Trends in the prevalence and incidence of Crohn's disease in Japan and the United States.

PURPOSE: This study is to describe patient demographic characteristics and estimate annual prevalence and incidence rates of Crohn's disease (CD) in Japan and the United States (US). METHODS: Two large employment-based healthcare claims databases (Japan Medical Data Center [JMDC] in Japan and Merative MarketScan [Merative] in the US) were used to identify patients with CD from 2010 to 2019. Cases were confirmed using an algorithm based on diagnostic with/without treatment codes. The Merative population was used for sex and age standardization of annual prevalence and incidence rates estimated from the JMDC. RESULTS: Patients with CD were generally younger in Japan than in the US at diagnosis (mean 33.6 vs. 39.4 years) and 71.5% were male versus 45.1% in the US. Annual prevalence per 100,000 population increased substantially in both countries, from 34.2 in 2010 to 54.5 in 2019 in Japan (standardized) and 163.3 to 224.2 in the US. Prevalence rates increased in both males and females in all age groups between 6 and < 65 years. Annual incidence rate per 100,000 person-years was almost fourfold higher in the US than Japan (21.0 vs. 5.5 [standardized] in 2019) but remained stable in both countries over time in both sexes and in all age groups. CONCLUSION: The epidemiology of CD differs between Japan and the US. Research to understand the basis of these differences could help to identify at-risk groups in each country, and guide implementation of preventive measures.

Age-specific hospitalization risk of primary and secondary respiratory syncytial virus infection among young children.

OBJECTIVES: Elucidating the infection dynamics that lead to severe respiratory syncytial virus (RSV) pneumonia and hospitalization among young children are critical. We explored the role of infection parity as well as age in months for RSV-associated hospitalization among young children in Japan. METHODS: We used a sequential transmission catalytic model to capture the transmission mechanisms of RSV among infants in an endemic state. We investigated data on the age-dependent seroprevalence and incidence rate of hospitalization in Japan, and jointly estimated the age-specific risk of hospitalization during primary RSV infection and relative risk of hospitalization during secondary infection in children aged <5 years. RESULTS: The estimated risk of hospitalization with primary infection was 0.08 (95% CI: 0.05-0.14) in infants aged 0-2 months. The estimated relative risk of hospitalization owing to secondary infection was 0.18 (95% CI: 0.01-2.04). CONCLUSION: Our simple models successfully captured the infection dynamics of RSV among young children in Japan. The age group of early infancy may be most vulnerable to infection and hospitalization, offering key insights into future vaccinations. The burden of hospitalization from secondary infection may be less important in young children.

Estimation of R(t) based on illness onset data: An analysis of 1907-1908 smallpox epidemic in Tokyo.

R(t), the actual average number of secondary cases per primary case at calendar time t, is epidemiologically useful in assessing transmission dynamics in a population with varying susceptibility levels. However, a technical limitation of existing methods of estimating R(t) is the reliance on the daily number of cases with illness onset and the distribution of the serial interval, although the estimator of R(t) should be calculated as the ratio of newly infected cases at time t to the total number of potentially infectious people at the same time. Using historical data of a smallpox outbreak in Tokyo City, Japan, approximately 100 years ago, we propose a new method to compute R(t) that can be estimated using information on illness onset. Our method decomposes the mechanism of transmission into two distinct pieces of information: the frequency of secondary transmission relative to disease age and the probability density function of the incubation period. Employing a piecewise constant model, our maximum likelihood estimates of R(t) dropped below unity (0.6; 95% confidence interval: 0.5-0.7) for the period from Day 64 to Day 79, indicating that the epidemic was under control in this period. R(t) was continuously below one through the remaining days. The model prediction captured the overall observed pattern of the epidemic well. Our method is appropriate for acute infectious diseases other than smallpox for which variations in infectivity relative to disease age should be considered to correctly estimate the transmission potential, such as the ongoing global epidemic of coronavirus disease 2019 (COVID-19).

Exploring secondary SARS-CoV-2 transmission from asymptomatic cases using contact tracing data.

