Homebound older adults who live independently in rural Japan: Prevalence and contributing factors during the COVID-19 pandemic.

Being homebound is a phenomenon of confining older adults to their homes owing to health, social, and psychological factors. During the COVID-19 pandemic, people were requested to refrain from going out to prevent infection. Consequently, the homebound status of older adults was influenced by social and environmental factors, resulting in an increase in the number of homebound older adults during the pandemic. This study aimed to determine the homebound prevalence and related factors among homebound older adults during the COVID-19 pandemic. In 2021, a cross-sectional study conducted in rural Saitama, Japan, included 1,020 participants aged 65 years and above who did not have long-term care insurance certification and were independent in instrumental activities of daily living. Herein, homebound individuals were defined as those who went out once a week or less. The relationships of homebound status with demographic, health, social, and psychological factors in older adults were examined. The prevalence of homebound independent older adults was estimated as 10.4 % (6.6 % males, 13.8 % females). Homebound status was significantly associated with one or more medical histories (odds ratio [OR] = 1.98, 95 % confidence interval [CI] = 1.00-3.90), no social or family roles (OR = 1.95, 95 % CI = 1.09-3.48), and no hobbies (OR = 1.84, 95 % CI = 1.02-3.34). Establishing social or family roles and promoting participation in hobbies may prevent older adults from being homebound. The social environment, which changed during the pandemic, should be improved to encourage older adults to go out.

Clinical impact and characteristics of erythroid dysplasia in adult aplastic anaemia: Results from a multicentre registry.

Morphological dysplasia in haematopoietic cells, defined by a 10% threshold in each lineage, is one of the diagnostic criteria for myelodysplastic neoplasms. Dysplasia limited to the erythroid lineage has also been reported in some cases of aplastic anaemia (AA); however, its significance remains unclear. We herein examined the impact of erythroid dysplasia on immunosuppressive therapy responses and survival in AA patients. The present study included 100 eligible AA patients without ring sideroblasts. Among them, 32 had dysplasia in the erythroid lineage (AA with minimal dysplasia [mini-D]). No significant sex or age differences were observed between AA groups with and without erythroid dysplasia. In severe/very severe AA and non-severe AA patients, a response to anti-thymocyte globulin + ciclosporin within 12 months was observed in 80.0% and 60.0% of AA with mini-D and 42.9% and 90.0% of those without dysplasia, with no significant difference (p = 0.29 and p = 0.24 respectively). Overall survival and leukaemia-free survival did not significantly differ between the groups. Collectively, the present results indicate that the presence of erythroid dysplasia did not significantly affect clinical characteristics or outcomes in AA patients, suggesting that its presence in AA is acceptable. Therefore, erythroid dysplasia should not exclude an AA diagnosis.

Incidence trends and risk factors for hyponatremia in epilepsy patients: A large-scale real-world data study.

Objective: This study aimed to evaluate the annual incidence and risk factors of hyponatremia in pediatric, adult, and older adult patients with epilepsy. Methods: We enrolled 26,179 patients: 8598 pediatric patients (aged 0-15 years), 16,476 adults (aged 16-64 years), and 1105 older adults (aged ≥65 years). Patients were included if their serum sodium levels were measured between January 2006 and December 2020. Moderate-severe hyponatremia was defined as a serum sodium level of less than 130 mEq/L. Results: From 2006 to 2020, 677 patients (2.6%) developed moderate-severe hyponatremia. The incidence of hyponatremia per 1000 person-years was 3.1 in the pediatric group, 19.8 in the adult group, and 50.4 in the older adult group. The incidence increased markedly from 36.8 in 2007 to 58.5 in 2020 in the older adult group but remained unchanged in the adult group and tended to decrease in the pediatric group. In the multiple logistic regression model, use of carbamazepine, valproate, phenytoin, phenobarbital, benzodiazepines, and antipsychotics was found to be a significant risk factor for hyponatremia. In adult patients, carbamazepine, benzodiazepine, and antipsychotics induced hyponatremia in a dose-dependent manner. Concomitant use of zonisamide reduced the risk of hyponatremia. Significance: Hyponatremia will become an increasingly important concern in clinical settings because the population of epilepsy patients is aging. Serum sodium levels should be monitored carefully when patients are receiving first-generation antiseizure medications or antipsychotics or combinations of these drugs. Our findings may help to minimize the risk of hyponatremia in epilepsy patients.

