Real World Data in Japan: Chapter II The Diagnosis Procedure Combination Database

Validity of operative information in Japanese administrative data: a chart review-based analysis of 1221 cases at a single institution

PURPOSE

To evaluate the validity of operative information recorded in the Diagnosis Procedure Combination (DPC) database, a national inpatient database including administrative claims data.

METHODS

We reviewed the medical charts of 1221 patients who underwent one of six surgeries (breast, esophageal, gastric, thyroid cancer surgery, appendectomy, or inguinal hernia repair) at a surgery department of a university hospital from April 2016 to March 2019. We compared operative information (type, date, laterality of procedure; type of anesthesia; transfusion; and duration of anesthesia) recorded in the DPC database with the information recorded in the medical charts.

RESULTS

The DPC data for type, date, laterality of surgery, and type of anesthesia were accurate in 99% of the reviewed patients. The sensitivity and specificity for identifying whether a patient received a transfusion procedure were 97.5% and 99.6%, respectively. Data regarding the duration of anesthesia in the DPC database were identical to those in medical chart records in 1114 of 1216 cases that received general or spinal anesthesia (91.5%). The duration of anesthesia in the DPC data was 53 min longer on average than the recorded operative time in the medical charts.

CONCLUSION

The DPC database had high validity for operative information.

Short-Term Outcomes Following Breast Cancer Surgery With and Without Neoadjuvant Chemotherapy: A Nationwide Administrative Database Study in Japan

PURPOSE

Although neoadjuvant chemotherapy (NAC) has become common for breast cancer, its impact on short-term surgical outcomes and the feasible chemotherapy-surgery interval remain unclear. Using a Japanese nationwide database, this study investigated the impact of NAC on short-term outcomes following breast cancer surgery.

METHODS

In this study of 11,722 patients with NAC and 120,538 patients without NAC who underwent surgery for stage 0-III breast cancer July 2010-March 2017, to cancel out site-specific effects, we generated a 1:4 matched-pair cohort matched for age, institution, and fiscal year of admission. We then conducted multivariable analyses adjusting for potential confounders to compare postoperative complications, duration of anesthesia, and total hospitalization costs. Additionally, we conducted three sensitivity analyses for patients with a short interval from NAC to surgery, patients receiving a particular NAC regimen, and patients undergoing a particular surgical procedure.

RESULTS

In total, the occurrence of postoperative complications was 6.0%, and the median interval from NAC to surgery was 31 (interquartile range, 24-39) days. The two groups did not differ significantly in terms of complications (odds ratio, 0.95; 95% confidence interval, 0.88-1.04), including local and general complications. NAC was significantly associated with shorter duration of anesthesia and lower total hospitalization costs. The sensitivity analyses showed similar results.

CONCLUSIONS

Our matched-pair cohort analyses revealed no significant differences in postoperative complications between patients with and without NAC for breast cancer, regardless of the interval, regimen, and surgical procedure. Patients can safely receive surgery and NAC without a lengthened interval.

Postoperative ICU admission following major elective surgery: A nationwide inpatient database study

BACKGROUND

Whether the routine use of the ICU after major elective surgery improves postoperative outcomes is not well established.

OBJECTIVES

To describe the association between use of postoperative ICU admission and clinical outcomes for patients undergoing major elective surgery.

DESIGN

Observational study.

SETTING

Nationwide inpatient database in Japan, July 2010 to March 2018.

PATIENTS

Patients undergoing one of 15 major elective orthopaedic, gastrointestinal, neurological, thoracic or cardiovascular surgical procedures.

INTERVENTION

ICU admission on the day of surgery. ICU was defined as a separate unit providing critical care services with around-the-clock physician staffing and nursing, the equipment necessary for critical care and a nurse-to-patient ratio at least one to two.

MAIN OUTCOME

In-hospital mortality. Patient-level and hospital-level analyses were performed.

RESULTS

Overall, 2 011 265 patients from 1524 hospitals were assessed. The cohort size ranged from 38 547 patients in 467 hospitals for surgical clipping for cerebral aneurysms to 308 952 patients in 599 hospitals for spinal fixation, laminectomy or laminoplasty. In the patient-level analyses, there were no significant mortality differences among patients undergoing the 12 major noncardiovascular surgical procedures, whereas postoperative ICU admission was associated with trends towards lower in-hospital mortality among patients undergoing coronary artery bypass grafting, risk difference -1.0% (95% CI -1.8 to -0.1) open aortic aneurysm repair, risk difference -0.6% (95% CI -1.3 to 0.1), and heart valve replacement, risk difference -0.7% (95% CI - 1.6 to 0.1). In the hospital-level analyses, similar to the results of the patient-level analyses, a higher proportion of postoperative ICU admission at hospital level was associated with trends toward lower in-hospital mortality for patients undergoing the three cardiovascular surgical procedures.

CONCLUSION

This nationwide observational study showed that postoperative ICU admission was associated with improved survival outcomes among patients undergoing three types of cardiac surgery but not among patients undergoing low-risk elective surgery.

Comparison of perioperative complications in anterior decompression with fusion and posterior decompression with fusion for thoracic ossification of the posterior longitudinal ligament -a retrospective cohort study using a nationwide inpatient database

BACKGROUND

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) is a rare disease, which can cause spinal cord compression leading to various neurological symptoms. There are limited treatment options for T-OPLL, surgery is generally considered the only effective treatment. However, few studies have investigated surgical complications in patients with T-OPLL, and there are no data regarding surgical risks in anterior decompression with fusion (ADF) when compared with posterior decompression with fusion (PDF) for T-OPLL.

METHODS

Patients who were diagnosed as T-OPLL and underwent ADF via the anterior approach and PDF via the posterior approach from April 1, 2012 to March 31, 2018, were extracted from the Diagnosis Procedure Combination (DPC) database. We analyzed perioperative systemic and local complication rates after ADF and PDF and compared them using propensity score matching (PSM) method. In each of the two groups, we investigated the details of length of stay, costs, mortality, and discharge destination.

RESULTS

In total 1344 patients (ADF: 88 patients, PDF: 1256 patients), 176 patients were investigated after PSM (88 pairs). While the incidence of overall systemic complication was significantly higher in the ADF group (ADF/PDF: 25.0%/8.0%, P = 0.002), there was no significant difference in the overall local complication rate (15.9%/19.3%, P = 0.55). Specifically, respiratory complications were more frequently observed in the ADF group (9.1%/0%, P = 0.004), however, other systemic and local complications did not differ significantly between the two groups. The length of stay was 1.7 times longer (P < 0.001) and the medical costs were 1.4 times higher (P < 0.001) in patients with perioperative complications, compared to those without perioperative complications.

CONCLUSION

We demonstrated the perioperative complications of ADF and PDF in patients with T-OPLL using a large national database. ADF showed a higher incidence of respiratory complications. Development of perioperative complications was associated with longer hospital stay and higher medical costs.

Impact of COVID-19 pandemic on healthcare service use for non-COVID-19 patients in Japan: retrospective cohort study

OBJECTIVES

We aimed to investigate the impact of the first and second waves of the COVID-19 pandemic on healthcare service use by non-COVID-19 patients.

DESIGN

Retrospective cohort study.

SETTING

Hospital-based claims database from anonymised hospitals in Japan.

PARTICIPANTS

Patients (n=785 495) who visited and/or were hospitalised in 26 anonymised hospitals in Japan between January 2017 and November 2020.

OUTCOME MEASURES

We compared changes in the monthly number of hospitalisations (overall or by diagnosis), outpatient visits, endoscopic fibrescopies (EFs), rehabilitations, outpatient chemotherapy treatments, maintenance haemodialysis treatments and outpatient prescriptions between pre-COVID-19 years and the same period in 2020.

RESULTS

The overall number of hospitalisations and outpatient visits decreased by 27% and 22%, respectively, in May 2020, of which the most substantial decrease was observed in the paediatrics department (65% and 51%, respectively). The number of hospitalisations for respiratory diseases, circulatory diseases, malignant neoplasms and digestive diseases decreased by a maximum of 55%, 32%, 10% and 26%, respectively, in 2020. The number of hospitalisations for non-COVID-19 pneumonia in patients aged <16 years, patients aged ≥16 years and patients with asthma decreased by 93%, 43% and 80%, respectively, in May 2020. EFs and outpatient rehabilitations decreased by >30%. In contrast, outpatient chemotherapy and maintenance haemodialysis treatments decreased by <10%, if at all. Outpatient prescriptions decreased by a maximum of 20% in 2020, with the largest decrease observed in drugs for obstructive airway diseases and cough and cold preparations.

CONCLUSIONS

The use of healthcare services by non-COVID-19 patients was most affected during the first wave of the COVID-19 pandemic in May 2020. The number of hospitalisations for respiratory diseases, particularly non-COVID-19 pneumonia and asthma, drastically decreased, while the number of hospitalisations and outpatient chemotherapies for malignant neoplasms or maintenance haemodialysis was less affected.

