Yamamoto, Hiroyuki



School of Medicine, Department of Health Policy and Management (Shinanomachi)


Senior Assistant Professor (Non-tenured)/Assistant Professor (Non-tenured)

Related Websites


Research Areas 【 Display / hide

  • Epidemiology and preventive medicine (Clinical epidemiology)

  • Life / Health / Medical informatics

  • Medical and hospital management

  • Kidney internal medicine


Papers 【 Display / hide

  • Impact of board certification system and adherence to the clinical practice guidelines for liver cancer on post-hepatectomy risk-adjusted mortality rate in Japan: A questionnaire survey of departments registered with the National Clinical Database.

    Junichi Arita, Hiroyuki Yamamoto, Takashi Kokudo, Kiyoshi Hasegawa, Hiroaki Miyata, Yasushi Toh, Mitsukazu Gotoh, Norihiro Kokudo, Yoshihiro Kakeji, Seto Yasuyuki

    Journal of hepato-biliary-pancreatic sciences  2021.05

    Research paper (scientific journal), Joint Work, Except for reviews

     View Summary

    BACKGROUND: It is unclear to what extent a board certification system and implementation of clinical guidelines improves the quality of hepatectomy. METHODS: A web-based questionnaire survey was administered to departments registered with the National Clinical Database (NCD) in Japan between 1 October 2014 and 31 January 2015. Quality indicators (QIs), including affiliations with academic societies, numbers of board-certified doctors affiliated with each institute, and adherence to clinical practice guidelines for hepatocellular carcinoma, were evaluated by calculating risk-adjusted odds ratios (AORs) for 90-day postoperative mortality of patients who had undergone hepatectomy in 2013 and 2014. RESULTS: Of 1255 departments that had registered at least one hepatectomy in NCD, 592 departments, performing 8601 hepatectomies in total, responded to the questionnaire. AORs were significantly lower in departments that were certified as training hospitals by the Japanese Society of Gastroenterological Society, Japanese Society of Hepato-Biliary Pancreatic Surgery (JSHBPS), and Japan Society of Hepatology than in non-certified departments. Affiliation of three or more JSHBPS-certified experts or instructors with an institution also contributed to low AORs. None of the QIs regarding implementation of guidelines significantly impacted on the AOR. CONCLUSIONS: QI measurements may improve quality of post-hepatectomy outcomes in Japan.

  • A risk model for prolonged air leak after lobectomy using the National Clinical Database in Japan.

    Yasushi Shintani, Hiroyuki Yamamoto, Yukio Sato, Kimihiro Shimizu, Shunsuke Endo, Morihito Okada, Kenji Suzuki, Eriko Fukuchi, Hiroaki Miyata, Masayuki Chida

    Surgery today (Surgery Today)   2021.05

    Research paper (scientific journal), Joint Work, Except for reviews,  ISSN  09411291

     View Summary

    PURPOSE: The objective of our study was to develop a clinical prediction model for prolonged air leak (PAL) after lobectomy for lung cancer using preoperative variables in a large patient dataset from the National Clinical Database (NCD) in Japan. METHODS: The preoperative characteristics of 57,532 and 30,967 patients who had undergone standard lobectomy for lung cancer were derived from the 2014 to 2015 and 2016 NCD datasets, respectively. PAL was defined as air leak persisting ≥ 7 days postoperatively or requiring postoperative interventional treatment, such as pleurodesis or reoperation. Risk models were developed from the 2014 to 2015 dataset and validated using the 2016 dataset. When performing model derivation, the least absolute shrinkage and selection operator (LASSO) method were applied for parameter selection. RESULTS: The rate of PAL was 4.5% in 2014-2015 and 5.3% in 2016. The age, sex, body mass index, comorbid interstitial pneumonia, smoking habits, forced expiratory volume in 1 s, tumor histology, multiple lung cancer, and tumor location were selected as important variables for PAL. Our risk model for predicting PAL was fair with a concordance index of 0.6895. CONCLUSION: The LASSO-based risk model for PAL after lobectomy provided important preoperative variables for PAL and risk weighting for each variable.

  • Comparison of outcomes between laparoscopic and open pancreaticoduodenectomy without radical lymphadenectomy: Results of coarsened exact matching analysis using national database systems.

    Kohei Nakata, Hiroyuki Yamamoto, Hiroaki Miyata, Yoshihiro Kakeji, Yuko Kitagawa, Masafumi Nakamura

    Asian journal of endoscopic surgery  2021.05

    Research paper (scientific journal), Joint Work, Except for reviews

     View Summary

    INTRODUCTION: Laparoscopic pancreaticoduodenectomy has recently been covered under Japan's insurance system for patients not requiring lymph node dissection. Only high-volume hospitals that meet specific criteria are permitted to perform laparoscopic pancreaticoduodenectomy. Although open and laparoscopic pancreaticoduodenectomy outcomes with lymph node dissection have been described previously, procedures performed without lymph node dissection have not been compared using a nationwide database. This study aimed to review the results of laparoscopic pancreaticoduodenectomy and compare them to those of open pancreaticoduodenectomy (OPD) using records from a nationwide database. METHODS: We collected patient demographic and medical data of 2900 patients who underwent pancreaticoduodenectomy (laparoscopic, n = 162; open, n = 2738) without lymph node dissection between 2016 and 2018 from the National Clinical Database in Japan. Coarsened exact matching was used to match patients in the laparoscopic and open pancreaticoduodenectomy groups. RESULTS: In-hospital mortality was not observed in the laparoscopic pancreaticoduodenectomy group. The rate of conversion to an open procedure was 6.8% (11 cases). After 1:1 matching, we obtained 141 pairs of patients for comparison. The mortality rate was comparable in the laparoscopic and open pancreaticoduodenectomy groups (0.0% vs 0.7%, respectively; P = 1.00). The laparoscopic approach showed more favorable results in terms of median blood loss. Postoperative pancreatic fistula formation and complications were comparable between the two groups. CONCLUSIONS: Our results indicate that laparoscopic pancreaticoduodenectomy could be introduced successfully, and the outcomes achieved by the institutions included in our study were comparable to those of open pancreaticoduodenectomy.