Clinical value of therapeutic drug monitoring for levetiracetam in pediatric patients with epilepsy.

PURPOSE: To identify pediatric patients who require therapeutic drug monitoring (TDM) of levetiracetam (LEV). METHODS: We retrospectively investigated 2413 routine therapeutic drug monitoring data on serum LEV concentration from 1398 pediatric patients (age, 0-15 years). Samples were grouped by age (infants, < 1 year; preschool children, 1-5 years; primary school children, 6-11 years; and adolescents, 12-15 years), and the LEV concentration-to-dose (CD) ratio was calculated. RESULTS: The mean CD ratio was highest in adolescents (analysis of variance, p < 0.001); 22.5 % and 15.7 % higher in adolescents than in preschool children and school children, respectively (Scheffé test, p < 0.001); and higher in infants than in preschool children. Preschool children had the lowest ratio and tended to show an increase in the ratio from age 2 to 5 years. Use of enzyme-inducing antiseizure medication reduced the CD ratio by 6.1 % in infants, 12.2 % in preschool children, 5.9 % in primary school children, and 9.4 % in adolescents. The mean CD ratio was 2.7 %, 26.9 %, and 39.3 % higher in preschool children, primary school children, and adolescents with defined chronic kidney disease (CKD) than in the respective age group of patients without CKD. The therapeutic concentration range for a long-term LEV therapy was 11 to 32 µg/mL. CONCLUSIONS: LEV pharmacokinetics are significantly different between infant and preschool children, so TDM of LEV is clinically useful in these patients. In pediatric patients at higher risk for CKD, glomerular filtration rate and LEV levels should be carefully monitored.

Decision analysis of allogeneic bone marrow transplantation versus immunosuppressive therapy for young adult patients with aplastic anemia.

BACKGROUND: Allogeneic bone marrow transplantation (BMT) from an HLA-matched sibling donor is recommended as an initial treatment for young patients. However, immunosuppressive therapy (IST) with cyclosporine and anti-thymocyte globulin may be a viable option even when an HLA-identical sibling donor is available. METHODS: We constructed a Markov model to simulate the 10-year clinical course of patients aged 21-40 years with newly diagnosed severe aplastic anemia. Immediate BMT and IST were compared as an initial treatment assuming the availability of an HLA-identical sibling donor. Transition probabilities after treatment were determined based on a registry data analysis for BMT and a long-term prospective study for IST. RESULTS: Quality-adjusted life years (QALYs) after treatment selection were 6.77 for BMT and 6.74 for IST. One-way sensitivity analysis revealed that the utility for being alive without GVHD after BMT, that for being alive with partial response after IST, and the response rate after initial IST strongly affected the results. CONCLUSIONS: BMT and IST produced similar QALY for young patients with severe aplastic anemia. An estimation of the response rate to the initial IST may enable an individualized comparison between BMT and IST.

Incidence of acquired pure red cell aplasia: a nationwide epidemiologic analysis with 2 registry databases in Japan.

Acquired pure red cell aplasia (PRCA) is a rare syndrome characterized by anemia with reticulocytopenia and a marked reduction in erythroid precursors. Given its rarity, the true incidence is largely unknown, and epidemiological data representing the general population, with a description of the full spectrum of etiologies, are scarce. An epidemiological study on PRCA in Japan conducted 30 years ago estimated the annual incidence as 0.3 per million. To update the data and investigate the incidence and demographics of PRCA, we conducted a nationwide epidemiological study using the Japanese Society of Hematology (JSH) Hematologic Disease Registry, a hematologic disease registration database managed by the JSH and the Diagnosis Procedure Combination (DPC) study data available at a website of the Ministry of Health, Labor, and Welfare (MHLW) of Japan. A total of 1055 patients with newly diagnosed acquired PRCA were identified between 2012 and 2019, and the average annual incidence was calculated at 1.06 (95% confidence interval [CI], 0.83-1.28) per million. The median age was 73 (range, 18-99) years. The female-to-male ratio was 1.5:1, and the female predominance was most prominent in the child-bearing age group. Sixty-nine percent of acquired PRCA was idiopathic. The incidence of PRCA was approximately 20% of that of aplastic anemia (AA) during the same period. Approximately 0.98 patients per million per year (95% CI, 0.89-1.07) required hospitalization for the treatment of PRCA. These results are expected to contribute to the discussion of resource allocation for PRCA in the aging population in many countries, including Japan.

