Background: Diabetes mellitus (DM) is prevalent among adults, many of whom require surgical interventions. Although metformin may improve postoperative outcomes by reducing inflammation, its effects on postoperative mortality and complications remain unclear. This study aimed to determine whether preoperative metformin use is associated with improved postoperative outcomes after noncardiac surgery. Methods: This retrospective study included adult patients with type 2 DM who underwent noncardiac surgery between 2011 and 2019. Patients were assigned to one of two groups based on the use of preoperative metformin at admission. To evaluate dose-related effects, patients in the metformin group were further divided into low- and high-dose groups based on daily dose (< or ≥ 1,000 mg). The primary outcome was one-year mortality after surgery, and the secondary outcomes were 30-day mortality, five-year mortality, and postoperative complications in major organs within 7 d. Results: Among 22 944 patients, 12 536 (54.6%) were exposed to preoperative metformin. After inverse probability of treatment weighting, preoperative metformin use was associated with a reduced one-year mortality (hazard ratio: 0.76, 95% CI [0.68–0.85]). For secondary outcomes, metformin use decreased postoperative complications in respiratory (odds ratio [OR]: 0.76, 95% CI [0.61−0.93]) and renal systems (OR: 0.66, 95% CI [0.58−0.74]). In a dose-related analysis, both doses were associated with a lower risk of postoperative mortality, with reductions in respiratory complications primarily due to high-dose metformin (OR: 0.69, 95% CI [0.54−0.89]). Conclusion Preoperative use of metformin is associated with reduced postoperative mortality and complications in diabetic patients undergoing noncardiac surgery.

Objective: This study aimed to evaluate the survival of removable partial dentures (RPDs) abutment teeth that had undergone root canal treatment (RCT) and to identify the factors influencing survival. Materials and Methods: Records from the Veterans Health Service Medical Center were reviewed to identify patients who received RPDs between 2014 and 2015 and had root canal-treated abutment teeth. Preoperative variables included patient demographics, tooth location, and periapical radiolucency, while postoperative variables included RPD classification, opposing dentition, crown-root ratio (CRR), root canal filling quality, post placement, and restoration type. Statistical analysis was performed using the Kaplan-Meier method and Cox proportional hazards models. Results: A total of 776 root canal-treated abutment teeth from 341 patients using RPDs (mean age, 72.03 years) were included. In the multivariate analysis, tooth-related conditions such as arch type and tooth location, presence of a periapical lesion, and presence of a core were significantly associated with poor prognosis. Kaplan-Meier survival analysis revealed that the 3-, 5-, 7-, and 10-year survival rates for all teeth were 93.5%, 84.4%, 77.1%, and 60.0%, respectively. Conclusion Arch type and tooth position, preoperative periapical radiolucency, and type of restoration are significantly associated with prognosis in patients with RPDs in whom the abutment teeth have previously undergone RCT.

Purpose: Mutations in the PIK3CA gene occur frequently in breast cancer patients. Activating PIK3CA mutations confer resistance to human epidermal growth factor receptor 2 (HER2)-targeted treatments. In this study, we investigated whether PIK3CA mutations were correlated with treatment response or duration in patients with HER2-positive (HER2+) breast cancer. Materials and Methods: We retrospectively reviewed the clinical information of patients with HER2+ breast cancer who received HER2-targeted therapy for early-stage or metastatic cancers. The pathologic complete response (pCR), progression-free survival (PFS), and overall survival were compared between patients with wild-type PIK3CA (PIK3CAw) and those with mutated PIK3CA (PIK3CAm). Next-generation sequencing was combined with examination of PFS associated with anti-HER2 monoclonal antibody (mAb) treatment. Results: Data from 90 patients with HER2+ breast cancer were analyzed. Overall, 34 (37.8%) patients had pathogenic PIK3CA mutations. The pCR rate of the PIK3CAm group was lower than that of the PIK3CAw group among patients who received neoadjuvant chemotherapy for early-stage cancer. In the metastatic setting, the PIK3CAm group showed a significantly shorter mean PFS (mPFS) with first-line anti-HER2 mAb. The mPFS of second-line T-DM1 was lower in the PIK3CAm group than that in the PIK3CAw group. Sequencing revealed differences in the mutational landscape between PIK3CAm and PIK3CAw tumors. Conclusion Patients with HER2+ breast cancer with activating PIK3CA mutations had lower pCR rates and shorter PFS with palliative HER2-targeted therapy than those with wild-type PIK3CA. Precise targeted-therapy is needed to improve survival of patients with HER2+/PIK3CAm breast cancer.

