A review of studies using the Japanese National Database of Health Insurance Claims and Specific Health Checkups

Impact of Coronavirus Disease 2019 Emergency Declarations on Surgeries for Deep Neck Infection Incidence in Japan

INTRODUCTION

Deep neck infections are lethal diseases; however, factors related to their prevention remain unclear. The national emergency declaration in April 2020, in response to COVID-19, spurred widespread adoption of nonpharmaceutical interventions (NPIs) such as hand washing, mask wearing, and social distancing.

METHODS

This retrospective cohort study examines the impact of these interventions on the incidence of deep neck infections in Japan through interrupted time series analysis using National Database of Health Insurance Claims and Specific Health Checkups of Japan Open Data. Aggregated yearly and monthly data from fiscal year 2014 to 2021 were analyzed. This study aimed to examine the time series changes in Japan, including the impact of COVID-19, by focusing on retropharyngeal, peritonsillar, and deep neck abscess surgeries.

RESULTS

A significant seasonal variation was observed in peritonsillar abscesses, with a peak in July. We assessed changes in surgery for deep neck infections before and after the emergency declaration. Interrupted time series analysis revealed changes in surgery for retropharyngeal abscess (level change, 0.59; 95% confidence interval [CI], 0.40-0.86; slope change, 0.98; 95% CI, 0.94-1.02), peritonsillar abscess (level change, 0.84; 95% CI, 0.75-0.94; slope change, 1.00; 95% CI, 0.99-1.01), and deep neck abscess (level change, 0.91; 95% CI, 0.77-1.08; slope change, 0.99; 95% CI, 0.97-1.01).

CONCLUSIONS

These findings suggest that the NPIs implemented due to the emergency declaration are effective in reducing the need for surgical intervention in retropharyngeal and peritonsillar abscess cases, highlighting the potential for these measures to prevent serious infections.

Machine-learning-based identification of patients with IgA nephropathy using a computerized medical billing database

The billing database of the universal healthcare system in Japan potentially includes large-cohort data of patients with immunoglobulin A nephropathy, diagnosis codes aimed at billing should not be directly used for clinical research because of the risk of misdiagnosis. To solve this problem, we aimed to develop a novel method for identifying patients with immunoglobulin A nephropathy from billing data using machine learning. The medical records and bills of 3,743 patients who consulted nephrologists at a single center were extracted. Patients were labeled to have been diagnosed with immunoglobulin A nephropathy through a review of medical records. A manual analysis of the diagnostic accuracy and machine learning was performed. For machine learning, the datasets were preprocessed in three patterns and assigned to the XGBoost program using five-fold cross-validation. Of all the participants, 437 were labeled as having been diagnosed with immunoglobulin A nephropathy. Bill codes for immunoglobulin A nephropathy were provided to approximately half of them. The manually created criteria consisting of the recommended examinations and treatments in the Japanese guidelines for immunoglobulin A nephropathy showed both specificity and sensitivity < 0.8. In contrast, with the receiver operating characteristic curve analysis, the machine learning process yielded area under the curve values over 0.9 with preprocessing from the clinical viewpoint. Applying machine learning technology to a dataset preprocessed from a clinical viewpoint achieved a high performance in detecting patients with immunoglobulin A nephropathy. This methodology contributes to the construction of a disease-specific cohort using big bill data.

Epidemiology of chronic pulmonary aspergillosis: A nationwide descriptive study

BACKGROUND

Chronic pulmonary aspergillosis (CPA) has recently gained attention owing to its substantial health burden. However, the precise epidemiology and prognosis of the disease are still unclear due to the lack of a nationwide descriptive analysis. This study aimed to elucidate the epidemiology of patients with CPA and to investigate their prognosis.

METHODS

Using a national administrative database covering >99% of the population in Japan, we calculated the nationwide incidence and prevalence of CPA from 2016 to 2022. Additionally, we clarified the survival rate of patients diagnosed with CPA and identified independent prognostic factors using multivariate Cox proportional hazard analysis.

RESULTS

During the study period, while the prevalence of CPA remained stable at 9.0-9.5 per 100,000 persons, its incidence declined to 2.1 from 3.5 per 100,000 person-years. The 1-, 3-, and 5-year survival rates were 65%, 48%, and 41%, respectively. During the year of CPA onset, approximately 50% of patients received oral corticosteroids (OCS) at least once, while about 30% underwent frequent OCS treatment (≥4 times per year) within the same timeframe. Increased mortality was independently associated with older age (>65 years) (hazard ratio [HR], 2.65; 95% confidence interval (CI), 2.54-2.77), males (1.24; 1.20-1.29), a history of chronic obstructive pulmonary disease (1.05; 1.02-1.09), lung cancer (1.12; 1.06-1.18); and ILD (1.19; 1.14-1.24); and frequent OCS use (1.13; 1.09-1.17). Conversely, decreased mortality was associated with a history of tuberculosis (HR, 0.81; 95% CI, 0.76-0.86), non-tuberculous mycobacteria (0.91; 0.86-0.96), and other chronic pulmonary diseases (0.89; 0.85-0.92).

CONCLUSIONS

The incidence of CPA decreased over the past decade, although the prevalence was stable and much higher than that in European countries. Moreover, the patients' prognosis was poor. Physicians should be vigilant about CPA onset in patients with specific high-risk underlying pulmonary conditions.

Regional variations in primary percutaneous coronary intervention for acute myocardial infarction patients: A trajectory analysis using the national claims database in Japan

BACKGROUND

Previous studies have demonstrated geographical disparities regarding the quality of care for acute myocardial infarction (AMI). The aim of this study was two-fold: first, to calculate the proportion of patients with AMI who received primary percutaneous coronary interventions (pPCIs) by secondary medical areas (SMAs), which provide general inpatient care, as a quality indicator (QI) of the process of AMI practice. Second, to identify patterns in their trajectories and to investigate the factors related to regional differences in their trajectories.

METHODS

We included patients hospitalized with AMI between April 2014 and March 2020 from the national health insurance claims database in Japan and calculated the proportion of pPCIs across 335 SMAs and fiscal years. Using these proportions, we conducted group-based trajectory modeling to identify groups that shared similar trajectories of the proportions. In addition, we investigated area-level factors that were associated with the different trajectories.

RESULTS

The median (interquartile range) proportions of pPCIs by SMAs were 63.5% (52.9% to 70.5%) in FY 2014 and 69.6% (63.3% to 74.2%) in FY 2020. Four groups, named low to low (LL; n = 48), low to middle (LM; n = 16), middle to middle (MM; n = 68), and high to high (HH; n = 208), were identified from our trajectory analysis. The HH and MM groups had higher population densities and higher numbers of physicians and cardiologists per capita than the LL and LM groups. The LL and LM groups had similar numbers of physicians per capita, but the number of cardiologists per capita in the LM group increased over the years of the study compared with the LL group.

CONCLUSION

The trajectory of the proportion of pPCIs for AMI patients identified groups of SMAs. Among the four groups, the LM group showed an increasing trend in the proportions of pPCIs, whereas the three other groups showed relatively stable trends.

Survey of pharyngeal foreign bodies in Japan: An ecological study using the nationwide claims data

OBJECTIVE

Pharyngeal foreign bodies (PFBs) are a prevalent disease affected by food culture and dietary habits, with fish bones as the leading cause. Most studies were limited to specific regions, and a nationwide survey was not conducted in Japan. In this ecological study, we aimed to conduct a nationwide analysis of outpatient PFB cases in Japan over three years, focusing on seasonal trends, sex- and age-stratified cases, and regional differences.

METHODS

We used the National Database of Health Insurance Claims and Specific Health Checkups of Japan open data from April 2019 to March 2022. The case data were analyzed by month, age, sex, and prefecture. Additionally, we calculated the standardized claim ratios (SCRs) for each prefecture and investigated the association between dietary habits, food culture, and SCR of PFBs using a two-level linear regression model.

RESULTS

We analyzed a total of 164,337 outpatient PFB cases in Japan, revealing an average incidence rate of 45.6 per 100,000 persons. The seasonal trend revealed a peak in July each year from 2019 to 2021, confirming seasonality in PFB incidents. Children reported a higher incidence rate. Living west of Japan and expenditure on fish and shellfish had a strongly positive association with the SCR of PFBs.

