Papers - Yamauchi, Keita

Temporal analysis of posts on a Japanese online message board for suicide risk monitoring

Takahiro Arai, Hiroyuki Shinkai, Keita Yamauchi

BMC Psychiatry  25 ( 1 ) 1111 - 1120 2025.11

Research paper (scientific journal), Joint Work, Last author, Accepted

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Clustering of health behaviors in male workers and comparisons of incidences of insomnia, sleep apnea, and depression between non-restorative sleep and restorative sleep

Tomoki Kishi, Chie Sato. Keita Yamauchi

Acta Psychologica (Elsevier)  261 2025.10

Research paper (scientific journal), Joint Work, Last author, Accepted

Increased Antidepressant Prescriptions for Children and Adolescents with Major Depressive Disorder in Japan Based on a Claims Database

Keisuke Nomoto, Ataru Inagaki, Keita Yamauchi

Neuropsychiatric Disease and Treatment (Taylor & Francis)  21   2385 - 2400 2025.10

Research paper (scientific journal), Joint Work, Last author, Accepted

Classifying Patient Characteristics and Determining a Predictor in Acute Stroke Patients: Application of Latent Class Analysis in Rehabilitation Practice

Junya Uchida, Moeka Yamada, Hirofumi Nagayama, Kounosuke Tomori, Kohei Ikeda, Keita Yamauchi

Journal of Clinical Medicine 14 ( 15 ) 5466 2025.08

Research paper (scientific journal), Joint Work, Last author, Accepted

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資源としての職場学習が就業継続意欲に与える影響： 病院に勤務する看護師を対象としたマルチレベル分析

宗像舞, 渡辺真弓, 山内慶太

日本医療・病院管理学会誌 62 ( 2 ) 34 - 44 2025.04

Research paper (scientific journal), Joint Work, Last author, Accepted

日本語版組織学習尺度の信頼性・妥当性の検証

渡辺 真弓, 宗像 舞, 山内 慶太

日本医療・病院管理学会誌 62 ( 1 ) 2 - 12 2025.01

Research paper (scientific journal), Joint Work, Last author, Accepted

BMI trajectory of 8,155,894 Japanese adults from exhaustive health checkup data: the contributions of age-related changes in height and weight: Epidemiology and Population Health

Uemura N., Nishida Y., Sasaki S., Yamada Y., Anzai T., Takahashi K., Yamauchi K., Katsukawa F.

International Journal of Obesity (Springer Nature)   2024.12

Research paper (scientific journal), Joint Work, Accepted,  ISSN  03070565

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This study aimed to clarify the trajectory of BMI alongside age-related changes in height and weight among Japanese adults. Data from annual health checkups between 2015 and 2020 by the Japan Health Insurance Association were retrospectively analyzed. A total of 4,777,891 men and 3,378,003 women (age 35–69 years) were stratified into 14 subgroups based on sex and 5-year age categories. We used linear mixed-effects model to estimate values for each outcome, with six-time points (2015–2020) as the independent variable. Mean BMI changes were positive across all subgroups, indicating a trend of increasing BMI (men, 0.02 to 0.14 kg/m2/year; women, 0.05 to 0.16 kg/m2/year). In younger subgroups, the changed were relatively large, with the weight transitions mirroring those of BMI. However, the mean changes were negative (men, −0.06 kg/year; women, −0.01 kg/year) in the oldest subgroups. Height reduction increased with age across subgroups (men, −0.14 to −0.03 cm/year; women, −0.18 to −0.01 cm/year). In conclusion, BMI tended to increase with age in both sexes across all age groups of Japanese adults. The increase in BMI appeared to be influenced by weight gain in young to middle age, whereas height reduction influenced increased BMI in older age groups.

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A cost-effectiveness analysis of three surgical options for treating displaced femoral neck fractures in active older patients in Japan: A full economic evaluation

Yokoyama K., Akune Y., Katoh H., Bito S., Fujita Y., Goto R., Yamauchi K.

