genome. The majority of ORs are orphan receptors with unknown ligands; however, recent studies have revealed their expression in non-olfactory tissues, implying that ORs may be involved in various physiological processes beyond olfaction. This review highlights recent findings on the roles of ORs in cancers, including prostate, breast, and lung cancer, as well as their involvement in other diseases, such as atherosclerosis, Alzheimer's disease, and viral infections. Additionally, we explore emerging knowledge about the role of ORs in metabolic regulation, focusing on their effect on triglyceride metabolism, glucagon-like peptide-1 secretion, and lipid accumulation. Advancements in technology, such as structural analysis, have accelerated research on OR ligands and their functions, potentially positioning ORs as novel therapeutic targets for various diseases. This review highlights the need for further research into the non-olfactory roles of ORs and their potential as targets for future therapeutic interventions.

Abdominal tuberculous lymphadenopathy is a rare condition that can cause obstructive jaundice. The feature of tuberculosis lymphadenopathy may resemble those of cancer, metastasis, or lymphoma on computed tomography (CT) or magnetic resonance imaging; therefore, physicians must perform appropriate examinations, make correct diagnoses, and conduct suitable treatment. Herein, we report a case of obstructive jaundice caused by tuberculous lymphadenopathy. The patient was 27 years old, with an initial serum total bilirubin level of 6.76 mg/dL and a direct bilirubin level of 5.64 mg/dL. Aspartate transaminase and alanine transaminase levels were 466 and 801 IU/L, respectively. Abdominal CT revealed a mass-like effect and extraluminal compression accompanying bile duct obstruction. An abrupt bile duct stricture was observed on endoscopic retrograde cholangiopancreatography; thus, a biopsy was performed. However, the specimen which was taken by endoscopic retrograde cholangiopancreatography was confirmed to constitute superficially biopsied bile duct mucosa and benign-looking epithelial cell stripes. Positron emission tomography-CT showed a hypermetabolic lesion in the hepato-duodenal ligament with small lymph nodes in the aortocaval and retrocaval spaces. Additionally, it showed hypermetabolism of the neck lymph node at level II. The neck lymph node was biopsied. Granulomatous inflammation was observed and nested tuberculosis polymerase chain reaction was positive. The patient was treated with anti-tuberculosis medications and underwent endoscopic retrograde biliary drainage without surgery.