CONCLUSION

Our nationwide survey reveals that, even within Japan, there were regional variations influenced by food culture and dietary habits. The data showed that PFB incidence was higher among children, highlighting the need for preventive education.

LEVEL OF EVIDENCE

Level 3.

Shifting paradigms in endoscopic sinus surgery: a comprehensive analysis from Japan's national database

BACKGROUND

In 2013, Japan established a standardized classification system for categorizing endoscopic sinus surgery (ESS) into types I-V, yet no evaluation has been conducted thereof.

OBJECTIVE

We assessed the ESS trends and status in Japan, focusing on outpatient and inpatient surgeries.

MATERIAL AND METHODS

This descriptive retrospective cohort study used Japan's National Database of Health Insurance Claims and Specific Health Checkups between 2014 and 2021. The distribution of ESS types I-V and outpatient and inpatient surgeries was analysed, along with age groups and regional differences, focusing on ESS type III.

RESULTS

Overall, 427,813 ESS procedures were performed, with types III and IV being most common. Outpatient ESS type III increased substantially compared to inpatient surgeries. Younger individuals favoured outpatient ESS type III over inpatient surgeries, with substantial regional variations across prefectures.

CONCLUSIONS AND SIGNIFICANCE

The adoption of a standardized ESS classification in Japan has facilitated a detailed understanding of surgical trends. The shift toward outpatient surgeries, especially for type III ESS, aligns with global trends toward minimally invasive procedures and reflects changing patient preferences and healthcare delivery practices. Consequently, continuous monitoring and research are crucial for adapting surgical practices to the evolving healthcare needs and patient expectations.

Association of Novel Antihyperglycemic Drugs Versus Metformin With a Decrease in Asthma Exacerbations

BACKGROUND

Similar to metformin, dipeptidyl peptidase-4 inhibitors (DPP-4 Is), glucagon-like peptidase 1 receptor agonists (GLP-1 RAs), and sodium glucose co-transporter-2 inhibitors (SGLT-2 Is) may improve control of asthma owing to their multiple potential mechanisms, including differential improvements in glycemic control, direct anti-inflammatory effects, and systemic changes in metabolism.

OBJECTIVE

To investigate whether these novel antihyperglycemic drugs were associated with fewer asthma exacerbations compared with metformin in patients with asthma comorbid with type 2 diabetes.

METHODS

Using a Japanese national administrative database, we constructed 3 active comparators-new user cohorts of 137,173 patients with a history of asthma starting the novel antihyperglycemic drugs and metformin between 2014 and 2022. Patient characteristics were balanced using overlap propensity score weighting. The primary outcome was the first exacerbation requiring systemic corticosteroids, and the secondary outcomes included the number of exacerbations requiring systemic corticosteroids.

RESULTS

DPP-4 Is and GLP-1 RAs were associated with a higher incidence of exacerbations requiring systemic corticosteroids compared with metformin (DPP-4 Is: 18.2 vs 17.4 per 100 person-years, hazard ratio: 1.09, 95% confidence interval [CI]: 1.05-1.14; GLP-1 RAs: 24.9 vs 19.0 per 100 person-years, hazard ratio: 1.14, 95% CI: 1.01-1.28). In contrast, the incidence of exacerbations requiring systemic corticosteroids was similar between the SGLT-2 Is and metformin groups (17.3 vs 18.1 per 100 person-years, hazard ratio: 1.00, 95% CI: 0.97-1.03). While DPP-4 Is and GLP-1 RAs were associated with more exacerbations requiring systemic corticosteroids, SGLT-2 Is were associated with slightly fewer exacerbations requiring systemic corticosteroids (53.7 vs 56.6 per 100 person-years, rate ratio: 0.95, 95% CI: 0.91-0.99).

CONCLUSIONS

While DPP-4 Is and GLP-1 RAs were associated with poorer control of asthma compared with metformin, SGLT-2 Is offered asthma control comparable to that of metformin.

Epidemiology of patients with severe asthma in Japan: a nationwide descriptive study

Background

The 2014 European Respiratory Society/American Thoracic Society guidelines defined severe asthma based on treatment intensity and estimated the proportion of severe asthma among all asthma cases to be 5-10%. However, data supporting the estimate and comprehensive and sequential data on asthma cases are scarce. We aimed to estimate the national prevalence and proportion of severe asthma during the last decade.

Methods

Using a Japanese national administrative database, which covers ≥99% of the population, we evaluated the prevalence and proportion of severe asthma in 2013, 2015, 2017 and 2019. Additionally, we elucidated the demographic characteristics, treatments and outcomes of patients with asthma.

Results

The national prevalence of mild-moderate and severe asthma in 2019 was 800 and 36 per 100 000 persons, respectively. While the prevalence of mild-moderate asthma remained almost constant in the study years, the prevalence of severe asthma decreased, resulting in a reduction in the proportion of severe asthma from 5.6% to 4.3%. Although treatment modalities have evolved, such as the increased use of combination inhalers and asthma biologics, approximately 15% of mild-moderate and 45% of severe asthma cases were still considered "uncontrolled". The number of deaths from asthma decreased in patients with both mild-moderate and severe asthma.

Conclusions

This study revealed that the prevalence of severe asthma in Japan decreased during the study period and fell below 5% in the most recent data. Despite treatment evolution, a substantial proportion of patients with both mild-moderate and severe asthma still have poor asthma control.

Medical resource usage for COVID-19 evaluated using the National Database of Health Insurance Claims and Specific Health Checkups of Japan

PURPOSE

The coronavirus disease 2019 (COVID-19) pandemic exhibited several different waves threatening global health care. During this pandemic, medical resources were depleted. However, the kind of medical resources provided to each wave was not clarified. This study aimed to examine the characteristics of medical care provision at COVID-19 peaks in preparation for the next pandemic.

METHODS

Using medical insurance claim records in Japan, we examined the presence or absence of COVID-19 infection and the use of medical resources for all patients monthly by age group.

RESULTS

The wave around August 2021 with the Delta strain had the strongest impact on the working population in terms of hospital admission and respiratory support. For healthcare providers, this peak had the highest frequency of severely ill patients. In the subsequent wave, although the number of patients with COVID-19 remained high, they were predominantly older adults, with relatively fewer patients receiving intensive care.

CONCLUSIONS

In future pandemics, we should refer to the wave around August 2021 as a situation of medical resource shortage resulting from the COVID-19 pandemic.

Early-onset dementia and risk of hip fracture and major osteoporotic fractures

INTRODUCTION

There is limited knowledge about early-onset dementia (EOD) on fracture risk.

METHODS

Individuals ages 50 to 64 were identified from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (2012 to 2019). The association between EOD and fractures and the association between cholinesterase inhibitors for EOD and fractures were evaluated using logistic regression analyses.

RESULTS

We identified 13,614 EOD patients and 9,144,560 cognitively healthy individuals. The analysis revealed that EOD was associated with an increased risk of hip fractures (adjusted odds ratio, 95% confidence interval: 8.79, 7.37-10.48), vertebral fractures (1.73, 1.48-2.01), and major osteoporotic fractures (2.05, 1.83-2.30) over 3 years. The use of cholinesterase inhibitors was significantly associated with a reduction in hip fractures among EOD patients (0.28, 0.11-0.69).

DISCUSSION

EOD patients have a higher risk of osteoporotic fractures than cognitively healthy individuals. The use of cholinesterase inhibitors may reduce the risk of hip fracture among EOD patients.

HIGHLIGHTS

It is unknown whether early-onset dementia (EOD) increases the risk of fractures. We identified 13,614 individuals with EOD using a nationwide administrative database. Patients with EOD have a higher risk of hip, vertebral, and major osteoporotic fractures. The use of cholinesterase inhibitors may reduce hip fracture among patients with EOD.

