Strategies for pneumococcal vaccination in older adults in the coming era

Pneumonia, predominantly caused by Streptococcus pneumoniae, remains a leading cause of global mortality. The 23-valent Pneumococcal polysaccharide vaccine (PPSV23) and conjugate vaccines (PCVs) are vital measures to fight against it. This paper discussed the changes in pneumococcal vaccination strategies, particularly for older adults, as vaccine effectiveness and epidemiological patterns shift. While PPSV23 maintains effectiveness against invasive pneumococcal disease (IPD), its effectiveness against pneumococcal pneumonia is declining. Conversely, PCV13 consistently demonstrates effectiveness against both IPD and pneumonia. Consequently, the US Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices recommends using PCVs, notably PCV20 and PCV15, over PPSV23. Japanese studies indicate a change in the efficacy/effectiveness of PPSV23 following PCV introduction in children, likely owing to serotype replacement and herd immunity. Additionally, recent data reveals a plateau in the reduction of PCV13 and PPSV23-covered serotypes, posing a challenge to current strategies. This paper indicates a paradigm shift in pneumonia management, acknowledging its chronic nature and potential to exacerbate other diseases. The future of pneumococcal vaccination lies in broader serotype coverage through PCVs, adapting to serotype changes driven by childhood vaccination programs. Furthermore, continuous research and vaccine development are crucial in this evolving field.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan

OBJECTIVES

This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity.

DESIGN

Retrospective observational study of a nationwide database.

SETTING

The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint.

PARTICIPANTS

This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018.

MAIN OUTCOME MEASURE

The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis.

RESULTS

The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years.

CONCLUSION

ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact.

TRIAL REGISTRATION NUMBER

Chiba University ID1049.

Pulmonary Tuberculosis Incidence among Interferon-Gamma Release Assay-Positive Individuals with Latent Tuberculosis Infection and Fibrotic Lesions in a Vulnerable Urban Population in Osaka City, Japan, 2015-2021

Latent tuberculosis infection (LTBI) with fibrotic lesions (FL) can progress to active tuberculosis (TB). Most previous studies have used tuberculin skin tests, which have lower specificity than interferon-gamma release assays (IGRAs), for LTBI diagnosis. This study evaluated the incidence of active TB among individuals with LTBI (diagnosed using IGRAs) and FL in Nishinari District, Osaka City. In total, 54 men (mean age: 68.7 years) were enrolled, of whom 10 (18.5%) were homeless, and 36 (66.7%) were welfare recipients. The median observation period was 1,084 days (range: 64-2,907 days). The incidence rate of active TB among individuals with LTBI and FL was 1.18 (95% confidence interval: 0.32-4.29) cases per 100 person-years. Among the 19 participants who had not been treated with anti-TB therapy, one (5.3%) progressed to active TB, and among the 30 participants who had completed anti-TB treatment, one (3.3%) progressed to active TB. The other 5 participants did not have TB. This study revealed the incidence of active TB among individuals with LTBI, diagnosed using IGRAs, and FL in a vulnerable urban population. The higher incidence than that reported in previous studies reinforces the importance of improved LTBI management strategies, including chest radiography screening, and LTBI treatment.

Antibody responses after BNT162b2 vaccination in Japanese geriatric intermediate care facilities

Background

To evaluate antibody responses against the primary series of vaccination of severe acute respiratory syndrome coronavirus-2 [SARS-CoV-2] vaccines in the staff and residents of Japanese geriatric intermediate care facilities.

Methods

All subjects (159 staff and 96 residents) received two doses of the BNT162b2 mRNA vaccine 3 weeks apart. Baseline data of subject were collected using a structured form. Serum samples were collected three times: before vaccination, 3 weeks after the first dose, and 4 weeks after the second dose, and anti-receptor binding domain of the spike protein of SARS-CoV-2 [anti-RBD] IgG was measured using two immunoassays.

Results

After the second dose, geometric mean titers [GMT] of anti-RBD with both the Abbott and Roche assay were significantly lower in residents than staff (2282 AU/mL vs. 8505 AU/mL, and 258 U/mL vs. 948 U/mL, respectively). Multivariate analysis of characteristics affecting antibody responses (≥1280 AU/mL for Abbott and > 210 U/mL for Roche) showed lower odds ratios [ORs] for older age (adjusted OR per 10 year increase [aOR] = 0.62, 95 % confidence interval [95 %CI]; 0.38-1.02), steroid usage (aOR = 0.09, 95 %CI; 0.01-0.60) and regular nonsteroidal anti-inflammatory drugs [NSAIDs] usage (aOR = 0.16, 95 %CI; 0.03-0.88).

Conclusions

Elderly people and steroid and NSAID users had lower antibody responses following the second vaccine dose.

Immunogenicity and safety of influenza vaccine in patients with lung cancer receiving immune checkpoint inhibitors: A single-center prospective cohort study

INTRODUCTION

Patients with lung cancer have a high risk of influenza complications. International guidelines recommend annual influenza vaccination for patients with cancer. Immune checkpoint inhibitors (ICIs) are progressively used to treat lung cancer. Data regarding immunogenicity and safety of influenza vaccine are limited in patients with lung cancer receiving ICIs; therefore, we conducted this single-center, prospective observational study in the Japanese population.

METHODS

Patients with lung cancer receiving ICIs and influenza immunization were enrolled. Blood samples were collected from patients for serum antibody titer measurement pre- and 4 ± 1 weeks post-vaccination. The primary endpoint was seroprotection rate (sP) at 4 ± 1 weeks post-vaccination. The secondary endpoints were geometric mean titer (GMT), mean fold rise, seroresponse rate (sR), seroconversion rate (sC), and immune-related adverse events (irAEs), defined as adverse effects caused by ICI administration, 6 months post-vaccination.

RESULTS

Influenza vaccination in the 23 patients included in the immunogenicity analyses significantly increased GMT for all strains, and sP, sR, and sC were 52%-91%, 26%-39%, and 26%-35%, respectively. In the 24 patients included in the safety analyses, 7 (29%) and 5 (21%) patients exhibited systemic and local reactions, respectively. Only one patient (4%) (hypothyroidism, grade 2) showed post-vaccination irAEs.

CONCLUSIONS

Overall, influenza vaccination in patients with lung cancer receiving ICIs showed acceptable immunogenicity and safety, thus supporting annual influenza vaccination in this population.

No association between inactivated influenza vaccination and influenza viral load at diagnosis among young Japanese children: An observational study of the 2013/2014 through 2017/2018 influenza seasons

BACKGROUND

The association between inactivated influenza vaccination and viral load in young children remains unclear.

METHODS

During the 2013/2014 to 2017/2018 influenza seasons in Japan, children under 6 years of age with pre-defined influenza-like illness and influenza-positive status by real-time RT-PCR were recruited at pediatric clinics for this observational study. Influenza viral load was measured for the most predominant subtype/lineage in each season. Using median dichotomized viral load as an outcome, a multilevel logistic regression model was applied to estimate the multivariable adjusted odds ratio (MOR) and 95% confidence interval (CI) for higher viral load.

RESULTS

A total of 1,185 influenza-positive children were analyzed. The median log10 viral load copy number (copies per milliliter) was 5.5 (interquartile range, 4.6 to 6.1) and did not differ by vaccination status: 5.5 for unvaccinated, 5.7 for one dose, and 5.5 for two doses (p = 0.67). The MOR of vaccinated (one or two doses) versus unvaccinated children was 1.19 (95% CI: 0.86-1.64). Other factors showing significant associations with higher viral load were positive results for A(H1N1)pdm09 and A(H3N2) in comparison with B/Yamagata. The respective MORs were 3.25 (95% CI: 2.28-4.64) and 1.81 (95% CI: 1.32-2.49). Significantly elevated MORs against higher viral load were also observed for higher body temperature at influenza diagnosis and shorter duration from fever onset to specimen collection.

CONCLUSION

No association was observed between inactivated-influenza vaccination and viral load at influenza-positive diagnosis. Influenza subtype/lineage, body temperature, and time elapsed since fever onset were significantly associated with viral load.

Influenza vaccine viruses and the development of seasonal vaccines: A Japanese perspective

In Japan, the Ministry of Health, Labour and Welfare (MHLW) designates one specific virus strain for each component of the quadrivalent seasonal influenza vaccine, and four domestic manufacturers produce egg-based influenza vaccines with the same formulation (inactivated, split-virus) using uniform vaccine strains. Thus, discussions of the development of effective seasonal influenza vaccines so far has focused solely on the antigenic match between the vaccine strains and epidemic viruses. However, in 2017, the Japanese selection system of vaccine viruses demonstrated that even a candidate vaccine virus that is antigenically similar to the predicted circulating viruses is not necessarily suitable for vaccine production, given lower productivity of the vaccine. Taking this experience into account, the MHLW reformed the scheme of vaccine strain selection in 2018, and instructed the Vaccine Epidemiology Research Group created by the MHLW to probe how the virus strains for the seasonal influenza vaccine should be selected in Japan. In this context, a symposium, entitled "Issues of the Present Seasonal Influenza Vaccines and Future Prospects", was held as part of the 22nd Annual Meeting of the Japanese Society for Vaccinology in 2018, and subjects related to the influenza vaccine viruses were discussed among relevant administrators, manufacturers, and researchers. This report summarizes the presentations given at that symposium in order to convey the present scheme of vaccine virus selection, the evaluation of the resulting vaccines, and the efforts at new vaccine formulation in Japan. Notably, from March 2022, the MHLW has launched a discussion of the merits of the seasonal influenza vaccines produced by foreign manufacturers.