Purpose: This study is to investigate the distribution of natural tooth shades in the Korean elderly population to quantify the correlation and changes of tooth color with age and gender. In addition, the possible effects of habits on tooth color were assessed. Materials and Methods: The tooth color of one of the maxillary central incisors of 200 Korean individuals aged 50 to 89 years, males and female, was measured using the portable intraoral spectrophotometer (VITA Easyshade V).CIELab and CIELCh color coordinates were recorded. We conducted the survey about the tobacco smoking, chronic disease, medication, eating habits, oral health behaviors and satisfaction with tooth color. Experimental data were statistically analyzed by using the t-test (P<0.05), two-way analysis of variance and Pearson’s correlation test.Result: The most frequent color in the Korean elderly population was 3M3 & A3.5 shade. L* and h* values decreased, whereas C*, a* and b* values increased progressively with age. There was a significant interaction between age and color coordinates for b* values (r=0.245, P<0.05). Males generally have significantly higher C*, a*, b* values and lower L*, h* value compared to females. Individuals who consumed alcohol had a higher L* value (P<0.05). Conclusion Within the limitation of this study, the central incisors were getting darker, more reddish, and yellowish with age. Information on the chromatic range of natural teeth by age and gender could help to select colors for esthetic dental restorations.

Background: The coronavirus disease 2019 (COVID-19) pandemic has caused the death of thousands of patients worldwide. Although age is known to be a risk factor for morbidity and mortality in COVID-19 patients, critical illness or death is occurring even in the younger age group as the epidemic spreads. In early 2022, omicron became the dominant variant of the COVID-19 virus in South Korea, and the epidemic proceeded on a large scale. Accordingly, this study aimed to determine whether young adults (aged ≤ 50 years) with critical COVID-19 infection during the omicron period had different characteristics from older patients and to determine the risk factors for mortality in this specific age group. Methods: We evaluated 213 critical adult patients (high flow nasal cannula or higher respiratory support) hospitalized for polymerase chain reaction-confirmed COVID-19 in nine hospitals in South Korea between February 1, 2022 and April 30, 2022. Demographic characteristics, including body mass index (BMI) and vaccination status; underlying diseases; clinical features and laboratory findings; clinical course; treatment received; and outcomes were collected from electronic medical records (EMRs) and analyzed according to age and mortality. Results: Overall, 71 critically ill patients aged ≤ 50 years were enrolled, and 142 critically ill patients aged over 50 years were selected through 1:2 matching based on the date of diagnosis. The most frequent underlying diseases among those aged ≤ 50 years were diabetes and hypertension, and all 14 patients who died had either a BMI ≥ 25 kg/m 2 or an underlying disease. The total case fatality rate among severe patients (S-CFR) was 31.0%, and the S-CFR differed according to age and was higher than that during the delta period. The S-CFR was 19.7% for those aged ≤ 50 years, 36.6% for those aged > 50 years, and 38.1% for those aged ≥ 65 years. In multivariate analysis, age (odds ratio [OR], 1.084; 95% confidence interval [CI], 1.043–1.127), initial low-density lipoprotein > 600 IU/L (OR, 4.782; 95% CI, 1.584–14.434), initial C-reactive protein > 8 mg/dL (OR, 2.940; 95% CI, 1.042–8.293), highest aspartate aminotransferase > 200 IU/L (OR, 12.931; 95% CI, 1.691–98.908), and mechanical ventilation implementation (OR, 3.671; 95% CI, 1.294–10.420) were significant independent predictors of mortality in critical COVID-19 patients during the omicron wave. A similar pattern was shown when analyzing the data by age group, but most had no statistical significance owing to the small number of deaths in the young critical group. Although the vaccination completion rate of all the patients (31.0%) was higher than that in the delta wave period (13.6%), it was still lower than that of the general population. Further, only 15 (21.1%) critically ill patients aged ≤ 50 years were fully vaccinated. Overall, the severity of hospitalized critical patients was significantly higher than that in the delta period, indicating that it was difficult to find common risk factors in the two periods only with a simple comparison. Conclusion Overall, the S-CFR of critically ill COVID-19 patients in the omicron period was higher than that in the delta period, especially in those aged ≤ 50 years. All of the patients who died had an underlying disease or obesity. In the same population, the vaccination rate was very low compared to that in the delta wave, indicating that non-vaccination significantly affected the progression to critical illness. Notably, there was a lack of prescription for Paxlovid for these patients although they satisfied the prescription criteria. Early diagnosis and active initial treatment was necessary, along with the proven methods of vaccination and personal hygiene. Further studies are needed to determine how each variant affects critically ill patients.