Epidemiology of patients with lymphangioleiomyomatosis: A descriptive study using the national database of health insurance claims and specific health checkups of Japan

BACKGROUND

Using patient registries or limited regional hospitalization data may result in underestimation of the incidence and prevalence of rare diseases. Therefore, we used the national administrative database to estimate the incidence and prevalence of lymphangioleiomyomatosis over six years (2014-2019) and describe changes in clinical practice and mortality.

METHODS

We extracted data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan between January 2013 and December 2020. This database covers ≥99% of the population. We used the diagnostic code for lymphangioleiomyomatosis to estimate the incidence and prevalence from 2014 to 2019. Additionally, we examined the demographic characteristics, treatments, comorbidities, and mortality of the patients.

RESULTS

In women, the incidence and prevalence of lymphangioleiomyomatosis in 2019 were approximately 3 per 1,000,000 person-years and 28.7 per 1,000,000 persons, respectively. While, in men, the incidence and prevalence of lymphangioleiomyomatosis were <0.2 per 1,000,000 person-years and 0.8 per 1,000,000 persons, respectively. From 2014 to 2019, the proportion of prescriptions of sirolimus and everolimus increased, while the use of home oxygen therapy, chest drainage, comorbid pneumothorax, and bloody phlegm decreased. The mortality rate remained stable at approximately 1%.

CONCLUSIONS

The incidence and prevalence of lymphangioleiomyomatosis were higher in women than those reported previously. Although the incidence did not change during the 6-year period, the prevalence gradually increased. Moreover, lymphangioleiomyomatosis was observed to be rare in men. The practice of treating patients with lymphangioleiomyomatosis changed across the six years while mortality remained low, at approximately 1%.

Higher participation rates for specific health checkups are associated with a lower incidence of treated ESKD in Japan

BACKGROUND

A Japanese cohort study previously reported that not attending health checkups was associated with an increased risk of treated end-stage kidney disease (ESKD). The present study aimed to examine this association at the prefecture level.

METHODS

We conducted an ecological study of all prefectures in Japan (n = 47) using five sources of nationwide open data. We explored associations of participation rates for Specific Health Checkups (SHC participation rates), the estimated prevalence of chronic kidney disease (CKD), and the ratio of nephrology specialists for each prefecture with prefecture-specific standardized incidence rates (SIRs) of treated ESKD using structural equation modeling.

RESULTS

Prefecture-specific SHC participation rates ranged from 44.2% to 65.9%, and were negatively correlated with prefecture-specific SIRs and prevalence of CKD, and positively correlated with the ratio of nephrology specialists. SHC participation rates had significant negative effects on prefecture-specific SIRs (standardized estimate (β) = - 0.38, p = 0.01) and prefecture-specific prevalence of CKD (β = - 0.32, p = 0.02). Through SHC participation rates, the ratio of nephrology specialists had a significant indirect negative effect on prefecture-specific SIRs (β= - 0.14, p = 0.02). The model fitted the data well and explained 14% of the variance in SIRs.

CONCLUSIONS

Our findings support the importance of increasing SHC participation rates at the population level and may encourage people to undergo health checkups.

Epidemiology of Angioid Streaks and Pseudoxanthoma Elasticum (2011-2020): A Nationwide Population-based Cohort Study

Purpose

We aimed to describe the epidemiology of angioid streaks (AS) and pseudoxanthoma elasticum (PXE), which are rare diseases, using a national claims database.

Design

This was a population-based longitudinal cohort study.

Participants

A total of 126 million individuals were covered by the universal health coverage system in Japan.

Methods

With permission from the Ministry of Health, Labor and Welfare, we accessed all data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan, which contains the nationwide health insurance claims data for 126 million Japanese. We identified individuals with AS and PXE between January 2011 and December 2020. The incidence rates, prevalence, overlap of AS and PXE, and mean age at death were calculated.

Main Outcome Measures

The incidence rates and prevalence of AS and PXE.

Results

A total of 6598 cases of AS and 1020 cases of PXE were identified during the 10-year study period. The incidence rates of AS and PXE were 0.52 (95% confidence interval, 0.48-0.56) and 0.08 (95% confidence interval, 0.07-0.10) per 100 000 person-years, respectively. On October 1, 2020, the prevalence of AS and PXE was 6.5 (95% confidence interval, 6.38-6.66) and 0.83 (95% confidence interval, 0.78-0.89) per 100 000 persons, respectively. The overlap of AS and PXE was 363 patients. The mean age at death of individuals with AS and PXE was 79.3 ± 0.51 and 77.1 ± 2.68 years, respectively.

Conclusion

This is the first population-based study to elucidate the epidemiology of AS and PXE. The mean age of death of both AS and PXE patients was younger than the mean life expectancy of the general Japanese population, thus, appropriate diagnosis and management are important to avoid preventable death.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Impact of preexisting interstitial lung disease on mortality in COVID-19 patients from the early pandemic to the delta variant epidemic: a nationwide population-based study

BACKGROUND

COVID-19 patients with preexisting interstitial lung disease (ILD) were reported to have a high mortality rate; however, this was based on data from the early stages of the pandemic. It is uncertain how their mortality rates have changed with the emergence of new variants of concern as well as the development of COVID-19 vaccines and treatments. It is also unclear whether having ILD still poses a risk factor for mortality. As COVID-19 continues to be a major concern, further research on COVID-19 patients with preexisting ILD is necessary.

METHODS

We extracted data on COVID-19 patients between January 2020-August 2021 from a Japanese nationwide insurance claims database and divided them into those with and without preexisting ILD. We investigated all-cause mortality of COVID-19 patients with preexisting ILD in wild-type-, alpha-, and delta-predominant waves, to determine whether preexisting ILD was associated with increased mortality.

RESULTS

Of the 937,758 adult COVID-19 patients, 7,333 (0.8%) had preexisting ILD. The proportion of all COVID-19 patients who had preexisting ILD in the wild-type-, alpha-, and delta-predominant waves was 1.2%, 0.8%, and 0.3%, respectively, and their 60-day mortality was 16.0%, 14.6%, and 7.5%, respectively. The 60-day mortality significantly decreased from the alpha-predominant to delta-predominant waves (difference - 7.1%, 95% confidence intervals (CI) - 9.3% to - 4.9%). In multivariable analysis, preexisting ILD was independently associated with increased mortality in all waves with the wild-type-predominant, odds ratio (OR) 2.10, 95% CI 1.91-2.30, the alpha-predominant wave, OR 2.14, 95% CI 1.84-2.50, and the delta-predominant wave, OR 2.10, 95%CI 1.66-2.66.

CONCLUSIONS

All-cause mortality rates for COVID-19 patients with preexisting ILD decreased from the wild-type- to the more recent delta-predominant waves. However, these patients were consistently at higher mortality risk than those without preexisting ILD. We emphasize that careful attention should be given to patients with preexisting ILD despite the change in the COVID-19 environment.

Continuous laxative use and its relationship to defecation among residents of nursing homes: A longitudinal observational study using the interRAI

AIM

To clarify the association between constipation, diarrhea, and long-term laxative use in Japanese nursing home residents.

METHODS

Data from 306 residents with chronic constipation aged over 75 years for basic characteristics, medication use, activities of daily living, and concurrent illness were collected via two consecutive 6-monthly surveys conducted using the Japanese interRAI assessment tool. We used bivariate and multivariate analyses to examine the associations between chronic constipation, diarrhea, and continuous laxative use.

RESULTS

Chronic constipation persisted in 74.5% of residents despite their continuous use of laxatives. Additionally, 14.4% experienced chronic diarrhea while on laxatives. Residents using salt laxatives had significantly lower chronic constipation than those not using salt laxatives (adjusted odds ratio [AOR] 0.52), while residents using novel laxatives had significantly higher chronic diarrhea than those not using novel laxatives (AOR 4.28).

CONCLUSIONS

Our findings reveal that bowel movement-related problems remain a concern and highlight the need for further research on the use of novel laxatives in nursing home residents. Geriatr Gerontol Int 2024; 24: 133-139.

