Coronavirus Disease 19 (COVID-19) Vaccine Effectiveness Against Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Delta-Dominant and Omicron-Dominant Periods in Japan: A Multicenter Prospective Case-control Study (Factors Associated with SARS-CoV-2 Infection and the Effectiveness of COVID-19 Vaccines Study).

BACKGROUND: Although several coronavirus disease 2019 (COVID-19) vaccines initially showed high efficacy, there have been concerns because of waning immunity and the emergence of variants with immune escape capacity. METHODS: A test-negative design case-control study was conducted in 16 healthcare facilities in Japan during the Delta-dominant period (August-September 2021) and the Omicron-dominant period (January-March 2022). Vaccine effectiveness (VE) against symptomatic severe acute respiratory syndrome coronavirus 2 infection was calculated for 2 doses for the Delta-dominant period and 2 or 3 doses for the Omicron-dominant period compared with unvaccinated individuals. RESULTS: The analysis included 5795 individuals with 2595 (44.8%) cases. Among vaccinees, 2242 (55.8%) received BNT162b2 and 1624 (40.4%) received messenger RNA (mRNA)-1273 at manufacturer-recommended intervals. During the Delta-dominant period, VE was 88% (95% confidence interval [CI], 82-93) 14 days to 3 months after dose 2 and 87% (95% CI, 38-97) 3 to 6 months after dose 2. During the Omicron-dominant period, VE was 56% (95% CI, 37-70) 14 days to 3 months since dose 2, 52% (95% CI, 40-62) 3 to 6 months after dose 2, 49% (95% CI, 34-61) 6+ months after dose 2, and 74% (95% CI, 62-83) 14+ days after dose 3. Restricting to individuals at high risk of severe COVID-19 and additional adjustment for preventive measures (ie, mask wearing/high-risk behaviors) yielded similar estimates, respectively. CONCLUSIONS: In Japan, where most are infection-naïve, and strict prevention measures are maintained regardless of vaccination status, 2-dose mRNA vaccines provided high protection against symptomatic infection during the Delta-dominant period and moderate protection during the Omicron-dominant period. Among individuals who received an mRNA booster dose, VE recovered to a high level.

Risk factors of partial IgA deficiency among low serum IgA patients: a retrospective observational study.

INTRODUCTION: Partial IgA deficiency (pIgAD), including selective IgA deficiency, is one of the most common types of immunodeficiency. Early detection is crucial to prevent complications, such as recurrent infections and anaphylactic reactions to blood derivatives. MATERIAL AND METHODS: Useful screening methods have not yet been established. We conducted a single-center retrospective observational study, with low serum IgA patients to clarify the risk factors of pIgAD among patients with low serum levels of IgA. All patients with low serum IgA levels treated in our outpatient clinic from April 2010 to March 2016 were retrospectively reviewed using electronic medical records. We performed c 2 tests and Student's t-tests for the univariate analysis, logistic regression analysis using the multiple imputation method for the multivariate analysis, and receiver operating characteristic (ROC) curve analysis. RESULTS: The univariate analysis showed statistically significant differences between the pIgAD group and the non-pIgAD group in age, gender, blood cell counts, serum protein levels, and renal function tests. The multivariate analysis revealed that female gender, a white blood cell counts lower than 10,000/µl, and a hemoglobin level of 10.0-15.0 g/dl are predictive factors of pIgAD. CONCLUSIONS: After estimating any missing data using the multiple imputation method, age younger than 60 years old was also statistically significant. ROC curve analysis confirmed the validity of the model used in our multivariate analysis. When clinicians encounter low serum IgA patients who are female, of younger age, and have normal blood cell counts, and hemoglobin levels, they should suspect the existence of pIgAD.

The association between consuming bivalves, and acute gastroenteritis and norovirus in Tokyo, Japan.

