Published papers

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.

Aims: We evaluated the cost-effectiveness of artificial intelligence (AI)-based diabetic retinopathy (DR) screening in Japan. This evaluation compared the simultaneous introduction of AI in nationwide health checkups, namely “specific health check-ups in Japan” (SHC), and diabetes complication management (AI-case) with the current situation where AI is not being introduced (conventional-case) from the healthcare payer's perspective. Methods: A cost-effectiveness analysis was conducted using a new individual-based state transition model. Model parameters, including the incidence and progression of DR, health utility values, and costs of screening and treatment, were based on literature data and expert opinion. The analysis estimated quality-adjusted life years (QALYs), cumulative costs, and incremental cost-effectiveness ratios (ICER). Results: The ICER comparing the AI-case with conventional-case was estimated to be JPY 1,598,244/QALY (USD 11,375/QALY), which is below the willingness-to-pay threshold of JPY 5 million/QALY (USD 35,584/QALY). Scenario analyses revealed that ICERs for the AI-based DR screening in SHC-only condition was JPY 1,895,226/QALY (USD 13,488/QALY) and JPY 3,960,839/QALY (USD 28,189/QALY) in diabetes management-only condition. Conclusions: The introduction of AI-based DR screening for SHC and diabetes management was cost-effective compared to the current situation in Japan.

Objectives: We examined shifts in labor productivity and their economic ramifications among adult patients with long COVID in Japan. Methods: A total of 396 patients were categorized into three groups based on symptom progression: non-long COVID, long COVID recovered, and long COVID persistent. Patient-reported outcomes were assessed at three time intervals: 3, 6, and 12 months after COVID-19 diagnosis. Labor productivity was gauged through presenteeism and absenteeism, measured using the World Health Organization Health and Work Performance Questionnaire. Results: Long COVID was observed in 52.7% of patients, and 29.3% of all the patients continued to experience long COVID symptoms 1 year after diagnosis. At all three time points (3, 6, and 12 months after diagnosis), the long COVID persistent group showed a statistically significant difference in absolute presenteeism compared with the non-long COVID and long COVID recovered groups (P <0.01). Economic loss owing to decrease in labor productivity was calculated as $21,659 per year in the long COVID persistent group and $9008 per year in the long COVID recovered group (P <0.01). Conclusion: The study's results revealed a notable decline in labor productivity over time, underscoring the importance of early detection and intervention to mitigate the socio-economic repercussions of long COVID, in addition to its health implications.

Background: Medical corporations, which are non-profit organizations that aim to operate hospitals, clinics, or long-term care facilities, account for more than half of all hospital beds and play a central role in the health care system in Japan. However, limited analysis of hospital integration has been performed. Examining the hospital integration trends of medical corporations can provide valuable insights for optimizing health care delivery and resource allocation in Japan. This study conducted a comprehensive analysis of trends in the hospital integration of medical corporations and market concentration in Japan using nationwide longitudinal data. Methods: This longitudinal study evaluated the hospital integration of medical corporations in Japan between 2017 and 2021 using medical corporation financial data provided by the Neostage Company. The target population was medical corporations that own hospitals in Japan. The primary outcomes were the horizontal and vertical integration of medical corporation hospitals. Horizontal integration was defined as the integration of two or more hospitals within the same corporation, while vertical integration was defined as the integration of a hospital with different types of health care facilities, such as clinics or long-term care facilities, within a single medical corporation. The Herfindahl–Hirschman Index (HHI) was calculated to measure hospital market concentration using hospital bed data for medical corporations in all prefectures. Results: The number of hospitals and hospital beds within medical corporations decreased from 5,670 to 848,174 in 2017 to 5,486 and 814,462 in 2021, respectively. Both horizontal and vertical integration among medical corporation facilities showed a gradual upward trend, increasing from 24.92% to 55.75% in 2017 to 26.92% and 59.42% in 2021, respectively. The mean (standard deviation [SD]) HHI increased slightly from 262.7 (178.6) in 2017 to 275.2 (187.9) in 2021, with rural areas being more concentrated than urban areas, although both remained unconcentrated. Conclusions: This longitudinal study revealed a gradual downward trend in the number of hospitals and hospital beds owned by medical corporations, while horizontal and vertical integration gradually progressed without any particular medical corporation dominating the market. These findings are expected to contribute to policymaking efforts aimed at providing optimal health care services in Japan.

