Quantitative and qualitative research explore various social phenomena using different methods. However, there has been a tendency to treat quantitative studies using complicated statistical techniques as more scientific and superior, whereas relatively few qualitative studies have been conducted in the medical and healthcare fields. This review aimed to provide a proper understanding of qualitative research. This review examined the characteristics of quantitative and qualitative research to help researchers select the appropriate qualitative research methodology. Qualitative research is applicable in following cases: (1) when an exploratory approach is required on a topic that is not well known, (2) when something cannot be explained fully with quantitative research, (3) when it is necessary to newly present a specific view on a research topic that is difficult to explain with existing views, (4) when it is inappropriate to present the rationale or theoretical proposition for designing hypotheses, as in quantitative research, and (5) when conducting research that requires detailed descriptive writing with literary expressions. Qualitative research is conducted in the following order: (1) selection of a research topic and question, (2) selection of a theoretical framework and methods, (3) literature analysis, (4) selection of the research participants and data collection methods, (5) data analysis and description of findings, and (6) research validation. This review can contribute to the more active use of qualitative research in healthcare, and the findings are expected to instill a proper understanding of qualitative research in researchers who review qualitative research reports and papers.

Background: A methodology for comprehensively and reasonably measuring the burden of disease due to adverse events has yet to be clearly established. In this study, a new and systematic method for measuring the burden of disease due to adverse events was tested by utilizing the results of a medical record review, which is commonly used as a gold standard. Methods: Using the characteristics of preventable adverse events identified in the 2019 Patient Safety Incidents Inquiry (PSII), conducted to monitor the level of patient safety in Korea accurately, the resulting disability-adjusted life years (DALYs) and economic costs were estimated. DALYs were calculated as the sum of the years lived with a disability for patients who suffered permanent disability, or more, due to preventable adverse events, and the years of life lost due to premature mortality was calculated for patients who died due to preventable adverse events. The economic cost was calculated using the main diagnostic codes of patients who suffered preventable adverse events, identified as prolonged hospitalization in PSII, and the average medical cost by disease category and age group. Results: Estimates of DALYs due to preventable adverse events were 1,114.4 DALYs per 100,000 population for the minimum standard and 1,658.5 DALYs per 100,000 population for the maximum standard. Compared to the 2015 Korea Burden of Disease results, the ranking of DALYs due to preventable adverse events was sixth for the minimum standard and third for the maximum standard. The annual medical cost of adverse events in 2016 was estimated to be approximately Korean Republic Won (KRW) 870 billion (700 million US dollars). Medical expenses due to preventable adverse events were calculated to be approximately KRW 150 billion (120 million US dollars) as a minimum standard and approximately KRW 300 billion (240 million US dollars) as a maximum standard. Conclusion If this more standard method of systematically calculating the disease burden due to adverse events is used, it will be possible to compare the size of the patient safety problem with that of other diseases. The results of this study indicate that we still need to pay more attention to the issue of patient safety.

It has been reported that some exercise could enhance the anti-viral antibody titers after vaccination including influenza and coronavirus disease 2019 vaccines. We developed SAT-008, a novel digital device, consists of physical activities and activities related to the autonomic nervous system. We assessed the feasibility of SAT-008 to boost host immunity after an influenza vaccination by a randomized, open-label, and controlled study on adults administered influenza vaccines in the previous year. Among 32 participants, the SAT-008 showed a significant increase in the anti-influenza antibody titers assessed by hemagglutination-inhibition test against antigen subtype B Yamagata lineage after 4 wk of vaccination and subtype B Victoria lineage after 12 wk (p<0.05). There was no difference in the antibody titers against subtype “A.” The SAT-008 also showed significant increase in the plasma cytokine levels of IL-10, IL-1β, and IL-6 at weeks 4 and 12 after the vaccination (p<0.05). A new approach using the digital device may boost host immunity against virus via vaccine adjuvant-like effects.