Direct oral anticoagulants versus warfarin for secondary prevention of cerebral infarction and bleeding in older adults with atrial fibrillation

BACKGROUND

Direct oral anticoagulants (DOACs) have been used for both primary and secondary prevention of cerebral infarction in older patients with atrial fibrillation (AF). However, whether DOACs are more effective and safer than warfarin for secondary prevention of cerebral infarction in older patients with AF remains unclear.

METHODS

Using the Japanese Diagnosis Procedure Combination database, we identified patients with AF who were hospitalized for cerebral infarction from January 1, 2015 to March 31, 2019 and were aged ≥75 years at admission. We performed propensity score-stabilized inverse probability of treatment weighting analyses to balance measured confounders between patients with AF receiving DOACs and those receiving warfarin after discharge. The primary outcomes were 365-day readmission for (a) benefit: cerebral infarction or (b) harm: bleeding events after discharge. The secondary outcomes were 365-day readmission for intracranial bleeding or gastrointestinal bleeding after discharge as well as all-cause death during readmission. Using a Fine-Gray model, we compared the subdistribution hazard ratios (SHRs) of readmission between the DOAC group and warfarin group.

RESULTS

We identified 101,389 eligible patients, including 80,726 patients receiving DOACs and 20,663 patients receiving warfarin. After the propensity score-stabilized inverse probability of treatment weighting, the adjusted SHRs of readmission (95% confidence interval [CI]) for cerebral infarction, bleeding events, and intracranial bleeding in the DOAC group as compared with the warfarin group were 0.76 (0.71-0.81), 0.78 (0.68-0.90), and 0.69 (0.57-0.82), respectively. There was no significant difference in readmission for gastrointestinal bleeding (SHR, 1.01; 95% CI, 0.72-1.41) between the DOAC and warfarin groups.

CONCLUSION

In this retrospective nationwide study, DOACs were more effective and safer than warfarin for preventing reinfarction and bleeding events in patients with AF aged ≥75 years who have a history of cerebral infarction.

Context and Considerations for Use of Two Japanese Real-World Databases in Japan: Medical Data Vision and Japanese Medical Data Center

In Japan, an increasing interest in real-world evidence for hypothesis generation and decision-making has emerged in order to overcome limitations and restrictions of clinical trials. We sought to characterize the context and concrete considerations of when to use Medical Data Vision (MDV) and JMDC databases, the main Japanese real-world data (RWD) sources accessible by pharmaceutical companies. Use cases for these databases, and related issues and considerations, were identified and summarized based on a literature search and experience-based knowledge. Studies conducted using MDV or JMDC were mostly descriptive in nature, or explored potential risk factors by evaluating associations with a target outcome. Considerations such as variable ascertainment at different time points, including issues relating to treatment identification and missing data, were highlighted for these two databases. Although several issues were commonly shared (e.g., only month of event occurrence reported), some database-specific issues were also identified and need to be accounted for. In conclusion, MDV and JMDC present limitations that are relatively typical of RWD sources, though some of them are unique to Japan, such as the identification of event occurrence and the inability to track patients visiting different healthcare settings. Addressing study design and careful result interpretation with respect to the specificities and uniqueness of the Japanese healthcare system is of particular importance. This aspect is especially relevant with respect to the growing global interest of conducting RWD studies in Japan.

Japanese Multicenter Research of COVID-19 by Assembling Real-world Data: A Study Protocol

BACKGROUND

Data on the evaluation of the clinical course of coronavirus disease 2019 (COVID-19) and the efficacy of treatments after hospitalization in Japan are limited.

OBJECTIVE

This study aimed to construct a database of confirmed COVID-19 cases in Japan and promptly address unresolved research issues.

METHODS

This multicenter observational study included patients who had a laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and were discharged from each participating institution between January 1 and September 31, 2020. We called for participating facilities and research proposals until the end of September 2020. The research steering committee members provided advice to co-investigators on refining their research proposals and analyses. After developing the research proposal, we collected clinical information, facility information, and laboratory data from each participating institution. Clinical information was also obtained from the Diagnosis Procedure Combination (DPC) data using a dedicated software called DPC hash application.

ANALYSIS

We planned to conduct an analysis based on the research proposal. Overall, 66 institutions from Japan announced their participation, and 102 research proposals were selected for the analyses. Research areas from the proposals included epidemiology, pathophysiology, therapeutic agents, ventilator settings, cost-benefit analyses, and prognosis prediction for COVID-19.

CONTRIBUTION AND SIGNIFICANCE TO THE FIELD

We have established an efficient data collection system and clinical research team for COVID-19 infection studies. The results of this study may be utilized in future response strategies for COVID-19.

Recombinant human soluble thrombomodulin for acute exacerbation of idiopathic pulmonary fibrosis: a nationwide observational study

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is the leading cause of death among patients with IPF. However, there is no established treatment for this condition. Hence, we aimed to investigate the effectiveness and safety of recombinant human soluble thrombomodulin (rTM) for the treatment of AE-IPF.

METHODS

Data were retrospectively collected from the Japanese Diagnosis Procedure Combination database from 1 January 2014 to 31 March 2018. We identified adult patients with IPF who received high-dose methylprednisolone (mPSL) therapy and mechanical ventilation upon admission. Eligible patients (n = 2814) were divided into those receiving high-dose mPSL alone (mPSL alone group, n = 2602) and rTM combined with high-dose mPSL (rTM group, n = 212). A stabilised inverse probability of treatment weighting (IPTW) using propensity scores was performed to compare outcomes between the two groups. The primary outcome was in-hospital mortality, and the secondary outcomes were 14- and 28-day mortality, bleeding events and length of hospital stay.

RESULTS

The in-hospital mortality rates of the mPSL alone and rTM groups were 75.9% and 76.9%, respectively. The results did not significantly differ between the two groups after performing a stabilised IPTW. The odds ratio of the rTM group compared to the mPSL alone group was 1.15 (95% confidence interval: 0.71-1.84; p = 0.57). Moreover, the secondary outcomes did not differ significantly between the two groups.

CONCLUSIONS

In patients with AE-IPF who developed severe respiratory failure, rTM in addition to high-dose mPSL was not associated with a better outcome.

Low- versus high-concentration intravenous immunoglobulin for children with Kawasaki disease in the acute phase

PURPOSE

Few studies have compared the effects of low-concentration (5%) and high-concentration (10%) intravenous immunoglobulin (IVIG) preparations for patients with Kawasaki disease (KD) in the acute phase. The purpose of this study was to compare outcomes between low- and high-concentration IVIG preparations in children with KD, using a national inpatient database in Japan.

METHOD

We used the Diagnostic Procedure Combination database to identify patients with KD treated with IVIG from April 2012 to March 2020. We identified those receiving high- and low-concentration IVIG preparations as an initial treatment. The outcomes included the proportions of patients with coronary artery abnormalities (CAAs) and IVIG resistance, length of stay, and medical costs. Propensity score-matched analyses were conducted to compare the outcomes between the 2 groups. Instrumental variable analyses were performed to confirm the results.

RESULT

We identified 48 046 patients with KD and created 4:1 propensity score-matched pairs between the low- and high-concentration IVIG groups. There was a significant difference in the percentage with IVIG resistance between the 2 groups (20.6% vs 24.1%; risk difference, 3.5% [95% confidence interval, 2.3-4.7]; P < .001). However, there was no significant difference in CAAs (1.6% vs 1.6%; risk difference, 0.013% [95% confidence interval, -0.34 to 0.37]; P = .953). The instrumental variable analyses showed similar results.

CONCLUSIONS

The proportion of CAAs did not differ significantly between those receiving low- and high-concentration IVIG. To confirm the results of this study, prospective studies adjusting for duration of IVIG administration and duration of observation are needed.

Incidence and outcomes of in-hospital cardiac arrest in Japan 2011-2017: a nationwide inpatient database study

Background

Although numerous studies have investigated out-of-hospital cardiac arrest, few studies have been conducted on in-hospital cardiac arrest (IHCA). Knowledge of the nationwide epidemiology of IHCA in Japan, with its super-aging society, is important to understand the current situation of IHCA and to establish evidenced-based medicine in the future. The present study aimed to determine the incidence and outcomes of IHCA and their trends in Japan.

Methods

This observational cohort study was performed using a national administrative inpatient database for more than 1600 acute-care hospitals covering about 50% of all acute-care hospital beds in Japan from April 2011 to March 2018. We defined cardiac arrest patients who received cardiopulmonary resuscitation (chest compression) during hospitalization as IHCA. We excluded out-of-hospital cardiac arrest patients from the source population. The incidence of IHCA per 1000 hospital admissions and survival to discharge rate was reported with trend analyses by calendar year 2011–2017.

Results

Among 53,871,101 hospitalized patients without out-of-hospital cardiac arrest patients in 1626 hospitals, 2,136,038 (4.0%) had cardiac arrest. Of them, 274,664 (12.9%) received cardiopulmonary resuscitation at least once during hospitalization and were identified as IHCA, and 1,861,374 (87.1%) did not receive cardiopulmonary resuscitation. The incidence of IHCA per 1000 hospital admissions was 5.1, with a significant decreasing trend from 6.1 in 2011 to 4.6 in 2017 (P for trend = 0.033). Our estimated incidence can be translated to approximately 87,000 IHCA cases in Japan each year. The percentage of IHCA patients among cardiac arrest patients was 12.9%, with a significant decreasing trend from 14.0% in 2011 to 12.2% in 2017 (P for trend = 0.006). The overall rate of survival to discharge was 12.7%, with a significant increasing trend from 10.5% in 2011 to 14.0% in 2017 (P for trend < 0.001).