Incidence and risk factors for norovirus-related diarrhea in Japanese geriatric intermediate care facilities: A prospective cohort study

AIM

The risk of developing infectious diarrhea among elderly residents at Japanese geriatric intermediate care facilities is unclear. We investigated the incidence rate and risk factors of norovirus-related diarrhea at such facilities.

METHODS

This prospective cohort study followed 1727 residents from November 2018 to April 2020 at 10 geriatric intermediate care facilities in Osaka, Japan regarding the occurrence of diarrhea. Resident data were collected from their medical records using structured forms at two to three of the following three time points: at recruitment, if they developed diarrhea, and when they left the facility. Residents who developed diarrhea were tested using rapid diagnostic tests for norovirus. Cox proportional hazard model was employed to hazard ratios (HRs) with 95% confidence intervals (CIs) to estimate the risk factors for norovirus-related diarrhea.

RESULTS

During the study period, 74 residents developed diarrhea, 13 of whom were norovirus positive. The incidence rate of norovirus-related diarrhea was 10.11 per 1000 person-years (95% CI: 4.61-15.61). In terms of risk factors, people with care-needs level 3 were at a higher risk for developing norovirus-related diarrhea (adjusted HR [aHR] = 7.35, 95% CI: 1.45-37.30). Residents with hypertension (aHR = 3.41, 95% CI: 1.05-11.04) or stroke (aHR = 8.84, 95% CI: 2.46-31.83), and those who walked with canes (aHR = 16.68, 95% CI: 1.35-206.52) also had a significantly higher risk for norovirus-related diarrhea.

CONCLUSIONS

Throughout the study period, the incidence of development of diarrhea was low. Care-needs level 3, stroke, hypertension and use of a cane were identified as risk factors for norovirus-related diarrhea in Japanese geriatric intermediate care facilities. Geriatr Gerontol Int 2023; 23: 179-187.

Smoking and drinking habits relating to development of ulcerative colitis in Japanese: A multicenter case-control study

Background and Aim

The number of patients with ulcerative colitis (UC) has been increasing in Japan. To elucidate the risk factors for developing UC in Japan, a hospital-based case-control study was conducted. This study examined the association between smoking/drinking habits and UC onset in detail.

Methods

Cases comprised 132 Japanese patients who had been newly diagnosed with UC between 2008 and 2014 at 38 collaborating hospitals in Japan, and controls comprised 167 patients without UC. Detailed data on smoking and drinking habits were collected using a self-administered questionnaire.

Results

Ex-smokers showed an increasing odds ratio (OR) for UC development compared with never smokers (OR 2.42, 95% confidence interval 1.24-4.72). The ORs of ex-smokers were particularly high among subjects aged less than 40 years, subjects who had smoked more than 10 pack-years, and subjects who were within 13 years of quitting smoking. Regarding drinking habits, ex-drinkers also showed a more than twofold higher OR for UC compared to never drinkers. Ex-drinkers 40 years or older, ex-drinkers who had consumed more than 364 drink-years, and subjects who were less than 6 years after quitting drinking showed increased ORs for UC.

Conclusion

These findings suggest the need for careful attention for UC onset among heavy smokers who quit smoking before 40 years of age and heavy drinkers who quit drinking at ≥40 years of age.

Survey of pediatricians concerning the human papillomavirus vaccine in Japan: Positive attitudes toward vaccination during the period of proactive recommendation being withheld

In 2013, the human papillomavirus (HPV) vaccine was introduced as a national immunization program in Japan. However, because of a wide range of symptoms after vaccination, the Japanese Ministry of Health, Labor and Welfare decided to withhold proactive recommendations, a situation that has continued for more than eight years. During the withholding, absent any scientific or epidemiological evidence to support a relationship between HPV vaccines and symptoms, we surveyed pediatricians at Osaka Pediatric Association and analyzed the changing of attitudes in 2020 (n = 200) and 2021 (n = 190). A total of 44.5% respondents in 2020 and 67.9% in 2021 offered HPV vaccination to targets at the time the questionnaire was administered, indicating that the rate of pediatricians providing vaccines had increased significantly (p < .001). A total of 74.0% of respondents in 2020 and 77.9% in 2021 had a positive opinion of HPV vaccination (p = .369), and 64.3% in 2020 and 78.3% in 2021 were "not at all concerned or had almost no concern" about HPV vaccination (p = .002). These results suggest that, in general, most physicians who are primarily responsible for HPV vaccination in a given field had a positive attitude toward vaccination during the proactive recommendation having been withheld.

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against community-acquired pneumonia in older individuals after the introduction of childhood 13-valent pneumococcal conjugate vaccine: A multicenter hospital-based case-control study in Japan

BACKGROUND

In the era of childhood pneumococcal conjugate vaccine (PCV) immunization, especially 13-valent pneumococcal conjugate vaccine (PCV13) immunization, serotype replacement of Streptococcus pneumoniae and herd immunity in adults have been reported worldwide. Therefore, continuous evaluation of the effectiveness of the pneumococcal vaccine in adults is crucial because vaccine effectiveness may change owing to these factors. The purpose of this study was to evaluate the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) against all-cause pneumonia and pneumococcal pneumonia in older individuals with community-acquired pneumonia (CAP) after the introduction of childhood PCV13 in Japan, a topic that has remained largely unexplored.

METHODS

We evaluated pneumococcal vaccine effectiveness in this multicenter, matched case-control study conducted in hospitals and clinics. Cases included patients (aged ≥ 65 years) newly diagnosed with CAP between October 2016 and September 2019. A maximum of five non-pneumonia control patients matched for sex, school grade, date of outpatient visit, and medical institution were selected for each case. Conditional logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of pneumococcal vaccines for the occurrence of all-cause CAP and pneumococcal CAP.

RESULTS

The analysis included 740 individuals (142 patients and 598 controls). The median age of participants was 75 years (men: 54%). The adjusted OR for pneumococcal vaccination against all-cause CAP was 1.31 (95% CI: 0.84-2.06), while that for PPSV23 vaccination in the previous 5 years was 1.33 (95% CI: 0.85-2.09). The adjusted OR for PPSV23 vaccination in the previous 5 years against pneumococcal CAP was 0.93 (95% CI: 0.35-2.50).

CONCLUSIONS

This study was unable to demonstrate the effectiveness of PPSV23 against all-cause and pneumococcal pneumonia after the introduction of childhood PCV13 in Japan. Nonetheless, additional studies are needed to validate these results.

Kinetics of anti-SARS-CoV-2 antibody titer in healthy adults up to 6 months after BNT162b2 vaccination measured by two immunoassays: A prospective cohort study in Japan

Background

Although several assays are used to measure anti-receptor-binding domain (RBD) antibodies induced after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccination, the assays are not fully comparable in practice. This study evaluated the immunogenicity of the BNT162b2 mRNA vaccine in healthy adults using two immunoassays.

Methods

This prospective cohort study included SARS-CoV-2-naïve adults, predominantly healthcare workers, aged 20–64 years, who received two BNT162b2 vaccine doses between March and May 2021. Blood samples were collected before the first vaccination (S0), before the second vaccination (S1), 4 weeks after the second vaccination (S2), and 6 months after the second vaccination (S3). anti-RBD antibodies were measured using the Architect SARS-CoV-2 IgG II Quant (Abbott Laboratory) and Elecsys anti-SARS-CoV-2 S (Roche Diagnostics) assays.

Results

Among the 385 participants, the geometric mean antibody titers (GMTs) on the Architect assay (AU/mL) were 7.5, 693, 7007, and 1030 for S0, S1, S2, and S3, respectively. The corresponding GMTs on the Elecsys assay (U/mL) were 0.40, 24, 928, and 659, respectively. The GMT ratio (S3/S2) was 0.15 on the Architect and 0.71 on the Elecsys assay. The correlation between antibody titers measured with the two assays were strong at all time points after vaccination (Spearman's correlation coefficient: 0.74 to 0.86, P < 0.01 for all). GMT was significantly lower in the older age group after vaccination (P < 0.01), with no significant differences according to sex. Seroprotection (≥5458 AU/mL on the Architect assay and ≥ 753 U/mL on the Elecsys) at each time point was 0 %, 1 %, 67 %, and 1 % on the Architect assay and 0 %, 1 %, 62 %, and 43 % on the Elecsys, respectively.

Conclusions

Two BNT162b2 vaccine doses resulted in adequate anti-RBD antibody response, which varied by age. As the two assays showed different kinetics, the results of single immunoassays should be interpreted with caution.

Annual trends in adverse events following mumps vaccination in Japan: A retrospective study

BACKGROUND

In Japan, a monovalent mumps vaccine is provided on a voluntary basis. Due to public concerns over post-vaccination aseptic meningitis, the vaccination coverage is not high enough. The present study investigated the incidence of adverse events, including aseptic meningitis, after Torii strain-derived mumps vaccination.