Objective This study assessed whether patients with potentially preventable emergency admissions had limited access to outpatient care immediately before admission and whether they received appropriate outpatient care during their outpatient visits. Design Retrospective observational study. Setting Linked outpatient and inpatient care records obtained from a nationwide claims database in Japan. Participants Patients who experienced emergency admissions for ambulatory care-sensitive conditions between April 2005 and March 2020. Patient and regional characteristics were examined to assess the types of patients who faced difficulties with outpatient visits and receiving outpatient care related to the disease that resulted in admissions (hereafter referred to as admission-related outpatient care). Main outcome measures (1) Whether patients had an outpatient visit during the 2 weeks preceding admission and (2) whether patients received admission-related outpatient care during the 2 weeks before admission. Results This study included 18 449 emergency admissions for ambulatory care-sensitive conditions, representing 16.3% (18 449/113 669) of all emergency admissions in our data. Among patients with emergency admissions for ambulatory care-sensitive conditions, 37.4% did not have an outpatient visit within the 2 weeks preceding admission and 29.9% did not receive admission-related outpatient care despite having an outpatient visit. In total, 67.4% did not receive admission-related outpatient care during the 2 weeks preceding admission. Patients in their 40s and 50s were less likely to have outpatient visits and receive admission-related outpatient care before admission. No evidence associates regional characteristics with outpatient visits and receiving admission-related outpatient care before admission. Conclusion Most patients who underwent emergency admissions for ambulatory care-sensitive conditions did not have an outpatient visit or receive admission-related outpatient care, despite having an outpatient visit immediately before admission. Our findings suggest that emergency admissions may be prevented by improving access to timely and effective outpatient care.

The use of quality-adjusted life year (QALY) as a measure of benefit is recommended in economic evaluation, which aims to provide evidence for the appropriate allocation of health care resources. This allows for an easier comparison of interventions' effects in different fields. A QALY value is calculated by weighting the life years (LYs) by the quality of life (QOL) score, which is determined by preference-based measure (PBM) and converted from 0 to 1. The QOL score should be obtained through domestic surveys because it reflects the value in the country's general population. In Japan, the data of the QOL scores for adults have been accumulated in recent years. However, few studies for children have been conducted due to various issues in evaluating pediatric health-related QOL (HRQOL). The PBM process for obtaining the QOL score can be divided into “measurement” and “valuation” of the health state to be evaluated. This process is implemented at once in direct methods, whereas it is carried out separately in indirect methods. Direct methods include the rating scale, the time trade-off, and the standard gamble, but children's feasibility, reliability, and validity must be thoroughly investigated. In indirect methods, which is currently the mainstream in general, multi-attribute utility instruments (MAUIs) are used, consisting of a questionnaire to measure the health state and a value set to value the measured health state. However, most MAUIs are designed for adult use and are not suitable for pediatric use because the questions are inappropriate, and the value set is intended to value adult health. In recent years, some MAUIs for pediatric use have been developed. Nevertheless, due to translations and the value set, these are not available in all countries. Additionally, there are no existing MAUIs available for children aged 3 years. Furthermore, issues concerning “measurement,” such as which domains should be assessed and how, and by whom, and issues concerning “valuation,” such as whose preferences should be reflected in developing the value set, and which perspectives should be used, remain. There have been no MAUIs for pediatric use in Japan, but the Japanese version of the EuroQol 5-dimension Youth version (EQ-5D-Y) and its value set have recently been published. It is necessary to fully understand the challenges and limitations in measuring and interpreting the QOL score in children.

Objectives Nationwide lifestyle intervention—specific health guidance (SHG) in Japan—employs counselling and education to change unhealthy behaviours that contribute to metabolic syndrome, especially obesity or abdominal obesity. We aimed to perform a model-based economic evaluation of SHG in a low participation rate setting. Design A hypothetical population, comprised 50 000 Japanese aged 40 years who met the criteria of the SHG, used a microsimulation using the Markov model to evaluate SHG’s cost-effectiveness compared with non-SHG. This hypothetical population was simulated over a 35-year time horizon. Setting SHG is conducted annually by all Japanese insurers. Outcome measures Model parameters, such as costs and health outcomes (including quality-adjusted life-years, QALYs), were based on existing literature. Incremental cost-effectiveness ratios were estimated from the healthcare payer’s perspective. Deterministic and probabilistic sensitivity analyses (PSA) were conducted to evaluate the uncertainty around the model input parameters. Results The simulation revealed that the total costs per person in the SHG group decreased by JPY53 014 (US$480) compared with that in the non-SHG group, and the QALYs increased by 0.044, wherein SHG was considered the dominant strategy despite the low participation rates. PSA indicated that the credibility intervals (2.5th–97.5th percentile) of the incremental costs and the incremental QALYs with the SHG group compared with the non-SHG group were −JPY687 376 to JPY85 197 (−US$6226 to US$772) and −0.009 to 0.350 QALYs, respectively. Each scenario analysis indicated that programmes for improving both blood pressure and blood glucose levels among other risk factors for metabolic syndrome are essential for improving cost-effectiveness. Conclusions This study suggests that even small effects of counselling and education on behavioural modification may lead to the prevention of acute life-threatening events and chronic diseases, in addition to the reduction of medication resulting from metabolic syndrome, which results in cost savings.