PLoS ONE 19 ( 10 October )  2024.10

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For older patients with displaced femoral neck fractures, in which primary osteosynthesis is usually not indicated, there are three primary prosthetic options—bipolar hemiarthroplasty (BHA), single-bearing total hip arthroplasty (SB-THA), and dual-mobility THA (DM-THA). However, the optimal choice for managing displaced femoral neck fractures remains controversial. Accordingly, this study aimed to evaluate the cost-effectiveness of BHA, SB-THA, and DM-THA in active older patients with displaced femoral neck fractures. A decision tree combined with a Markov model was employed to analyze the cost and quality-adjusted life years (QALYs) of BHA, SB-THA, and DM-THA for the management in the Japanese healthcare system. By simulating the five-year trajectory of a 75-year-old woman treated for a displaced femoral neck fracture, the cost-effectiveness of the three surgical options was evaluated. One-way sensitivity analysis and probabilistic sensitivity analysis (PSA) were used to assess parameter uncertainty. Additionally, two scenario analyses were conducted for other settings. The treatment was considered to be cost-effective when the incremental cost-effectiveness ratio (ICER) was below the 5,000,000 yen/QALY threshold. Compared with BHA, SB-THA exhibited higher costs but greater health benefits, resulting in an ICER of 1,499,440 yen/QALY. DM-THA offered additional health benefits compared with SB-THA, with an ICER of 4,145,777 yen/QALY. One-way sensitivity analysis revealed some influential parameters. PSA indicated that the probability of DM-THA, SB-THA, and BHA being cost-effective was 40.1%, 38.5%, and 21.4%, respectively. SB-THA was more cost-effective than BHA in patients aged 65–85 years, while DM-THA was more cost-effective than SB-THA in patients aged 65–75 years. The results suggest that SB-THA is a cost-effective alternative to BHA for displaced femoral neck fractures in active older patients, whereas DM-THA is more cost-effective than SB-THA in relatively younger patients. It is, therefore, recommended that orthopedic surgeons select the most appropriate surgical option based on the individual patient’s physiological age.

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病院に勤務する看護職の超過勤務の要因

渡辺 真弓, 宗像 舞, 山内 慶太, 金井Pak 雅子

日本看護科学会誌 44   308 - 316 2024.10

Research paper (scientific journal), Accepted

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Clustering of restorative sleep and lifestyle habits in Japanese male working population.

Tomoki Kishi, Chie Sato. Keita Yamauchi

Discover Public Health 21 ( 90 )  2024.09

Research paper (scientific journal), Joint Work, Last author, Accepted

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潜在クラス分析を用いた社会生活基本調査ミクロデータにおける介 護負担と睡眠時間に関する検討

新井崇弘, 山内慶太, 椿広計, 渡辺美智子

統計研究彙報 (総務省統計研究研修所)   ( 81 ) 1 - 12 2024.03

Research paper (scientific journal), Joint Work, Accepted

Effect of overweight/obesity and metabolic syndrome on frailty in middle-aged and older Japanese adults

Yuki Nishida, Yosuke Yamada, Satoshi Sasaki, Eiichiro Kanda, Yoshihiko Kanno, Tatsuhiko Anzai, Kunihiko Takahashi, Keita Yamauchi, Fuminori Katsukawa

Obesity Science and Practice (Johm Wiley & Sons)  10 ( 1 ) 1 - 13 2024.02

Research paper (scientific journal), Joint Work, Accepted

Multimorbidity patterns in the working age population with the top 10% medical cost from exhaustive insurance claims data of Japan Health Insurance Association

Yuki Nishida,Tatsuhiko Anzai,Kunihiko Takahashi,Takahide Kozuma,Eiichiro Kanda,Keita Yamauchi,Fuminori Katsukawa