Abstinence from prolonged psychostimulant use prompts stimulant withdrawal syndrome. Molecular adaptations within the dorsal striatum have been considered the main hallmark of stimulant abstinence. Here we explored striatal miRNA-target interaction and its impact on circulating miRNA marker as well as behavioral dysfunctions in methamphetamine (MA) abstinence. We conducted miRNA sequencing and profiling in the nonhuman primate model of MA abstinence, followed by miRNA qPCR, LC-MS/MS proteomics, immunoassays, and behavior tests in mice. In nonhuman primates, MA abstinence triggered a lasting upregulation of miR-137 in the dorsal striatum but a simultaneous downregulation of circulating miR-137. In mice, aberrant increase in striatal miR-137-dependent inhibition of SYNCRIP essentially mediated the MA abstinence-induced reduction of circulating miR-137. Pathway modeling through experimental deduction illustrated that the MA abstinence-mediated downregulation of circulating miR-137 was caused by reduction of SYNCRIP-dependent miRNA sorting into the exosomes in the dorsal striatum. Furthermore, diminished SYNCRIP in the dorsal striatum was necessary for MA abstinence-induced behavioral bias towards egocentric spatial learning. Taken together, our data revealed circulating miR-137 as a potential blood-based marker that could reflect MA abstinence-dependent changes in striatal miR-137/SYNCRIP axis, and striatal SYNCRIP as a potential therapeutic target for striatum-associated cognitive dysfunction by MA withdrawal syndrome.

OBJECTIVE: To determine the most valuable cardiac magnetic resonance feature tracking (CMR-FT) parameters for evaluating aortic stenosis (AS) and determine whether they can predict the prognosis in asymptomatic AS patients with preserved ejection fraction (pEF).MATERIALS AND METHODS: A prospective cohort of 123 moderate to severe AS patients (60 males, 68.6 ± 9.2 years) and 32 control subjects (14 males, 67.9 ± 4.4 years) underwent echocardiography and 3T CMR imaging from 2011–2015. CMR cine images were analyzed using CMR-FT to assess the left ventricular radial, circumferential, and longitudinal peak strain (PS) in 2- and 3-dimensions. The primary endpoints were clinical cardiac events (CCEs), including cardiac death, heart failure, and AS-associated symptom development. For statistical analysis, logistic regression and log-rank tests were used.RESULTS: Global PSs differed between AS patients and controls and between severe and moderate AS patients (p < 0.05). Two-dimensional (2D) global radial and longitudinal PSs changed gradually with the severity of AS groups (p < 0.001). Twenty-two of 67 asymptomatic AS patients with pEF experienced CCEs during the follow-up (median: 31.1 months). 2D global longitudinal PS (GLPS) was the single risk factor for CCE (p = 0.017). The relative risk for CCE was 3.9 (p = 0.016, 95% confidence interval: 1.2–11.9) based on 2D GLPS with a cutoff of −17.9% according to receiver operating characteristic curve analysis. Survival analysis demonstrated that asymptomatic AS patients with pEF having impaired 2D GLPS experienced worse event-free survival than the others (p = 0.041).CONCLUSION: 2D global longitudinal and radial PSs may reflect cardiac dysfunction according to the degree of AS. 2D GLPS might be a prognostic predictor of CCEs in asymptomatic AS patients with pEF.
Aortic Valve Stenosis ; Cohort Studies ; Death ; Disease-Free Survival ; Echocardiography ; Follow-Up Studies ; Heart Failure ; Humans ; Logistic Models ; Male ; Prognosis ; Prospective Studies ; Risk Factors ; ROC Curve