Clinical impact of myositis-specific autoantibodies on long-term prognosis of juvenile idiopathic inflammatory myopathies: multicentre study.

OBJECTIVES: This study aimed to investigate the clinical characteristics, treatment and prognosis of juvenile idiopathic inflammatory myopathies (JIIM) in Japan for each myositis-specific autoantibody (MSA) profile. METHODS: A multicentre, retrospective study was conducted using data of patients with JIIM at nine paediatric rheumatology centres in Japan. Patients with MSA profiles, determined by immunoprecipitation using stored serum from the active stage, were included. RESULTS: MSA were detected in 85 of 96 cases eligible for the analyses. Over 90% of the patients in this study had one of the following three MSA types: anti-melanoma differentiation-associated protein 5 (MDA5) (n = 31), anti-transcriptional intermediary factor 1 alpha and/or gamma subunits (TIF1γ) (n = 25) and anti-nuclear matrix protein 2 (NXP2) (n = 25) antibodies. Gottron papules and periungual capillary abnormalities were the most common signs of every MSA group in the initial phase. The presence of interstitial lung disease (ILD) was the highest risk factor for patients with anti-MDA5 antibodies. Most patients were administered multiple drug therapies: glucocorticoids and MTX were administered to patients with anti-TIF1γ or anti-NXP2 antibodies. Half of the patients with anti-MDA5 antibodies received more than three medications including i.v. CYC, especially patients with ILD. Patients with anti-MDA5 antibodies were more likely to achieve drug-free remission (29 vs 21%) and less likely to relapse (26 vs 44%) than others. CONCLUSION: Anti-MDA5 antibodies are the most common MSA type in Japan, and patients with this antibody are characterized by ILD at onset, multiple medications including i.v. CYC, drug-free remission, and a lower frequency of relapse. New therapeutic strategies are required for other MSA types.

Clonal hematopoiesis in adult pure red cell aplasia.

Idiopathic pure red cell aplasia (PRCA) and secondary PRCA associated with thymoma and large granular lymphocyte leukemia are generally considered to be immune-mediated. The PRCA2004/2006 study showed that poor responses to immunosuppression and anemia relapse were associated with death. PRCA may represent the prodrome to MDS. Thus, clonal hematopoiesis may be responsible for treatment failure. We investigated gene mutations in myeloid neoplasm-associated genes in acquired PRCA. We identified 21 mutations affecting amino acid sequences in 11 of the 38 adult PRCA patients (28.9%) using stringent filtering of the error-prone sequences and SNPs. Four PRCA patients showed 7 driver mutations in TET2, DNMT3A and KDM6A, and 2 PRCA patients carried multiple mutations in TET2. Five PRCA patients had mutations with high VAFs exceeding 0.3. These results suggest that clonal hematopoiesis by stem/progenitor cells might be related to the pathophysiology of chronic PRCA in certain adult patients.

External validation of the EULAR/ACR idiopathic inflammatory myopathies classification criteria with a Japanese paediatric cohort.

OBJECTIVES: To assess the performance of the EULAR/ACR idiopathic inflammatory myopathies (IIMs) classification criteria to classify juvenile IIMs (JIIMs) in an Asian paediatric population. METHODS: Sixty-eight JIIM patients and 49 non-JIIM patients diagnosed at seven major paediatric rheumatology centres in Japan between 2008 and 2015 were enrolled. Retrospective data were collected, and each patient's data form was submitted. The expert group reviewed the forms and re-examined the diagnoses. The EULAR/ACR criteria were then applied and the probability of having JIIM was determined for each case. The sensitivity and specificity of the EULAR/ACR criteria were compared with those of other existing criteria. RESULTS: The sensitivity/specificity of the EULAR/ACR classification criteria were 92.1/100% with muscle biopsy data (n = 38); 86.7/100% without muscle biopsy data (n = 30) and 89.7/100% in our total cohort (n = 68). The sensitivity of Bohan and Peter's criteria and Tanimoto's criteria were 80.9 and 64.7% in our total cohort, respectively. Among 68 physician-diagnosed JIIM patients, seven cases (three JDM and four overlap myositis) were not classified as JIIM because the probability did not reach the cut-off point (55%). The three JDM patients all presented with only one of the three skin manifestations that are listed in the criteria: Gottron's sign. CONCLUSION: Our validation study with Japanese JIIM cases indicates that the EULAR/ACR classification criteria for IIM generally perform better than existing diagnostic criteria for myositis.