METHODS

This retrospective, observational study used data collected by a vaccine manufacturer regarding adverse events following mumps vaccinations at medical institutions between 1992 and 2018. In addition, the number of Torii strain-derived mumps vaccines shipped each year was obtained. The incidence (per 100,000 doses) and 95% confidence intervals (CIs) were calculated for all adverse events and each adverse event, categorized as aseptic meningitis, encephalitis, mumps, mumps complications, and others.

RESULTS

During the study period, 8,262,121 mumps vaccine doses were shipped, and 688 subjects reported adverse events. The incidence for all adverse events (per 100,000 doses) was 8.33, and the incidence was 4.19 for aseptic meningitis, 0.33 for encephalitis, 0.80 for mumps, 0.25 for mumps complications, and 3.78 for others. The incidence of aseptic meningitis (per 100,000 doses) was 7.90 (95% CI: 5.61-10.18) between 1998 and 2000 but declined by half, to 3.91 (2.46-5.36), between 2001 and 2003. The most recent incidence (per 100,000 doses) of aseptic meningitis, for the period 2016 to 2018, was 2.78 (1.94-3.62).

CONCLUSION

The incidence of post-vaccination aseptic meningitis has declined significantly since 2001, and the incidence has remained stable at fewer than 3 cases per 100,000 doses since 2010. Multiple factors might have contributed to the decline in aseptic meningitis incidence, including (i) lowered misclassification of aseptic meningitis resulting from echovirus infection; (ii) changes in the vaccine manufacturing process in 2000; and (iii) publication in 2008 of the recommendation for vaccination of children at 1 year of age.

Geographic distribution of the incidence of osteonecrosis of the femoral head in Japan and its relation to smoking prevalence

OBJECTIVES

Alcohol intake and smoking are modifiable lifestyle-related risk factors for osteonecrosis of the femoral head (ONFH). We investigated geographic differences in ONFH incidence in Japan and the correlation with alcohol intake and smoking to develop prevention strategies for ONFH in Japan.

METHODS

This ecological study was conducted in Japan primarily using the following data sources: nationwide epidemiological survey and national survey. We estimated the annual ONFH incidence and the prevalence of alcohol drinking and smoking in each prefecture. Prefectural incidence and prevalence were calculated by sex and age-standardization.

RESULTS

The mean annual ONFH incidence per 100,000 population was 3.08 in men and 1.63 in women, respectively. There was no significant correlation between ONFH incidence and the prevalence of any levels of alcohol intake, while smoking ≥20 cigarettes/day showed a significant and moderate correlation in men (r = 0.47, p = .01). This correlation remained significant after adjustment for the prevalence of any levels of alcohol intake (standardized partial regression coefficient = 0.47-0.49, p = .009-.01).

CONCLUSION

ONFH incidence is geographically variable in Japan, and this may be partly explained by the distribution of smoking prevalence. Smoking cessation may contribute to an effective decline in the overall ONFH incidence in Japan.

A nationwide epidemiological survey of adolescent patients with diverse symptoms similar to those following human papillomavirus vaccination: background prevalence and incidence for considering vaccine safety in Japan

BACKGROUND

Since June 2013, Japan has suspended proactive recommendation of human papillomavirus (HPV) vaccination due to self-reported diverse symptoms, including pain and motor dysfunction, as possible serious adverse events following immunization. Although these symptoms may be seen in adolescents without HPV vaccination, their frequency taking into account disease severity has not been examined.

METHODS

A two-stage, descriptive, nationwide epidemiological survey was conducted in 2016 with a 6-month targeted period from July 1 to December 31, 2015 to estimate the prevalence and incidence of diverse symptoms among Japanese adolescents without HPV vaccination. Participants were 11,037 medical departments in hospitals selected nationwide by stratified random sampling. Eligible patients had to satisfy four criteria: (1) aged 12-18 years upon visiting hospital; (2) having at least one of four symptoms/disorders (pain or sensory dysfunction, motor dysfunction, autonomic dysfunction, or cognitive impairment); (3) symptoms/disorders persisting for at least three months; and (4) both criteria (2) and (3) influence attendance at school or work. We further extracted patients with diverse symptoms similar to those after HPV vaccination while considering opinions of doctors in charge.

RESULTS

Estimated 6-month period prevalence of diverse symptoms among girls aged 12-18 years without HPV vaccination was 20.2 per 100,000. Annual incidence was estimated to be 7.3 per 100,000.

CONCLUSION

Adolescent Japanese girls without HPV vaccination also visited hospitals with diverse symptoms similar to those following HPV vaccination. Our findings predicted the medical demands for diverse symptoms that are temporally associated with but not caused by vaccination of Japanese adolescents.

655Association between Crohn's disease onset and oral hygiene: a Japanese multicenter case-control study

Background

The prevalence of Crohn’s disease is increasing in Japan, but risk factors for this disease have yet to be characterized. A recent study using mice, indicated that Klebsiella strains in the oral cavity may be associated with inflammatory bowel disease. We investigated the association between oral hygiene and Crohn’s disease onset.

Methods

We conducted a multicenter case-control study and compared oral hygiene in 69 patients with newly diagnosed Crohn’s disease to that in 113 control patients (patients with other diseases matched for institution, age, and sex). The exposure variables were number of teeth, use of dentures, implant treatment, and frequency of brushing. A conditional logistic model was used to calculate odds ratios and 95% confidence intervals of these factors for Crohn’s disease onset.

Results

The decreased odds ratios of brushing teeth were observed with increasing daily frequency (trend for p = 0.039), with 0.52 (0.20–1.33) for twice daily brushings and 0.26 (0.07–0.97) for three or more daily brushings, (reference category: brushing no or once a day). No other oral hygiene factors were associated with the onset of Crohn's disease.

Conclusions

Our findings suggest that frequent brushing may have a protective association with the development of Crohn's disease.

Key messages

This result may provide a clue to the possible involvement of oral bacteria in the development of inflammatory bowel disease.

674The incidence and risk factors of acute infectious diarrhea at Japanese geriatric intermediate care facilities

Background

Norovirus infection and Clostridioides difficile infection (CDI) are major causes of acute infectious diarrhea at medical facilities. “Geriatric intermediate care facilities” are a type of medical facility that tend to the daily life needs of elderly Japanese people. However, there is no research about norovirus- or CDI-related diarrhea at Japanese geriatric intermediate care facilities.

Methods

This prospective cohort study included 1445 residents at 10 geriatric intermediate care facilities in Osaka between November 2018 and October 2019. The study subjects were followed regarding the occurrence of acute infectious diarrhea and the results of rapid diagnostic tests for norovirus and CDI. We calculated incidence rates and hazard ratios (HR) with 95% confidential intervals (CI) to identify the risk factors of infectious diarrhea.

Results

Thirty-seven residents developed diarrhea during the observation period, although none of them was positive for norovirus or CDI. The total incidence rate was 1.21/10,000 person-days (95%CI: 0.82-1.60). Compared with residents aged 87-91 years, those aged ≤ 80 years had a significantly higher risk of diarrhea (HR = 3.85, 95%CI: 1.27-11.66). Moreover, residents with thyroid diseases had a significantly higher risk of diarrhea than those without thyroid disease (HR = 5.33, 95%CI: 2.32-12.25).

Conclusions

The incidence of acute infectious diarrhea is relatively low. However, residents who are &lt; 80 years old and those with thyroid diseases are more likely to develop diarrhea.

Key messages

We describe the situation of acute infectious diarrhea at Japanese geriatric intermediate care facilities

Epidemiological study of osteonecrosis of the femoral head using the national registry of designated intractable diseases in Japan

OBJECTIVES

We aimed to investigate the epidemiological characteristics of osteonecrosis of the femoral head (ONFH) using the designated intractable diseases (DID) database in Japan.

METHODS

Data on patients who had received public subsidies for medical costs due to ONFH from 2012 to 2013 were extracted from the DID database. The incidence and prevalence of ONFH, distribution of gender, age, and the prevalence of associated risk factors were assessed. These epidemiological characteristics were compared with those of another nationwide ONFH survey conducted during a similar period.

RESULTS

Data on 3264 newly diagnosed patients (incident cases) and 20,042 patients registered until 2013 (prevalent cases) were evaluated. The corrected annual incidence and prevalence of ONFH per 100,000 were 3.0 and 18.2-19.2, respectively. The ratio of males to females was 1.4 in 2012 and 1.2 in 2013, respectively. Peak distribution was observed at ages 40s and 60s in males and females, respectively. The prevalence of the risk factors were steroid-associated: 39%, alcohol-associated: 30%, both: 4%, and none: 27%.

CONCLUSIONS

The DID database data showed a similar distribution of gender and age to that in other nationwide surveys but lower incidence and prevalence of ONFH. Sampling bias may affect the epidemiological characteristics of ONFH.

