ABSTRACT
Background@#After the first case of coronavirus disease 2019 (COVID-19) in January 2020, Korea has experienced three waves in 2020. This study aimed to analyze changes in health care utilization according to the period of the 1st to 3rd waves of the COVID-19 pandemic. @*Methods@#We analyzed 3,354,469,401 national health insurance claims from 59,104 medical facilities between 2017 and 2020.Observed-to-expected ratios (O:E ratio) with data from 2017 to 2019 as expected values and data from 2020 as observed values were obtained to analyze changes in medical utilization. T-test was used to test whether the difference of observed and expected values was statistically significant. @*Results@#In 2020, the O:E ratio was 0.894, indicating a decrease in health care utilization overall during the pandemic. The O:E ratio of the 1st wave was 0.832, which was lower than those of the second (0.886) and third (0.873) waves. Health care utilization decreased relatively more among outpatient, women, children and adolescents, and health insurance patients. And health care utilization decreased more in small medical facilities and in Daegu and Gyeongbuk during the first wave. During the pandemic, the O:E ratios of respiratory diseases were 0.486-0.694, while chronic diseases and mental diseases were more than 1.0. @*Conclusion@#Health care utilization decreased during the COVID-19 pandemic overall, and there were differences by COVID-19 waves, and by the characteristics of patients and medical facilities. It is necessary to understand the cause of changes in health care utilization in order to cope with the prolonged COVID-19 pandemic.
ABSTRACT
PURPOSE: Although radiation-induced fibrosis is one of the common sequelae occurring after irradiation of skin and soft tissues, the treatment methods are not well standardized. This study aimed to establish the skin fibrosis mouse model by fractionated radiation for the further mechanism studies or testing the efficacy of therapeutic candidates. MATERIALS AND METHODS: The right hind limbs of BALB/c mice received two fractions of 20 Gy using a therapeutic linear accelerator. Early skin damages were scored and tissue fibrosis was assessed by the measurement of a leg extension. Morphological changes were assessed by H&E staining and by Masson's Trichrome staining. TGF-beta1 expression from soft tissues was also detected by immunohistochemistry and PCR. RESULTS: Two fractions of 20 Gy irradiation were demonstrated as being enough to induce early skin damage effects such as erythema, mild skin dryness, dry and wet desquamation within several weeks of radiation. After 13 weeks of irradiation, the average radiation-induced leg contraction was 11.1+/-6.2 mm. Morphologic changes in irradiated skin biopsies exhibited disorganized collagen and extracellular matrix fibers, as well as the accumulation of myofibroblasts compared to the non-irradiated skin. Moreover, TGF-beta1 expression in tissue was increased by radiation. CONCLUSION: These results show that two fractions of 20 Gy irradiation can induce skin fibrosis in BALB/c mice accompanied by other common characteristics of skin damages. This animal model can be a useful tool for studying skin fibrosis induced by radiation.