  • Japanese Current Status of Curative-Intent Surgery for Malignant Pleural Mesothelioma.

    Masaki Hashimoto, Hiroyuki Yamamoto, Shunsuke Endo, Morihito Okada, Hiroaki Miyata, Seiki Hasegawa, Masayuki Chida

    The Annals of thoracic surgery  2021.04

    Research paper (scientific journal), Joint Work, Except for reviews

     View Summary

    BACKGROUND: Few reports about surgical outcomes in malignant pleural mesothelioma (MPM) were based on reliable nationwide databases. Here we analyzed the incidence, surgical outcome, and operative risk factors using Japanese nationwide database. METHODS: Characteristics and perioperative data from 622 patients who underwent curative-intent surgery for MPM between January 2014 and December 2017 were recorded from National Clinical Database of Japan. We analyzed the incidence, surgical outcomes, and risk factors for surgical complications after two surgical procedures (extrapleural pneumonectomy, EPP; and pleurectomy/decortication, P/D). RESULTS: During 4 years, EPP was performed in 279 patients and P/D in 343. EPP was more frequently performed in less-MPM-experienced institutions, while P/D was more frequently performed in well-MPM-experienced institutions (P < .001), especially in high-volume centers with more than 10 cases during this period. P/D was more frequently performed, especially in high-volume centers. The morbidity rates were 45.2% in EPP and 35.9% in P/D. Heart failure and pneumonia were most frequent in EPP, while prolonged air leakage was most frequent in P/D. Thirty-day- and in-hospital mortality rates were 1.1% and 3.2% (EPP) and 1.2% and 3.2% (P/D), respectively. Regression analyses revealed that higher age (>65 years) was associated with operative complications in EPP (odds ratio, OR: 3.56 [1.26-8.56]), whereas no risk factor was observed in P/D. CONCLUSIONS: In Japanese nationwide annual database, P/D was more frequently performed, especially in high-volume centers. Morbidity was higher in EPP than P/D; however, the mortality rates were quite low in Japan regardless surgical procedures.

  • Publisher Correction to: Estimates of the effects of centralization policy for surgery in Japan: does centralization affect the quality of healthcare for esophagectomies?

    Arata Takahashi, Hiroyuki Yamamoto, Yoshihiro Kakeji, Shigeru Marubashi, Mitsukazu Gotoh, Yasuyuki Seto, Hiroaki Miyata

    Surgery today (Surgery Today)  51 ( 6 ) 1020 - 1021 2021.04

    Joint Work, Except for reviews,  ISSN  09411291

     View Summary

    In the original publication, under Introduction section, the sentence starting with: “In addition,…” should read as: In addition, the revised Medical Care Act of September 2015 established the "Regional Medical Cooperation Promotion Agency" system [5–6], making it possible for multiple hospitals and nursing care facilities with different management bases to share functions and improve the quality of services as if they were one hospital. Under the heading Definition of ultra-low-volume hospitals and centralization of Method section, the sentence starting with: “In this study….” should read as: In this study, based on previous studies and discussions with clinical experts, we defined an "ultra-low-volume hospital" as a hospital with fewer than two esophagectomy cases per year [11, 26]. In Table 3, the value “0.856 (95% CI 0.639–1.147) *p = 0.298” should be listed under the year “2014”. The updated Table 3 is given in this correction. (Table presented.).

display all >>

Papers, etc., Registered in KOARA 【 Display / hide

Reviews, Commentaries, etc. 【 Display / hide

  • NCD24,233例を用いた、術前治療が胸腔鏡下食道切除術の短期成績に与える影響の研究結果とその課題

    吉田 直矢, 山本 博之, 宮田 裕章, 馬場 祥史, 長井 洋平, 馬場 秀夫

    日本外科学会定期学術集会抄録集 ((一社)日本外科学会)  119回   SF - 072 2019.04

    Other article, Joint Work

  • National Clinical Databaseにおけるデータの質検証結果報告(2014-2015年症例)

    高橋 新, 福地 絵梨子, 隈丸 拓, 一原 直昭, 山本 博之, 平原 憲道, 宮田 裕章

    日本医師事務作業補助研究会全国大会集録 ((NPO)日本医師事務作業補助研究会)  7回   50 - 50 2017.11

    Other article, Joint Work,  ISSN  2187-7939

  • National Clinical Database(NCD)自施設データ活用におけるダウンロードデータの特徴と注意点

    高橋 新, 福地 絵梨子, 隈丸 拓, 一原 直昭, 山本 博之, 平原 憲道, 宮田 裕章

    診療情報管理 (日本診療情報管理学会)  29 ( 2 ) 207 - 207 2017.08

    Other article, Joint Work,  ISSN  1883-7972

Research Projects of Competitive Funds, etc. 【 Display / hide

  • 診療報酬データに加え他領域のレジストリ情報を用いた周術期腎不全の医療経済評価


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 山本 博之, Grant-in-Aid for Early-Career Scientists , Principal Investigator

  • 大規模データベースを用いた慢性腎臓病・透析症例の周術期リスクと管理戦略の検討


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 山本 博之, Grant-in-Aid for Early-Career Scientists , Principal Investigator