Conclusions

We found substantial associations between mortality and loss of health and IHCA in Japan. The incidence of IHCA showed a decreasing trend over time, the percentage of treated cardiac arrest patients also had a decreasing trend, and the overall survival to discharge rate improved over time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00601-y.

Ambient temperature and hospital admissions for acute cholecystitis: a nationwide inpatient database study in Japan

BACKGROUND

The incidence of acute cholecystitis has a seasonal peak in summer. However, the reason for such seasonality remains unclear. This retrospective cohort study was performed to examine the association between ambient temperature and acute cholecystitis.

METHODS

We identified admissions for acute cholecystitis from January 2011 to December 2017 from a nationwide inpatient database in Japan. We performed a Poisson regression analysis to investigate the association between ambient temperature and admission for acute cholecystitis with adjustment for relative humidity, national holidays, day of the week, and year. We accounted for clustering of the outcome within prefectures using a generalized estimating equation.

RESULTS

We analyzed 601 665 admissions for acute cholecystitis. With an ambient temperature of 5.0 °C-9.9 °C as a reference, Poisson regression showed that the number of admissions increased significantly with increasing temperature (highest above 30 °C; relative risk, 1.35; 95% confidence interval, 1.34-1.37). An ambient temperature of <5.0 °C was also associated with higher admission for acute cholecystitis than an ambient temperature of 5.0 °C-9.9 °C (relative risk, 1.23; 95% confidence interval, 1.21-1.25).

CONCLUSION

The present nationwide Japanese inpatient database study showed that high temperature (≥10.0 °C) and low temperature (<5.0 °C) were associated with increased admission for acute cholecystitis.

Acute Pancreatitis in Japan: Comparison of Before and After Revision of the Clinical Guidelines

OBJECTIVES

Cases of acute pancreatitis (AP) are increasing worldwide, and mortality remains high in severe cases. In 2015, the Japanese guidelines for the management of AP were revised. We aimed to clarify the clinical practice of AP in Japan and its trend during the revision of the guidelines using a Japanese nationwide administrative database.

METHODS

We retrospectively analyzed 102,119 patients with AP who were hospitalized between April 2014 and March 2018. The study period was divided into the first period (the time before the revision: fiscal years 2014 and 2015) and second period (after the revision: 2016 and 2017).

RESULTS

Severe cases of AP accounted for 27.7% of total cases. The in-hospital mortality in severe cases was 5.7%. The mortality within 14 days of admission improved from 3.2% in the first period to 2.6% in the second period (P = 0.022). Referred patients had more severe diseases and a higher mortality. The mortality in patients who underwent endoscopic ultrasound-guided fistuloplasty for local complications (11.6%) was lower than that in patients who underwent percutaneous drainage (23.4%) or AP surgery (22.6%) (P < 0.001).

CONCLUSIONS

We clarified the clinical practice of AP including the improved mortality after the revision of the guidelines.

Interstitial lung disorders following postoperative radiotherapy with concurrent or sequential hormonal therapy for breast cancer: a nationwide database study in Japan

BACKGROUND

Hormonal therapy and radiotherapy are conducted concurrently or sequentially after breast cancer surgery. It remains unclear whether concurrent or sequential treatment is safer in terms of lung complications. Using a Japanese nationwide database, this study aimed to compare the occurrence of severe lung complications between concurrent and sequential treatments.

METHODS

We identified patients who underwent partial mastectomy for stage 0-III breast cancer from July 2010 to March 2020 and received adjuvant hormonal therapy and radiotherapy concurrently (n = 1851) or sequentially (n = 18,429). Two propensity score analyses (1:4 matching and overlap weighting) were conducted to compare hospitalization for radiation pneumonitis and pneumonia within 1 year after surgery, and intensive care unit admission and mortality during the hospitalization. We conducted additional analyses stratified by hormonal drugs (aromatase inhibitors and tamoxifen).

RESULTS

The propensity score-matched analysis showed no significant differences in occurrence of hospitalization for radiation pneumonitis (0.27 vs. 0.58%, p = 0.10) and pneumonia (0.16 vs. 0.58%, p = 0.05) between the concurrent and sequential treatments. The overlap propensity score-weighted analysis also showed no significant differences (0.25 vs. 0.56%, p = 0.08 and 0.15 vs. 0.44%, p = 0.06, respectively). Intensive care unit admission and in-hospital mortality did not differ significantly between the two treatments. The stratified analysis showed similar results.

CONCLUSION

Our propensity score analyses revealed no significant differences in severe lung complications between concurrent and sequential hormonal therapy with radiotherapy following breast cancer surgery, regardless of the type of hormonal drugs. Clinicians can provide concurrent or sequential treatment with equivalent attention to early lung complications.

Effectiveness of early rehabilitation following aortic surgery: a nationwide inpatient database study

OBJECTIVE

Exercise immediately after aortic surgery is controversial with limited evidence. The present study aimed to assess whether early rehabilitation commencing within 3 days of aortic surgery improves physical functions at discharge more than usual care in patients after aortic surgery.

METHODS

We used the Japanese Diagnosis Procedure Combination database, a nationwide inpatient database from more than 1600 acute care hospitals that covers approximately 75% of all intensive care unit (ICU) beds in Japan. We identified patients who underwent open or endovascular aortic surgery and were admitted to the ICU between July 2010 and March 2018. Patients beginning rehabilitation within 3 days of aortic surgery were defined as the early rehabilitation group and the remaining patients as the usual care group. We used inverse probability of treatment weighting analyses to compare outcomes between the two groups.

RESULTS

Among 121,024 eligible patients, there were 44,746 (37.0%) in the early rehabilitation group and 76,278 (63.0%) in the usual care group. In inverse probability of treatment weighting analyses, Barthel index scores at discharge were significantly higher in the early rehabilitation group than in the usual care group (difference, 4.0; 95% confidence interval, 2.8-5.2). The early rehabilitation group had significantly lower in-hospital mortality, lower total hospitalization costs, shorter ICU stay, and shorter hospital stay than the usual care group.

CONCLUSION

Early rehabilitation within 3 days of aortic surgery was associated with improved physical functions at discharge, shorter ICU and hospital stays, and lower hospitalization costs without increased mortality.

Development of Deep Learning Models for Predicting In-Hospital Mortality Using an Administrative Claims Database: Retrospective Cohort Study

BACKGROUND

Administrative claims databases have been used widely in studies because they have large sample sizes and are easily available. However, studies using administrative databases lack information on disease severity, so a risk adjustment method needs to be developed.

OBJECTIVE

We aimed to develop and validate deep learning-based prediction models for in-hospital mortality of acute care patients.

METHODS

The main model was developed using only administrative claims data (age, sex, diagnoses, and procedures on the day of admission). We also constructed disease-specific models for acute myocardial infarction, heart failure, stroke, and pneumonia using common severity indices for these diseases. Using the Japanese Diagnosis Procedure Combination data from July 2010 to March 2017, we identified 46,665,933 inpatients and divided them into derivation and validation cohorts in a ratio of 95:5. The main model was developed using a 9-layer deep neural network with 4 hidden dense layers that had 1000 nodes and were fully connected to adjacent layers. We evaluated model discrimination ability by an area under the receiver operating characteristic curve (AUC) and calibration ability by calibration plot.

RESULTS

Among the eligible patients, 2,005,035 (4.3%) died. Discrimination and calibration of the models were satisfactory. The AUC of the main model in the validation cohort was 0.954 (95% CI 0.954-0.955). The main model had higher discrimination ability than the disease-specific models.

CONCLUSIONS

Our deep learning-based model using diagnoses and procedures produced valid predictions of in-hospital mortality.

Analysis of the risk factors of mortality in elderly patients with hip fracture using a combined database of medical and long-term care insurance claims data

BACKGROUND

The present study evaluated the risk of mortality in elderly hip fracture, focusing on comorbidities and nursing care levels.

METHODS

The present study was an observational cohort study that used a combined database of medical and long-term care insurance (LTCI) claims data from one prefecture in Japan between 2011 and 2016. In total, 6125 patients aged 65 years and older were selected from acute care hospitals with a diagnosis of "hip fracture" between March 2011 and March 2012. The impact of long-term care insurance claim evaluation levels and comorbidities at recruitment time was investigated using this dataset. These patients were followed up monthly until March 2016. Based on this person-month dataset, survival analysis was performed with death as the endpoint. Cases in which receipt data were missing during the middle of the observation period and cases in which the patient survived at the end of the observation period were censored.