This study aimed to assess and evaluate the prevalence and methodological quality of systematic reviews (SRs) published in major Korean medical journals (KMJs). The top 15 journals with the highest Korean Medical Citation Index, published between 2018 to 2021, were selected. We assessed the methodological quality of SRs using A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2). In total, 126 SRs were included, with an average of 32 SRs being reported annually. The overall prevalence of SRs in KMJs was 2.8%, with an increase from 2.6% in 2018 to 3.4% in 2021. Overall, the methodological quality of SRs was low (9.5% low, 90.5% critically low). More than 80% of the studies adhered to critical domain items such as a comprehensive literature search and risk of bias assessment, but for items such as protocol registration and listing excluded studies and the justification for exclusion, the adherence rate was less than 15%. While the number of SRs in KMJs steadily increased, the overall confidence in the methodological quality was low to critically low. Therefore, in order to provide the best evidence for decision-making in clinical and public health areas, editors, reviewers, and authors need to pay more attention to improving the quality of SRs.

Background: Numerous patients around the globe are dying from coronavirus disease 2019 (COVID-19). While age is a known risk factor, risk analysis in the young generation is lacking. The present study aimed to evaluate the clinical features and mortality risk factors in younger patients (≤ 50 years) with a critical case of COVID-19 in comparison with those among older patients (> 50 years) in Korea. Methods: We analyzed the data of adult patients only in critical condition (requiring high flow nasal cannula oxygen therapy or higher respiratory support) hospitalized with PCR-confirmed COVID-19 at 11 hospitals in Korea from July 1, 2021 to November 30, 2021 when the delta variant was a dominant strain. Patients’ electronic medical records were reviewed to identify clinical characteristics. Results: During the study period, 448 patients were enrolled. One hundred and forty-two were aged 50 years or younger (the younger group), while 306 were above 50 years of age (the older group). The most common pre-existing conditions in the younger group were diabetes mellitus and hypertension, and 69.7% of the patients had a body mass index (BMI) > 25 kg/m 2 .Of 142 younger patients, 31 of 142 patients (21.8%, 19 women) did not have these pre-existing conditions. The overall case fatality rate among severity cases was 21.0%, and it differed according to age: 5.6% (n = 8/142) in the younger group, 28.1% in the older group, and 38% in the ≥ 65 years group. Age (odds ratio [OR], 7.902; 95% confidence interval [CI], 2.754–18.181), mechanical ventilation therapy (OR, 17.233; 95% CI, 8.439–35.192), highest creatinine > 1.5 mg/dL (OR, 17.631; 95% CI, 8.321–37.357), and combined blood stream infection (OR, 7.092;95% CI, 1.061–18.181) were identified as independent predictors of mortality in total patients.Similar patterns were observed in age-specific analyses, but most results were statistically insignificant in multivariate analysis due to the low number of deaths in the younger group.The full vaccination rate was very low among study population (13.6%), and only three patients were fully vaccinated, with none of the patients who died having been fully vaccinated in the younger group. Seven of eight patients who died had a pre-existing condition or were obese (BMI > 25 kg/m 2 ), and the one remaining patient died from a secondary infection. Conclusion About 22% of the patients in the young critical group did not have an underlying disease or obesity, but the rate of obesity (BMI > 25 kg/m2 ) was high, with a fatality rate of 5.6%. The full vaccination rate was extremely low compared to the general population of the same age group, showing that non-vaccination has a grave impact on the progression of COVID-19 to a critical condition. The findings of this study highlight the need for measures to prevent critical progression of COVID-19, such as vaccinations and targeting young adults especially having risk factors.

