A 'circadian rhythm' is a self-sustained biological rhythm (cycle) that repeats itself approximately every 24 hours. Circadian rhythms are generated by an internal clock, or pacemaker, and persist even in the absence of environmental time cues, collectively termed 'zeitgebers.' Although organisms generate circadian rhythms internally, they are entrained by environmental stimuli, particularly the light-dark cycle. Measurement of the endogenous melatonin rhythm provides relatively reliable surrogate way of assessing the timing of the internal circadian clock. Also, core body temperature and cortisol can be used as markers of circadian rhythms. The sleep-wake cycle, body temperature, and melatonin rhythm have a stable internal phase relationship in humans and other diurnal species. They play an important role in controlling daily behavioral rhythms including task performance, blood pressure, and synthesis and secretion of several hormones. In this review, we address not only the properties, methods of measurement, and markers of circadian rhythms, but also the physiological and psychological importance of human circadian rhythms.
Blood Pressure ; Body Temperature ; Circadian Clocks ; Circadian Rhythm* ; Cues ; Humans ; Hydrocortisone ; Melatonin ; Photoperiod ; Task Performance and Analysis

PURPOSE: Parenteral nutrition (PN) is known to provide therapeutic beneficial improvements in malnourished patients for whom enteral nutrition is not feasible. The objective of this study was to investigate the current clinical characteristics and utilization of PN in Korea. METHODS: We analyzed the Health Insurance Review Agency National Inpatients Sample database from 2014 to 2016, which included 13% of all hospitalized patients in Korea. Adult patients aged 20 years or older and receiving premixed multi-chamber bag containing PN were included for this study. Patient characteristics, admission type, primary diagnosis, and hospital demographics were evaluated. SAS version 9.4 was used for data analysis. RESULTS: From 2014 to 2016, 149,504 patients received premixed PN, with 226,281 PN prescriptions being written. The mean patient age was 65.0 years, and 81,876 patients (54.8%) were male. Premixed 3-chamber bag and 2-chamber bag PN solutions were utilized in 131,808 (88.2%) and 32,033 (21.4%) patients, respectively. The number of patients hospitalized through the emergency department were 70,693 (47.3%), whereas 43,125 patients (28.8%) were administered PN in intensive care units. In the adult PN patients, the highest primary diagnosis was malignant neoplasm of the stomach (8,911, 6.0%), followed by organism unspecified pneumonia (7,008, 4.7%), and gastroenteritis and colitis of unspecified origin (6,381, 4.3%). Overall, 34% of adult PN patients were diagnosed with malignancies, the most common being neoplasm of the stomach (17.7%), neoplasm of bronchus/lung (11.2%), neoplasm of colon (11.1%), and neoplasm of liver/intrahepatic bile ducts (10.0%). PN solutions were most frequently administered in the metropolitan area (55.0%) and in hospitals with more than 1,000 beds (23.6%). CONCLUSION: PN was commonly administered in older patients, with primary diagnosis of malignancy in a significant number of cases. This study is the first large-scale description of PN-prescribing patterns in real-world clinical practice in South Korea.
Adult* ; Bile Ducts ; Colitis ; Colon ; Demography ; Diagnosis ; Emergency Service, Hospital ; Enteral Nutrition ; Gastroenteritis ; Humans ; Inpatients ; Insurance, Health ; Intensive Care Units ; Korea* ; Male ; Nutritional Support ; Parenteral Nutrition* ; Pneumonia ; Prescriptions ; Statistics as Topic ; Stomach

PURPOSE: To evaluate the clinical manifestations of adverse drug reactions (ADRs) of parenteral nutrition (PN) use in Korea. METHODS: The Korean Adverse Event Reporting System (KAERS) database records in 2015 on PN-treated patients were used. ADRs classified as “certain,”“probable,” and “possible” based on the WHO-Uppsala Monitoring Centre criteria were analyzed. RESULTS: In total, 21,436 ADRs from 2,346 patients were included for analysis. The mean patient age was 57.1 years and the mean number of ADRs per patient was 9.1. ADRs were reported frequently with amino acids solutions (682 events, 40.8%), followed by combinations products (519 events, 31.1%), and fat emulsions (363 events, 21.7%). The frequent ADRs were gastrointestinal (507 events, 30.3%), skin (343 events, 20.5%), general disorders (239 events, 14.3%), and central/peripheral nervous system disorders (165 events, 9.9%). The common clinical symptoms were nausea (321 events, 19.2%), vomiting (105 events, 6.3%), and vein pain (102 events, 6.1%). Serious ADRs accounted for 220 patients (9.4%) and dyspnea was the most frequent clinical manifestation. CONCLUSION: This study analyzed the KAERS data in 2015 from patients treated with PN and revealed gastrointestinal and skin disorders to be the leading ADRs.
Amino Acids ; Drug-Related Side Effects and Adverse Reactions ; Dyspnea ; Emulsions ; Humans ; Korea* ; Nausea ; Nervous System Diseases ; Parenteral Nutrition* ; Skin ; Veins ; Vomiting