IMPORTANCE The evidence for and against screening for chronic kidney disease in youths who are asymptomatic is inconsistent worldwide. Japan has been conducting urinary screening in students for 50 years, allowing for a full economic evaluation that includes the clinical benefits of early detection and intervention for chronic kidney disease. OBJECTIVES To evaluate the clinical effectiveness and cost-effectiveness of school urinary screening in Japan, with a focus on the benefits of the early detection and intervention for IgA nephropathy, and to explore key points in the model that are associated with the cost-effectiveness of the school urinary screening program. DESIGN, SETTING, AND PARTICIPANTS This economic evaluation with a cost-effectiveness analysis used a computer-simulated Markov model from the health care payer's perspective among a hypothetical cohort of 1 000 000 youths aged 6 years in first grade in Japanese elementary schools, followed up through junior and high school. The time horizon was lifetime. Costs and clinical outcomes were discounted at a rate of 2%per year. Costs were calculated in Japanese yen and 2020 US dollars (¥107 = US $1). INTERVENTIONS School urinary screening for IgA nephropathy was compared with no screening. MAIN OUTCOMES AND MEASURES Outcomes were costs and quality-adjusted life-years (QALYs). Cost-effectiveness was determined by evaluating whether the incremental cost-effectiveness ratio (ICER) per QALY gained remained less than ¥7 500 000 (US $70 093). RESULTS In the base case analysis, the ICERwas ¥4 186 642 (US $39 127)/QALY, whichwas less than the threshold. There were 60.3 patients/1 000 000 patients in the no-screening strategy and 31.7 patients/1 000 000 patients in the screening strategy with an end-stage kidney disease. Costeffectiveness improved as the number of screenings decreased (screening frequency <3 times: incremental cost, -¥75 [US $0.7]; incremental QALY, 0.00025; ICER, dominant), but the number of patients with end-stage kidney disease due to IgA nephropathy increased (40.9 patients/1 000 000 patients). Assuming the disutility due to false positives had a significant impact on the analysis; assuming a disutility of 0.01 or more, the population with no IgA nephropathy had an ICER greater than the threshold (¥8 304 093 [US $77 608]/QALY). CONCLUSIONS AND RELEVANCE This study found that Japanese school urinary screening was cost-effective, suggesting that it may be worthy of resource allocation. Key factors associated with cost-effectiveness were screening cost, the probability of incident detection outside of screening, and IgA nephropathy incidence, which may provide clues to decision-makers in other countries when evaluating the program in their own context.

Background: An early report has shown the clinical benefit of the asymptomatic preoperative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) screening test, and some clinical guidelines recommended this test. However, the cost-effectiveness of asymptomatic screening was not evaluated. We aimed to investigate the cost-effectiveness of universal preoperative screening of asymptomatic patients for SARS-CoV-2 using polymerase chain reaction (PCR) testing. Methods: We evaluated the cost-effectiveness of asymptomatic screening using a decision tree model from a payer perspective, assuming that the test-positive rate was 0.07% and the screening cost was 8500 Japanese yen (JPY) (approximately 7601 US dollars [USD]). The input parameter was derived from the available evidence reported in the literature. A willingness-to-pay threshold was set at 5 000 000 JPY/quality-adjusted life-year (QALY). Results: The incremental cost of 1 death averted was 74 469 236 JPY (approximately 566 048 USD) and 291 123 368 JPY/QALY (approximately 2 212 856 USD/QALY), which was above the 5 000 000 JPY/QALY willingness-to-pay threshold. The incremental cost-effectiveness ratio fell below 5 000 000 JPY/QALY only when the test-positive rate exceeded 0.739%. However, when the probability of developing a postoperative pulmonary complication among SARS-CoV-2-positive patients was below 0.22, asymptomatic screening was never cost-effective, regardless of how high the test-positive rate became. Conclusions: Asymptomatic preoperative universal SARS-CoV-2 PCR screening is not cost-effective in the base case analysis. The cost-effectiveness mainly depends on the test-positive rate, the frequency of postoperative pulmonary complications, and the screening costs; however, no matter how high the test-positive rate, the cost-effectiveness is poor if the probability of developing postoperative pulmonary complications among patients positive for SARS-CoV-2 is sufficiently reduced.