Estimating nationwide cases of sexually transmitted diseases in 2015 from sentinel surveillance data in Japan.

BACKGROUND: The rates of newly diagnosed cases of sexually transmitted diseases, including genital chlamydial infection and gonorrhea, are important for prevention and control of these diseases. However, nationwide rates are not reported in Japan. METHODS: We used the number of cases of sexually transmitted diseases reported by nationwide sentinel surveillance in 2015, together with the number of all disease outpatients in September 2014 at all medical institutions, drawn from the Survey of Medical Institutions of Japan. The number of cases of sexually transmitted diseases in the total population was estimated using the ratio estimation method with the number of all disease outpatients as auxiliary information. This method is currently used for estimating influenza cases from sentinel surveillance data in Japan. RESULTS: The estimated number of newly diagnosed cases per 100,000 population in 2015 in Japan was 244 (95% confidence interval 211-277) for genital chlamydial infection, 87 (95% confidence interval 74-100) for genital herpes, 61 (95% confidence interval 29-93) for condyloma acuminatum, and 89 (95% confidence interval 64-113) for gonorrhea. CONCLUSION: We estimated the nationwide number of newly diagnosed cases of sexually transmitted diseases in Japan from sentinel surveillance data. This provides useful information for public health policy-making.

First external validation of sensitivity and specificity of the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for idiopathic inflammatory myopathies with a Japanese cohort.

OBJECTIVE: To externally validate the performance of the new European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria set for idiopathic inflammatory myopathies (IIM) with a Japanese cohort. METHODS: This study included 420 IIM and 402 non-IIM cases. Probability of having IIM in each patient was calculated using the collected data set. The cut-off probability was set at 55%, as recommended by EULAR/ACR. Patients classified as IIM by the criteria were further subclassified with classification trees. RESULTS: When the probability cut-off was set at 55%, the sensitivity/specificity of the new criteria to diagnose IIM were 89.3%/91.0% in the total cohort, 88.1%/95.1% without muscle biopsy data and 90.4%/65.5% with biopsy data. The cohort included 12 overlap syndrome patients with biopsy data, who were included as non-IIM cases in accordance with traditional Japanese methods. When they were included in the IIM cases, the specificity in patients with biopsy increased to 74.4%. The sensitivity/specificity of the new criteria to diagnose polymyositis/dermatomyositis (PM/DM) plus juvenile and amyopathic DM in the Japanese cohort was 87.4%/92.4%, which were greater than those of the Tanimoto's criteria revised to enable classification of amyopathic DM (ADM) (71.2%/87.8%) and were comparable with those of Bohan & Peter's criteria to diagnose those diseases except for ADM (88.4%/88.3%). CONCLUSIONS: Our study externally validated high specificity of the new criteria for the first time, although with several limitations, including low percentage of child patients. The new criteria have higher sensitivity and/or specificity in classification of PM/DM than the previously reported criteria, demonstrating its usefulness for interethnic patients.

Prevalence and risk factors for hyponatremia in adult epilepsy patients: Large-scale cross-sectional cohort study.

PURPOSE: To evaluate the risk factors and prevalence of hyponatremia among epilepsy patients in relation to use of antiepileptic drugs (AEDs). METHODS: We retrospectively reviewed 14,620 adult patients (aged 18-103 years) and classified them into the following 3 groups: patients without AED treatment (n = 2165, Group I), patients receiving antiepileptic drugs other than carbamazepine (n = 7442, Group II), and patients treated with carbamazepine (n = 5013, Group III). This study did not include the patients receiving oxcarbazepine or eslicarbazepine acetate because these AEDs are not marketed in Japan. Severe hyponatremia was defined as a serum sodium level < 130 mEq/L. RESULTS: In Groups I, II, and III, the mean sodium level was 140, 139, and 137 mEq/L, respectively. The highest frequency of severe hyponatremia was observed in Group III (7%), and it was much higher than in Group I (0.8%) or Group II (1.2%). In Groups II and III, old age, low body weight, and concomitant use of phenobarbital, benzodiazepines, or antipsychotics were risk factors for hyponatremia. In Group III, the sodium level decreased as the carbamazepine dose increased. At a carbamazepine dose exceeding 600 mg/day, there was 10.9-fold higher prevalence of hyponatremia, and the risk was potentiated by concomitant use of valproate. CONCLUSION: The serum sodium level should be monitored carefully when patients are receiving AED polypharmacy combined with antipsychotics. In particular, concomitant administration of valproate enhances the risk of hyperammonemia in patients receiving carbamazepine. These findings may help clinicians to avoid hyponatremia in patients with epilepsy.