RESULTS

The number of deaths during the observation period was 635 (10.4%). The impact of comorbidities and nursing care level on mortality were both significant as follows: high nursing care level before the fracture (hazard ratio: 1.09, P < 0.001), comorbidities of malignant diseases (HR: 1.45, P < 0.001), heart disease (hazard ratio: 1.20, P = 0.037), pneumonia (hazard ratio: 1.27, P < 0.001), chronic obstructive pulmonary disease (hazard ratio: 1.28, P = 0.026), renal failure (hazard ratio: 1.44, P < 0.001), and dementia (hazard ratio: 1.27, P = 0.013).

CONCLUSION

The results of this study showed that a high level of nursing care and presence of comorbidities such as malignant diseases, heart diseases, pneumonia, chronic obstructive pulmonary disease, renal failure, and dementia increased mortality in elderly patients with hip fracture. Furthermore, this study showed the usefulness of a combined database of medical and LTCI claims data for clinical and health service-related research in the field of orthopedics.

Explanation of machine learning models using shapley additive explanation and application for real data in hospital

BACKGROUND AND OBJECTIVE

When using machine learning techniques in decision-making processes, the interpretability of the models is important. In the present paper, we adopted the Shapley additive explanation (SHAP), which is based on fair profit allocation among many stakeholders depending on their contribution, for interpreting a gradient-boosting decision tree model using hospital data.

METHODS

For better interpretability, we propose two novel techniques as follows: (1) a new metric of feature importance using SHAP and (2) a technique termed feature packing, which packs multiple similar features into one grouped feature to allow an easier understanding of the model without reconstruction of the model. We then compared the explanation results between the SHAP framework and existing methods using cerebral infarction data from our hospital.

RESULTS

The interpretation by SHAP was mostly consistent with that by the existing methods. We showed how the A/G ratio works as an important prognostic factor for cerebral infarction using proposed techniques.

CONCLUSION

Our techniques are useful for interpreting machine learning models and can uncover the underlying relationships between features and outcome.

Association Between Diabetes and Major Bleeding Complications of Renal Biopsy

Introduction

Nephrologists have recently recognized the heterogeneity of kidney diseases among patients with diabetes and begun to actively perform percutaneous renal biopsies (PRBs). Nevertheless, the association between diabetes and major bleeding complications of PRB remains unclear.

Methods

In this retrospective cohort study using the Diagnosis Procedure Combination database in Japan, we identified patients who underwent an elective PRB from July 2010 to March 2018. The primary outcome was the occurrence of major bleeding complications, defined as red blood cell transfusion within 7 days after PRB or invasive hemostasis after PRB. Multivariable regression analysis was performed to analyze the association between diabetes and major bleeding complications with adjustment for patient and hospital characteristics.

Results

We identified 76,302 patients, including 8245 with diabetes. The proportion of PRBs performed for patients with diabetes continuously increased over time. Major bleeding complications occurred in 678 patients (0.9%), including 622 (0.8%) with red blood cell (RBC) transfusion and 109 (0.1%) with invasive hemostasis. Diabetes was significantly associated with major bleeding complications (relative risk [RR] = 2.41; 95% CI 2.00–2.90). Among patients with diabetes, multiagent or insulin treatment had significant association with major bleeding complications (RR = 1.57; 95% CI 1.18–2.10), compared with single-agent diabetes treatment.

Conclusion

Diabetes is significantly associated with major bleeding complications of PRBs. Moreover, severity of diabetes has association with increases in major bleeding complications. Thus, nephrologists should carefully judge whether the anticipated benefits outweigh the relatively high risk of major bleeding complications when considering PRB for patients with diabetes.

Postoperative outcomes of cancer surgery in patients with and without kidney failure with dialysis therapy: A matched-pair cohort study

Background

The difference in outcomes of cancer surgery between patients with and without kidney failure with dialysis therapy (KFDT) remains uncertain.

Methods

Using 2010–18 data in a national inpatient database in Japan, we identified patients who had undergone resection of colorectal, lung, gastric or breast cancer. We matched selected patient characteristics, type of cancer, surgical procedure and hospital of up to four patients without KFDT to each patient with KFDT. We assessed 30-day mortality and postoperative complications.

Results

Through matching, we identified 2248 patients with KFDT (807 with colorectal, 579 with lung, 500 with gastric and 362 with breast cancer) and 8210 patients without KFDT (2851 with colorectal, 2216 with lung, 1756 with gastric and 1387 with breast cancer). Postoperative complications occurred in a higher proportion of patients with KFDT than of those without KFDT after colorectal {20.3% versus 14.6%; risk difference (RD): 5.7% [95% confidence interval (95% CI) 2.6%–8.8%]}, lung [18.0% versus 12.9%; RD: 5.1% (95% CI 1.6%–8.4%)], gastric [25.0% versus 13.2%; RD: 11.8% (95% CI 7.6%–16.2%)] and breast cancer surgery [7.5% versus 3.5%; RD: 3.9% (95% CI 1.1%–6.9%)]. Patients with KFDT had a higher 30-day mortality than those without KFDT after gastric cancer surgery [1.6% versus 0.3%; RD: 1.3% (95% CI 0.1%–2.3%)]. Heart failure and ischemic heart disease occurred more frequently in patients with KFDT.

Conclusions

Patients with KFDT had higher rates of postoperative complications and 30-day mortality; however, RDs varied between cancer types. The higher rates of postoperative complications in patients with KFDT were mainly attributable to cardiovascular complications.

Clinical epidemiology and pharmacoepidemiology studies with real-world databases

Hospital-based registry data, including patients' information collected by academic societies or government based research groups, were previously used for clinical research in Japan. Now, real-world data routinely obtained in healthcare settings are being used in clinical epidemiology and pharmacoepidemiology. Real-world data include a database of claims originating from health insurance associations for reimbursement of medical fees, diagnosis procedure combinations databases for acute inpatient care in hospitals, a drug prescription database, and electronic medical records, including patients' medical information obtained by doctors, derived from electronic records of hospitals. In the past ten years, much evidence of clinical epidemiology and pharmacoepidemiology studies using real-world data has been accumulated. The purpose of this review was to introduce clinical epidemiology and pharmacoepidemiology approaches and studies using real-world data in Japan.

Impact of body mass index on short-term outcomes after differentiated thyroid cancer surgery: a nationwide inpatient database study in Japan

INTRODUCTION

Recent studies have shown worse post-operative outcomes following several surgeries in underweight or obese patients. However, the association between body mass index (BMI) and short-term outcomes following thyroid cancer surgery remains unclear because of the small number of patients, deficits in background data known as risk factors (e.g. cancer stage, operative procedure, intraoperative device use and hospital volume) and categorisation of BMI.

METHODS

We identified patients who underwent thyroidectomy for differentiated thyroid cancer from July 2010 to March 2017 using a Japanese nationwide inpatient database. We used restricted cubic spline (RCS) analyses to investigate potential non-linear associations between BMI (without categorisation) and outcomes: post-operative complications (local and general), duration of anaesthesia, post-operative length of hospital stay and hospitalisation costs. The analyses were adjusted for demographic and clinical backgrounds including the above-stated factors. We also performed multivariable regression analyses for the outcomes with categorisation of BMI.

RESULTS

Among 59,671 eligible patients, the median BMI was 22.9 kg/m2 (interquartile range (IQR), 20.7-25.6 kg/m2). In total, 3860 patients (6.5%) had local complications and 787 patients (1.3%) had general complications. Although there were no significant associations with local complications, such as bleeding, recurrent laryngeal nerve paralysis and surgical site infection, the occurrence of general complications was significantly associated with higher BMI. BMI showed a linear association with the duration of anaesthesia and U-shaped associations with post-operative length of stay and hospitalisation costs. The lowest points of the U-shaped curves occurred at a BMI of approximately 24 kg/m2. The multivariate regression analyses showed consistent results with the RCS analyses.

DISCUSSION/CONCLUSION

Whereas RCS analyses revealed no significant associations between BMI and post-operative local complications, obesity was significantly associated with the occurrence of general complications. The linear association between BMI and duration of anaesthesia corresponds to previous studies. Although post-operative length of stay and total hospitalisation costs demonstrated U-shaped associations, the slight differences would not be clinically important. Even if surgeons must pay attention to general complications in obese patients undergoing thyroid cancer surgery as well as other surgeries, underweight and overweight patients can undergo thyroidectomy as safely as patients with normal BMI.

Intensive care unit versus high-dependency care unit for patients with acute heart failure: a nationwide propensity score-matched cohort study

Background

A structure and staffing model similar to that in general intensive care unit (ICUs) is applied to cardiac intensive care unit (CICUs) for patients with acute heart failure. However, there is limited evidence on the structure and staffing model of CICUs. The present study aimed to assess whether critical care for patients with acute heart failure in the ICUs is associated with improved outcomes than care in the high-dependency care units (HDUs), the hospital units in which patient care levels and costs are between the levels found in the ICU and general ward.

Methods

This nationwide, propensity score-matched, retrospective cohort study was performed using a national administrative inpatient database in Japan. We identified all patients who were hospitalized for acute heart failure and admitted to the ICU or HDU on the day of hospital admission from April 2014 to March 2019. Propensity score-matching analysis was performed to compare the in-hospital mortality between acute heart failure patients treated in the ICU and HDU on the day of hospital admission.