Kawasaki Disease and Vaccination: Prospective Case-Control and Case-Crossover Studies among Infants in Japan

The causal effects of vaccines on Kawasaki disease (KD) remain elusive. We aimed to examine the association between vaccines administered during infancy and the development of KD in Japan. We conducted a multicenter prospective case-control study using questionnaires and compared the vaccination status of infants (age: 6 weeks to 9 months) who developed KD (KD group; n = 102) and those who did not develop KD (non-KD group; n = 139). Next, we performed a case-crossover study of 98 cases in the KD group and compared the status of vaccinations between the case and control periods. We also compared the incidence of KD in children for each 5-year period before and after the addition of new vaccines (2012–2013) using data from the Nationwide Survey of KD. In the case-control study, the vaccination status of the KD and control groups did not differ to a statistically significant extent. Multivariable analysis of the vaccination status and patient backgrounds showed no significant association between vaccination and KD development. In the case-crossover study, the status of vaccinations during the case and control periods did not differ to a statistically significant extent. In the analysis of data from the Nationwide Survey of KD, the incidence of KD in children of ages subject to frequent vaccination showed no significant increases in the latter five years, 2014–2018. Based on these prospective analyses, we confirmed that vaccination in early infancy did not affect the risk of KD.

Lifestyles Associated with Prognosis After Eradication of Hepatitis C Virus: A Prospective Cohort Study in Japan

BACKGROUND

Hepatocellular carcinoma develops in some patients with hepatitis C virus (HCV), even after achieving sustained virological response (SVR).

AIMS

We examined factors associated with liver disease progression in a prospective cohort study of SVR patients.

METHODS

Participants were patients who had visited a hospital for clinical follow-up of chronic HCV infection in 2005 and had reached SVR as a result of subsequent antiviral treatment. Baseline information including lifestyle and dietary habits before SVR was collected in 2005 using self-administered questionnaires, and clinical information before SVR was collected from medical records in 2005. Study outcome was liver disease progression such as liver cirrhosis, hepatocellular carcinoma, and/or liver disease-related death after SVR. Proportional hazard models were employed to calculate hazard ratios (HRs) and 95% confidence intervals for each variable.

RESULTS

Of 180 SVR patients, 27 patients (15%) showed liver disease progression after SVR: 26 (14%) were diagnosed with liver cirrhosis, two (1%) with hepatocellular carcinoma, and/or one (0.6%) with liver-disease-related death. Besides older age at SVR (HR = 11.9, P < 0.01) and aspartate aminotransferase-to-platelet ratio index score ≥ 1.0 before SVR (HR = 2.63, P = 0.03), alcohol drinkers before SVR (HR = 2.82, P = 0.06) were suggested to be associated with liver disease progression after SVR, whereas higher consumption of vitamin B12 before SVR showed a decreased HR for liver disease progression (HR = 0.41, P = 0.09).

CONCLUSIONS

Alcohol drinking might be associated with liver disease progression, whereas vitamin B12 intake might have protective effects against liver disease progression after eradication of HCV. Further studies are needed to confirm these findings.

Association of Dietary Fatty Acid Intake With the Development of Ulcerative Colitis: A Multicenter Case-Control Study in Japan

BACKGROUND

Dietary fatty acids can affect chronic intestinal inflammation and have been reported to be associated with the development of ulcerative colitis (UC), mainly in Europe and the United States. The association of dietary intake of fatty acids and the risk for UC was investigated in Japan, where dietary habits lead to lower meat and higher fish consumption than in Western countries.

METHODS

A multicenter case-control study of 83 newly diagnosed patients with UC and 128 age- and sex-matched control patients in the hospital was conducted from 2008 to 2014. Dietary fatty acid intake in the preceding 1 month and 1 year were examined using a self-administered diet history questionnaire that was developed for Japanese people.

RESULTS

About 92% of patients had experienced the first symptoms of UC within the preceding 11 months. Regarding dietary habits in the preceding year, the risk for UC was significantly decreased in patients who consumed n-6/n-3 polyunsaturated fatty acids at a ratio of ≥5.2 (odds ratio [OR] = 0.26; 95% confidence interval [CI], 0.10-0.68). Conversely, an increased risk for UC was observed in the highest tertiles of consumption of docosahexaenoic acid (OR = 7.22; 95% CI, 2.09-24.95), eicosapentaenoic acid (OR = 6.91; 95% CI, 1.88-25.44), and docosapentaenoic acid (OR = 4.83; 95% CI, 1.56-14.95).

CONCLUSIONS

The ratio of n-6/n-3 polyunsaturated fatty acid intake was associated with a decreased risk for UC development. However, high intakes of docosahexaenoic acid, eicosapentaenoic acid, and docosapentaenoic acid may increase the risk for UC development.

Japanese Orthopaedic Association 2019 Guidelines for osteonecrosis of the femoral head

PURPOSE

The Clinical Practice Guidelines for Osteonecrosis of the Femoral Head (ONFH) 2019 Edition, written by the working group for ONFH guidelines of the Japanese Investigation Committee (JIC) for ONFH under the auspices of the Japanese Ministry of Health, Labour, and Welfare and endorsed by the Japanese Orthopaedic Association, were published in Japanese in October 2019. The objective of this guideline is to provide a support tool for decision-making between doctors and patients.

METHODS

Procedures for developing this guideline were based on the Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014, which proposed an appropriate method for preparing clinical guidelines in Japan.

RESULTS

This clinical practice guideline consists of 7 chapters: epidemiology; pathology; diagnosis; conservative therapy; surgical treatment: bone transplantation/cell therapy; surgical treatment: osteotomy; and surgical treatment: hip replacement. Twelve background questions and 13 clinical questions were determined to define the basic features of the disease and to be addressed when deciding treatment in daily practice, respectively.

CONCLUSIONS

The clinical practice guidelines for the ONFH 2019 edition will be useful for physicians, investigators, and medical staff in clinical practice, as well as for patients, during the decision-making process when defining how to treat ONFH.

Cluster of Severe Acute Respiratory Syndrome Coronavirus 2 Infections Linked to Music Clubs in Osaka, Japan

BACKGROUND

It is important to understand the mode of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for disease control. We aimed to clarify how soon SARS-CoV-2 transmission can occur after infection by asymptomatically infected individuals.

METHODS

We analyzed the publicly available epidemiological information for a cluster of 108 cases of coronavirus disease 2019 (COVID-19) cases in Osaka, Japan.

RESULTS

Among cases, 51 cases attended a live music club only once and were considered to have a single visit. Ten remained asymptomatic at the time of COVID-19 diagnosis by reverse-transcription polymerase chain reaction, which was on average 20 days after exposure. Three routes of secondary transmission were identified, with 2-4 days from infection to transmission. All index cases for secondary transmission were asymptomatic at the time of contact with other people. Based on the date of symptom onset in the remaining 41 cases, the period from exposure to illness ranged from 2 to 17 days.

CONCLUSIONS

Seemingly healthy people could spread SARS-CoV-2 during intense activities in enclosed environments without sufficient ventilation. Asymptomatically infected persons can transmit the virus as soon as 2 days after infection. Continuous efforts to avoid crowding and to maintain personal hygiene are needed for effective control of COVID-19.

Risk factors for hepatocellular carcinoma in treated chronic hepatitis C patients-Relationship to smoking and alcohol

Background and Aim

The purpose of this study was to identify lifestyle risk factors, such as cigarette smoking and alcohol consumption, in relation to the development of hepatocellular carcinoma (HCC) among chronic hepatitis C patients who have achieved a sustained virologic response (SVR).

Methods

This cross-sectional study was conducted between 2014 and 2017 using self-administered questionnaires and medical information at two tertiary hospitals in Osaka, Japan. Study subjects were chronic hepatitis C patients who had achieved SVR without HCC following antiviral treatment that was completed more than 1 year earlier. A logistic regression model was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the development of post-SVR HCC for each factor.

Results

Of 202 participants, 18 patients were diagnosed with post-SVR HCC. After considering potential confounders, former drinkers at the time of SVR (OR, 9.51; 95% CI, 1.08-83.90) and patients with a history of gastric or duodenal ulcer (OR, 4.14; 95% CI, 1.37-12.46) were significantly associated with HCC. In addition, among patients with severe fibrosis, current smokers at the time of SVR had an increased OR for HCC compared with never smokers, with marginal significance (OR, 5.61; 95% CI, 0.97-32.63).

Conclusions

In chronic hepatitis C patients with severe fibrosis, continuing smoking after achieving SVR could be a risk factor for post-SVR HCC. The relationship between gastric or duodenal ulcer history and post-SVR HCC should be investigated further.

Comparison of immunogenicity between candidate influenza A(H3N2) virus vaccine strains in Japan: A randomized controlled trial using a monovalent vaccine of A/Saitama/103/2014 (CEXP-002) and A/Hong Kong/4801/2014 (X-263)

BACKGROUND

For the 2017-18 influenza season, A/Saitama/103/2014 (CEXP-002) (Saitama strain) was antigenically more similar to prior circulating strains than A/Hong Kong/4801/2014 (X-263) (Hong Kong strain) in a ferret model and was selected as the A(H3N2) vaccine virus strain in Japan. However, the Saitama strain grew poorly, and the Japanese government switched to the Hong Kong strain, raising public concerns of poor effectiveness. To enhance understanding of the correlation between antigenicity in experimental models and immunogenicity, as a surrogate measure of vaccine effectiveness, in the human population, we compared the immunogenicity of specially-prepared single dose monovalent influenza A(H3N2) vaccines containing the Saitama or the Hong Kong strain.