Annual trends of ophthalmic surgeries in Japan's super-aged society, 2014-2020: a national claims database study

This study aimed to analyze the trends and factors influencing the number of ophthalmic surgeries in Japan using the open data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan published by the Ministry of Health, Labour and Welfare. We calculated the number of cataract, glaucoma, and vitreoretinal surgeries, categorized by sex, age, and surgical type, for the fiscal years (FY) 2014 to 2020. The number of cataract surgeries remained stable at approximately 1.45 million cases from FY 2014 to 2018, increased to nearly 1.6 million cases in FY 2019, and decreased to 1.45 million cases in FY 2020. Among glaucoma surgeries, surgical treatments were increased 1.8 times over 7 years, from 33,000 to 60,000 cases. Laser treatment remained steady at around 55,000 cases from FY 2014 to 2017 and then increased to approximately 60,000 cases. The number of vitreoretinal surgeries was increased 1.2 times from FY 2014 to 2019, from 120,000 to 140,000, and decreased to 130,000 by FY 2020. Trends in ophthalmic surgeries over the past 7 years may be influenced by population aging, minimally invasive surgery, and the coronavirus disease pandemic. These findings have implications on surgical decision-making and resource allocation.

Dose reduction of olaparib in older patients: Insights from an analysis of a National Database in Japan

AIM

Although the advent of a poly polymerase inhibitors has greatly advanced the tailoring of cancer treatment, there is a dearth of real-world evidence on the actual use of olaparib in aging populations, especially those using national-level data.

METHODS

We extracted and analyzed all prescriptions of olaparib in female outpatients from the National Database Open Data Japan (NDB Open Data) from April 2019 to March 2021. The recommended standard dose of olaparib is four tablets of the 150 mg formulation per day, while the 100 mg formulation of olaparib can be considered as an alternative dose in the occurrence of hematologic toxicity. We calculated the proportion of 100 mg compared to the 150 mg prescriptions across age groups. A Cochrane-Armitage trend test was used to examine the association of age groups with the proportion of 100 mg prescriptions.

RESULTS

The total number of prescriptions of the 100 mg formulation and the 150 mg formulation were 1449 222, and 4233 625, respectively. Overall, 45.1% (2567 513/5682 847 prescriptions) of olaparib were prescribed for patients 65 years of age or older in females. Stratified by age group, the proportion of 100 mg compared to the 150 mg prescriptions significantly increased with age (p < 0.0001).

CONCLUSIONS

Given that the 100 mg formulation of olaparib can be considered as an alternative dose in Japan in the occurrence of hematologic toxicity, our observations indicate the dose reduction of olaparib in older patients in Japan. Further investigations are necessary to assess its efficacy and safety at a reduced dose.

Changes in the characteristics and outcomes of COVID-19 patients from the early pandemic to the delta variant epidemic: a nationwide population-based study

The coronavirus disease 2019 (COVID-19) pandemic has dramatically changed because of virus mutations, vaccine dissemination, treatment development and policies, among other factors. These factors have a dynamic and complex effect on the characteristics and outcomes of patients. Therefore, there is an urgent need to understand those changes and update the evidence. We used a large-scale real-world data set of 937,758 patients with COVID-19 from a nationwide claims database that included outpatients and inpatients in Japan to investigate the changes in their characteristics, outcomes and risk factors for severity/mortality from the early pandemic to the delta variant-predominant waves. The severity of COVID-19 was defined according to the modified World Health Organization clinical-progression ordinal scale. With changing waves, mean patient age decreased, and proportion of patients with comorbidities decreased. The incidences of "severe COVID-19 or death (i.e. ≥severe COVID-19)" and "death" markedly declined (5.0% and 2.9%, wild-type-predominant; 4.6% and 2.2%, alpha variant-predominant and 1.4% and 0.4%, delta variant-predominant waves, respectively). Across the wave shift, risk factors for ≥ severe COVID-19 and death, including older age, male, malignancy, congestive heart failure and chronic obstructive pulmonary disease, were largely consistent. The significance of some factors, such as liver disease, varied as per the wave. This study, one of the largest population-based studies on COVID-19, showed that patient characteristics and outcomes changed during the waves. Risk factors for severity/mortality were similar across all waves, but some factors were inconsistent. These data suggest that the clinical status of COVID-19 will change further with the coming epidemic wave.

Association between the number of teeth and incident pre-diabetes among middle-aged adults with periodontal disease: a retrospective cohort analysis of Japanese claims data

OBJECTIVES

To investigate the association between the number of teeth and the new onset of pre-diabetes.

DESIGN

Retrospective cohort study.

SETTING

The National Database of Health Insurance Claims and Specific Health Checkups of Japan, which holds information from both the yearly health check-up programme known as the 'Specific Health Checkup' and health insurance claims data.

PARTICIPANTS

1 098 371 normoglycaemic subjects who participated in the Specific Health Checkup programme every year from fiscal year (FY) 2015 to FY 2018 and had dental insurance claims data with a diagnosis of periodontal disease during FY 2016.

OUTCOME MEASURES

Incidence of pre-diabetes or diabetes observed at the Specific Health Checkup during FY 2018.

RESULTS

Among the participants, 1 77 908 subjects developed pre-diabetes, and 579 developed diabetes at the check-up during the subsequent follow-up year. Compared with the subjects with 26-28 teeth, those with 20-25, 15-19 or 1-14 teeth were associated with an increased likelihood of developing pre-diabetes or diabetes onset with adjusted ORs of 1.03 (95% CI: 1.02 to 1.05), 1.06 (1.03 to 1.09) and 1.07 (1.04 to 1.11), respectively. No clear modifications were observed for age, sex, body mass index or current smoking.

CONCLUSIONS

Having fewer teeth was associated with a higher incidence of pre-diabetes. Due to the limitations of this study, however, causality remains undetermined.

The impact of the COVID-19 pandemic on radiotherapy delivery in Japan: An observational study based on the national database

BACKGROUND

This study analyzed the impact of the coronavirus disease 2019 (COVID-19) pandemic on radiotherapy delivery in Japan using a high-quality Japanese national database based on universal health coverage.

METHODS

We performed a retrospective observational study using National Database of Health Insurance Claims and Specific Health Checkups of Japan open data focused on radiotherapy between fiscal year (FY) 2019 and FY2020 and the number of COVID-19 cases from the Ministry of Health, Labour, and Welfare. We statistically analyzed the relationship between the number of COVID-19 cases and the number of radiotherapy deliveries in Japan as a whole and by prefecture.

RESULTS

The total number of external beam radiotherapy (EBRT) fractions was 4,472,140 in FY2019 and 4,227,673 in FY2020 (-5.8%). EBRT courses were 250,395 in FY2019 and 240,329 in FY2020 (-4.0%), stereotactic radiotherapy courses were 27,619 in FY2019 and 31,786 in FY2020 (+15.1%), and single-fraction palliative radiotherapy courses were 4124 in FY2019 and 5255 in FY2020 (+21.5%). The total number of breast and prostate hypofractionated radiotherapy (HFRT) fractions was 155,773 and 48,188 in FY2019, and 200,256 and 84,230 in FY2020 (+28.6% and +74.8%), respectively. In the Pearson correlation analysis, EBRT fractions were lower, and breast HFRT fractions were higher in prefectures with more COVID-19 cases.

CONCLUSIONS

Overall, radiotherapy delivery in Japan was relatively stable after the pandemic, with an increase in HFRT. Also, EBRT fractions decreased, and breast HFRT were more likely to be used in prefectures with more COVID-19 cases.

Prescription of anti-influenza drugs in Japan, 2014-2020: A retrospective study using open data from the national claims database

BACKGROUND

Both physicians and patients are proactive towards managing seasonal influenza in Japan and six drugs are approved. Although many countries have national influenza surveillance systems, data on nationwide prescription practices of anti-influenza drugs are lacking. Therefore, we aimed to clarify the status of anti-influenza drug use in Japan by analyzing real-world data.

METHODS

This retrospective study analyzed open data from the National Database of Health Insurance Claims and Specific Health Checkups, which covers most claims data from national health insurance. We estimated the annual number of patients prescribed anti-influenza drugs, which drugs they were prescribed, the patients' age and sex distribution, drug costs, and regional disparities for the period 2014-2020.