Background: Medical professionals who experience patient safety incidents (PSIs) are vulnerable to emotional pain and other difficulties; such individuals are referred to as “second victims.” This study quantitatively examines the characteristics of physicians’ experiences of PSIs, along with the consequent difficulties and levels of post-traumatic stress disorder (PTSD), and post-traumatic embitterment disorder (PTED) regarding the events. Methods: An anonymous, self-report online survey was administered to physicians. This collected information regarding PSI characteristics (e.g., type, severity of harm) and impact (e.g., sleep disorder, consideration of career change), as well as participants' socio-demographic characteristics. Meanwhile, to quantitatively assess PSI impacts, PTSD and PTED scales were also administered. PSI characteristics and impacts were analyzed using frequency analysis, and the differing effects of indirect and direct PSI experience regarding consequent difficulties were analyzed using chi-square tests. Factors associated with PTSD and PTED scores were identified using linear regression. Results: Of 895 physicians, 24.6% and 24.0% experienced PSI-induced sleep disorder and eating disorder, respectively. Moreover, 38.9% reported being overly cautious in subsequent similar situations, and 12.6% had considered changing jobs or career. Sleep disorder was significantly more common among participants who directly experienced a PSI (32.8%) than among those with indirect experience (15.3%; P < 0.001). Linear regression showed that indirectly involved physicians had a lower mean PTSD score (by 8.44; 95% confidence interval, −12.28 to −4.60) than directly involved physicians. Conclusion This study found that many physicians experience PSI-induced physical symptoms and behavioral responses, and that the severity of these symptoms varies depending on the type of incident and degree of harm involved. Our findings can provoke more active discussion regarding programs for supporting second victims, and can also encourage the establishing of a system for addressing PSIs that have already occurred, such as through disclosure of PSIs.

OBJECTIVE: To investigate the diagnostic validity of coronary computed tomography angiography (cCTA) in vasospastic angina (VA) and factors associated with discrepant results between invasive coronary angiography with the ergonovine provocation test (iCAG-EPT) and cCTA. MATERIALS AND METHODS: Of the 1397 patients diagnosed with VA from 2006 to 2016, 33 patients (75 lesions) with available cCTA data from within 6 months before iCAG-EPT were included. The severity of spasm (% diameter stenosis [%DS]) on iCAG-EPT and cCTA was assessed, and the difference in %DS (Δ%DS) was calculated. Δ%DS was compared after classifying the lesions according to pre-cCTA-administered sublingual nitroglycerin (SL-NG) or beta-blockers. The lesions were further categorized with %DS ≥ 50% on iCAG-EPT or cCTA defined as a significant spasm, and the diagnostic performance of cCTA on identifying significant spasm relative to iCAG-EPT was assessed. RESULTS: Compared to lesions without SL-NG treatment, those with SL-NG treatment showed a higher Δ%DS (39.2% vs. 22.1%, p = 0.002). However, there was no difference in Δ%DS with or without beta-blocker treatment (35.1% vs. 32.6%, p = 0.643). The significant difference in Δ%DS associated with SL-NG was more prominent in patients who were aged < 60 years, were male, had body mass index < 25 kg/m2, and had no history of hypertension, diabetes, or dyslipidemia. Based on iCAG-EPT as the reference, the per-lesion-based sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of cCTA for VA diagnosis were 7.5%, 94.0%, 60.0%, 47.1%, and 48.0%, respectively. CONCLUSION: For patients with clinically suspected VA, confirmation with iCAG-EPT needs to be considered without completely excluding the diagnosis of VA simply based on cCTA results, although further prospective studies are required for confirmation.
Angina Pectoris, Variant ; Angiography ; Body Mass Index ; Constriction, Pathologic ; Coronary Angiography ; Diagnosis ; Dyslipidemias ; Ergonovine ; Humans ; Hypertension ; Male ; Nitroglycerin ; Prospective Studies ; Sensitivity and Specificity ; Spasm