METHODS

A randomized controlled trial of 100 healthy adults aged 20-64 years (n = 50/group) was conducted. Virus neutralization assay was performed on sera from days 0 (pre-vaccination) and 21 (post-vaccination). Geometric mean titer (GMT), mean fold rise (MFR), seroconversion proportion (SCP), and seroprotection proportion (SPP) were calculated for vaccine strains and a representative circulating A(H3N2) virus strain (A/Osaka/188/2017).

RESULTS

For the Hong Kong strain, post-vaccination GMT was significantly higher in the Hong Kong vaccine recipients (1:546 vs 1:260, p < 0.01), but MFR, SCP, and SPP were similar for both vaccine groups. For the Saitama strain, post-vaccination GMT (1:116 vs 1:61, p = 0.01) and SPP (86% vs 68%, p = 0.03) were significantly higher in the Hong Kong vaccine recipients, but MFR and SCP were similar for both vaccine groups. Against A/Osaka/188/2017, post-vaccination GMT and MFR were similar in both vaccine groups, but SCP (32% vs 4%, p < 0.01) and SPP (28% vs. 6%, p < 0.01) were significantly higher in the Hong Kong vaccine recipients.

CONCLUSION

The Hong Kong vaccine induced better or equivalent immunogenicity in comparison to the Saitama vaccine. Our trial showed that antigenic similarity in experimental models does not necessarily correlate with immunogenicity in the human population.

CLINICAL TRIAL REGISTRATION

UMIN000029293.

Risk of Seasonal Influenza by Occupation in a Railway Company in a Metropolitan Area of Japan during Three Influenza Seasons

Station staff may be at high risk for influenza due to high frequency contact with other people. We examined the risk of influenza by occupational group in a railway company. A retrospective observational study was conducted among employees at a branch office of a railway company in eastern Japan, located in a metropolitan area, for 2012/13, 2013/14, and 2014/15 influenza seasons. The study population included employees who had received influenza vaccination for the season in question and the previous season. Outcome was defined as self-reported influenza illness during the respective season, identified through the vaccine screening questionnaire in the following season. Study participants included employees whose outcome information could be obtained. Standardized morbidity ratios (SMRs) by occupational group (station staff, engineers, train crew) for each season were calculated. For 2012/13, 2013/14, and 2014/15 seasons, attack rates were 4.7% (19/403), 5.2% (21/407), and 7.8% (31/397), respectively. Among the participants, SMRs of station staff were lower in the 2012/13 (SMR = 57; 95% confidence intervals [CI] = 18-133) and 2014/15 (SMR = 75; 95%CI = 36-138) seasons and similar to other groups in the 2013/14 season. Enhanced countermeasures, regardless of occupational group, may be effective in preventing the spread of influenza infection.

Estimated Prevalence of Cronkhite-Canada Syndrome, Chronic Enteropathy Associated With SLCO2A1 Gene, and Intestinal Behçet's Disease in Japan in 2017: A Nationwide Survey

Background

Cronkhite-Canada syndrome (CCS), chronic enteropathy associated with SLCO2A1 gene (CEAS), and intestinal Behçet’s disease (BD) are classified as intractable intestinal disorders in Japan. However, the national prevalence of these diseases remains unknown. We performed a nationwide survey to estimate the patient numbers and prevalence rates of these diseases throughout Japan in 2017.

Methods

We conducted a mail-based survey targeting hospitals across Japan to estimate the annual numbers of patients with CCS, CEAS, and intestinal BD in 2017. Using a stratified random sampling method, we selected 2,979 hospital departments and asked them to report the number of patients who met specific diagnostic criteria. The total number of patients for each disease was estimated by multiplying the reported numbers by the reciprocal of the sampling rate and response rate. The corresponding prevalence rates per 1,000,000 population were calculated based on the mid-year population of Japan in 2017.

Results

The overall survey response rate was 68.1% (2,029 departments). The estimated numbers of patients with CCS, CEAS, and intestinal BD were 473 (95% confidence interval [CI], 357–589), 388 (95% CI, 289–486), and 3,139 (95% CI, 2,749–3,529), respectively; the prevalence rates per 1,000,000 population were 3.7 (male: 4.0; female: 3.5), 3.1 (male: 3.0; female: 3.1), and 24.8 (male: 24.5; female: 25.0), respectively. The male-to-female ratios were 1.10, 0.94, and 0.93 for patients with CCS, CEAS, and intestinal BD, respectively.

Conclusions

Estimates of the national prevalence of CCS, CEAS, and intestinal BD in Japan were generated and found to be higher than those previously reported.

Safety of influenza vaccination on adverse birth outcomes among pregnant women: A prospective cohort study in Japan

BACKGROUND

Pregnant women are in the highest priority group for receiving influenza vaccination. However, they may be reluctant to receive the vaccination due to concerns about the influence of vaccination on the fetuses.

METHODS

This prospective cohort study of 10 330 pregnant women examined the safety of influenza vaccination in terms of adverse birth outcomes. Influenza vaccination during pregnancy was determined from questionnaires before and after the 2013/2014 influenza season. All subjects were followed until the end of their pregnancy. Adverse birth outcomes, including miscarriage, stillbirth, preterm birth, low birth weight, and malformation, were assessed by obstetrician reports.

RESULTS

Adverse birth outcomes were reported for 641 (10%) of the 6387 unvaccinated pregnant women and 356 (9%) of the 3943 vaccinated pregnant women. Even after adjusting for potential confounders, vaccination during pregnancy showed no association with the risk of adverse birth outcomes (odds ratio 0.90, 95% confidence interval 0.76-1.07). Vaccination during the first or second trimester displayed no association with adverse birth outcomes, whereas vaccination during the third trimester was associated with a decreased risk of adverse birth outcomes (odds ratio 0.70, 95% confidence interval 0.51-0.98).

CONCLUSIONS

Influenza vaccination during pregnancy did not increase the risk of adverse birth outcomes, regardless of the trimester in which vaccination was performed, when compared to unvaccinated pregnant women.

Surgery trends for osteonecrosis of the femoral head: a fifteen-year multi-centre study in Japan

PURPOSE

The most appropriate procedure and at what type and stage of osteonecrosis of the femoral head (ONFH) these procedures had been argued. We attempted to clarify the trend in surgical operations with respect to the age of patients, type classification, and stage of ONFH over a period of 15 years by using the multi-center sentinel monitoring system in Japan.

METHODS

We evaluated the hips of 3844 patients using this system in three phases of every five  years from 2003 to 2017. We classified the surgical procedures as osteotomy (OT), hemiarthroplasty (Hemi), and total hip arthroplasty (THA). We assessed the trend in age, type classification, and stage of ONFH over three time periods; "early," and the "late." We calculated the proportion of surgeries for ONFH in each period. We used the Cochran-Armitage test to evaluate trends in proportion of two levels of characteristics across three time periods.

RESULTS

The proportion of younger patients significantly decreased. The proportion of OT and Hemi decreased over time, while the proportion of THA increased. The proportion of patients with types C1 and C2 who underwent OT and Hemi decreased over time. In contrast, that of THA increased. The proportion of patients who underwent OT and Hemi significantly decreased; the proportion of patients who underwent THA significantly increased over time at all stages.

CONCLUSIONS

In Japan, the younger patients underwent surgery for ONFH decreased. The patients who underwent OT and Hemi for ONFH decreased, while that of THA increased over time.

Correction to: Estimated prevalence of ulcerative colitis and Crohn's disease in Japan in 2015: an analysis of a nationwide survey

The authors would like to correct the errors in the publication of the original article.

Estimated prevalence of ulcerative colitis and Crohn's disease in Japan in 2014: an analysis of a nationwide survey

BACKGROUND

Almost a quarter century has passed since the first nationwide survey on ulcerative colitis (UC) and Crohn's disease (CD) was conducted in Japan. In this study, we used a nationwide survey to estimate the number of patients and prevalence of these diseases in Japan in 2014.

METHODS

We conducted a mail-based survey targeting hospitals to estimate the annual numbers of patients with UC and CD in 2014. Respondents were asked to report the numbers of patients who met specific diagnostic criteria for these two conditions. A stratified random sampling method was used, and a total of 3712 departments (internal medicine, surgery, pediatrics, and pediatric surgery) were selected for analysis. The overall and sex-specific annual numbers of UC and CD patients were estimated. The corresponding prevalence rates per 100,000 population were calculated by dividing the number of patients with each disease by the mid-year population of Japan in 2014.

RESULTS

The overall survey response rate was 56.7% (2016 departments). The estimated numbers of patients with UC and CD were 219,685 (95% confidence interval: 183,968-255,403) and 70,700 (56,702-84,699), respectively. The annual prevalence rates of UC and CD per 100,000 population were 172.9 (men: 192.3; women: 154.5) and 55.6 (men: 79.5; women: 33.1), respectively. These numbers are almost tenfold increase in comparing the previous survey (22,300 in UC and 7,400 in CD). The male-to-female ratios were 1.24 for UC and 2.40 for CD, and the UC-to-CD ratio was 3.11.

CONCLUSIONS

The prevalence of UC and CD in Japan has risen substantially over the past two decades, and their disease burden requires further examination.