PLoS ONE (PLoS ONE)  18 ( 9 ) e0291554 2023.09

Research paper (scientific journal), Joint Work, Accepted

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Although the economic burden of multimorbidity is a growing global challenge, the contribution of multimorbidity in patients with high medical expenses remains unclear. We aimed to clarify multimorbidity patterns that have a large impact on medical costs in the Japanese population. We conducted a cross-sectional study using health insurance claims data provided by the Japan Health Insurance Association. Latent class analysis (LCA) was used to identify multimorbidity patterns in 1,698,902 patients who had the top 10% of total medical costs in 2015. The present parameters of the LCA model included 68 disease labels that were frequent among this population. Moreover, subgroup analysis was performed using a generalized linear model (GLM) to assess the factors influencing annual medical cost and 5-year mortality. As a result of obtaining 30 latent classes, the kidney disease class required the most expensive cost per capita, while the highest portion (28.6%) of the total medical cost was spent on metabolic syndrome (MetS) classes, which were characterized by hypertension, dyslipidemia, and type 2 diabetes. GLM applied to patients with MetS classes showed that cardiovascular diseases or complex conditions, including malignancies, were powerful determinants of medical cost and mortality. MetS was classified into 7 classes based on real-world data and accounts for a large portion of the total medical costs. MetS classes with cardiovascular diseases or complex conditions, including malignancies, have a significant impact on medical costs and mortality.

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社会生活基本調査匿名データの活用で広がる可能性 －単身男性介護者の社会的孤立要因の検討－

田上紀代美, 新井崇弘, 山内慶太, 渡辺美智子

統計研究彙報 (総務省統計研究研修所)   ( 80 ) 79 - 96 2023.03

Research paper (scientific journal), Joint Work, Accepted

Short-Term Outcomes of Surgery and Rehabilitation on Activities of Daily Living after Displaced Femoral Neck Fractures: Structural Equation Modeling

Yokoyama K., Katoh H., Bito S., Fujita Y., Yamauchi K.

Journal of Clinical Medicine (Journal of Clinical Medicine)  12 ( 3 )  2023.02

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In order to explore the factors affecting patients’ level of activities of daily living (ADL) on discharge after undergoing bipolar hemiarthroplasty or total hip arthroplasty for displaced femoral neck fractures at an acute care hospital, patient data were analyzed with the following statistical tools: multiple regression analysis (MRA), structural equation modeling (SEM), and simultaneous analysis of several groups (SASG). The Barthel Index (BI) on discharge was set as the objective variable, while age, sex, degree of dementia, BI on admission, number of days from admission to surgery, surgical option, and number of rehabilitation units per day were set as explanatory variables. Factors such as age, sex, degree of dementia, BI on admission, and number of rehabilitation units per day were significant in MRA. While not significant in MRA, the number of days from admission to surgery was significant in SEM. According to the SASG, the number of rehabilitation units per day was significant for patients without dementia but not for patients with dementia. Analysis of real-world data suggests that early surgery and rehabilitation affect ADL on discharge to a greater degree than the surgical method. For patients without dementia, longer daily rehabilitation was significantly associated with better ADL on discharge.

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COVID-19感染拡大による自殺率上昇の把握と対策に資する質的／量的混合アプローチ

岡檀，椿広計，山内慶太

横幹 (特定非営利活動法人横断型基幹科学技術研究団体連合)  16 ( 2 ) 54 - 59 2022.10

Research paper (scientific journal), Joint Work, Accepted

日本におけるCOVID-19パンデミック後の自殺率上昇の地域差及び性差に関する分析－全国市区町村の産業構造に着目して－

岡檀, 久保田貴文, 椿広計, 山内慶太

統計数理 (統計数理研究所)  70 ( 1 ) 115 - 126 2022.07

Research paper (scientific journal), Last author, Accepted

Functional Independence Measure Subtypes among Inpatients with Subacute Stroke: Classification via Latent Class Analysis

Hiroaki Furuta, Katsuhiro Mizuno, Kei Unai, Hiroki Ebata, Keita Yamauchi, Michiko Watanabe

Progress in Rehabilitation Medicine (The Japanese Association of Rehabilitation Medicine)  7 2022.04

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2432-1354

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Assessment of coding-based frailty algorithms for long-term outcome prediction among older people in community settings: a cohort study from the Shizuoka Kokuho Database