Results

Of 202,866 eligible patients, 78,646 (39%) and 124,220 (61%) were admitted to the ICU and HDU, respectively, on the day of admission. After propensity score matching, there was no statistically significant difference in in-hospital mortality between patients who were admitted to the ICU and HDU on the day of admission (10.7% vs. 11.4%; difference, − 0.6%; 95% confidence interval, − 1.5% to 0.2%). In the subgroup analyses, there was a statistically significant difference in in-hospital mortality between the ICU and HDU groups among patients receiving noninvasive ventilation (9.4% vs. 10.5%; difference, − 1.0%; 95% confidence interval, − 1.9% to − 0.1%) and patients receiving intubation (32.5% vs. 40.6%; difference, − 8.0%; 95% confidence interval, − 14.5% to − 1.5%). There were no statistically significant differences in other subgroup analyses.

Conclusions

Critical care in ICUs was not associated with lower in-hospital mortality than critical care in HDUs among patients with acute heart failure. However, critical care in ICUs was associated with lower in-hospital mortality than critical care in HDUs among patients receiving noninvasive ventilation and intubation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-021-00592-2.

Associations between Early Surgery and Postoperative Outcomes in Elderly Patients with Distal Femur Fracture: A Retrospective Cohort Study

Previous literature has provided conflicting results regarding the associations between early surgery and postoperative outcomes in elderly patients with distal femur fractures. Using data from the Japanese Diagnosis Procedure Combination inpatient database from April 2014 to March 2019, we identified elderly patients who underwent surgery for distal femur fracture within two days of hospital admission (early surgery group) or at three or more days after hospital admission (delayed surgery group). Of 9678 eligible patients, 1384 (14.3%) were assigned to the early surgery group. One-to-one propensity score matched analyses showed no significant difference in 30-day mortality between the early and delayed groups (0.5% versus 0.5%; risk difference, 0.0%; 95% confidence interval, −0.7% to 0.7%). Patients in the early surgery group had significantly lower proportions of the composite outcome (death or postoperative complications), shorter hospital stays, and lower total hospitalization costs than patients in the delayed surgery group. Our results showed that early surgery within two days of hospital admission for geriatric distal femur fracture was not associated with a reduction in 30-day mortality but was associated with reductions in postoperative complications and total hospitalization costs.

Associations of Government-issued ICU Admission Criteria with Clinical Practices, Outcomes, and ICU Bed Occupancy

RATIONALE

In Japan, the government officially issued intensive care unit (ICU) admission criteria that require ICU units to admit patients who need a certain level of monitoring and procedures to ensure their reimbursement for ICU costs from April 2014.

OBJECTIVE

To assess whether the newly issued health policy on ICU admission criteria based on financial incentives for monitoring and procedures had any impact on clinical practices, outcomes, and ICU bed occupancy.

METHODS

Using a nationwide inpatient health claims database in Japan, we identified patients who were admitted to the ICU from April 2012 to March 2018. Outcomes were monitoring and procedures in the ICU, clinical outcomes, and ICU bed occupancy. The outcomes of monitoring and procedures and clinical outcomes were adjusted for patient characteristics. Interrupted time-series analyses were used to compare the trends in outcomes for two separate periods before and after the issue of the new health policy on ICU admission criteria in April 2014.

RESULTS

A total of 1,660,601 patients in 259 ICU-equipped hospitals were eligible. There were significant upward slope changes between the pre- and post-issue periods for all monitoring and procedures in the ICU, including invasive arterial pressure monitoring (5.62% change in trend per year; 95% CI, 4.75%-6.49%) and central venous pressure monitoring (1.22% change in trend per year; 95% CI, 0.78%-1.67%). There was no significant slope change between the pre- and post-issue periods for in-hospital mortality, but there were significant upward slope changes for complications of pneumonia (0.27% change in trend per year; 95% CI, 0.14%-0.39%) and catheter-related bloodstream infection (0.02% change in trend per year; 95% CI, 0.00%-0.14%). There were also significant upward slope changes in length of hospital stay, length of ICU stay, and hospitalization costs between the pre- and post-issue periods. There was no significant slope change between the pre- and post-issue periods for ICU bed occupancy.

CONCLUSIONS

The health policy on ICU admission criteria based on financial incentives for actions taken by providers was associated with increased monitoring and procedures, complications, lengths of hospital and ICU stay, and hospitalization costs without decreasing ICU bed occupancy.

Validity of a model using routinely collected data for identifying infections following gastric, colorectal, and liver cancer surgeries

PURPOSE

Validating outcome measures is a prerequisite for using administrative databases for comparative effectiveness research. Although the Japanese Diagnosis Procedure Combination database is widely used in surgical studies, the outcome measure for postsurgical infection has not been validated. We developed a model to identify postsurgical infections using the routinely-collected Diagnosis Procedure Combination data.

METHODS

We retrospectively identified inpatients who underwent surgery for gastric, colorectal, or liver cancer between April 2016 and March 2018 at four hospitals. Chart reviews were conducted to identify postsurgical infections. We used bootstrap analysis with backwards variable elimination to select independent variables from routinely-collected diagnosis and procedure data. Selected variables were used to create a score predicting the chart review-identified infections, and the performance of the score was tested.

RESULTS

Among the 756 eligible patients, 102 patients (13%) had postoperative infections. Three variables were identified as predictors: diagnosis of infectious disease recorded as a complication arising after admission, addition of an intravenous antibiotic, and bacterial microscopy or culture. The prediction model had a C-statistic of 0.891 and pseudo-R² of 0.380. A cut-off of 1 point of the score showed a sensitivity of 92% and specificity of 71%, and a cut-off of 2 points showed a sensitivity of 77% and specificity of 91%.

CONCLUSIONS

Our model using routinely-collected administrative data accurately identified postoperative infections. Further external validation would lead to the application of the model for research using administrative databases. This article is protected by copyright. All rights reserved.

Clinical Characteristics and Incidences of Benign and Malignant Insulinoma Using a National Inpatient Database in Japan

CONTEXT

Insulinoma is the most common pancreatic functional neuroendocrine neoplasm, yet little information on recent clinical practice in patients with insulinoma, especially malignant insulinoma, is available.

OBJECTIVE

This work aims to clarify the characteristics and practice patterns in patients with insulinoma using a national inpatient database.

METHODS

Using the Japanese Diagnosis Procedure Combination database, we retrospectively identified patients with insulinoma admitted between 2010 and 2018. We compared background characteristics and therapeutic interventions between patients with benign and malignant insulinoma. We also estimated the incidence of insulinoma using the number of patients with newly diagnosed insulinoma in 2012.

RESULTS

We identified 844 patients with benign insulinoma and 102 patients with malignant insulinoma. Patients with malignant insulinoma were younger (median, 55.5 vs 66.0 years, P < .001) and less likely to be female (55.9% vs 65.3%, P = .061) than patients with benign insulinoma. Analysis of therapeutic interventions revealed that patients with malignant insulinoma more frequently received medications (71.6% vs 49.6%, P < .001) but less frequently underwent pancreatic surgery (57.8% vs 72.0%, P = .003). Older patients were a smaller proportion of those undergoing surgery and a larger proportion of those managed with medications without surgery (P < .001). The incidence of insulinoma was estimated to be 3.27 (95% CI, 2.93-3.61) individuals per million Japanese adult population per year.

CONCLUSION

The present study using a nationwide database had a larger sample size than previous studies and revealed definitive differences in patient characteristics and therapeutic patterns between benign and malignant insulinoma.

Association between adjunct clindamycin and in-hospital mortality in patients with necrotizing soft tissue infection due to group A Streptococcus: a nationwide cohort study

Necrotizing soft tissue infection (NSTI) due to group A Streptococcus (GAS) is a severe life-threatening microbial infection. The administration of adjunct clindamycin has been recommended in the treatment of NSTIs due to GAS. However, robust evidence regarding the clinical benefits of adjunct clindamycin in NSTI patients remains controversial. We aimed to investigate the association between early administration of adjunct clindamycin and in-hospital mortality in patients with NSTI attributed to GAS. The present study was a nationwide retrospective cohort study, using the Japanese Diagnosis Procedure Combination inpatient database focusing on the period between 2010 and 2018. Data was extracted on patients diagnosed with NSTI due to GAS. We compared patients who were administered clindamycin on the day of admission (clindamycin group) with those who were not (control group). A propensity score overlap weighting method was adopted to adjust the unbalanced backgrounds. The primary endpoint was in-hospital mortality and survival at 90 days after admission. We identified 404 eligible patients during the study period. After adjustment, patients in the clindamycin group were not significantly associated with reduced in-hospital mortality (19.2% vs. 17.5%; odds ratio, 1.11; 95% confidence interval, 0.59-2.09; p = 0.74) or improved survival at 90 days after admission (hazard ratio, 0.92; 95% confidence interval, 0.51-1.68; p = 0.80). In this retrospective study, early adjunct clindamycin does not appear to improve survival. Therefore, the present study questions the benefits of clindamycin as an adjunct to broad spectrum antibiotics in patients with NSTI due to GAS.