BACKGROUND: Previous studies have noted that the simultaneous use of sulfonylureas and antimicrobials, which is common, could increase the risk of hypoglycemia. In particular, an age of 65 years or older is a known risk factor for sulfonylurea-related hypoglycemia in hospitalized patients. Therefore, we performed this study to determine the potential risk of hypoglycemia from the concurrent use of antimicrobials and sulfonylureas. METHODS: We performed a cross-sectional study on the National Health Insurance Service-National Sample Cohort from 2013. The eligibility criteria included patients of 65 years of age or older taking a sulfonylurea with 25 different antimicrobials. Different risk ratings of severity in drug-drug interactions (potential DDIs), level X, D, or C in Lexi-Interact™online, and contraindicated, major, or moderate severity level in Micromedex® were included. SAS version 9.4 was used for data analysis. RESULTS: A total of 6,006 elderly patients with 25,613 prescriptions were included. The largest age group was 70 to 74 (32.7%), and 39.7% of patients were men. The mean number of prescriptions was 4.3 per patient. The most frequently used antimicrobials were levofloxacin (6,583, 25.7%), ofloxacin (6,549, 25.6%), fluconazole (4,678, 18.0%), and ciprofloxacin (2,551, 9.8%). Among sulfonylureas, glimepiride was prescribed most frequently, followed by gliclazide, glibenclamide, and glipizide. CONCLUSION: Of the antimicrobials with a high potential of hypoglycemia, levofloxacin, ofloxacin, fluconazole, and ciprofloxacin were used frequently. Thus, the monitoring of clinically relevant interactions is required for patients concurrently administered sulfonylureas and antimicrobials.
Aged* ; Anti-Infective Agents ; Ciprofloxacin ; Cohort Studies ; Cross-Sectional Studies ; Drug Interactions ; Fluconazole ; Gliclazide ; Glipizide ; Glyburide ; Humans ; Hypoglycemia* ; Korea* ; Levofloxacin ; Male ; National Health Programs ; Ofloxacin ; Prescriptions ; Risk Factors ; Statistics as Topic ; Sulfonylurea Compounds

BACKGROUND: 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) effectively reduce serum levels of low-density lipoprotein (LDL) and total cholesterol. High-intensity statins are recommended for all patients aged ≤75 with clinical atherosclerotic cardiovascular disease (ASCVD), diabetes mellitus aged 40–75 with ≥7.5% estimated 10-year ASCVD risk and LDL-C ≥190 mg/ dL. High-intensity statins associated with more frequent adverse events (AEs) compared to moderate- to low-intensity statins. The aim of this study was to compare AEs between high-intensity and moderate- to low-intensity statin group using the Korea Adverse Event Reporting System (KAERS) database. METHODS: Adults (≥18 years) with statin-associated AEs from July 2009-June 2014 were included. Only AEs classified as “certain”, “probable” and “possible” based on the WHO-Uppsala Monitoring Center criteria were analyzed. RESULTS: In total, 247 AEs from 196 patients [high-intensity statin group (HG), n = 25 (13%); moderate- to lowintensity statin group (MLG), n = 171 (87%)] were included. Mean age was higher in HG compared with MLG (67 ± 14 vs 62 ± 12). The HG showed a significant higher frequency of liver/biliary system disorders (37% vs 14%, p = 0.001). Hepatic function abnormal was reported more frequently in HG compared to MLG (26% vs 9%, p = 0.006). CONCLUSION: According to KAERS data, liver/biliary system disorders were more frequently reported in HG compared to MLG.
Adult ; Cardiovascular Diseases ; Cholesterol ; Coenzyme A ; Diabetes Mellitus ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors* ; Korea ; Lipoproteins ; Oxidoreductases

Various digital healthcare devices and apps, such as blood glucose meters, blood pressure monitors, and step-trackers are commonly used by patients; however, digital healthcare devices have not been widely accepted in the medical market as of yet. Despite the various legal and privacy issues involved in their use, the main reason for its poor acceptance is that users do not use such devices voluntarily and continuously. Digital healthcare devices generally do not provide valuable information to users except for tracking self-checked glucose or walking. To increase the use of these devices, users must first understand the health data produced in the context of their personal health, and the devices must be easy to use and integrated into everyday life. Thus, users need to know how to manage their own data. Medical staff must teach and encourage users to analyze and manage their patient-generated healthcare data, and users should be able to find medical values from these digital devices. Eventually, a single customized service that can comprehensively analyze various medical data to provide valuable customized services to users, and which can be linked to various heterogeneous digital healthcare devices based on the integration of various health data should be developed. Digital healthcare professionals should have detailed knowledge about a variety of digital healthcare devices and fully understand the advantages and disadvantages of digital healthcare to help patients understand and embrace the use of such devices.