BACKGROUND: Metformin, sulfonylurea, and dietary fiber are known to affect gut microbiota in patients with type 2 diabetes mellitus (T2DM). This open and single-arm pilot trial investigated the effects of the additional use of fiber on glycemic parameters, insulin, incretins, and microbiota in patients with T2DM who had been treated with metformin and sulfonylurea. METHODS: Participants took fiber for 4 weeks and stopped for the next 4 weeks. Glycemic parameters, insulin, incretins during mixed-meal tolerance test (MMTT), lipopolysaccharide (LPS) level, and fecal microbiota were analyzed at weeks 0, 4, and 8. The first tertile of difference in glucose area under the curve during MMTT between weeks 0 and 4 was defined as ‘responders’ and the third as ‘nonresponders,’ respectively. RESULTS: In all 10 participants, the peak incretin levels during MMTT were higher and LPS were lower at week 4 as compared with at baseline. While the insulin sensitivity of the ‘responders’ increased at week 4, that of the ‘nonresponders’ showed opposite results. However, the results were not statistically significant. In all participants, metabolically unfavorable microbiota decreased at week 4 and were restored at week 8. At baseline, metabolically hostile bacteria were more abundant in the ‘nonresponders.’ In ‘responders,’ Roseburia intestinalis increased at week 4. CONCLUSION: While dietary fiber did not induce additional changes in glycemic parameters, it showed a trend of improvement in insulin sensitivity in ‘responders.’ Even if patients are already receiving diabetes treatment, the additional administration of fiber can lead to additional benefits in the treatment of diabetes.
Bacteria ; Diabetes Mellitus, Type 2 ; Dietary Fiber ; Gastrointestinal Microbiome ; Glucose ; Humans ; Incretins ; Insulin ; Insulin Resistance ; Metformin ; Microbiota ; Sulfonylurea Compounds

Erdheim-Chester disease (ECD) is a rare non-Langerhan's cell histiocytosis disorder characterized by replacement of normal tissue by lipid-laden histiocytes affecting various organs. A few pediatric cases have been reported worldwide. Here we present a child with leukemia who was diagnosed as ECD. A 2-year and 11-month old boy diagnosed with high risk acute lymphoblastic leukemia (ALL) at the age of 17 months, received allogeneic hematopoietic stem cell transplantation (HSCT) at the age of 2 years old. Six months after the transplantation, the patient was admitted to the hospital with palpable left calf nodules. Bone marrow study suggested ECD without leukemia with complete chimerism status. Excisional biopsy of the left calf nodule showed ‘aggregation of non-Langerhan's cell type epitheloid histiocytes’; clinically suggestive of ECD. The patient was started on vinblastine and corticosteroid treatment.
Biopsy ; Bone Marrow ; Child* ; Chimerism ; Erdheim-Chester Disease* ; Hematopoietic Stem Cell Transplantation ; Histiocytes ; Histiocytosis ; Humans ; Leukemia* ; Male ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; Vinblastine

The aim of this study is to examine the correlation between tooth wear and age by quantitatively measuring maxillary first molar wear in children. A total of 150 maxillary dental models were analyzed in 30 subjects (male, 11; female, 19) with an age range of 6–14 years. Maxillary first molar wear were assessed based on area, volume and the shortest distance from the buccal occlusal plane to the central pit point (BCPH). The area and volume of the tooth cusps were measured at four different offset-plane heights (0.2, 0.4, 0.6, and 0.8 mm). Relationship between age and the amount of wear or BCPH were statistically analyzed. Correlation and regression analyses were also performed, and age estimation was obtained with linear regression analysis. Repeated measures analysis of variance (ANOVA) revealed significant differences between age and the amount of wear based on area, volume, and offset-plane height. Except age of 8 and 10, 12 and 14's 0.2-mm offset-plane-measured volume, all area and volume measurement of all ages and offset-plane height showed a significant amount of increase. Wear speeds were calculated using the BCPH. Among age and measurement variables, the correlation coefficient was strongest when the volume was measured from the 0.4-mm offset-plane. As age increases, the amount of wear, as quantified by area and volume measurements, also increases. According to this study, a regression equation that can be used for age estimation is follows: Age (y)=0.16×0.4V+0.85 (R²=0.490) using volume.
Child* ; Dental Models ; Dental Occlusion ; Female ; Humans ; Linear Models ; Longitudinal Studies* ; Molar* ; Tooth ; Tooth Wear