A prospective matched case-control study was conducted to evaluate associations between dietary histories, including consumption of bivalves, diarrhea, and norovirus positive diarrhea in adult ambulatory patients at an outpatient clinic of a hospital in Tokyo, Japan. Ambulatory cases with diarrhea were matched with nondiarrheal control patients, who visited the same clinic. A standardized questionnaire was used to obtain patients' information, including histories of food consumption and clinical information. Norovirus infection was confirmed using real-time reverse transcription polymerase chain reaction. A total of 207 patients, including 69 diarrheal cases and 138 nondiarrheal cases were included in the analysis. Among them, 60 (29.0%) participants reported consuming bivalves. Norovirus was detected in 35% (24/69) of diarrheal cases. Of those, 10 (41.7%) reported consumption of bivalves and of those, 6 (60.0%) consumed raw bivalves. The proportion of those who consumed raw bivalves was significantly higher in norovirus-positive diarrheal cases than in norovirus-negative diarrheal cases (25.0% vs 6.7%; odds ratio [OR], 4.67; 95% confidence interval [CI], 1.1-20.7) and matched nondiarrheal controls (25.0% vs 6.3%, OR: 5.00; 95% CI, 1.1-22.2). The attributable fraction of consuming raw bivalves for norovirus-associated diarrhea to matched nondiarrheal controls was 20.0%. Consuming raw bivalves was substantially attributed to norovirus-associated diarrhea in adult ambulatory patients and preventive measures for reducing the risk associated with consumption of raw bivalves could decrease the incidence of norovirus-associated diarrhea.

Evaluation of risk factors for perforated peptic ulcer.

BACKGROUND: The aim of this study was to evaluate the prediction factors for perforated peptic ulcer (PPU). METHODS: At St. Luke's International Hospital in Tokyo, Japan, a case control study was performed between August 2004 and March 2016. All patients diagnosed with PPU were included. As control subjects, patients with age, sex and date of CT scan corresponding to those of the PPU subjects were included in the study at a proportion of 2 controls for every PPU subject. All data such as past medical histories, physical findings, and laboratory data were collected through chart reviews. Univariate analyses and multivariate analyses with logistic regression were conducted, and receiver operating characteristic curves (ROCs) were calculated to show validity. Sensitivity analyses were performed to confirm results using a stepwise method and conditional logistic regression. RESULTS: A total of 408 patients were included in this study; 136 were a group of patients with PPU, and 272 were a control group. Univariate analysis showed statistical significance in many categories. Four different models of multivariate analyses were conducted, and significant differences were found for muscular defense and a history of peptic ulcer disease (PUD) in all models. The conditional forced-entry analysis of muscular defense showed an odds ratio (OR) of 23.8 (95% confidence interval [CI]: 5.70-100.0), and the analysis of PUD history showed an OR of 6.40 (95% CI: 1.13-36.2). The sensitivity analysis showed consistent results, with an OR of 23.8-366.2 for muscular defense and an OR of 3.67-7.81 for PUD history. The area under the curve (AUC) of all models was high enough to confirm the results. However, anticoagulants, known risk factors for PUD, did not increase the risk for PPU in our study. The conditional forced-entry analysis of anticoagulant use showed an OR of 0.85 (95% CI: 0.03-22.3). CONCLUSIONS: The evaluation of prediction factors and development of a prediction rule for PPU may help our decision making in performing a CT scan for patients with acute abdominal pain.

A prediction rule for the development of delirium among patients in medical wards: Chi-Square Automatic Interaction Detector (CHAID) decision tree analysis model.