BACKGROUND: Individuals with asymptomatic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can propagate the virus unknowingly and thus have been a focus of public health attentions since the early stages of the pandemic. Understanding viral transmissibility among asymptomatic individuals is critical for successful control of coronavirus disease 2019 (COVID-19). The present study aimed to understand SARS-CoV-2 transmissibility among young asymptomatic individuals and to assess whether symptomatology was associated with transmission of symptomatic vs. asymptomatic infections. METHODS: We analyzed one of the first-identified clusters of SARS-CoV-2 infections with multiple chains of transmission that occurred among university students in March 2020 in Kyoto prefecture, Japan, using discrete and two-type branching process models. Assuming that the number of secondary cases resulting from either primary symptomatic or asymptomatic cases independently followed negative binomial distributions, we estimated the relative reproduction numbers of an asymptomatic case compared with a symptomatic case. To explore the potential association between symptomatology and transmission of symptomatic vs. asymptomatic incident infections, we also estimated the proportion of secondary symptomatic cases produced by primary symptomatic and asymptomatic cases. RESULTS: The reproduction number for a symptomatic primary case was estimated at 1.14 (95% confidence interval [CI]: 0.61-2.09). The relative reproduction number for asymptomatic cases was estimated at 0.19 (95% CI: 0.03-0.66), indicating that asymptomatic primary cases did not result in sufficient numbers of secondary infections to maintain chains of transmission. There was no apparent tendency for symptomatic primary cases to preferentially produce symptomatic secondary cases. CONCLUSIONS: Using data from a transmission network during the early epidemic in Japan, we successfully estimated the relative transmissibility of asymptomatic cases of SARS-CoV-2 infection at 0.22. These results suggest that contract tracing focusing on symptomatic index cases may be justified given limited testing capacity.

Assessing Interventions against Coronavirus Disease 2019 (COVID-19) in Osaka, Japan: A Modeling Study.

Estimation of the effective reproduction number, R(t), of coronavirus disease (COVID-19) in real-time is a continuing challenge. R(t) reflects the epidemic dynamics based on readily available illness onset data, and is useful for the planning and implementation of public health and social measures. In the present study, we proposed a method for computing the R(t) of COVID-19, and applied this method to the epidemic in Osaka prefecture from February to September 2020. We estimated R(t) as a function of the time of infection using the date of illness onset. The epidemic in Osaka came under control around 2 April during the first wave, and 26 July during the second wave. R(t) did not decline drastically following any single intervention. However, when multiple interventions were combined, the relative reductions in R(t) during the first and second waves were 70% and 51%, respectively. Although the second wave was brought under control without declaring a state of emergency, our model comparison indicated that relying on a single intervention would not be sufficient to reduce R(t) < 1. The outcome of the COVID-19 pandemic continues to rely on political leadership to swiftly design and implement combined interventions capable of broadly and appropriately reducing contacts.

Transmissibility of asymptomatic COVID-19: Data from Japanese clusters.

BACKGROUND: The epidemiological importance of asymptomatic individuals who would never develop illness, compared to those who eventually develop symptoms, has yet to be fully clarified. METHODS: The very first cluster data in Tokyo and Kanagawa (n = 36) were analyzed. Movement of all close contact was restricted for 14 days and they underwent laboratory testing with polymerase chain reaction. The reproduction numbers of symptomatic and asymptomatic cases were estimated. RESULTS: The reproduction number for symptomatic cases was estimated to be 1.2 (95% confidence interval (CI): 0.5-2.9). The relative infectiousness of asymptomatically infected cases was estimated to be 0.27 (95% CI: 0.03-0.81) of symptomatic cases. CONCLUSION: The relative transmissibility of asymptomatic cases is limited. Observing clusters starting with symptomatic transmission might be sufficient for the control.

Treatment patterns and health care resource utilization among Japanese patients with ankylosing spondylitis: A hospital claims database analysis.

OBJECTIVES: To understand the current state of treatment patterns and health care resource utilization among patients in Japan with ankylosing spondylitis (AS) managed in the real-world setting. METHODS: Patient records from the Medical Data Vision database were analyzed to identify patients with ICD-10 AS from April 2009 through July 2017. Measures evaluated included demographic, clinical, and other characteristics at diagnosis; treatment patterns; health care resource utilization; and costs. RESULTS: Four hundred and seventeen patients met the study's inclusion criteria. Treatments observed during the first year after the initial AS diagnosis included nonsteroidal anti-inflammatory drugs (79.6%), corticosteroids (39.3%), methotrexate (22.3%), sulfasalazine (16.8%), adalimumab (14.2%), and infliximab (12.2%). At any time during the mean 33 months of study follow-up, biologic disease-modifying antirheumatic drugs (bDMARDs) were initiated by 115 patients. During the study follow-up, patients who initiated bDMARDs had higher median total per-patient annual health care costs ($26,937 vs $15,323), lower median per-patient hospitalization costs ($29,817 vs. $39,509), and fewer median hospital days per admission (7.0 vs. 11.0 days) compared with the overall group of patients diagnosed with AS. CONCLUSION: This database study provides knowledge of patient characteristics, treatment patterns, HCRU, and costs for patients with AS in Japan. The study outcomes demonstrate a need for increased awareness of proper AS management.

Efficacy and safety of ixekizumab treatment for Japanese patients with moderate to severe plaque psoriasis, erythrodermic psoriasis and generalized pustular psoriasis: Results from a 52-week, open-label, phase 3 study (UNCOVER-J).