RESULTS

For 2014-2019, an estimated 6.7-13.4 million patients per year were prescribed anti-influenza drugs, with an annual cost of 22.3-48.0 billion JPY (Japanese Yen). In addition, 21.1-32.0 million rapid antigen tests were performed at a cost of 30.1-47.1 billion JPY. In 2017, laninamivir was the most frequently prescribed anti-influenza drug (48%), followed by oseltamivir (36%), while in 2018, the newly introduced baloxavir accounted for 40.8% of prescriptions. After the emergence of COVID-19, the estimated number of patients prescribed anti-influenza drugs in 2020 dropped to just 14,000. In 2018, 37.6% of prescriptions were for patients aged < 20 years compared with 12.2% for those aged ≥ 65 years. Prescriptions for inpatients accounted for 1.1%, and the proportion of prescriptions for inpatients increased with age, with men were more likely than women to be prescribed anti-influenza drugs while hospitalized.

CONCLUSIONS

Based on our clarification of how influenza is clinically managed in Japan, future work should evaluate the clinical and economic aspects of proactively prescribing anti-influenza drugs.

Prevalence trends of metabolic syndrome in residents of postdisaster Fukushima: a longitudinal analysis of Fukushima Health Database 2012-2019

OBJECTIVES

The study aimed to evaluate the long-term metabolic risk profiles of Fukushima residents after the Great East Japan Earthquake of March 2011.

STUDY DESIGN

This was a cross-sectional and a longitudinal design.

METHODS

The Fukushima Health Database (FDB) contains 2,331,319 annual health checkup records of participants aged 40-74 years between 2012 and 2019. We checked the validity of the FDB by comparing the prevalence of metabolic factors with the National Database of Health Insurance Claims and Specific Health Checkups (NDB). We applied a regression analysis to determine the changes and project the trends of metabolic factors over the years.

RESULTS

Compared to the NDB, the prevalence of metabolic factors in Fukushima was higher than the country average from 2013 to 2018, and they showed the same trends as those from the FDB. The prevalence of metabolic syndrome (MetS) increased from 18.9% in 2012 to 21.4% in 2019 (an annual increase of 2.74%) in men and from 6.8 to 7.4% (an annual increase of 1.80%) in women in Fukushima. The standardized prevalence of MetS, being overweight, and diabetes is projected to continue increasing, with disparities among subareas being higher in evacuees than in non-evacuees. An annual decrease of 0.38-1.97% in hypertension was mainly observed in women.

CONCLUSIONS

The prevalence of metabolic risk is higher in Fukushima as compared to the country average. The increasing metabolic risk in subareas, including the evacuation zone, highlights the need to control MetS in Fukushima residents.

A Review of Studies Using Japanese Nationwide Administrative Claims Databases

BACKGROUND

Administrative claims databases are increasingly being used worldwide for research purposes. We reviewed original published articles that used one of the four nationwide administrative claims databases in Japan: the National Database of Health Insurance Claims and Specific Health Checkups (NDB), NDB Open Data, the JMDC Claims Database, and the Diagnosis Procedure Combination (DPC) database.

METHODS

Studies published from January 2010 to July 2022 using the JMDC and DPC databases, and from January 2013 to July 2022 using the NDB and NDB Open Data were identified using PubMed. The number of original articles was divided into 19 fields. The annual growth rate of the number of studies was calculated using the four databases.

RESULTS

Overall, 1047 studies were included (95 for the NDB, 31 for the NDB Open Data, 222 for the JMDC database, and 699 for the DPC databases). Studies using one of these four databases increased from around 2010, and the average annual growth rate was approximately 41% from 2010 to 2021. DPC database studies had a higher proportion of articles on surgery (19.2%), urology (3.0%), neurosurgery (6.2%), anesthesiology (1.9%), and emergency medicine (14.0%), whereas the NDB and JMDC data had higher proportions of those regarding internal medicine.

CONCLUSIONS

Since 2010, these four databases have increasingly attracted attention, and the number of studies using them has grown rapidly. Our review suggests that each has unique features, and researchers should understand the database characteristics to operate their studies.

Prefecture-specific prevalence of overweight/obesity is associated with regional variation in the incidence of treated ESKD in Japan

BACKGROUND

Overweight/obesity is a significant risk factor for chronic kidney disease and end-stage kidney disease (ESKD) in the general population. This study evaluated the impact of sex- and prefecture-specific prevalence of overweight/obesity on standardized incidence rates (SIRs) of treated ESKD in Japan.

METHODS

We conducted an ecological study of all prefectures in Japan (n = 47) using data from the Japanese Society of Dialysis Therapy, national census, the NDB Open Data, and the Statistics of Physicians, Dentists and Pharmacists. We calculated the prevalence of overweight/obesity and proteinuria, standardized mortality ratio, and ratio of nephrology specialists for each prefecture, and explored associations of these variables with sex- and prefecture-specific SIRs of treated ESKD using bivariate association analysis, multiple regression analysis, and structural equation modeling (SEM).

RESULTS

Prefecture-specific SIRs ranged from 0.72 to 1.24 for men and 0.69-1.41 for women. Prefecture-specific SIRs were significantly correlated with both the prevalence of overweight/obesity and prevalence of proteinuria. The prevalence of overweight/obesity showed direct, positive, and significant associations with prefecture-specific SIRs in men (standardized estimate (β) = 0.43, p < 0.001) and women (β = 0.40, p < 0.001). The prevalence of proteinuria showed a significant association with prefecture-specific SIRs only in women (β = 0.33, p = 0.01). The SEM models explained 26% of the variance in SIR for men and 28% for women.

CONCLUSIONS

Our findings provide evidence that the prefecture-specific prevalence of overweight/obesity in Japan can explain regional variation in prefecture-specific SIRs of treated ESKD in both sexes.

Validation study on definition of cause of death in Japanese claims data

Identifying the cause of death is important for the study of end-of-life patients using claims data in Japan. However, the validity of how cause of death is identified using claims data remains unknown. Therefore, this study aimed to verify the validity of the method used to identify the cause of death based on Japanese claims data. Our study population included patients who died at two institutions between January 1, 2018 and December 31, 2019. Claims data consisted of medical data and Diagnosis Procedure Combination (DPC) data, and five definitions developed from disease classification in each dataset were compared with death certificates. Nine causes of death, including cancer, were included in the study. The definition with the highest positive predictive values (PPVs) and sensitivities in this study was the combination of "main disease" in both medical and DPC data. For cancer, these definitions had PPVs and sensitivities of > 90%. For heart disease, these definitions had PPVs of > 50% and sensitivities of > 70%. For cerebrovascular disease, these definitions had PPVs of > 80% and sensitivities of> 70%. For other causes of death, PPVs and sensitivities were < 50% for most definitions. Based on these results, we recommend definitions with a combination of "main disease" in both medical and DPC data for cancer and cerebrovascular disease. However, a clear argument cannot be made for other causes of death because of the small sample size. Therefore, the results of this study can be used with confidence for cancer and cerebrovascular disease but should be used with caution for other causes of death.

Lifestyle habits to prevent the development of benign prostatic hyperplasia: Analysis of Japanese nationwide datasets

Objectives

Benign prostatic hyperplasia (BPH) refers to nonmalignant hyperplasia of prostate tissue, which causes lower urinary tract symptoms and has become a global public health concern in the aging population. The purpose of this study is to identify modifiable factors, which would prevent or delay BPH development.

Methods

The association between BPH marker drugs and climate-, socioeconomic-, health condition-, and lifestyle habits-related variables was investigated by analyzing nationwide datasets which were collected in 2018, aggregated by prefecture (administrative unit), and published by Japanese ministries. Uroselective α₁ receptor blockers and dutasteride were used as marker drugs referring to BPH prevalence. Correlation analysis, multiple linear regression analysis, and binomial logistic regression analysis were conducted with 47 Japanese prefectures as the unit.

Results

The variables which showed |r| > 0.5 by correlation analysis were exercise habits (r = -0.5696), smoking habits (r = 0.6116), and daily drinking (r = 0.6001) for uroselective α₁ receptor blockers, and antihypertensive medication (r = 0.5971), smoking habits (r = 0.6598), a small amount of drinking (r = -0.5292), and serum alanine aminotransferase (r = 0.6814) for dutasteride. Multiple linear regression equations were constructed by including these variables (R ²  = 0.5453 for uroselective α₁ receptor blockers and R ²  = 0.5673 for dutasteride). Binomial logistic regression analysis found a significant association between climate in the resident area and BPH development.