OBJECTIVE: To predict development of delirium among patients in medical wards by a Chi-Square Automatic Interaction Detector (CHAID) decision tree model. METHODS: This was a retrospective cohort study of all adult patients admitted to medical wards at a large community hospital. The subject patients were randomly assigned to either a derivation or validation group (2:1) by computed random number generation. Baseline data and clinically relevant factors were collected from the electronic chart. Primary outcome was the development of delirium during hospitalization. All potential predictors were included in a forward stepwise logistic regression model. CHAID decision tree analysis was also performed to make another prediction model with the same group of patients. Receiver operating characteristic curves were drawn, and the area under the curves (AUCs) were calculated for both models. In the validation group, these receiver operating characteristic curves and AUCs were calculated based on the rules from derivation. RESULTS: A total of 3,570 patients were admitted: 2,400 patients assigned to the derivation group and 1,170 to the validation group. A total of 91 and 51 patients, respectively, developed delirium. Statistically significant predictors were delirium history, age, underlying malignancy, and activities of daily living impairment in CHAID decision tree model, resulting in six distinctive groups by the level of risk. AUC was 0.82 in derivation and 0.82 in validation with CHAID model and 0.78 in derivation and 0.79 in validation with logistic model. CONCLUSION: We propose a validated CHAID decision tree prediction model to predict the development of delirium among medical patients.

High sleep duration variability is an independent risk factor for weight gain.

OBJECTIVE: This study was conducted to evaluate the association between weight gain and variability of sleep duration. METHODS: A retrospective cohort study was conducted involving apparently healthy individuals aged 20 years or older who underwent annual health checkup at the Center for Preventive Medicine, St. Luke's International Hospital, between 2007 and 2010. The body mass index (BMI) of each participant was measured, and the change in BMI during the study period was calculated. The sleep duration was obtained using a questionnaire that was filled out by participants each year, and the variability in the sleep duration was calculated by dividing the standard deviation (SD) of the sleep duration for 3 years by the square root of the number of data points. Multivariate linear regression analysis was used to explore the association between the change in BMI and the variability of the sleep duration, adjusting for age, sex, alcohol consumption, current smoking, baseline sleep duration, past medical history, and level of physical activity. RESULTS: A total of 21,148 participants were included in this study. The mean age (SD) was 51 (12) years, and 10,993 (49.6%) participants were male. The mean baseline BMI was 22.4 (SD 3.2). According to the self-reported data, the mean sleep duration (SD) was 6.2 (1.0) h, and the mean of the SD of sleep duration for each participant was 0.32 (min-max, 0-7). The result of the linear regression analysis showed that greater variability in the sleep duration was independently related to an increase in BMI (ß coefficient = 0.31; 95% CI = 0.01-0.61). CONCLUSION: The variability of sleep duration is related to body weight gain. Maintaining a constant sleep duration may be recommended for controlling body weight.

Risk factors for adverse reactions from contrast agents for computed tomography.

BACKGROUND: Symptoms of an adverse reaction to contrast agents for computed tomography are diverse ranging, and sometimes serious. The goal of this study is to create a scoring rule to predict adverse reactions to contrast agents used in computed tomography. METHODS: This was a retrospective cohort study of all adult patients undergoing contrast enhanced CT scan for 7 years. The subjects were randomly divided into either a derivation or validation group. Baseline data and clinically relevant factors were collected from the electronic chart. Primary outcome was any acute adverse reactions to contrast media, observed for during 24 hours after administration. All potential candidate predictors were included in a forward stepwise logistic regression model. Prediction scores were assigned based on ß coefficient. A receiver operating characteristic (ROC) curve was drawn, and the area under the curve (AUC) and incidence of acute adverse reactions at each point were obtained. The same process was performed in the validation group. RESULTS: 36,472 patients underwent enhanced CT imaging: 20,000 patients in the derivation group and 16,472 in the validation group. A total of 409 (2.0%, 95% CI:1.9-2.3) and 347 (2.1%, 95% CI:1.9-2.3) acute adverse reactions were seen in the derivation and validation groups. Logistic regression analysis revealed that prior adverse reaction to contrast agents, urticaria, an allergic history to drugs other than contrast agents, contrast agent concentration >70%, age <50 years, and total contrast agent dose >65 g were significant predictors of an acute adverse reaction. AUC was 0.70 (95% CI:0.67-0.73) and 0.67 (95% CI:0.64-0.70) in the derivation and validation groups. CONCLUSIONS: We suggest a prediction model consisting of six predictors for acute adverse reactions to contrast agents used in CT.