Association between dietary iron and zinc intake and development of ulcerative colitis: A case-control study in Japan

BACKGROUND AND AIM

The prevalence of ulcerative colitis (UC) has been increasing in Japan. Trace elements, such as iron, zinc, magnesium, and copper, can cause digestive symptoms where there is a deficiency or excess. We focused on the dietary intake of trace elements and their associations with UC development.

METHODS

A multicenter, hospital-based case-control study was conducted in Japan. Cases were 127 newly diagnosed UC patients, and 171 age-matched and sex-matched hospital controls were recruited. We considered that UC patients had potentially changed their dietary habits due to disease symptoms. The dietary habits were investigated using a self-administered diet history questionnaire to analyze the dietary intakes and frequencies at two points, the previous 1 month and 1 year before.

RESULTS

In the assessment of dietary habits 1 year before, the highest intake of iron showed an increased odds ratio (OR) for UC on multivariate analysis (OR = 4.05, 95% confidence interval, 1.46-11.2, P < 0.01). The highest intake of zinc 1 year before showed a decreased OR for UC (OR = 0.39, 95% confidence interval, 0.18-0.85, P = 0.01). Intakes of magnesium and copper had no significant association with UC. Because most UC cases had experienced the first symptom of UC within the previous 11 months, these intakes at 1 year before represented an association with pre-illness dietary habits.

CONCLUSION

A high intake of iron has some effect on the development of UC. In contrast, a high intake of zinc has a protective effect on the development of UC.

Nationwide Survey of Pediatric Inpatients With Hand, Foot, and Mouth Disease, Herpangina, and Associated Complications During an Epidemic Period in Japan: Estimated Number of Hospitalized Patients and Factors Associated With Severe Cases

BACKGROUND

Severe pediatric cases of hand, foot, and mouth disease (HFMD), herpangina (HA), and associated complications caused by enterovirus 71 (EV71) infection have brought substantial public health impact in Asia. This study aimed to elucidate the epidemiology of these pediatric cases in Japan.

METHODS

A nationwide survey was conducted using stratified random sampling of hospital pediatric departments. We estimated the number of inpatients with HFMD, HA, and associated complications between April 1 and September 30, 2010, during which EV71 was circulating predominantly. Factors associated with severe cases with ≥7 days of admission, sequelae, or outcome of death were analyzed using multivariate logistic regression.

RESULTS

During the 6-month epidemic period, the number of pediatric inpatients aged <15 years was about 2,900 (estimated cumulative incidence of hospitalized cases: 17.0 per 100,000 population). Severe cases were significantly associated with younger age. Compared to patients ≥5 years of age, the odds ratios (ORs) for <1 year of age and 1 to <3 years of age were 5.74 (95% confidence interval [CI], 2.14-15.4) and 2.94 (95% CI, 1.02-8.51), respectively. Elevated ORs for hyperglycemia (plasma glucose level of ≥8.3 mmol/L) on admission (OR 3.60; 95% CI, 0.94-13.8) were also observed.

CONCLUSIONS

Disease burden of pediatric inpatients with HFMD, HA, and associated complications in Japan was described for the first time. During an EV71 epidemic, younger age and, suggestively, hyperglycemia may have been critical factors requiring more careful treatment.

Japanese periodical nationwide epidemiologic survey of aberrant portal hemodynamics

AIM

Idiopathic portal hypertension (IPH), extrahepatic portal obstruction (EHO), and Budd-Chiari syndrome (BCS) are characterized by aberrant portal hemodynamics of unknown etiology. The aim of this study was to explore trends in the descriptive epidemiology of these diseases through periodical nationwide surveys.

METHODS

Nationwide epidemiologic surveys were undertaken in 1999, 2005, and 2015 using the same protocol. The survey targets were selected from all departments of gastrointestinal medicine, surgery, pediatrics, and pediatric surgery in Japan by stratified random sampling according to the number of beds. We asked each department to complete a mail-back questionnaire on the annual numbers of patients with IPH, EHO, and BCS during the preceding year.

RESULTS

The estimated number of BCS patients increased from 280 (95% confidence interval, 200-360) in 1999 survey to 410 (300-530) in 2015 survey, whereas the number of IPH and EHO patients has remained largely unchanged during the 15 years (IPH was approximately 1000; EHO was approximately 770 in 2015 survey). The mean age at symptom onset was approximately 45 years for IPH, 30 years for EHO, and 40 years for BCS over the past 15 years. Those who described disease aggravation from the time of diagnosis accounted for approximately 10% of IPH, 15% of EHO, and 20% of BCS patients in each of the three surveys.

CONCLUSIONS

In Japan, the prevalence of BCS is increasing, while those of IPH and EHO appear to be stable. Clinical characteristics, including prognoses, have remained largely unchanged in the past 15 years.

Lower dietary variety is a relevant factor for malnutrition in older Japanese home-care recipients: a cross-sectional study

Background

Nutritional status of the older people is affected by various life-style factors. Although dietary habit is one of the life-style factors, it is unknown which of older home-care recipients’ dietary habits are associated with malnutrition.

The purpose of this study was to examine the association of dietary variety, as an evaluation index for dietary habits, with malnutrition in Japanese older home-care recipients.

Methods

This cross-sectional study was conducted in a single city, Hyogo Prefecture, Japan between July and October 2016. Three hundred thirty-three community-dwelling older care recipients (aged 65 years or older who were receiving home-visit nursing care services) were enrolled. Their nutritional status (Mini Nutritional Assessment®-short form: MNA®-SF), dietary variety (Food frequency score [FFS]), socio-demographic characteristics (age, sex, marital status, etc.), health indicators (comorbidity [Charlson Comorbidity Index] and dysphagia status [Dysphagia Severity Scale]) were assessed. The participants were classified into two groups: malnourished (0–7 points) and non-malnourished (8–14 points), according to their MNA®-SF scores. Multivariate logistic regression analysis was used to examine the factors associated with malnutrition.

Results

A total of 317 participants were analyzed (118 men, 199 women, median age: 84 years). Compared to the fourth (highest) quartile of FFS, odds ratios (OR) (95% confidence intervals [CI]) of the third, second, and first (lowest) quartiles of FFS were 1.08 (0.42–2.80), 1.29 (0.56–2.98), and 2.30 (1.02–5.19), respectively (p for trend = 0.049). Higher Charlson Comorbidity Index score and the presence of dysphagia were also significantly associated with malnutrition (OR: 2.08, 95% CI: 1.08–4.00 and OR: 3.86, 95% CI: 2.08–7.17, respectively).

Conclusion

Lower dietary variety was significantly associated with malnutrition in Japanese older home-care recipients.

Nationwide survey on cerebral amyloid angiopathy in Japan

BACKGROUND AND PURPOSE

A nationwide survey was conducted to understand the epidemiology of cerebral amyloid angiopathy-related intracerebral hemorrhage (CAA-related ICH) and cerebral amyloid angiopathy-related inflammation/vasculitis (CAA-ri) in Japan.

METHODS

To estimate the total number and clinical features of patients with CAA-related ICH and CAA-ri between January 2012 and December 2014 and to analyze their clinical features, questionnaires were sent to randomly selected hospitals in Japan.

RESULTS

In the first survey, 2348 of 4657 departments responded to the questionnaire (response rate 50.4%). The total numbers of reported patients with CAA-related ICH and CAA-ri were 1338 and 61, respectively, and their total numbers in Japan were estimated to be 5900 [95% confidence interval (CI) 4800-7100] and 170 (95% CI 110-220), respectively. The crude prevalence rates were 4.64 and 0.13 per 100 000 population, respectively. The clinical information of 474 patients with CAA-related ICH obtained in the second survey was as follows: (i) the average age of onset was 78.4 years; (ii) the prevalence increased with age; (iii) the disease was common in women; and (iv) hematoma most frequently occurred in the frontal lobe. Sixteen patients with CAA-ri for whom data were collected in the second survey had the following characteristics: (i) median age of onset was 75 years; (ii) cognitive impairment and headache were the most frequent initial manifestations; and (iii) focal neurological signs, such as motor paresis and visual disturbance, were frequently observed during the clinical course.

CONCLUSIONS

The numbers of patients with CAA-related ICH and CAA-ri in Japan were estimated.

Protective Effect of Maternal Influenza Vaccination on Influenza in Their Infants: A Prospective Cohort Study

Background

Infants <6 months of age are too young to receive influenza vaccine, despite being at high risk for severe influenza-related complications.

Methods

To examine the effectiveness of maternal influenza vaccination in preventing influenza in their infants, we conducted a prospective cohort study of 3441 infants born at participating hospitals before the 2013-2014 influenza season. At the time of recruitment, their mothers completed a questionnaire about influenza vaccination status for the 2013-2014 season. A follow-up survey was conducted after the end of the 2013-2014 season to collect information regarding influenza diagnosis and hospitalization among infants.

Results

During the 2013-2014 influenza season, 71 infants (2%) had influenza diagnosed, and 13 infants (0.4%) were hospitalized with influenza. Maternal influenza vaccination (especially prenatal vaccination) decreased the odds of influenza among infants. The effectiveness of prenatal vaccination was 61% (95% confidence interval, 16%-81%), whereas that of postpartum vaccination was 53% (-28%-83%). Although maternal influenza vaccination was also associated with a decreased odds of influenza-related hospitalization among infants, vaccine effectiveness (73%) did not reach statistical significance, owing to the limited number of infants hospitalized because of influenza.