Conclusion

This ecological study, analyzing Japanese nationwide datasets, demonstrates that healthy lifestyle habits, especially avoidance of smoking, implementation of exercise in daily life, and a small amount of alcohol consumption, are important to prevent or delay BPH development. High blood pressure and high serum alanine aminotransferase are suggested as risk factors of BPH development.

Nationwide Long-Term Evaluation of Polypharmacy Reduction Policies Focusing on Older Adults in Japan

Polypharmacy is a serious health issue for older adults worldwide, including in Japan, which has a rapidly aging society. The "Proper Medication Guideline for Older Adults" was published for healthcare providers in May 2018, and polypharmacy reduction incentives were initiated for medical facilities in April 2016 and April 2018. This study identified the long-term reduction in polypharmacy prescriptions focusing on older adults aged 75 years and above from April 2015 to March 2019. The national health insurance claims database, which covers most reimbursement claims in Japan, was selected as the primary data source. In this study, polypharmacy was defined as the simultaneous prescription of seven or more medications or multi-psychotropic medications. The primary outcome was the polypharmacy reduction ratio, which indicates the decrease in polypharmacy proportion based on the number of medications on an outpatient prescription. A total polypharmacy reduction of 19.3% for the "75-89 years" subgroup and 16.5% for the "90 years and above" subgroup was observed over four years. Based on prefecture analysis, the mean values of polypharmacy proportion showed a statistically significant reduction over four years. This study showed a successful nationwide reduction in polypharmacy prescriptions after implementing the polypharmacy management guidelines for older adults and incentive-based policies.

Use of the dental formula from the National Database of Health Insurance Claims and Specific Health Checkups of Japan

The National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) is a database including health insurance claim and specific health checkup data. Observational studies using real-world big data attract attention because they have certain strengths, including external validity and a large sample size. This review focused on research using the dental formula of the NDB because the number of teeth is an important indicator of oral health. The number of teeth present calculated using the dental formula of periodontitis patients was similar to that from the Survey of Dental Diseases. In addition, the graphs of the presence rates of tooth types by 5-year age groups from the NDB were smoother and had less overlap than those from the Survey of Dental Diseases, and they could detect slight changes in the presence rate that reflected sugar consumption before and after World War II. Using the NDB, a low number of teeth was associated with high medical care expenditures, high risk of aspiration pneumonia, and high risk of Alzheimer’s disease. Although there are some restrictions on the use of the NDB, we hope that dental research using the NDB will be further promoted in the future.

National trends in gastrostomy in older adults between 2014 and 2019 in Japan

AIM

Previous studies have shown temporal trends in the number of gastrostomies until 2016, but the recent trend is yet to be analyzed. This study aimed to evaluate temporal trends in gastrostomy (mostly percutaneous endoscopic gastrostomy) in older adults in Japan in more recent years.

METHODS

We extracted data on the numbers of gastrostomies and swallowing function assessment prior to gastrostomy, using the national aggregated open data (NDB Open Data) from 2014 to 2019.

RESULTS

Adults in their 80s accounted for the largest portion of gastrostomy during the study period. A decreasing trend in the total number of gastrostomy was observed in older adults from 2014 to 2016, but became almost stable thereafter (57 103 in 2014, 47 228 in 2016, and 47 944 in 2019). The age group-stratified numbers of gastrostomy per 100 000 individuals decreased by -33.9% (≥90 years group) to -6.1% (65-69 years group) from 2014 to 2019. The implementation rate of the swallowing function assessment remained relatively low, despite a slight increase (21.4% in 2015 to 23.7% in 2019).

CONCLUSION

We showed that the total number of gastrostomies remained almost stable after 2016 despite population aging. We considered that the avoidance of gastrostomy in frail or disabled older adults might explain the decrease, particularly for those aged over 80 years. Our findings would regain attention to appropriate decision-making for gastrostomy. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2022; ••: ••-••.

Incidence and Clinical Practice of Exudative Age-related Macular Degeneration

Purpose

To elucidate the incidence and treatment pattern of active exudative age-related macular degeneration (AMD).

Design

A population-based cohort study conducted using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), a national claims database managed by the Japanese Ministry of Health, Labour, and Welfare (MHLW).

Participants

The entire Japanese population aged 40 years or older (76 million people).

Methods

With the permission of the MHLW, we accessed the complete NDB dataset and identified patients with newly diagnosed active exudative AMD between 2011 and 2018. The incidence of active exudative AMD was categorized by age and sex per year between 2011 and 2018; moreover, details regarding first-line therapy and number of anti-vascular endothelial growth factor (VEGF) injections per elapsed year since initial treatment were obtained and changes in treatment pattern were investigated.

Main Outcome Measures

Incidence rate of active exudative AMD.

Results

During the specified 8-year period, 246 064 incident cases of active exudative AMD were identified; 61.4% of these patients were men. The overall incidence rate was 40.66 per 100 000 person-years (95% confidence interval [CI], 40.49–40.82) in the general population aged 40 years or older, 53.22 (95% CI, 52.95–53.49) in men, and 29.78 (95% CI, 29.60–29.98) in women. Mean age of onset was lower in men than in women (72.51 ± 10.50 years vs. 73.90 ± 10.46 years). Among patients with newly diagnosed active exudative AMD, 92.9% received anti-VEGF injections for initial treatments, whereas 1.8% underwent combination therapy with photodynamic therapy. The number of anti-VEGF injections in the first year (0–12 months), second year (13–24 months), and third year (25–36 months) after the initial injection was 3.66 ± 2.30, 1.39 ± 2.20, and 1.23 ± 2.19, respectively. Patients who received fewer injections in the first year received fewer injections in subsequent years and vice versa.

Conclusions

This is a relatively large population-based study on the detailed epidemiology and actual treatment patterns of active exudative AMD in clinical practice. Our results can be a fundamental information source to ensure healthy eyes and promote well-being for all at all ages.

Analysis of antiretroviral therapy switch rate and switching pattern for people living with HIV from a national database in Japan

To report the status of switch rates and time-to-switch of antiretroviral therapy (ART) regimens by evaluating anchor drug classes and common switching patterns in Japanese people living with human immunodeficiency virus (HIV, PLWH). This cross-sectional cohort study extracted data of 28,089 PLWH from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), which contains data representing the entire population of Japan. PLWH with first prescription records of ART administered between January 2011 and March 2019 were identified (n = 16,069). The median time-to-switch and switch rates of anchor drug classes were estimated by Kaplan-Meier analysis. Brookmeyer-Crowley and Greenwood methods were used to estimate 95% confidence intervals for switch rates and median days, respectively. Switch rates were compared between anchor drug classes by year using log-rank tests. A total of 3108 (19.3%) PLWH switched anchor drug classes from first to second regimens. Switch rates increased continuously over 8 years for non-nucleoside reverse transcriptase inhibitors (NNRTIs) (14.9-65.5%) and protease inhibitors (PIs) (13.2-67.7%), with median time-to-switch of 1826 and 1583 days, respectively. Integrase strand transfer inhibitors (INSTIs) maintained a low switch rate (3.0-7.6%), precluding median-days calculation. Overall, the majority of patients treated initially with NNRTIs and PIs switched to INSTIs regardless of switching times (< 1 year: 67.3% and 85.9%, respectively; ≥ 1 year: 95.5% and 93.6%, respectively). The foremost switching strategies for first-to-second ART regimens are from NNRTIs or PIs to INSTIs regimens that maintain low switch rates long term. There was no observable difference in trend between sex, age and status of AIDS disease at first ART regimen. INSTIs HIV agents may be the most durable anchor drug class for PLWH receiving ART.

Comorbidities and co-medications among 28 089 people living with HIV: A nationwide cohort study from 2009 to 2019 in Japan

OBJECTIVES

Comorbidities are associated with a high burden of disease in people living with HIV (PLWH). The objective was to investigate the prevalence of chronic comorbidities and use of co-medications in PLWH in Japan.