Reversible Cerebral Vasoconstriction Syndrome Associated with Vasospasm of the Colic Arteries and Possibly Coronary Vasospasm.

BACKGROUND Reversible cerebral vasoconstriction syndrome (RCVS) is a disorder characterized by recurrent thunderclap headaches and reversible cerebral vasoconstriction. CASE REPORT Herein, we present the case of a man in his forties with a disease entity related to RCVS accompanied by vasospasm of the extracerebral blood vessels throughout the body. The patient presented to the Emergency Department with a severe headache and epigastric pain. Initially receiving a misdiagnosis of functional pain, he continued to experience severe recurrent headaches, most often after urinating or defecating and was referred to our department. Suspecting RCVS, we performed magnetic resonance angiography, which revealed beaded irregularity in the right anterior cerebral and V4 vertebral arteries. The patient also had epigastric pain that coincided with each headache. Electrocardiography revealed pronounced ST-segment elevation in leads I and aVL and inverted T wave in lead III, while abdominal computed tomography angiography showed narrowing of the colic arteries. We named this disease "reversible systemic vasoconstriction syndrome" (RSVS) as a potential suggested terminology for the future. CONCLUSIONS RSVS is a clinical syndrome characterized by thunderclap headaches and simultaneous unbearable pain in extracerebral organs. To the best of our knowledge, this is the first case report of RCVS with coronary and colic artery vasospasm. We need to take great care of patients with chest or abdominal pain accompanied by recurrent thunderclap headaches, since they can be misdiagnosed with functional or psychogenic disorders.

Third cranial nerve palsy due to COVID-19 infection.

We report a case of a previously healthy man in his 40s who presented with mild SARS-CoV-2 infection (COVID-19) concomitant with acute onset of left third cranial nerve palsy with restricted supraduction, adduction and infraduction. Our patient did not present any history of hypertension, hyperlipidaemia, diabetes mellitus or smoking. The patient recovered spontaneously without any antiviral treatment. To our knowledge, this is the second report of third cranial nerve palsy spontaneously resolved without any risk factors of vascular disease, specific image findings, nor any possible causes other than COVID-19. In addition, we reviewed 10 other cases of third cranial nerve palsy associated with COVID-19, which suggested that the aetiology varies greatly. As a clinician, it is important to recognise COVID-19 as a differential diagnosis for third cranial nerve palsy. Finally, we aimed to encapsulate the aetiologies and the prognosis of the third cranial nerve palsy associated with COVID-19.

Hepatic Encephalopathy Caused by Long-Term Amiodarone Use.

This case describes a 72-year-old Japanese woman with hypertrophic cardiomyopathy and non-sustained ventricular tachycardia who had received a total of 215 g of amiodarone over six years and presented with hepatic encephalopathy. The abdominal non-contrast computed tomography showed diffusely increased attenuation of the liver parenchyma. The liver biopsy revealed drug-induced steatohepatitis. No genetic variations in the urea cycle were found. She was ultimately diagnosed with drug-induced steatohepatitis and urea cycle abnormalities caused by long-term amiodarone use. Amiodarone may cause drug-induced steatohepatitis and urea cycle abnormalities, which could induce hyperammonemia. Although case reports of amiodarone-induced hyperammonemia and hepatic encephalopathy have already been reported, we present a typical picture of an amiodarone-induced bright liver, including the mechanism of amiodarone-induced hyperammonemia, to provide an educational learning point for many readers.

Characteristics of participants in a public rubella antibody testing program conducted at a Japan professional football league venue.

Background: Hypothesizing that soccer-associated public health campaigns influence men more than women, we investigated the characteristics and motivations of participants who received rubella antibody testing at a Japanese professional football league event. Methods: This was a survey-based cross sectional study, comparing the characteristics and motivations between men and women regarding rubella antibody testing. Results: Free and convenient testing was the biggest behavioral influencer, but the information provided by healthcare professionals and athletes also played a strong motivating role. Men reported more influence from celebrity athletes than women. Conclusions: Public health attention raised by celebrity athletes may facilitate rubella awareness among male spectators.