Background: It is important to assess whether the early detection of breast cancer affects medical care costs. However, research remains scant on the actual medical care costs associated with breast cancer treatment in Japan. This study aimed to determine the medical care costs of breast cancer treatment based on its stage using national health insurance claims data. Methods: This was an observational study including patients with breast cancer who had undergone breast cancer treatment, as defined by the disease name and related treatment codes. Between August 2013 and June 2016, patients who underwent surgical treatment without axillary lymph node dissection and other radical treatment were classified as the curable group, while those who underwent palliative treatment were classified as the non-curable group. Patients were further stratified by subtype. The total and treatment-specific medical care costs for the five years were calculated using the national health insurance claims data of Hachioji City between August 2013 and May 2021. Results: The mean total medical care costs for the curable and non-curable groups for the 5 years were JPY 3958 thousand (standard deviation 2664) and JPY 8289 thousand (8482), respectively. The mean medical care costs for specific breast cancer treatment for the curable and non-curable groups were JPY 1142 (728) thousand and JPY 3651 thousand (5337), respectively. Further, human epidermal growth factor receptor 2 + , Hormone + patients had the highest mean cost over the 5 years. Conclusions: The results suggest that the early detection of breast cancer may reduce medical care costs at the patient level.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly since 2019, and the number of reports regarding long COVID has increased. Although the distribution of long COVID depends on patient characteristics, epidemiological data on Japanese patients are limited. Hence, this study aimed to investigate the distribution of long COVID in Japanese patients. This study is the first nationwide Japanese prospective cohort study on long COVID. Methods: This multicenter, prospective cohort study enrolled hospitalized COVID-19 patients aged ≥18 years at 26 Japanese medical institutions. In total, 1200 patients were enrolled. Clinical information and patient-reported outcomes were collected from medical records, paper questionnaires, and smartphone applications. Results: We collected data from 1066 cases with both medical records and patient-reported outcomes. The proportion of patients with at least one symptom decreased chronologically from 93.9% (947/1009) during hospitalization to 46.3% (433/935), 40.5% (350/865), and 33.0% (239/724) at 3, 6, and 12 months, respectively. Patients with at least one long COVID symptom showed lower quality of life and scored higher on assessments for depression, anxiety, and fear of COVID-19. Female sex, middle age (41–64 years), oxygen requirement, and critical condition during hospitalization were risk factors for long COVID. Conclusions: This study elucidated the symptom distribution and risks of long COVID in the Japanese population. This study provides reference data for future studies of long COVID in Japan.

Objectives: The purpose of this study is to examine the cost-effectiveness of nivolumab (NIVO) plus ipilimumab (IPI) combination therapy (NIVO + IPI) compared with the sunitinib (SUN) therapy for Japanese patients with advanced renal cell carcinoma from the perspective of a Japanese health insurance payer. Methods: A lifetime horizon was applied, and 2% per annum was set as the discount rate. The threshold was set as $ 75 000 per quality-adjusted life-year (QALY) gained. For the analytical method, we used a partitioned survival analysis model to estimate the incremental cost-effectiveness ratio (ICER), which is calculated by dividing incremental costs by incremental QALYs. Progression-free survival, progressive disease, and death were set as health states. Additionally, cost parameters and utility weights were set as key parameters. We set the intermediate/poor-risk population as the base case. Scenario analysis was conducted for the intention-to-treat population and the favorable risk population. Furthermore, one-way sensitivity analysis and probabilistic sensitivity analysis were conducted for each population. Results: In the base-case analysis, the QALYs of NIVO + IPI and SUN were 4.32 and 2.99, respectively. NIVO + IPI conferred 1.34 additional QALYs. Meanwhile, the total costs in the NIVO + IPI and SUN were $692 288 and $475 481, respectively. As a result, the ICER of NIVO + IPI compared with SUN was estimated to be $162 243 per QALY gained. The parameter that greatly affected the ICER was the utility weight of progression-free survival in NIVO + IPI. Conclusions: NIVO + IPI for advanced renal cell carcinoma seems to be not cost-effective compared with the SUN in the Japanese healthcare system.