Outcomes of Nonoperative Treatment for Gastroduodenal Ulcer Perforation: a Nationwide Study of 14,918 Inpatients in Japan

BACKGROUND

Gastroduodenal ulcer perforation is a common abdominal emergency that may be curable without surgical repair in non-elderly patients with localized and stable symptoms. However, the outcomes of nonoperative approaches have rarely been described.

METHODS

Using a Japanese national inpatient database, we identified 14,918 patients with gastroduodenal ulcer perforation who were hospitalized and received nonoperative treatment from July 2010 to March 2017. We categorized these patients into three groups according to age: 18 to 64 years (young group, n=8407), 65 to 74 years (old group, n=2616), and ≥75 years (old-old group, n=3895). We investigated the characteristics, treatments, and outcomes in each group.

RESULTS

Most of the patients were men (71%), and the median patient age was 62 years (interquartile range, 47-75 years). The old and old-old groups had more comorbidities than the young group. Whereas most patients were administered proton pump inhibitors and various antibiotics (96% and 90%, respectively), only 58% of patients underwent gastric tube placement. Surgical repair >3 days after admission was performed in 7.1% of all patients (6.3% vs. 7.9% vs. 5.5%, P<0.001). The old and old-old groups showed higher mortality (1.4% vs. 8.3% vs. 18%, P<0.001) and morbidity (6.6% vs. 15% vs. 17%, P<0.001) than the young group. The median length of stay was almost 2 weeks (13 vs. 17 vs. 20 days, P<0.001).

DISCUSSION

Unlike previous studies, many patients aged >65 years received nonoperative treatment in this nationwide cohort. Our findings provide useful information for clinicians and patients hospitalized for gastric ulcer perforation.

Evaluation of quality indicators near death in older adult cancer decedents in Japan: A nationwide retrospective cohort study

OBJECTIVES

End-of-life cancer care is important; however, data on hospitalization and costs for older patients have been lacking. We aimed to examine quality indicators and costs for older patients in Japan.

METHODS

Using the Diagnosis Procedure Combination database, a national database of acute-care hospitals in Japan, we retrospectively collected data on cancer decedents aged ≥65 years. We evaluated the quality indicators (hospitalizations, length of stay in the hospital, emergency hospitalizations, emergency hospitalizations using an ambulance, intensive care unit [ICU] admissions, length of stay in the ICU, interval between last chemotherapy use and death, and chemotherapy within 14 days before death) and hospitalization costs at 30, 90 and 180 days before death. We compared the outcomes across age groups (65-74, 75-84 and ≥ 85 years).

RESULTS

Between January 2011 and March 2015, we identified 369 616 cancer decedents. From 180 to 30 days before death, there were increases in emergency hospitalizations, emergency hospitalizations using an ambulance, and the mean costs per hospital day. Overall, 16.7% of patients receiving chemotherapy last received this treatment on the day before death or the day of death. Costs decreased with increasing age. The group aged ≥85 years had the shortest hospital and ICU stays and the lowest multiple hospitalizations, ICU admissions, chemotherapy within 14 days before death, and costs.

CONCLUSIONS

Many older adult patients had emergency hospitalizations and received chemotherapy just prior to death, and there is room for improvement in appropriate end-of-life care. Oldest old patients consumed relatively few medical resources.

Routine varicella vaccination program and hospitalization for herpes zoster in Japan

Whether reducing exposure to varicella by the implementation of the routine varicella vaccination program for children leads to increased incidence of herpes zoster (HZ) remains controversial. The aim of the present study was to identify the trend in the hospitalization associated with HZ before and after the introduction of routine varicella vaccination by using nationally representative data from an inpatient database in Japan. Data were obtained on the number of inpatients hospitalized for HZ from the "Survey on the effect of the introduction of Diagnosis Procedure Combination (DPC) database" and the total population in Japan from the Population Estimates created by the former Statistics Bureau between fiscal years 2013 and 2018. The data from the DPC hospitals only and all hospitals in the survey were analyzed separately. The trends in the annual incidence of HZ hospitalization were identified. The trends in the annual hospitalization for HZ per 100,000 persons were then analyzed by age group (0-20, 21-40, 41-60, 61-79, and ≥80 years of age). The annual number of hospitalizations for HZ was approximately 20,000 in the DPC hospitals and 25,000 in all hospitals, showing no upward trend. The age-specific annual hospitalization rate for HZ did not increase in all the age groups. As age increased, the hospitalization rate also increased. This study presents no upward trend in the hospitalizations for HZ after the implementation of the routine varicella vaccination program in Japan.

Effect of antithrombin III among patients with disseminated intravascular coagulation in obstetrics: a nationwide observational study in Japan

OBJECTIVE

Pregnant women may develop disseminated intravascular coagulation (DIC), possibly resulting in massive maternal haemorrhage and perinatal death. The Japan guideline recommends use of antithrombin III (ATIII) for DIC in obstetrics; however, its effect remains uncertain. The present study aimed to investigate the effect of ATIII for DIC in obstetrics, using a national inpatient database in Japan.

DESIGN

Nationwide observational study.

SETTING

Japan.

POPULATION

We used the Diagnosis Procedure Combination inpatient database to identify patients who delivered at hospital and were diagnosed with DIC from July 2010 to March 2018.

METHODS

Propensity score matching analyses were performed to compare in-hospital maternal mortality and hysterectomy during hospitalisation between users and non-users of ATIII on the day of delivery.

MAIN OUTCOME MEASURES

In-hospital mortality, hysterectomy.

RESULTS

A total of 9920 patients were enrolled, including 4329 patients (44%) who used ATIII and 5511 patients (56%) who did not use ATIII. One-to-one propensity score matching created 3290 pairs. In-hospital maternal mortality did not differ significantly between the propensity-matched groups (0.3% in the ATIII group versus 0.5% in the control group; odds ratio 0.73; 95% CI 0.35-1.54). A significantly lower proportion of patients in the ATIII group, compared with those in the control group, underwent hysterectomy during hospitalisation (5.3% versus 8.7%; absolute risk difference -2.9%; 95% CI -4.2 to -1.6%).

CONCLUSIONS

Although the present study did not show a mortality-reducing effect of ATIII for patients with DIC in obstetrics, it may have clinical benefit in terms of reducing the number of patients undergoing hysterectomy.

TWEETABLE ABSTRACT

This study did not show mortality-reducing effect of antithrombin III for patients with DIC in obstetrics.

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.

Intensive care unit versus high-dependency care unit for mechanically ventilated patients with pneumonia: a nationwide comparative effectiveness study

Background

Many mechanically ventilated patients in Japan are treated in high-dependency care units (HDUs) rather than intensive care units (ICUs). HDUs can provide intermediate-level care with reduced costs; however, there is limited evidence on whether mechanically ventilated patients should be treated in the ICU or HDU.

Methods

This was a comparative effectiveness study using a nationwide administrative database in Japan. We identified mechanically ventilated patients with pneumonia in ICU or HDU on the day of admission in the Japanese Diagnosis Procedure Combination inpatient database from April 2014 to March 2019. The primary outcome was 30-day in-hospital mortality. Propensity score matching analysis was performed to compare this outcome between patients treated in the ICU and HDU. The robustness of the analyses was evaluated with multivariable regression, overlap weighting, and instrumental variable analyses.

Findings

Of 14,859 mechanically ventilated patients with pneumonia, 7,528 (51%) were treated in the ICU and 7,331 (49%) were treated in the HDU. After propensity score matching, patients treated in the ICU had significantly lower 30-day in-hospital mortality than did those treated in the HDU (24.0% vs. 31.2%; difference, −7.2%; 95% confidence interval, −10.0% to −4.4%). The multivariable regression, overlap weighting, and instrumental variable analyses showed a similar direction and magnitude of association.

Interpretation

Critical care for mechanically ventilated patients with pneumonia in the ICU was associated with a 7.2% decrease in 30-day in-hospital mortality vs. care in the HDU. Residual confounding may still play a role in the effect estimates.

Funding

This study received funding from Ministry of Health, Labour and Welfare, Japan, and Ministry of Education, Culture, Sports, Science and Technology, Japan.

New machine learning scoring system for predicting postoperative mortality in gastroduodenal ulcer perforation: A study using a Japanese nationwide inpatient database

BACKGROUND

Conventional prediction models for estimating risk of postoperative mortality in gastroduodenal ulcer perforation have suboptimal prediction ability. We aimed to develop and validate new machine learning models and an integer-based score for predicting the postoperative mortality.

METHODS

We retrospectively identified patients with gastroduodenal ulcer perforation who underwent surgical repair, using a nationwide Japanese inpatient database. In a derivation cohort from July 2010 to March 2016, we developed 2 machine learning-based models, Lasso and XGBoost, using 45 candidate predictors, and also developed an integer-based score for clinical use by including important variables in Lasso. In a validation cohort from April 2016 to March 2017, we measured the prediction performances of the models by computing area under the curve and comparing it to the conventional American Society of Anesthesiology risk score.