Various digital healthcare devices and apps, such as blood glucose meters, blood pressure monitors, and step-trackers are commonly used by patients; however, digital healthcare devices have not been widely accepted in the medical market as of yet. Despite the various legal and privacy issues involved in their use, the main reason for its poor acceptance is that users do not use such devices voluntarily and continuously. Digital healthcare devices generally do not provide valuable information to users except for tracking self-checked glucose or walking. To increase the use of these devices, users must first understand the health data produced in the context of their personal health, and the devices must be easy to use and integrated into everyday life. Thus, users need to know how to manage their own data. Medical staff must teach and encourage users to analyze and manage their patient-generated healthcare data, and users should be able to find medical values from these digital devices. Eventually, a single customized service that can comprehensively analyze various medical data to provide valuable customized services to users, and which can be linked to various heterogeneous digital healthcare devices based on the integration of various health data should be developed. Digital healthcare professionals should have detailed knowledge about a variety of digital healthcare devices and fully understand the advantages and disadvantages of digital healthcare to help patients understand and embrace the use of such devices.

Background: The prevalence of both obstructive sleep apnea and allergic rhinitis is high and these often co-exist. This study investigated the association between allergic rhinitis-related factors and the risk of sleep apnea in Korean adults. Methods: We conducted a cross-sectional study involving 8,956 Korean adults aged 40 years or older who participated in the 8th Korea National Health and Nutrition Examination Survey between 2019 and 2021. Allergic rhinitis-related factors were divided into two categories: allergic rhinitis symptoms (symptoms) and prevalence of allergic disease (prevalence). Symptoms were investigated through a questionnaire and the prevalence of allergic disease was based on the doctor’s diagnosis. The risk of sleep apnea was calculated through the STOP-Bang questionnaire (snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, gender), and a score of ≥3 is considered as a high-risk group. Logistic regression analysis was used to investigate the effect of symptoms or prevalence on the risk of sleep apnea. Results: The risk of sleep apnea increased 1.26 times (95% confidential interval [CI], 1.10–1.44) in patients with symptoms and was higher in patients with severe rhinitis (odds ratio [OR], 1.43; 95% CI, 1.12–1.83). A higher risk of sleep apnea was associated with allergic disease, including allergic rhinitis, asthma, and atopic dermatitis (OR, 1.31; 95% CI, 1.02–1.66, adjusted for general characteristics). Conclusion Severe allergic rhinitis symptoms and a history of allergic disease increased the risk of obstructive sleep apnea.

Background: The prevalence of both obstructive sleep apnea and allergic rhinitis is high and these often co-exist. This study investigated the association between allergic rhinitis-related factors and the risk of sleep apnea in Korean adults. Methods: We conducted a cross-sectional study involving 8,956 Korean adults aged 40 years or older who participated in the 8th Korea National Health and Nutrition Examination Survey between 2019 and 2021. Allergic rhinitis-related factors were divided into two categories: allergic rhinitis symptoms (symptoms) and prevalence of allergic disease (prevalence). Symptoms were investigated through a questionnaire and the prevalence of allergic disease was based on the doctor’s diagnosis. The risk of sleep apnea was calculated through the STOP-Bang questionnaire (snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, gender), and a score of ≥3 is considered as a high-risk group. Logistic regression analysis was used to investigate the effect of symptoms or prevalence on the risk of sleep apnea. Results: The risk of sleep apnea increased 1.26 times (95% confidential interval [CI], 1.10–1.44) in patients with symptoms and was higher in patients with severe rhinitis (odds ratio [OR], 1.43; 95% CI, 1.12–1.83). A higher risk of sleep apnea was associated with allergic disease, including allergic rhinitis, asthma, and atopic dermatitis (OR, 1.31; 95% CI, 1.02–1.66, adjusted for general characteristics). Conclusion Severe allergic rhinitis symptoms and a history of allergic disease increased the risk of obstructive sleep apnea.

Background: The prevalence of both obstructive sleep apnea and allergic rhinitis is high and these often co-exist. This study investigated the association between allergic rhinitis-related factors and the risk of sleep apnea in Korean adults. Methods: We conducted a cross-sectional study involving 8,956 Korean adults aged 40 years or older who participated in the 8th Korea National Health and Nutrition Examination Survey between 2019 and 2021. Allergic rhinitis-related factors were divided into two categories: allergic rhinitis symptoms (symptoms) and prevalence of allergic disease (prevalence). Symptoms were investigated through a questionnaire and the prevalence of allergic disease was based on the doctor’s diagnosis. The risk of sleep apnea was calculated through the STOP-Bang questionnaire (snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, gender), and a score of ≥3 is considered as a high-risk group. Logistic regression analysis was used to investigate the effect of symptoms or prevalence on the risk of sleep apnea. Results: The risk of sleep apnea increased 1.26 times (95% confidential interval [CI], 1.10–1.44) in patients with symptoms and was higher in patients with severe rhinitis (odds ratio [OR], 1.43; 95% CI, 1.12–1.83). A higher risk of sleep apnea was associated with allergic disease, including allergic rhinitis, asthma, and atopic dermatitis (OR, 1.31; 95% CI, 1.02–1.66, adjusted for general characteristics). Conclusion Severe allergic rhinitis symptoms and a history of allergic disease increased the risk of obstructive sleep apnea.