METHODS

This study retrospectively analysed clinical information from PLWH receiving antiretroviral therapy (ART) between April 2009 and March 2019. Demographic characteristics, numbers and types of chronic comorbidities, and numbers and types of non-ART co-medications, were described by age groups. The source of data was the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB).

RESULTS

Overall, 28 089 PLWH (male 91.9%) who used ART were identified. Out of 28 089 PLWH, 81.5% had at least one chronic comorbidity. The numbers of AIDS-defining cancers and non-AIDS-defining cancers in this Japanese cohort were 2432 (8.7%) and 2485 (8.8%), respectively. The cumulative burden of comorbidities including non-AIDS-defining cancer increased with age. Changes in trend between 2009 and 2019 were observed, including a higher proportion of PLWH diagnosed at ≥ 70 years old [2019 (4.7%) vs. 2009 (2.4%)] and a decreasing percentage of patients with AIDS-defining cancers (down from 6.3% to 4.8% between 2009 and 2019). The most common co-medications during the most recent 3-month period were lipid-regulating/anti-atheroma preparations (11.3%), antacids, antiflatulents and anti-ulcerants (9.6%), and agents acting on the renin-angiotensin system (8.1%). The three most common therapeutic categories of co-medications during the study period were antacids, antiflatulents and anti-ulcerants (35.0%), systemic antihistamines (33.7%) and psycholeptics (27.1%). More than 30% of PLWH aged > 40 years used at least one co-medication in a 3-month period, while more than half of PLWH aged > 30 years had at least one co-medication prescribed concomitantly for a total of ≥ 90 days during the study period, and the numbers of co-medications used were greater in the older age groups.

CONCLUSIONS

The burden of chronic comorbidities and co-medication were found to be greater in older, as compared to younger patients, among 28 089 PLWH in a nationwide study in Japan. This finding suggests the need to identify elderly PLWH and to appropriately manage their HIV and comorbidities.

Effectiveness of polypharmacy reduction policy in Japan: nationwide retrospective observational study

Background Polypharmacy is an important global health issue. In Japan, an amended policy has been implemented since April 2016 to offer incentives that allow claiming a payment of approximately 22.5 US$ per patient to hospitals and clinics that succeed to reduce two or more medications. However, there is no evidence on the nationwide effectiveness of polypharmacy reduction policy. Aim To evaluate the effectiveness of the polypharmacy reduction policy in Japan using nationwide outpatient prescription fee reimbursement claims data in Open Data of the National Database of Health Insurance Claims and Specific Health Checkups of Japan. Method This nationwide retrospective observational study was conducted over 3 years (April 2015 to March 2018). The primary outcome was the polypharmacy reduction ratio calculated by the polypharmacy proportion. Factors associated with policy effectiveness were identified by performing a multiple linear regression analysis using independent variables. Results After implementing the new policy, a 7.3 % polypharmacy reduction ratio was observed, particularly in the elderly (8.2 %). Multiple linear regression analysis revealed that the proportion of elderly residents (aged ≥65 years), number of hospitals per 100,000 residents, and number of clinics per 100,000 residents were statistically significantly associated with this reduction. Conclusion The polypharmacy reduction policy indicated an association with polypharmacy reduction in Japan. The proportion of elderly residents and availability of hospitals and clinics are important factors to enhance the effectiveness of the polypharmacy reduction policy.

Delayed diagnosis of human immunodeficiency virus infection in people diagnosed with syphilis: A nationwide cohort study from 2011 to 2018 in Japan

Early treatment of HIV infection depends on timely diagnosis, but many persons living with HIV/AIDS (PLWHA) are unaware of their infection. Though many patients seeking medical attention for sexually transmitted diseases have HIV, many patients' HIV co-infection is undiagnosed in Japan. This is the first report to analyze the timing of syphilis infection in PLWHA of all ages through the use of the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), containing clinical data of the largest group of HIV-positive patients available in Japan. Overall, 1521 PLWHA (male 93.2%) newly diagnosed and started on antiretroviral therapy were identified in 2016, and 646 (42.5%) patients had a diagnosis of syphilis between 2011 and 2018. Although 100 patients were diagnosed with syphilis before their HIV diagnosis, only 17 (17.0%) had been tested for HIV. Over 50 patients per year became infected with syphilis even after their HIV diagnosis (2017, n = 65 (4.3%); 2018, n = 58 (3.8%)). Although early diagnosis of HIV infection is important, most syphilis patients in Japan had not been properly tested for HIV infection. Since a certain number of HIV patients developed syphilis after HIV diagnosis, education for newly diagnosed HIV patients is important.

Incidence of Sympathetic Ophthalmia after Inciting Events: A National Database Study in Japan

PURPOSE

To analyze the incidence of sympathetic ophthalmia (SO) after inciting events (eye trauma or intraocular surgery).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Patients experiencing inciting events between 2012 and 2019. Onset of SO was defined as the first date of SO diagnosis.

METHODS

Using a nationwide administrative claims database in Japan, we calculated the cumulative incidence of SO after inciting events stratified by sex, 10-year age groups, and a categorical variable of primary or repeated, reflecting the history of inciting events in the past year (no inciting events, inciting events without trauma, or inciting events with trauma) using the Kaplan-Meier approach. We also estimated the adjusted hazard ratio (aHR) by Cox regression. We then restricted the population to those with only 1 inciting event during the observation period to investigate the pure effect of each inciting event.

MAIN OUTCOME MEASURES

Cumulative incidence of SO over 60 months.

RESULTS

A total of 888 041 inciting events (704 717 patients) were eligible. The total number of SO cases was 263, and the cumulative incidence of SO was 0.044% over 60 months. Female sex was not associated with onset of SO (aHR, 1.01; 95% confidence interval [CI], 0.79-1.29; P = 0.95). The group 40 to 49 years of age showed the highest incidence of 0.104% among the age groups (aHR vs. ≥80 years of age group [0.041%], 2.44 [95% CI, 1.56-3.80]; P < 0.001). Repeated inciting events with and without trauma showed higher incidences of SO (0.469% and 0.072%, respectively) than primary inciting events (0.036%) (aHR 11.68 [7.74-17.64] and 2.21 [95% CI, 1.59-3.07], respectively); P < 0.001 and P < 0.001, respectively). The incidence of SO after vitrectomy was much lower than after trauma (0.016% vs. 0.073%), and the incidence after scleral buckling was even lower.

CONCLUSIONS

The cumulative incidence of SO over 60 months was estimated to be 0.044% at minimum. Repeated inciting events, especially those with trauma, increased the risk of SO developing. Trauma was 4 to 5 times as likely to induce SO than vitrectomy. The present findings will be valuable for counseling patients about the risks of SO after trauma and before performing intraocular surgeries.

Incidence of central serous chorioretinopathy (2011-2018): a nationwide population-based cohort study of Japan

AIMS

The aim of this study was to elucidate the epidemiological background of central serous chorioretinopathy (CSC), including its incidence and treatment pattern.

METHODS

This was a population-based longitudinal cohort study using a nationwide health insurance claims database of the Japan Ministry of Health, Labour and Welfare (MHLW). As Japan employs universal health coverage, the database covers more than 95% of claims issued in Japan. We accessed all data stored in the database with permission from the MHLW. We traced all individuals aged 30 years or older and identified individuals with new onset of CSC between January 2011 and December 2018. CSC cases were categorised by age and sex for each year, and incidence rate was calculated. We also identified major treatments for CSC to elucidate the initial treatment pattern.

RESULTS

During the 8-year period, 247 930 incidences of CSC were identified, among which 75.9% were men. The crude incidence rate (per 100 000 person-years) in the general population aged 30 years or older was 34.0 (95% CI 33.9 to 34.2), in men was 54.2 (95% CI 53.9 to 54.4) and in women was 15.7 (95% CI 15.5 to 15.8). The mean age of onset was lower in men than in women (50.5±12.5 years vs 54.7±13.5 years). Most of the patients with newly diagnosed CSC (86.8%) did not receive major treatment.