Effectiveness of BA.1- and BA.4/BA. 5-Containing Bivalent COVID-19 mRNA Vaccines Against Symptomatic SARS-CoV-2 Infection During the BA.5-Dominant Period in Japan.

In this multicenter, prospective, test-negative, case-control study in Japan, the effectiveness of both BA.1-containing and BA.4/BA.5-containing bivalent coronavirus disease 2019 mRNA vaccines against symptomatic infection during the BA.5-dominant period was high compared with no vaccination (65% and 76%) and moderate compared with monovalent vaccines administered over half a year earlier (46% combined).

Immune escape and waning immunity of COVID-19 monovalent mRNA vaccines against symptomatic infection with BA.1/BA.2 and BA.5 in Japan.

BACKGROUND: Repeated emergence of variants with immune escape capacity and waning immunity from vaccination are major concerns for COVID-19. We examined whether the surge in Omicron subvariant BA.5 cases was due to immune escape or waning immunity through vaccine effectiveness (VE) evaluation. METHODS: A test-negative case-control study was conducted in 16 clinics/hospitals during the BA.1/BA.2-dominant and BA.5-dominant periods. VE against symptomatic infection was estimated after adjusting for age, sex, comorbidity, occupation, testing frequency, prior infection, close contact history, clinic/hospital, week, and preventive measures. Absolute VE (aVE) was calculated for 2/3/4 doses, compared to the unvaccinated. Relative VE (rVE) was calculated, comparing 3 vs 2 and 4 vs 3 doses. RESULTS: 13,025 individuals were tested during the BA.1/BA.2-dominant and BA.5-dominant periods with similar baseline characteristics. For BA.1/BA.2, aVE was 52 % (95 %CI:34-66) 14 days-3 months post-dose 2, 42 % (29-52) > 6 months post-dose 2, 71 % (64-77) 14 days-3 months post-dose 3, and 68 % (52-79) 3-6 months post-dose 3. rVE was 49 % (38-57) 14 days-3 months post-dose 3 and 45 % (18-63) 3-6 months post-dose 3. For BA.5, aVE was 56 % (27-73) 3-6 months post-dose 2, 32 % (12-47) > 6 months post-dose 2, 70 % (61-78) 14 days-3 months post-dose 3, 59 % (48-68) 3-6 months post-dose 3, 50 % (29-64) > 6 months post-dose 3, and 74 % (61-83) ≥ 14 days post-dose 4. rVE was 56 % (45-65) 14 days-3 months post-dose 3, 39 % (27-48) 3-6 months post-dose 3, 25 % (-2-45) > 6 months post-dose 3, and 30 % (-6-54) ≥ 14 days post-dose 4. CONCLUSIONS: Booster doses initially provided high protection against BA.5 at a level similar to that against BA.1/BA.2. However, the protection seemed shorter-lasting against BA.5, which likely contributed to the surge. Furthermore, rVE post-dose 4 was low even among recent vaccinees. These results support the introduction of variant-containing vaccines and emphasize the need for vaccines with longer duration of protection.

The optimal screening interval for gastric cancer using esophago-gastro-duodenoscopy in Japan.