Treatment consensus for management of polymyositis and dermatomyositis among rheumatologists, neurologists and dermatologists.

Although rheumatologists, neurologists and dermatologists see patients with polymyositis (PM) and dermatomyositis (DM), their management appears to vary depending on the physician's specialty. The aim of the present study was to establish the treatment consensus among specialists of the three fields to standardize the patient care. We formed a research team supported by a grant from the Ministry of Health, Labor and Welfare, Japan. Clinical questions (CQ) on the management of PM and DM were raised. A published work search on CQ was performed primarily using PubMed. Using the nominal group technique, qualified studies and results in the published work were evaluated and discussed to reach consensus recommendations. They were sent out to the Japan College of Rheumatology, Japanese Society of Neurology and Japanese Dermatological Association for their approval. We reached a consensus in 23 CQ and made recommendations and a decision tree for management was proposed. They were officially approved by the three scientific societies. In conclusion, a multidisciplinary treatment consensus for the management of PM and DM was established for the first time.

Treatment consensus for management of polymyositis and dermatomyositis among rheumatologists, neurologists and dermatologists.

Although rheumatologists, neurologists and dermatologists see patients with polymyositis (PM) and dermatomyositis (DM), their management appears to vary depending on the physician's specialty. The aim of the present study was to establish the treatment consensus among specialists of the three fields to standardize the patient care. We formed a research team supported by a grant from the Ministry of Health, Labor and Welfare, Japan. Clinical questions (CQ) on the management of PM and DM were raised. A published work search on CQ was performed primarily using PubMed. Using the nominal group technique, qualified studies and results in the published work were evaluated and discussed to reach consensus recommendations. They were sent out to the Japan College of Rheumatology, Japanese Society of Neurology and Japanese Dermatological Association for their approval. We reached a consensus in 23 CQ and made recommendations and a decision tree for management was proposed. They were officially approved by the three scientific societies. In conclusion, a multidisciplinary treatment consensus for the management of PM and DM was established for the first time.

Interobserver concordance of assessments of dysplasia and blast counts for the diagnosis of patients with cytopenia: From the Japanese central review study.

The diagnosis of myelodysplastic syndromes (MDS) is based on morphology and cytogenetics. However, limited information is currently available on the interobserver concordance of the assessment of dysplastic lineages (<10% or ≥10% in bone marrow (BM)). The revised International Prognostic Scoring System (IPSS-R) described a new threshold (2%) for BM blasts. However, the interobserver concordance of the categories (0-≤2% and >2-<5%) has limited data. The purpose of the present study was to investigate the assessment of dysplastic lineages and IPSS-R reproducibility. Our study was divided into two Steps. In each Step, the microscopic examinations were performed separately by two morphologists. Regarding the category of BM blasts ≤2% and >2-<5%, interobserver agreement was more than 'moderate' in all pairs (kappa test: 0.43-0.90). Regarding dysgranulopoiesis (dysG) and dyserythropoiesis (dysE) in BM, interobserver agreement was more than 'moderate' in all pairs (kappa test, dysG: 0.45-0.96, dysE: 0.45-0.81). Regarding the category of dysmegakaryopoiesis (dysMgk) in BM, interobserver agreement was more than moderate in 4 out of 5 pairs (kappa test: 0.58-1.00), and was fair for one pair (kappa test: 0.37). We consider that high interobserver concordance may be possible for the BM blast cell count (≤2% or >2-<5%) and dysplasia (<10% or ≥10%) of each lineage.

Clinical practice guideline for Sjögren's syndrome 2017.