Conclusions

The present findings indicated that pregnant women and postpartum women should receive influenza vaccination to protect their infants.

The association between environmental factors and the development of Crohn's disease with focusing on passive smoking: A multicenter case-control study in Japan

BACKGROUND

The number of patients with Crohn's disease (CD) in Japan has recently been increasing. We examined the association between environmental factors and the development of CD in Japanese focusing on passive smoking.

METHODS

We conducted a multicenter case-control study and compared the environmental factors of 93 cases who were newly diagnosed with CD to the environmental factors of 132 controls (hospital-, age-, and sex-matched patients with other diseases). The odds ratio (OR) of each factor for the development of CD and the 95% confidence interval (CI) were calculated using a logistic regression model. The association between the details of passive smoking history and the development of CD was examined for those who had an active smoking history "no". Odds ratios of number of passively smoked cigarettes (per day), time of passive smoking (per day) and period of passive smoking (year) were calculated using "passive smoking 'No'" as a reference.

RESULTS

History of appendicitis, family history of inflammatory bowel disease, and active smoking history were not significantly associated with the development of CD. Drinking history showed a decreased OR for the development of CD (0.39, 0.19-0.77). "Passive smoking Yes" showed significantly increased OR (2.49, 1.09-5.73). Regarding the association between passive smoking and the development of CD, the OR increased as the number of cigarettes per day, smoking time per day, and smoking duration increased, and there was a dose-response relationship (trend P = 0.024, 0.032, 0.038).

CONCLUSIONS

The association between environmental factors and the development of CD among Japanese was examined by case-control study. It was suggested that the passive smoking history may be associated to the development of CD.

Nationwide epidemiologic study of norovirus-related hospitalization among Japanese older adults

Background

Older adults are vulnerable to hospitalization or death from norovirus infection, but the actual disease burden remains unknown. Therefore, we conducted a nationwide survey to estimate the number of inpatients with norovirus gastroenteritis and associated deaths among Japanese older adults.

Methods

We performed a nationwide two-step query targeting 4184 hospital departments selected from 17,575 departments using stratified random sampling according to the number of beds. We asked each department to complete a mail-back questionnaire on the annual numbers of inpatients with infectious gastroenteritis and associated deaths between administrative years 2012 and 2014, and the implementation status of norovirus infection testing. In a second query, we investigated the annual number of inpatients with norovirus gastroenteritis and associated deaths in departments that had reported infectious gastroenteritis inpatients in the first query. Clinical information was collected for inpatients with norovirus gastroenteritis in administrative year 2014.

Results

Norovirus testing for patients hospitalized for acute gastroenteritis was routinely conducted in 16% of the responding departments. Although half the departments responded that some acute gastroenteritis inpatients received such testing but others did not. In this situation, numbers of inpatients with norovirus gastroenteritis in Japan were estimated as 31,800 (95% CI: 25,700-37,900) in administrative year 2012, 21,600 (95% CI: 17,700–25,500) in administrative year 2013, and 15,700 (95% CI: 12,900–18,500) in administrative year 2014. The estimated number of associated deaths was approximately 600 in each administrative year. Factors associated with death included higher age, living in long-term care facilities, underlying illnesses such as chronic respiratory diseases, and complications such as aspiration pneumonia.

Conclusions

The actual number of norovirus inpatient would be higher than the estimated here due to the low rate of routinely implemented norovirus testing. Considering Japan’s rapidly aging society and the disease burden of norovirus infection among Japanese older adults, it is important to protect this high-risk population from norovirus infection.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4007-2) contains supplementary material, which is available to authorized users.

Preventive effects of pneumococcal and influenza vaccines on community-acquired pneumonia in older individuals in Japan: a case-control study

At present, there are few reports that have clarified the effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPSV23) against all-cause pneumonia or pneumococcal pneumonia in community-acquired pneumonia (CAP) in older individuals in Japan. We conducted a hospital-based matched case-control study to investigate separately the preventive effects of PPSV23 and trivalent influenza vaccine (TIV) on all-cause CAP and pneumococcal CAP in older individuals in Japan. Cases were individuals aged 65 years or older who were newly diagnosed with CAP from October 2010 to September 2014. Two control patients with a different disease (one respiratory medicine and one non-respiratory medicine) matched for sex, age, date of outpatient visit, and medical institution were selected for each case. Odds ratios (ORs) and 95% confidence intervals (CIs) of PPSV23 and TIV for the occurrence of all-cause CAP and pneumococcal CAP were calculated using conditional and unconditional logistic regression models. The analysis included 161 cases and 308 controls from the 4-year period. The adjusted OR for the occurrence of all-cause CAP was 0.76 (95%CI = 0.44-1.32) with PPSV23 vaccination and 0.79 (95%CI = 0.50-1.25) with TIV vaccination compared with unvaccinated individuals. When the outcome index was restricted to pneumococcal CAP, the adjusted OR significantly decreased to 0.23 (95%CI = 0.08-0.66) with PPSV23 vaccination, but not with TIV vaccination (adjusted OR = 0.65, 95%CI = 0.31-1.36). PPSV23 vaccination is likely effective in reducing incidence of pneumococcal CAP in older individuals, although its preventive effect for all-cause CAP has not been achieved.

Background Risk Factors Associated with Shunt Intervention for Possible Idiopathic Normal Pressure Hydrocephalus: A Nationwide Hospital-Based Survey in Japan

Background:

Patients with idiopathic normal-pressure hydrocephalus (iNPH) are typically older adults with multiple comorbidities that are associated with a reduction in the efficacy of iNPH treatment via cerebrospinal fluid (CSF) shunt placement.

Objective:

The present study aimed to investigate the effectiveness of CSF shunt for iNPH using data from a nationwide epidemiological survey in Japan.

Methods:

We examined 1,423 patients (581 women) aged ≥60 years (median age [25%–75%]: 77 [73–80] years) who were diagnosed with iNPH following a hospital visit in 2012. Patients who experienced an improvement of at least one modified Rankin Scale (mRS) grade after the CSF shunt were classified as “improvement” while the remaining patients were classified as “non-improvement.” The efficacy of the shunt intervention (n = 842) was analyzed using a binomial logistic regression analysis.

Results:

An analysis of risk factors associated with shunt placement in patients with mRS grade 2 revealed an association between comorbid chronic ischemic lesions (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.11–4.67; p = 0.025) and cervical spondylosis (OR, 3.62; 95% CI, 1.15–11.34; p = 0.027). Patients with mRS grade 3 at study entry had an association with comorbid Alzheimer’s disease (OR, 3.02; 95% CI, 1.44–6.31; p = 0.003).

Conclusions:

The results presented here showed that any age-related risk is minimal and should not be cause for rejection of surgical treatment options. Clinical decisions regarding CSF shunt should be individualized to each patient, with adequate consideration of the relative risks and benefits, including maximizing a healthy life expectancy.

Etiologic Classification Criteria of ARCO on Femoral Head Osteonecrosis Part 2: Alcohol-Associated Osteonecrosis

BACKGROUND

Although alcohol is a leading risk factor for osteonecrosis of the femoral head (ONFH) and its prevalence reportedly ranges from 20% to 45%, there are no unified classification criteria for this subpopulation. In 2015, Association Research Circulation Osseous decided to develop classification criteria for alcohol-associated ONFH.

METHODS

In June of 2017, Association Research Circulation Osseous formed a task force to conduct a Delphi survey. The task force invited 28 experts in osteonecrosis/bone circulation from 8 countries. Each round of the Delphi survey included questionnaires, analysis of replies, and feedback reports to the panel. After 3 rounds of the survey, consensus was reached on the classification criteria. The response rates for the 3 Delphi rounds were 100% (round 1), 96% (round 2), and 100% (round 3).

RESULTS

The consensus on the classification criteria of alcohol-associated ONFH included the following: (1) patients should have a history of alcohol intake >400 mL/wk (320 g/wk, any type of alcoholic beverage) of pure ethanol for more than 6 months; (2) ONFH should be diagnosed within 1 year after alcohol intake of this dose; and (3) patients should not have other risk factor(s).

CONCLUSION

ARCO-established classification criteria to standardize clinical studies concerning AA-ONFH.