RESULTS

Of 25,886 patients, 1,176 (4.5%) died after surgical repair. For the validation cohort, Lasso and XGBoost had significantly higher prediction abilities than the American Society of Anesthesiology score (Lasso area under the curve = 0.84; 95% confidence interval 0.81-0.86; American Society of Anesthesiology score area under the curve = 0.70; 95% confidence interval 0.65-0.74, P < .001). The integer-based risk score, which had 13 factors, had a prediction ability similar to those of Lasso and XGBoost (area under the curve = 0.83; 95% confidence interval 0.81-0.86). According to the integer-based score, the mortalities were 0.1%, 2.3%, 9.3%, and 29.0% for the low (score, 0), moderate (1-2), high (3-4), and very high (≥5) score groups, respectively.

CONCLUSION

Machine learning models and the integer-based risk score performed well in predicting risk of postoperative mortality in gastroduodenal ulcer perforation. These models will help in decision making.

Pulmonary disease as a risk factor for transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a severe condition characterised by noncardiogenic pulmonary oedema that develops within 6 h of blood transfusion. Patient factors and blood products have both been implicated in the development of TRALI; however, the role of pulmonary disease has not been investigated. We aimed to determine whether pulmonary disease is a risk factor for TRALI.

We conducted a nested case-control study using data from the Diagnosis Procedure Combination database, a nationwide inpatient database in Japan, between July 2010 and March 2015. Case patients who developed TRALI were 1:4-matched with control patients for sex, age and same hospital for receipt of blood transfusion. We conducted a multivariable conditional logistic regression analysis to evaluate the associations of TRALI with various factors including comorbidities, body mass index (BMI) and plasma-containing blood products.

We identified 2 019 501 hospitalised patients who received a blood transfusion. Among these patients, 72 developed TRALI. The 72 case patients had higher proportions of haematological malignancy, trauma and interstitial lung disease (ILD) than the 288 matched control patients. The multivariable conditional logistic regression analysis showed that occurrence of TRALI was associated with ILD (odds ratio, 3.88; 95% confidence interval, 1.11–13.6), BMI ≥25.0 kg·m⁻² (2.10; 1.05–4.24) and plasma-containing blood products (1.94; 1.10–3.42), but not with infectious lung disease or obstructive airway disease.

In conclusion, ILD was an independent risk factor for the development of TRALI. Physicians should be aware of the increased risk of TRALI in patients with ILD.

Physicians should be aware of the risk of developing transfusion-related acute lung injury when performing a blood transfusion in patients with interstitial lung disease.https://bit.ly/3jdoZQP

Comparisons of postoperative outcomes after breast cancer surgery in patients with and without renal replacement therapy: a matched-pair cohort study using a Japanese nationwide inpatient database

BACKGROUND

Although patients receiving renal replacement therapy (RRT) have more comorbidities and higher mortality and morbidity risks than the general population, surgery during breast cancer treatment is crucial because of limitations in anticancer agents for patients with renal insufficiency. We aimed to compare the short-term postoperative outcomes between patients with and without RRT.

METHODS

Patients who underwent surgery for stages 0-III breast cancer between July 2010 and March 2017 were retrospectively identified in a Japanese nationwide inpatient database and divided into those with RRT (RRT group, n = 1547) and those without RRT (control group, n = 364,047). We generated a 1:4 matched-pair cohort matched for age, institution, and fiscal year at admission. We conducted multivariable regression analyses to compare postoperative complications, 30-day readmission, and anesthesia duration between the two groups.

RESULTS

The RRT group was more likely to have comorbidities (95.0% vs. 24.1%) and undergo total mastectomy (64.2% vs. 47.0%) than the control group. The RRT group was not significantly associated with complications (odds ratio 1.18; 95% confidence interval [CI] 0.89-1.56) and 30-day readmission (odds ratio 0.88; 95% CI 0.65-1.18), but was associated with shorter anesthesia duration (difference, - 6.8 min; 95% CI - 10.7 to - 3.0 min) compared with the control group.

CONCLUSIONS

The matched-pair cohort analyses revealed no significant differences in postoperative complications after breast cancer surgery between patients with and without RRT. Breast cancer surgery in patients with RRT may be as safe as that in patients without RRT, if comorbidities other than chronic renal failure are adequately addressed.

Early Electroconvulsive Therapy in Patients With Major Depressive Disorder: A Propensity Score-Matched Analysis Using a Nationwide Inpatient Database in Japan

OBJECTIVES

This study aimed to evaluate whether early electroconvulsive therapy (ECT) can reduce length of hospital stay and total hospitalization costs in major depressive disorder (MDD) patients.

METHODS

Using the Japanese Diagnosis Procedure Combination inpatient database from April 2011 to March 2018 linked with the Annual Report for Functions of Medical Institutions, we identified patients admitted for MDD. Patients who received ECT within 8 days of admission were assigned to the early ECT group and the remaining patients to the control group. The primary outcomes were length of hospital stay and total hospitalization costs. The secondary outcomes were in-hospital mortality and fatal adverse events. Propensity score-matched analyses were performed to compare the outcomes between the 2 groups.

RESULTS

We identified 41,248 eligible patients, comprising 1169 in the early ECT group and 40,079 in the control group. After 1:1 propensity score matching, patients in the early ECT group had significantly shorter length of hospital stay than those in the control group (difference: -12.6 days; 95% confidence interval: -17.4 to -7.7 days). There was no significant difference in total hospitalization costs between the 2 groups. Early ECT was not significantly associated with increased in-hospital mortality or fatal adverse events.

CONCLUSIONS

Early ECT may reduce length of hospital stay without increasing total hospitalization costs or fatal adverse events in patients with MDD.

Validity of initial cancer diagnoses in the Diagnosis Procedure Combination data in Japan

BACKGROUND

In Japan, the Diagnosis Procedure Combination (DPC) data have been used as a nationwide administrative hospital discharge database for clinical studies. However, few studies have evaluated the validity of recorded diagnoses of cancer in the database.

METHODS

We compared the DPC data with hospital-based cancer registries in Osaka Prefecture, Japan to assess the validity of the recorded cancer diagnoses in the DPC data. Fifteen types of cancer were included in the analysis. Cancer stage with tumor-node-metastasis (TNM) classification was assessed for eight cancer types with >400 patients. We evaluated concordance and positive predictive value of cancer diagnosis, and concordance of cancer stage between the DPC data and the hospital-based cancer registry.

RESULTS

In total, we identified 29,180 eligible patients. The five types of cancer with the highest number of patients were as follows: 6,765 (23.2 %) colorectal, 6,476 (22.2 %) stomach, 4,862 (16.7 %) breast, 4,445 (15.2 %) lung, and 2,257 (7.7 %) liver. Concordance of diagnosis ranged from 63.9 %-99.5 %, and twelve of the fifteen types of cancers had concordance of over 90 %. Positive predictive values of diagnosis ranged from 86.8 %-100 %. Regarding cancer stage, the overall degree of concordance was 67.2 % in all patients and the concordance was over 70 % in four types of cancers.

CONCLUSIONS

The DPC data had high validity of cancer diagnosis. However, the potential impact of the misclassifications and low concordance in cancer stage among specific type of cancers in the DPC data should be considered.

Risk factors for early in-hospital death in patients who developed coagulopathy during induction therapy for acute promyelocytic leukemia: a nationwide analysis in Japan

To prevent early death, management of coagulopathy is important in patients with untreated acute promyelocytic leukemia (APL). This study aimed to clarify factors associated with in-hospital death in patients with coagulopathy during induction therapy for APL. We retrospectively identified patients with newly diagnosed APL who received induction therapy including all-trans retinoic acid (ATRA) and developed coagulopathy, using a nationwide inpatient database in Japan. Of 1115 eligible patients, 175 (15%) died at a median of 13 days (interquartile range, 7-30) after admission. In the multivariable analysis, compared with younger patients (aged < 40 years), the occurrence of in-hospital death was significantly more common among older patients (aged ≥ 40 and < 60 years: odds ratio = 2.58 [95% confidence interval: 1.29-5.19]; aged ≥ 60 and < 80 years: 7.66 [3.89-15.10]; aged ≥ 80 years: 16.83 [7.41-38.21]). Delayed initiation of ATRA and no conventional chemotherapy were significantly associated with in-hospital death (1.79 [1.16-2.76] and 2.40 [1.47-3.92], respectively). A total of 699 patients (63%) received anticoagulant therapies, but none of these was significantly associated with lower mortality. Although the present study was constrained by a lack of laboratory findings because of database limitations, the results showed that untreated patients with APL, especially the elderly, had a poor prognosis. Immediate administration of ATRA may reduce in-hospital mortality.

Variations in hip fracture inpatient care in Japan, Korea, and Taiwan: an analysis of health administrative data

BACKGROUND

Little is known about hip fracture inpatient care in East Asia. This study examined the characteristics of patients, hospitals, and regions associated with delivery of hip fracture surgeries across Japan, Korea, and Taiwan. We also analyzed and compared how the resource use and a short-term outcome of the care in index hospitals varied according to factors in the respective health systems.

METHODS

We developed comparable, nationwide, individual-level health insurance claims datasets linked with hospital- and regional-level statistics across the health systems using common protocols. Generalized linear multi-level analyses were conducted on length of stay (LOS) and total cost of index hospitalization as well as inpatient death.