OBJECTIVES: The objective of this study is to develop clinical practice guideline (CPG) for Sjögren's syndrome (SS) based on recently available clinical and therapeutic evidences. METHODS: The CPG committee for SS was organized by the Research Team for Autoimmune Diseases, Research Program for Intractable Disease of the Ministry of Health, Labor and Welfare (MHLW), Japan. The committee completed a systematic review of evidences for several clinical questions and developed CPG for SS 2017 according to the procedure proposed by the Medical Information Network Distribution Service (Minds). The recommendations and their strength were checked by the modified Delphi method. The CPG for SS 2017 has been officially approved by both Japan College of Rheumatology and the Japanese Society for SS. RESULTS: The CPG committee set 38 clinical questions for clinical symptoms, signs, treatment, and management of SS in pediatric, adult and pregnant patients, using the PICO (P: patients, problem, population, I: interventions, C: comparisons, controls, comparators, O: outcomes) format. A summary of evidence, development of recommendation, recommendation, and strength for these 38 clinical questions are presented in the CPG. CONCLUSION: The CPG for SS 2017 should contribute to improvement and standardization of diagnosis and treatment of SS.

Validation of the revised International Prognostic Scoring System in patients with myelodysplastic syndrome in Japan: results from a prospective multicenter registry.

The Japanese National Research Group on Idiopathic Bone Marrow Failure Syndromes has been conducting prospective registration, central review, and follow-up study for patients with aplastic anemia and myelodysplastic syndrome (MDS) since 2006. Using this database, we retrospectively analyzed the prognosis of patients with MDS. As of May 2016, 351 cases were registered in this database, 186 of which were eligible for the present study. Kaplan-Meier analysis showed that overall survival (OS) curves of the five risk categories stipulated by the revised international prognostic scoring system (IPSS-R) were reasonably separated. 2-year OS rates for the very low-, low-, intermediate-, high-, and very high-risk categories were 95, 89, 79, 35, and 12%, respectively. In the same categories, incidence of leukemic transformation at 2 years was 0, 10, 8, 56, and 40%, respectively. Multivariate analysis revealed that male sex, low platelet counts, increased blast percentage (>2%), and high-risk karyotype abnormalities were independent risk factors for poor OS. Based on these data, we classified Japanese MDS patients who were classified as intermediate-risk in IPSS-R, into the lower risk MDS category, highlighting the need for careful assessment of treatments within low- and high-risk treatment protocols.

Estimated Number of Patients with Influenza A(H1)pdm09, or Other Viral Types, from 2010 to 2014 in Japan.

Infectious disease surveillance systems provide information crucial for protecting populations from influenza epidemics. However, few have reported the nationwide number of patients with influenza-like illness (ILI), detailing virological type. Using data from the infectious disease surveillance system in Japan, we estimated the weekly number of ILI cases by virological type, including pandemic influenza (A(H1)pdm09) and seasonal-type influenza (A(H3) and B) over a four-year period (week 36 of 2010 to week 18 of 2014). We used the reported number of influenza cases from nationwide sentinel surveillance and the proportions of virological types from infectious agents surveillance and estimated the number of cases and their 95% confidence intervals. For the 2010/11 season, influenza type A(H1)pdm09 was dominant: 6.48 million (6.33-6.63), followed by types A(H3): 4.05 million (3.90-4.21) and B: 2.84 million (2.71-2.97). In the 2011/12 season, seasonal influenza type A(H3) was dominant: 10.89 million (10.64-11.14), followed by type B: 5.54 million (5.32-5.75). In conclusion, close monitoring of the estimated number of ILI cases by virological type not only highlights the huge impact of previous influenza epidemics in Japan, it may also aid the prediction of future outbreaks, allowing for implementation of control and prevention measures.

Epidemiologic analysis of the clinical features of Japanese patients with polymyositis and dermatomyositis.

OBJECTIVES: This study aimed to investigate the clinical characteristics of polymyositis/dermatomyositis (PM/DM) in Japan by analyzing data from the nationwide registration system. METHODS: The data of the registration system in 2009 were analyzed to investigate patient numbers, sex, clinical symptoms, therapies, complications, and prognosis of PM/DM. RESULTS: The total number of PM/DM cases was approximately 17,000, and the female/male sex ratio was 2.7:1. Almost all patients improved as a result of therapy, but many suffered from sequelae such as muscle weakness. CONCLUSIONS: The results characterize significant aspects of Japanese PM/DM patients. However, a further prospective survey is required to clarify the true epidemiology and natural history of PM/DM.