Shiori Nishimura, Hiraku Kumamaru, Satoshi Shoji, Eiji Nakatani, Hiroyuki Yamamoto, Nao Ichihara, Yoshiki Miyachi, Alexander T Sandhu, Paul A Heidenreich, Keita Yamauchi, Michiko Watanabe, Hiroaki Miyata, Shun Kohsaka

Age and Ageing (Oxford University Press)  51 ( 3 )  2022.03

Research paper (scientific journal), Joint Work, Accepted,  ISSN  00020729

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Objectives: To assess the applicability of Electronic Frailty Index (eFI) and Hospital Frailty Risk Score (HFRS) algorithms to Japanese administrative claims data and to evaluate their association with long-term outcomes. Study Design and Setting: A cohort study using a regional government administrative healthcare and long-term care (LTC) claims database in Japan 2014-18. Participants: Plan enrollees aged ≥50 years. Methods: We applied the two algorithms to the cohort and assessed the scores' distributions alongside enrollees' 4-year mortality and initiation of government-supported LTC. Using Cox regression and Fine-Gray models, we evaluated the association between frailty scores and outcomes as well as the models' discriminatory ability. Results: Among 827,744 enrollees, 42.8% were categorised by eFI as fit, 31.2% mild, 17.5% moderate and 8.5% severe. For HFRS, 73.0% were low, 24.3% intermediate and 2.7% high risk; 35 of 36 predictors for eFI, and 92 of 109 codes originally used for HFRS were available in the Japanese system. Relative to the lowest frailty group, the highest frailty group had hazard ratios [95% confidence interval (CI)] of 2.09 (1.98-2.21) for mortality and 2.45 (2.28-2.63) for LTC for eFI; those for HFRS were 3.79 (3.56-4.03) and 3.31 (2.87-3.82), respectively. The area under the receiver operating characteristics curves for the unadjusted model at 48 months was 0.68 for death and 0.68 for LTC for eFI, and 0.73 and 0.70, respectively, for HFRS. Conclusions: The frailty algorithms were applicable to the Japanese system and could contribute to the identifications of enrollees at risk of long-term mortality or LTC use.

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Medical Costs and Readmissions After Intensive Poststroke Rehabilitation: Japanese Claims Data

Hirofumi Nagayama, Kounosuke Tomori, Kohei Ikeda, Keita Yamauchi

Journal of Post-Acute and Long-Term Care Medicine (Elsevier)  22 ( 8 ) 1762 - 1766.e1 2021.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  15258610

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Objectives: This study examined the association between intensive rehabilitation for subacute stroke patients and medical costs and readmission ratio during the year after discharge. Design: This was a natural experiment study. Setting and Participants: We identified individuals with a diagnosis of cerebrovascular disorder (ICD-10: I60-I69 cerebrovascular disease) in an insurance claims database in Japan from January 2005 to December 2017. From the database, 980 patients who were admitted to a convalescent rehabilitation unit with stroke were identified. After excluding 575 patients, 405 were eligible for the study. Methods: In Japan, from April 2011, a new policy was established that allows special costs to be added as rehabilitation time increases. This policy provides an additional medical fee for inpatients in a convalescent rehabilitation unit who receive more than 120 minutes of rehabilitation therapy. We defined high-intensity rehabilitation as transfer from hospitalization to a convalescent rehabilitation unit after April 2011. Outcomes were total direct medical costs and readmission ratio during the year after discharge from the convalescent rehabilitation unit. Results: Daily rehabilitation time, total rehabilitation time, and total medical costs of the high-intensity rehabilitation group were significantly higher than those of the low-intensity rehabilitation group (P < .001, P < .001, P = .011, respectively). However, there was no significant difference in the medical costs during the year after discharge (P = .653) or in the readmission ratio (hazard ratio: 1.09, 95% confidence interval: 0.55-2.18, P = .804). Conclusions and Implications: Intensive rehabilitation did not reduce medical costs or the readmission ratio during the first year after discharge. Future studies should consider the necessary rehabilitation intensity given the severity of the patient's condition, using large sample sizes.

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