Prior vaccinations improve immunogenicity of inactivated influenza vaccine in young children aged 6 months to 3 years: A cohort study

In young children, infrequent antigen exposure, which is partly characterized by fewer vaccinations, may be a factor impairing the immunogenicity of inactivated influenza vaccine.We assessed the effects of prior vaccinations on age-specific immune responses in Japanese children aged 6 months to 3 years, using data from a cohort study with 266 children who had received 2 doses (0.25 mL/dose for < 3 years old, 0.5 mL/dose for 3 years old) in the 2006/2007 season. Serological measures, primarily seroprotection rates, between previously vaccinated and vaccine-naïve children were compared within 1-year age strata. The seroprotection rate was defined in 2 ways as the proportion of subjects who achieved an antibody titer of 1:40 or 1:160. Multivariate logistic regression was also performed to estimate the independent effect of prior vaccination on seroprotection rate.After the first dose, seroprotection rates with the threshold of 1:40 in vaccine-naïve 1-year-olds remained low (28% for AH1, 26% for AH3, 2% for B), similar to those of 0-year-olds. In contrast, seroprotection rates in previously vaccinated 1-year-olds (77% for AH1, 86% for AH3, 18% for B) were significantly higher than those in vaccine-naïve 1-year-olds. These seroprotection rates for AH1 and AH3 were comparable with those in previously vaccinated 2- and 3-year-olds. Although seroprotection rates for B remained low in every age stratum even after the second dose, seroprotection rate in previously vaccinated 1-year-olds (50%) was similar to that in 3-year-olds. After adjustment for age, baseline antibody titer and experience of acute febrile respiratory illness in the preceding season, odds ratios showed a significant independent positive effect of prior vaccination on seroprotection rate for every strain. After the seroprotection threshold was changed from 1:40 to 1:160, the results of the effects of prior vaccinations on immunogenicity were similar or became more evident, which demonstrate the robustness of our findings.Our study found that prior vaccinations improved poor immunogenicity among young children, especially in 1-year-olds.

Shunt Intervention for Possible Idiopathic Normal Pressure Hydrocephalus Improves Patient Outcomes: A Nationwide Hospital-Based Survey in Japan

Background and Purpose: This study aimed to investigate the efficacy of cerebrospinal fluid shunt intervention for idiopathic normal pressure hydrocephalus (iNPH) using data from a nationwide epidemiological survey in Japan.

Methods: We conducted a cross-sectional study using data from a nationwide epidemiological survey performed in Japan. Propensity score matching was used to select 874 patients from 1,423 patients aged ≥60 years, who were diagnosed with iNPH based on clinical guidelines following a hospital visit in 2012. Patients who experienced an improvement of at least 1 modified Rankin Scale (mRS) grade after the intervention were classified as “improved,” while the remaining patients were classified as “non-improved.” In the shunt intervention (n = 437) and non-shunt intervention (n = 437) groups, the differences in mRS grade improvement were analyzed using the Mann-Whitney U-test. Finally, we examined subjects in the shunt intervention group (n = 974) to compare the outcomes and complications of ventriculoperitoneal (VP) shunt (n = 417) with lumboperitoneal (LP) shunt (n = 540).

Results: We examined subjects with iNPH to compare the non-shunt intervention group to the shunt intervention group following adjustment for age and mRS grade at baseline by propensity score matching (0.31–0.901). The mRS grade (mean [SD]) was found to improve with non-shunt intervention (2.46 [0.88]) and shunt intervention (1.93 [0.93]) (p < 0.001) in iNPH patients. The mRS outcome score and complications comparison between the VP and LP shunt groups did not show significant difference.

Conclusions: In this study, analysis of the efficacy of shunts for possible iNPH conducted in Japan indicated a significant improvement in the mRS grade between baseline and outcome within 1 year, regardless of the surgical technique, and shunt intervention was found to be effective.

Nationwide multicenter follow-up cohort study of hip arthroplasties performed for osteonecrosis of the femoral head

PURPOSE

To identify modifiable factors related to post-operative dislocation and reoperation in patients with osteonecrosis of the femoral head (ONFH) in a large cohort.

METHODS

We studied 4995 hip arthroplasties: total hip arthroplasty (THA) was performed in 79% of patients; bipolar hemiarthroplasty (BP), 17%; total resurfacing arthroplasty (tRS), 3%; and hemi-resurfacing arthroplasty (hRS), 1%. A new type of BP (accounting for 49% of BPs) comprised a femoral component with a polished or smooth, small-diameter (approximately 10 mm) neck with a round or oval axial cut surface and no sharp corners.

RESULTS

The infection rate was relatively low (0.56%) even though 58% of cases of ONFH were associated with systemic steroid use, a known risk factor for infection. Post-operative dislocation occurred in 4.3% of cases, with re-operation needed in 3.9%. The dislocation rate was related to surgery type: 5.2% in THA, 0.9% in BP, and 0% in tRS and hRS. Among total arthroplasties with six month or longer follow-up (3670 THAs and 159 tRSs), the risk factors for post-operative dislocation were younger (≤ 40 years) or older (≥ 62 years) age, higher body weight, posterolateral approach, and smaller prosthetic head diameter. Regarding the need for re-operation, higher body weight and surgery type were identified as risk factors.

CONCLUSIONS

The relatively high dislocation rate of 5.2% in THA is a cause for concern. The identified risk factors for dislocation should be considered when selecting THA for treatment. Prosthesis survivorship in hRSs was inferior to that in BPs or THAs. Body weight also affected the survivorship of hip arthroplasties.

Effectiveness of 23-valent pneumococcal polysaccharide vaccine and seasonal influenza vaccine for pneumonia among the elderly - Selection of controls in a case-control study

We conducted a case-control study to elucidate associations between pneumonia in elderly individuals and 23-valent pneumococcal polysaccharide vaccine (PPSV23) and seasonal influenza vaccine (influenza vaccine). Here, we examined selection of controls in our study using an analytic epidemiology approach. The study period was from October 1, 2009 through September 30, 2014. Cases comprised ≥65-year-old patients newly diagnosed with pneumonia. For every case with pneumonia, two patients with other diseases (one respiratory medicine, one non-respiratory medicine) who were sex-, age-, visit date- and visit hospital-matched were selected as controls. Odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for pneumonia were calculated using conditional logistic regression model. Similar analyses were also conducted based on the clinical department of controls. Analysis was conducted in 234 cases and 438 controls. Effectiveness of pneumococcal vaccination or influenza vaccination against pneumonia was not detected. Proportions of either vaccination in controls were greater among respiratory medicine (pneumococcal vaccine, 38%; influenza vaccine, 55%) than among non-respiratory medicine (23%; 48%). Analysis using controls restricted to respiratory medicine showed marginally significant effectiveness of pneumococcal vaccination (OR, 0.59; 95%CI, 0.34-1.03; P=0.064) and influenza vaccination (0.64; 0.40-1.04; 0.072). However, this effectiveness might have been overestimated by selection bias of controls, as pneumonia cases are not necessarily respiratory medicine patients. In the analysis using controls restricted to non-respiratory medicine, OR of pneumococcal vaccination for pneumonia was close to 1, presumably because the proportion of pneumococcal vaccination was higher in cases than in controls. Because pneumococcal vaccine was not routinely administered during the study period, differences in recommendations of vaccination by physician in different clinical departments might have greatly affected vaccination proportions. When we select controls, we should consider the background factors (underlying diseases, clinical department, etc.) which affect physicians' recommendation of vaccination.

Estimating influenza disease burden among pregnant women: Application of self-control method

To evaluate influenza disease burden among pregnant women, an epidemiological study using the self-control method was conducted. Study subjects were 12,838 pregnant women who visited collaborating maternity hospitals and clinics in Osaka Prefecture, Japan, before the 2013/14 influenza season. As a study outcome, hospitalization due to respiratory illnesses between the 2010/11 and 2013/14 seasons was collected from each study subject through a baseline survey at the time of recruitment and a second survey after the 2013/14 season. The hospitalization rates during pregnancy and non-pregnancy periods was calculated separately. To compare the hospitalization rate during pregnancy with that during non-pregnancy within the same single study subject, Mantel-Haenzel rate ratios (RR_MH) were calculated. During the four seasons examined in this study, nine and 17 subjects were hospitalized due to respiratory illnesses during pregnancy and non-pregnancy periods, respectively. The hospitalization rate was 2.54 per 10,000 woman-months during pregnancy and 1.08 per 10,000 woman-months during non-pregnancy. The RR_MH for the hospitalization rate during pregnancy compared with that during non-pregnancy was 4.30 (95% confidence interval, 1.96-9.41). Our results suggest that during the influenza season, pregnant women have a higher risk than non-pregnant women for hospitalization due to respiratory illnesses. The self-control method appears to be an appropriate epidemiological method for evaluating the disease burden of influenza among pregnant women.

Nationwide Survey of 741 Patients with Systemic Amyloid Light-chain Amyloidosis in Japan

Objective To retrospectively investigate the clinical manifestations of systemic amyloid light-chain (AL) amyloidosis in Japanese patients and the treatment strategy for the condition. Methods We conducted a survey of Japanese AL amyloidosis patients, who were treated between January 1, 2012, and December 31, 2014. Results A total of 741 AL amyloidosis patients were included in this study (436 men and 305 women; median age: 65 years old, range: 31-93). The most frequently affected organ was the kidneys (n=542), followed by the heart (n=252), gastrointestinal (GI) tract (n=164), autonomic nervous system (n=131), liver (n=71), and peripheral nervous system (n=71). Diagnostic findings were most commonly detected in the GI tract (upper GI tract: 350 cases, lower GI tract: 167 cases), followed by the bone marrow and kidneys. An abdominal fat-pad biopsy was only conducted in 128 patients. Autologous stem cell transplants (ASCTs) and bortezomib were used to treat 126 and 276 patients, respectively. Conclusion The clinical features of Japanese patients with systemic AL amyloidosis are similar to those reported previously for cases in the US and Europe. Regarding treatment, a significant number of ASCTs were performed in Japan as well as in Western countries. Surprisingly, a marked number of patients received bortezomib as a treatment for AL amyloidosis.