Background: Coronavirus disease 2019 (COVID-19) is often accompanied by secondary infections, such as invasive aspergillosis. In this study, risk factors for developing COVID-19-associated pulmonary aspergillosis (CAPA) and their clinical outcomes were evaluated. Methods: This multicenter retrospective cohort study included critically ill COVID-19 patients from July 2020 through March 2021. Critically ill patients were defined as patients requiring high-flow respiratory support or mechanical ventilation. CAPA was defined based on the 2020 European Confederation of Medical Mycology and the International Society for Human and Animal Mycology consensus criteria. Factors associated with CAPA were analyzed, and their clinical outcomes were adjusted by a propensity score-matched model. Results: Among 187 eligible patients, 17 (9.1%) developed CAPA, which is equal to 33.10 per 10,000 patient-days. Sixteen patients received voriconazole-based antifungal treatment. In addition, 82.4% and 53.5% of patients with CAPA and without CAPA, respectively, received early high-dose corticosteroids (P = 0.022). In multivariable analysis, initial 10-day cumulative steroid dose > 60 mg of dexamethasone or dexamethasone equivalent dose) (adjusted odds ratio [OR], 3.77; 95% confidence interval [CI], 1.03–13.79) and chronic pulmonary disease (adjusted OR, 4.20; 95% CI, 1.26–14.02) were independently associated with CAPA. Tendencies of higher 90-day overall mortality (54.3% vs. 35.2%, P= 0.346) and lower respiratory support-free rate were observed in patients with CAPA (76.3% vs. 54.9%, P = 0.089). Conclusion Our study showed that the dose of corticosteroid use might be a risk factor for CAPA development and the possibility of CAPA contributing to adverse outcomes in critically ill COVID-19 patients.

Background: An epidural blood patch (EBP) is a procedure to treat intracranial hypotension that does not respond to conservative treatment. EBPs are commonly repeated when the symptoms persist. In this study, we used a large single-center retrospective cohort and evaluated the factors associated with repeated EBPs. Methods: From January 2010 to December 2020, a total of 596 patients were treated with EBPs for intracranial hypotension. We evaluated the factors associated with repeated EBPs in the entire population, in patients with spontaneous intracranial hypotension (SIH), and in those with available myelographies. Results: In a total of 596 patients, 125 (21.1%) patients required repeated EBPs, and 96/278 (34.5%) in SIH and 29/314 (9.2%) in iatrogenic population. In patients with SIH, international normalized ratio (INR) and cerebrospinal fluid (CSF) leakage on myelographies consistently exhibited significant associations (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.02–1.87; P = 0.043 and OR, 2.18; 95% CI, 1.28–3.69; P = 0.004). In patients with iatrogenic injury, INR and CSF leakage on myelogram did not show difference in repeated EBPs. Conclusions Repeated EBPs may be more frequently required in patients with SIH.Prolonged INR and CSF leakage were associated with repeated EBPs in patient with SIH. Further studies are needed to determine factors associated with repeated EBP requirements.

Objective: To investigate the long-term clinical outcomes of pallidal deep brain stimulation (GPi-DBS) in patients with pantothenate kinase-associated neurodegeneration (PKAN). Methods: We reviewed the records of patients with genetically confirmed PKAN who received bilateral GPi-DBS for refractory dystonia and were clinically followed up for at least 2 years postoperatively at two centers in Korea. Pre- and postoperative Burke– Fahn–Marsden Dystonia Rating Scale motor subscale (BFMDRS-M) scores, disability subscale (BFMDRS-D) scores, and qualitative clinical information were prospectively collected. Descriptive analysis was performed for BFMDRS-M scores, BFMDRSD scores, and the orofacial, axial, and limb subscores of the BFMDRS-M at 6–12, 24–36, and 60–72 months postoperatively. Results: Five classic-type, four atypical-type, and one unknown-type PKAN cases were identified. The mean preoperative BFMDRS-M score was 92.1 for the classic type and 38.5 for the atypical or unknown type, with a mean BFMDRS follow-up of 50.7 months and a clinical follow-up of 69.0 months. The mean improvements in BFMDRS-M score were 11.3%, 41.3%, and 30.5% at 6–12, 24–36, and 60–72 months, respectively. In four patients with full regular evaluations until 60–72 months, improvements in the orofacial, axial, and limb subscores persisted, but the disability scores worsened from 24–36 months post-operation compared to the baseline, mainly owing to the aggravation of eating and feeding disabilities. Conclusion The benefits of GPi-DBS on dystonia may persist for more than 5 years in PKAN. The effects on patients’ subjective disability may have a shorter duration despite improvements in dystonia owing to the complex manifestations of PKAN.