CONCLUSIONS

The current study provides the nationwide population-based evidence to clarify the detailed epidemiology of CSC. These results could help to understand the pathogenesis and mechanisms of CSC in the future.

The use of Japanese long-term care insurance claims in health services research: current status and perspectives

This study aims to evaluate the current status and perspectives on the use of Japanese long-term care (LTC) claims databases for research. We conducted a comprehensive literature search of PubMed and the Japan Medical Abstracts Society (Ichushi-Web), focusing on LTC claims data analyses published between 2000 and 2020. We summarized the study characteristics, database characteristics, and the research areas related to health services that were studied. In total, 86 journal articles (12 in Japanese and 74 in English) were included in our review. A particularly remarkable increase in the number of publications from 2016 to 2020 was observed. We extracted more publications with combined databases (n = 64) than those that only used a single source of the LTC claims databases (n = 22). More than half of the studies analyzed healthcare expenditure, healthcare utilization, and quality of care which were relevant to health services research. The most frequently mentioned limitation was the lack of validation in variables stored in the LTC claims databases. In conclusion, the LTC claims databases could serve as important sources of information for the evaluation of healthcare delivery, quality of care, and LTC policy.

Current Status, Challenges, and Future Perspectives of Real-World Data and Real-World Evidence in Japan

Abstract

The aim of this article is to help develop a common understanding of the current status, challenges, and future perspectives of real-world data (RWD) and real-world evidence (RWE) in Japan. RWD and RWE are very widely used terms, but standardized definitions are lacking. Given broad and growing applications of RWD/RWE from the perspective of clinical development and medical affairs, the PhRMA Japan Medical Affairs Committee Working Group 1 have proposed the following definitions: “RWD are the data relating to patient health status and/or the delivery of health care routinely collected from a variety of sources” and “RWE is the evidence derived from analysis of RWD.” The key challenges for RWD and RWE in Japan include restricted access and linkage of RWD, as well as a lack of universally accepted methodological approaches, which reduces the potential for patient and healthcare benefits. These challenges for RWD/RWE are by no means unique to Japan and similar challenges exist for countries in Europe and the USA. The quality of data and analysis, study design, and the transparency of reporting should be discussed more to ensure credibility and acceptance by decision-makers as the demand for RWD and RWE increases. The future developments around Japan’s RWD and RWE are expected to include improved RWD access, data linkage, and increased acceptance by decision-makers, all supported by innovative technology. Improvements in RWD access and database linkage will enable both public and private sectors to assemble more comprehensive health information in Japan.

Video abstract

Regional Distribution of Cardiologists and Prescription Patterns of Sodium-Glucose Transporter-2 Inhibitors in Japan

The clinical evidence is accumulating since 2015 that anti-diabetic sodium-glucose cotransporter 2 (SGLT2) inhibitors have the beneficial effect of cardiovascular and, recently, renal protection. Although it is not well analyzed how the transfer of this new evidence into daily practice has expedited, we hypothesize that the recent usage of the drugs is positively associated with several certified cardiologists in each region.The 2016 annual and 2016-2017 increased number of SGLT2 inhibitor tablets, based on the National Database of Health Insurance Claims and Specific Health Checkups of Japan, were divided by the estimated number of patients with type 2 diabetes mellitus for each of the 47 prefectures. Then, regression analyses were performed to investigate the potential association of the number of certified cardiologists with the drug prescription.The 2016 prescription of ipragliflozin, dapagliflozin, luseogliflozin, canagliflozin, and empagliflozin was 2.7- to 4.4-fold different between prefectures. The 2016-2017 increased prescription volume also varied among prefectures by as large as 7.3-fold for ipragliflozin. Regression analysis revealed that the annual and increased prescription volume of all the SGLT2 inhibitors except luseogliflozin were higher in regions with more certified cardiologists (P < 0.05), even after adjusting for regional parameters.In conclusion, the regional number of certified cardiologists was positively associated with a 2016 annual of and 2016-2017 increase in SGLT2 inhibitor prescription amount, implying an early adopter role of clinical experts in healthcare delivery.

Association between number of teeth and Alzheimer's disease using the National Database of Health Insurance Claims and Specific Health Checkups of Japan

Associations of numbers of teeth present and of missing teeth with Alzheimer’s disease were cross-sectionally analyzed using the National Database of Health Insurance Claims and Specific Health Checkups of Japan. Dental care claims data of patients aged 60 years or older diagnosed with periodontitis (n = 4,009,345) or missing teeth (n = 662,182) were used to obtain information about the numbers of teeth present and of missing teeth, respectively, and they were combined with medical care claims data including the diagnosis of Alzheimer’s disease. Numbers of teeth present and of missing teeth excluding third molars were calculated using the dental formula in the claims for periodontitis and missing teeth, respectively, and categorized into three groups each. Percentages of subjects treated for Alzheimer’s disease with 20–28, 10–19, and 1–9 teeth present were 1.95%, 3.87%, and 6.86%, respectively, in patients diagnosed as having periodontitis, and those treated for Alzheimer’s disease with 1–13, 14–27, and 28 missing teeth were 2.67%, 5.51%, and 8.70%, respectively, in patients diagnosed as having missing teeth. Logistic regression models using treatment for Alzheimer’s disease as an outcome variable and adjusting for age and sex showed that odds ratios (95% confidence intervals) for patients with 10–19 and 1–9 teeth (reference: 20–28 teeth) were 1.11 (1.10–1.13) and 1.34 (1.32–1.37), respectively, (p<0.001), in patients diagnosed as having periodontitis, and odds ratios (95% confidence intervals) for patients with 14–27 missing teeth and 28 missing teeth (reference: 1–13 missing teeth) were 1.40 (1.36–1.44) and 1.81 (1.74–1.89), respectively, (p<0.001), in patients diagnosed as having missing teeth. In conclusion, the results of the present study using Japanese dental claims data showed that older people visiting dental offices with fewer teeth present and a greater number of missing teeth are more likely to have Alzheimer’s disease.

Factors correlated with drug use for constipation: perspectives from the 2016 open Japanese National Database

BACKGROUND

The prevalence of chronic constipation is increased in females and with age or environmental (low temperature), racial, socioeconomic, and habitual risk factors. The impact of low outside temperature on constipation drug use remains unclear. Here, we investigated risk factors for constipation drug use by evaluating data from the Japanese National Database.

METHODS

This ecological study used the 2016 open Japanese National Database of health insurance claims (prescriptions) to acquire the number of health insurance prescription claims in all 47 prefectures for drugs to relieve constipation, antihypertensives, vasodilators, as well as medical check-ups and questionnaire responses. Internet survey on room temperatures in 2010 were also used. Pearson correlation coefficients (r) between the number of population-based prescriptions for each item were calculated and multiple linear regression analysis (MLR) was performed.

RESULTS

Prescriptions for magnesium laxatives significantly correlated with aging (r = 0.58), vasodilators (r = 0.53), being female (r = 0.43), antihypertensives (r = 0.39), and inversely with eating ≤2 h before bedtime (r = - 0.37), total crime rate (r = - 0.33), insomnia (r = - 0.33), and population density (r = - 0.31). Stimulant laxatives (sennoside and picosulfate) were significantly correlated with antihypertensives (r = 0.79), aging (r = 0.69), vasodilators (r = 0.67), and being female (r = 0.56), and were inversely associated with average outside temperature (r = - 0.62), total crime rate (r = - 0.52), average income (r = - 0.51), and 30-min of vigorous exercise (r = - 0.44). Fecal interventions were significantly correlated with aging (r = 0.55) and female (r = 0.59), and inversely correlated with population density (r = - 0.41) and total crime rate (r = - 0.38). MLR analysis identified aging as the only significant risk factor for magnesium laxative use (partial slope [β] = 1241.0). Female sex and antihypertensives were independent risk factors for stimulant laxative prescriptions (β = 44,547.0 and 0.2) and average outside temperature and 30-min of vigorous exercise were independent preventive factors (β = - 616.8 and - 219.1).

CONCLUSION

We identified associations of magnesium laxatives with aging, stimulant laxatives with female sex, antihypertensives, low outside temperature and less 30 min of vigorous exercise.