BACKGROUND: Gastric cancer is one of the most significant diseases, and esophago-gastro-duodenoscopy (EGD) is one of screening methods for gastric cancer. This study was conducted to identify the optimal screening interval for gastric cancer using EGD in healthy adults. METHODS: A retrospective cohort study was conducted on 3,723 healthy participants without a known diagnosis of gastric cancer at baseline from January 2005 to December 2010. Participants underwent annual health screenings, including EGD, at the Center for Preventive Medicine at St Luke's International Hospital, a community teaching hospital in Japan. Participants with cytological abnormalities underwent further examination. A generalized estimating equation (GEE) was used to analyze the longitudinal data. We decided 0.5% of incidence of gastric cancer as a cutoff point for interval. RESULTS: The mean age (SD) of the participants was 55 (11) years, and 1,879 (50.5%) were male. During the study period, gastric cancer was detected in 35 participants. However, the incidence varied based on their ages. In the age groups <40, 40-49, 50-59, 60-69 and ≥70 years old, the 5-year cumulative incidences (95%CI) of gastric cancer were 0% (0-0%), 0.3% (0.1-1.0%), 1.0% (0.5-1.8%), 1.4% (0.8-2.4%) and 1.9% (0.8-3.8%), respectively. The odds ratios of the incidence of gastric cancer per year, which were evaluated using GEE models for the age groups 40-49, 50-59, 60-69 and ≥70 years old, were 1.51 (95%CI: 0.91-2.49), 1.94 (95%CI: 1.31-2.86), 1.59 (95%CI: 1.23-2.06) and 1.46 (95%CI: 1.06-2.02), respectively. CONCLUSIONS: A screening for gastric cancer using EGD may be appropriate annually for healthy people over 70 years old, every two or three years for people 60-69 years old and every four years for people 50-59 years old. People younger than 50 years old may only need repeat screenings every five years or more.

Pylephlebitis after sigmoid colonic polypectomy.

A man in his 40s presented with a 7-day history of fever and abdominal pain after polypectomy of the sigmoid colon. On physical examination, he had mild tenderness on deep palpation of the left lower abdominal quadrants without guarding, rigidity or rebound tenderness. Contrast-enhanced CT revealed the thrombosis of the inferior mesenteric vein and the portal vein. Blood cultures were positive for Escherichia coli We diagnosed him with pylephlebitis after colonic polypectomy, as a rare complication. He was started on cefmetazole and heparin. Antibiotic and anticoagulation therapy were initiated. He had a complete recovery within 17 days. The patient had no evidence of underlying hypercoagulable condition, and no signs of recurrence at a 3-month follow-up. Pylephlebitis after colonic polypectomy is extremely rare. Although bacteraemia after colonoscopy was a rare complication, phlebitis should be considered in the differential diagnosis of patients who present with persisted fever and abdominal pain after polypectomy.

Adverse reactions of BNT162b2 vaccine booster against COVID-19 in Japan.

Female participants had a higher incidence of headache, nausea, myalgia, arthralgia, redness, pruritus, and inoculation site redness and pruritus (p 0.05). Low grade fever, headache, malaise, myalgia, and inoculation site induration and heat were associated with age group (p 0.05).

Behavioral factors associated with SARS-CoV-2 infection in Japan.

BACKGROUND: The relative burden of COVID-19 has been less severe in Japan. One reason for this may be the uniquely strict restrictions imposed upon bars/restaurants. To assess if this approach was appropriately targeting high-risk individuals, we examined behavioral factors associated with SARS-CoV-2 infection in the community. METHODS: This multicenter case-control study involved individuals receiving SARS-CoV-2 testing in June-August 2021. Behavioral exposures in the past 2 weeks were collected via questionnaire. SARS-CoV-2 PCR-positive individuals were cases, while PCR-negative individuals were controls. RESULTS: The analysis included 778 individuals (266 [34.2%] positives; median age [interquartile range] 33 [27-43] years). Attending three or more social gatherings was associated with SARS-CoV-2 infection (adjusted odds ratio [aOR] 2.00 [95% CI 1.31-3.05]). Attending gatherings with alcohol (aOR 2.29 [1.53-3.42]), at bars/restaurants (aOR 1.55 [1.04-2.30]), outdoors/at parks (aOR 2.87 [1.01-8.13]), at night (aOR 2.07 [1.40-3.04]), five or more people (aOR 1.81 [1.00-3.30]), 2 hours or longer (aOR 1.76 [1.14-2.71]), not wearing a mask during gatherings (aOR 4.18 [2.29-7.64]), and cloth mask use (aOR 1.77 [1.11-2.83]) were associated with infection. Going to karaoke (aOR 2.53 [1.25-5.09]) and to a gym (aOR 1.87 [1.11-3.16]) were also associated with infection. Factors not associated with infection included visiting a cafe with others, ordering takeout, using food delivery services, eating out by oneself, and work/school/travel-related exposures including teleworking. CONCLUSIONS: We identified multiple behavioral factors associated with SARS-CoV-2 infection, many of which were in line with the policy/risk communication implemented in Japan. Rapid assessment of risk factors can inform decision making.