Psoriasis, a chronic, immune-mediated skin disease characterized by red, scaly plaques, affects approximately 0.3% of the population in Japan. The aim of this open-label study was to evaluate the long-term efficacy and safety of ixekizumab, a humanized, anti-interleukin-17A monoclonal antibody, in Japanese patients with plaque psoriasis (n = 78, including 11 psoriatic arthritis), erythrodermic psoriasis (n = 8) and generalized pustular psoriasis (n = 5). Ixekizumab was administrated s.c. at baseline (week 0, 160 mg), from weeks 2 to 12 (80 mg every 2 weeks), and from weeks 16 to 52 (80 mg every 4 weeks). At week 52, 92.3% of patients with plaque psoriasis achieved Psoriasis Area and Severity Index (PASI) 75, 80.8% achieved PASI 90, 48.7% achieved PASI 100, and 52.6% had remission of plaques (by static Physician Global Assessment, sPGA [0]). Difficult to treat areas of psoriasis (nail or scalp) also responded to ixekizumab. All patients with psoriatic arthritis who were assessed (5/5) achieved an American College of Rheumatology 20 response. Most patients with erythrodermic psoriasis or generalized pustular psoriasis responded to ixekizumab and the clinical outcome was maintained over 52 weeks (75% and 60% of patients achieved sPGA [0, 1] at week 52, respectively). Mostly mild or moderate treatment-emergent adverse events were reported by 79 of 91 patients; the most common were nasopharyngitis, eczema, seborrheic dermatitis, urticaria and injection site reactions. In conclusion, 52-week ixekizumab treatment was efficacious and well tolerated in Japanese patients with plaque psoriasis. Efficacy was also observed in patients with erythrodermic psoriasis, generalized pustular psoriasis and psoriatic arthritis.

Efficacy and safety of 40 mg or 60 mg duloxetine in Japanese adults with diabetic neuropathic pain: Results from a randomized, 52-week, open-label study.

INTRODUCTION: To examine the long-term efficacy and safety of duloxetine in the treatment of Japanese patients with diabetic neuropathic pain, we carried out a 52-week, randomized, open-label extension of a 12-week, double-blind, placebo-controlled study. MATERIALS AND METHODS: Japanese adults with diabetic neuropathic pain who completed the double-blind study were eligible for this long-term study, carried out at 71 sites in Japan (March 2008 to March 2010). Participants (n = 258) were re-randomized (1:1) to 40 mg/day or 60 mg/day duloxetine. Pain (Brief Pain Inventory severity and interference), quality of life (Patient's Global Impression of Improvement), and safety (primary outcome; adverse events, vital signs, metabolic measures) were measured. RESULTS: Significant (P < 0.0001) and sustained improvements (change ± standard deviation; n = 257) were observed in Brief Pain Inventory severity (average pain score -2.1 ± 1.7). Improvements were also seen in Brief Pain Inventory interference (mean of subscores -0.96 ± 1.52) and Patient's Global Impression of Improvement (-0.9 ± 1.1) scores; these scores decreased significantly (P < 0.0001) during the long-term study. Frequently reported adverse events included somnolence (13.6%), constipation (13.2%) and nausea (10.5%). Increases were observed in plasma glucose, glycosylated hemoglobin and total cholesterol levels, and in bodyweight and heart rate; however, none of these were clinically meaningful. Overall, there were no clinically significant safety concerns. CONCLUSIONS: This is the first publication of a long-term study carried out in Asia with an entirely Japanese patient population to suggest that long-term duloxetine therapy for diabetic neuropathic pain is effective and has an acceptable safety profile.

Splenic abscess caused by Lactobacillus paracasei.

Splenic abscess is relatively uncommon. Infections caused by lactobacilli, which are usually one of the constituents of normal flora of human gut and vagina, are also very uncommon. Here we report a case of splenic abscess caused by Lactobacillus paracasei. We performed a literature review for this rare entity. Immunocompromised status of the patient, who had uncontrolled diabetes, could have contributed to the pathogenesis of this rare disease.

[The analysis of the sensitivity and the specificity of the mass screening system of BSE].

Since the first infected case of BSE(Bovine Spongiform Encephalopathy) was identified in September, 2001 in Japan, Japanese people have been deeply concerned about safety of meat despite a mass screening system established by Japanese government. In the system all the cows for food must be examined with ELISA as screening and additionally with more accurate tests such as western blot etc. if the screened result is positive. To investigate the accuracy of the system, we calculated the number of false negatives and positives using computer simulation. Consequently, the sensitivity analysis towards ELISA showed that even if Japanese cattle were in a low risk group, a few of them are likely to be misdiagnosed as "negative" in spite of true BSE under the current screening system. Also we indicated how to improve the current system to get less false negatives. We believe the analysis of this study can contribute to risk communication with people to minimize the fear or irrationality caused by BSE epidemic.