Introduction Surgical site infections (SSIs) are among the most common nosocomial infections in surgery patients. Two types of preparations, povidone-iodine and chlorhexidine-alcohol, are commonly used in preoperative antiseptic procedures worldwide. However, there are inconsistencies among international guideline recommendations concerning skin antiseptics. This trial aimed to evaluate the superiority of olanexidine, which reduced SSI rates more than povidone-iodine in our previous randomised trial, over chlorhexidine-alcohol in clean-contaminated surgery. Methods and analysis This multicentre randomised controlled clinical trial will compare two antiseptics (1.5% olanexidine and 1.0% chlorhexidine-alcohol) to prevent SSI in clean-contaminated gastrointestinal surgeries with surgical wounds. On providing consent, patients aged <18 years will be included. The primary outcome will be the postoperative 30-day overall SSI rate, while the secondary outcomes will be the postoperative 30-day superficial incisional SSI rate, deep incisional SSI rate, organ/space SSI rate, positive bacterial wound culture rate, cultured bacterial strains, rates of intervention-related toxicity and allergic events (eg, erythema, pruritus, dermatitis and other symptoms of allergy around the region disinfected by the antiseptic during surgery), rate of reoperations due to SSI, medical economic effect indicators (based on health insurance claims) and hospital duration. The Mantel-Haenszel method will be used to estimate the adjusted risk ratio and its 95% CI for the primary analysis, which will compare the treatment effects. Ethics and dissemination The protocol was approved by the Institutional Review Board of Keio University School of Medicine and subsequently by the board of each participating site. Participant recruitment began in January 2023. The final results will be published in medical journals after international peer review. Trial registration number UMIN000049712.

Objective: We aimed to determine how municipal subsidies for seasonal influenza vaccines for the elderly affected vaccination coverage and health outcomes and how responses to vaccine prices changed during the COVID-19 pandemic. Study design and methods: This ecological study includes 1245 municipalities in Japan between 2019 and 2020. Fixed-effects regression analysis was performed to evaluate the effect of influenza vaccine cost subsidy for people aged 65 years or older on vaccination coverage, all-cause mortality, and influenza-related mortality. Results: The vaccination rate increased when patients' copayments decreased, and reducing the copayment by 1000 Japanese Yen (JPY) was estimated to increase the vaccination rate by 6.3% (95% confidence interval [CI] 4.5–8.2%) in the adjusted model. When examining the additional effect of a zero price compared to a nearly zero price, we found that a zero price increased the immunization rate by 6.4% (95% CI 1.4–11.5%). The effect of copayment on the increase in vaccination coverage was significantly lower during the pandemic than in the pre-pandemic period. The municipal and prefectural analyses found no association between influenza vaccine copayments and all-cause, influenza, or pneumonia mortality. Conclusion: Cost subsidies and the zero-price effect were shown to increase vaccination coverage but were not associated with relevant mortality measures. Although the impact was attenuated under pandemic conditions, cost subsidy effectively increases the vaccination rate.

Background: Strict glycemic control is important to prevent perinatal complications in patients with gestational diabetes mellitus (GDM). Patients often require insulin injection, and frequent hospital visits are necessary to adjust the dose of insulin, which is considered burdensome for pregnant patients. Telemedicine may reduce the burden of hospital visits, and previous studies have reported its safety in GDM patients. This study aimed to evaluate the efficacy of telemedicine in GDM patients, focusing on patient satisfaction and health economic indicators. Methods: This is a single-center, two-arm, randomized, open-label parallel-group study. Subjects will be selected from the patient population attending the Department of Endocrinology, Metabolism, and Nephrology, Keio University School of Medicine, Japan. Patients diagnosed with GDM by an oral glucose tolerance test (OGTT) by 29 weeks and 6 days of gestation who have undergone self-monitoring of blood glucose (SMBG) and insulin injection are eligible for inclusion. In the intervention group, telemedicine will be administered using the MeDaCa telemedicine system developed by the Medical Data Card, Inc., Tokyo, Japan. Subjects in the control group will be examined face-to-face every 2–3 weeks, as usual. We set health economic indicators and patient satisfaction as the primary endpoints, and will perform a cost-consequence analysis. Glycemic control indicators and perinatal outcomes will be evaluated as secondary endpoints. Conclusions: Eligible patients are currently being recruited. Recruitment will be completed when the expected number of patients are enrolled.