An early intensive intervention for inducing inactive asthma in adults--a one-year follow-up observation study.

BACKGROUND: Treatment strategy that reduces dependence on long-term medication for chronic asthma is preferable. The purpose of the study is to investigate the efficacy of an early intensive intervention for inducing inactive asthma in adults and identify factors that affect the efficacy. METHODS: A prospective study was conducted on subjects who had asthma for two years or less. An intensive intervention consisting of systemic corticosteroid treatment for two weeks followed by inhaled corticosteroid for further 16 weeks with concomitant administration of bronchodilator(s) was administrated on 109 subjects. As a control group, 33 subjects were treated according to the current asthma treatment guidelines for 18 weeks. The primary outcome of the intervention was assessed with symptomatology and use of medication during 12 months after the cessation of treatment period. RESULTS: At one year after the intervention, significantly more patients in the intensive intervention group (41%) than in the control group (24%) had no respiratory symptoms and were medication-free or had experienced minor upper respiratory symptoms (inactive asthma) (P = 0.01). The intensive intervention maintained a significant factor associated with one-year inactive asthma (adjusted odds ratio: 3.61, 95% confidence interval: 1.20-10.84; P = 0.02). Infection as onset cause, asthma duration and pre-treatment %FEV(1.0) were also identified independently associated with inactive asthma. As the limitation, the study was not randomized trial. CONCLUSIONS: Intensive therapy in the early stage is very likely to contribute to increasing one-year asthma inactivity, which may reduce patients' dependence on long-term management by medical treatment.

Resident Burnout and Work Environment.

Objective We examined the prevalence of burnout among resident doctors and its relationship with specific stressors. Method We conducted a nationwide, online, cross-sectional survey in Japan with 604 resident doctors in 2018-2019. Materials Participants completed the Maslach Burnout Inventory-General Survey to evaluate burnout and provided details of their individual factors and working environmental factors. Chi-square tests and t-tests were conducted for categorical and continuous variables, respectively. The association between burnout and resident-reported causes of stress, ways of coping with stress, number of times patient-safety incidents were likely to occur, and individuals who provide support when in trouble was analyzed using logistic regression analyses after controlling for confounding variables. Results A total of 28% met the burnout criteria, 12.2% were exhausted, 2.8% were depressed, and 56.9% were healthy. After adjusting for sex, postgraduate years, type of residency program, marital status, number of inpatients under residents' care, number of working hours, number of night shifts, number of days off, and resident-reported causes of stress - excessive paperwork [odds ratio (OR): 2.24, 95% confidence interval (CI): 1.32-3.80], excessive working hours (OR: 2.75, 95% CI: 1.24-6.04), low autonomy (OR: 3.92, 95% CI: 2.01-7.65), communication problems at the workplace (OR: 2.24, 95% CI: 1.05-4.76), complaints from patients (OR: 6.62, 95% CI: 1.21-36.1), peer competition (OR: 2.22, 95% CI: 1.25-3.93), and anxiety about the future (OR: 2.13, 95% CI: 1.28-3.56) - were independently associated with burnout. The burnout group had more reported patient-safety incidents that were likely to occur per year (>10) (OR: 2.65, 95% CI: 1.01-6.95) and a lack of individuals who could provide support when in trouble (OR: 1.83, 95% CI: 1.01-3.34) than the non-burnout group. Conclusion This study described the prevalence of burnout among residents who responded to our survey. We detected an association between burnout and resident-reported causes of stress, patient-safety incidents, and a lack of individuals who provide support when in trouble. Further interventional studies targeting ways to reduce these concerns are warranted.