RESULTS

The majority of patients were female and aged 75 or older. The standardized LOS of the hospitalization for hip fracture surgery was 32.5 (S.D. = 18.7) days in Japan, 24.7 (S.D. = 12.4) days in Korea, and 7.1 (S.D. = 2.9) days in Taiwan. The total cost per admission also widely varied across the systems. Hospitals with a high volume of hip fracture surgeries had a lower LOS across all three systems, while other factors associated with LOS and total cost varied across countries.

CONCLUSION

There were wide variations in resource use for hip fracture surgery in the index hospital within and across the three health systems with similar social health insurance schemes in East Asia. Further investigations into the large variations are necessary, along with efforts to overcome the methodological challenges of international comparisons of health system performance.

Intravenous cyclophosphamide in acute exacerbation of rheumatoid arthritis-related interstitial lung disease: A propensity-matched analysis using a nationwide inpatient database

OBJECTIVES

We aimed to investigate the effect of intravenous cyclophosphamide (CYC) as the initial therapy in patients with acute exacerbation of rheumatoid arthritis-related interstitial lung disease.

METHODS

This was a retrospective observational study. Using the Japanese Diagnosis Procedure Combination inpatient database from July 2010 to March 2018, we identified patients with acute exacerbation of rheumatoid arthritis-related interstitial lung disease (RA-ILD) who received high-dose methylprednisolone within 3 days after admission. RA-ILD was defined as having either the diagnosis of RA-ILD or the diagnoses of both RA and ILD, based on the ICD-10 codes recorded by attending physicians. Patients were divided into two groups: those receiving intravenous CYC within 3 days after admission (CYC group) and those who did not (control group). One-to-four propensity-score matching analyses were performed.

RESULTS

A total of 6130 eligible patients were included. After propensity score matching, 129 patients in the CYC group and 516 patients in the control group were further analyzed. 90-day in-hospital mortality, defined as all-cause mortality during hospitalization within 90 days after admission, was not significantly different between the CYC and control groups (50.4% versus 42.2%, hazard ratio 1.20, 95% confidence interval 0.91-1.58). A larger proportion of patients in the CYC group received platelet transfusion than that in the control group (7.0% versus 2.3%, odds ratio 3.05, 95% confidence interval 1.20-7.73).

CONCLUSION

In this retrospective database study, the initial therapy with CYC did not show a survival benefit in patients with acute exacerbation of RA-ILD. CYC was associated with a larger proportion of platelet transfusion.

Body mass index and in-hospital mortality in patients with acute exacerbation of idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterised by chronic fibrosis, and acute exacerbation of IPF (AE-IPF) is the leading cause of death in patients with IPF. Data on the association between the body mass index (BMI) and prognosis of AE-IPF are lacking. This study was performed to evaluate the association between BMI and in-hospital mortality in patients who developed AE-IPF using a national inpatient database.

Methods

Using the Japanese Diagnosis Procedure Combination database, we retrospectively collected data of inpatients with AE-IPF from 1 July, 2010 to 31 March, 2018. We performed a multivariable logistic regression analysis to evaluate the association between all-cause in-hospital mortality and BMI, categorised as underweight (<18.5 kg·m⁻²), low-normal weight (18.5–22.9 kg·m⁻²), high-normal weight (23.0–24.9 kg·m⁻²), overweight (25.0–29.9 kg·m⁻²) and obese (≥30.0 kg·m⁻²).

Results

In total, 14 783 patients were eligible for this study. The in-hospital mortality rate was 59.0%, 55.0%, 53.8%, 54.8% and 46.0% in the underweight, low-normal weight, high-normal weight, overweight and obese groups, respectively. Underweight patients had a significantly higher mortality rate (OR 1.25, 95% CI 1.10–1.42) and obese patients had a significantly lower mortality rate (OR 0.71, 95% CI 0.54–0.94) than low-normal weight patients.

Conclusion

Among patients with AE-IPF, the underweight group had higher mortality and the obese group had lower mortality.

Among patients with acute exacerbation of idiopathic pulmonary fibrosis, underweight patients have higher mortality and obese patients lower mortalityhttps://bit.ly/3eoVMOR

Comparison of postoperative infection after emergency inguinal hernia surgery with enterectomy between mesh repair and non-mesh repair: a national database analysis

PURPOSE

Synthetic non-absorbable mesh is used for elective inguinal hernia repair but is not commonly used for incarcerated or strangulated inguinal hernia requiring enterectomy to reduce the risk of surgical-site infection. This study aimed to evaluate the safety of synthetic non-absorbable mesh repair in patients with incarcerated or strangulated inguinal hernia requiring enterectomy versus non-mesh repair.

METHODS

We analyzed patients with incarcerated or strangulated inguinal hernia with enterectomy from April 2012 to March 2017 using a nationwide inpatient database in Japan. We conducted overlap propensity score-weighted analyses to compare surgical-site infection (SSI), duration of anesthesia, antibiotic use at > 3 days after surgery, postoperative hospital stay, and 30 day readmission. Two sensitivity analyses were performed. First, we compared the proportions of patients requiring wound culture at ≥ 3 days after surgery. Second, we performed overlap propensity score-weighted logistic regression analyses for surgical-site infection.

RESULTS

We identified 668 eligible patients, comprising 223 patients with mesh repair and 445 with non-mesh repair. Overlap propensity score-weighted analyses showed no significant differences between the mesh repair and non-mesh repair groups for SSI (2.5 vs. 2.8%, P = 0.79). Secondary outcomes did not differ significantly between the groups. Proportion of wound culture at ≥ 3 days after surgery was similar in the two groups (11.1 vs. 14.6%, P = 0.18). Logistic regression analysis showed no significant association between mesh repair and SSI (odds ratio, 0.93; 95% confidence interval, 0.34-2.57).

CONCLUSION

Synthetic non-absorbable mesh use may be safe for incarcerated or strangulated inguinal hernia requiring enterectomy.

Treatments and outcomes of generalized pustular psoriasis: A cohort of 1516 patients in a nationwide inpatient database in Japan

BACKGROUND

Because generalized pustular psoriasis (GPP) is rare, there are few studies reporting treatments and outcomes for large numbers of patients.

OBJECTIVE

To report treatments and outcomes in a large cohort of patients hospitalized with GPP.

METHODS

Using a Japanese national inpatient database, we identified 1516 patients with GPP who required hospitalization between July 2010 and March 2019. We categorized patients into 3 medication groups: biologics (294 patients), oral agents without biologics (948 patients), and systemic corticosteroids only (274 patients). We investigated their characteristics, treatments, and outcomes.

RESULTS

Mean age was 66 years (interquartile range: 52-77 years). Fifty patients (3.3%) were admitted to the intensive care unit, 125 (8.2%) required blood pressure support, and 63 (4.2%) died. Patients who received biologics were younger and had fewer comorbidities. In-hospital mortality was lower in the biologics group (1.0% [biologics group] vs 3.7% [oral-agents group] vs 9.1% [corticosteroids-only group]; P < .001) as was morbidity (5.4% vs 8.2% vs 12%, respectively; P = .02). Among those who received biologics, IL-17 inhibitor use increased over time, with in-hospital mortality and morbidity comparable to those of tumor necrosis factor inhibitors.

LIMITATIONS

Retrospective study design. Some patients received multiple medications.

CONCLUSION

Biologic treatments showed favorable outcomes compared with other treatments.

Prognosis and treatment of myositis-associated severe interstitial lung disease: A descriptive study using a nation-wide inpatient database in Japan

OBJECTIVES

The aim of this study was to determine the prognosis, clinical course, and current management of severe interstitial lung disease (ILD) associated with myositis in Japan.

METHODS

We conducted a retrospective descriptive study using a nation-wide database for inpatient care of acute illness in Japan. Among a total of approximately 66 million inpatient admissions, we identified patients with severe ILD associated with polymyositis (PM) or dermatomyositis (DM) which required mechanical ventilation and methylprednisolone pulse therapy (≥1g/day usage of methylprednisolone) from July 2010 to March 2018.

RESULTS

We identified 155 patients with PM and 394 with DM who fulfilled the above criteria. The median age of patients was 65 years old; DM patients were significantly younger than PM patients (64 vs. 68 years old; p<0.001). The numbers of patients who were treated with calcineurin inhibitors, intravenous cyclophosphamide and Polymyxin B immobilized fiber column direct hemoperfusion (PMX-DHP) were 403 (73.4%), 318 (57.9%) and 78 (14.2%), respectively. All these treatments were given significantly more frequently to the patients with DM compared with those with PM. The uses of other treatment options were much less frequent. The median hospital days of initiating methylprednisolone pulse therapy, calcineurin inhibitors, mechanical ventilation, intravenous cyclophosphamide, PMX-DHP, and in-hospital death among patients with DM were 2, 4, 7, 8, 17, and 36, respectively. In-hospital mortality was significantly higher in patients with DM than in those with PM (76.6% vs. 56.8%, p<0.001).

CONCLUSION

The mortality of patients with myositis-associated severe ILD that requires mechanical ventilation is extremely high despite aggressive and prompt interventions.