Identification of asthma cases in Japan using health insurance claims data: Positive and negative predictive values of proposed discrimination criteria: A single-center study.

BACKGROUND: Asthma cases have been increasingly investigated using claims data. However, the validity of defining asthma cases using health insurance claims in Japan is unclear. This study aims to assess the positive and negative predictive values of our proposed discrimination criteria for asthma. METHODS: We developed discrimination criteria for asthma based on both the International Statistical Classification of Diseases and Related Health Problems (ICD)-10 disease codes for asthma and health insurance claims data for prescriptions and the treatment of asthma. Inclusion criteria were patients aged ≥16 years with at least one health insurance claim from April 2018 to March 2019 in all departments of our hospital. Physician-diagnosed asthma documented in the charts was used as the reference standard. Positive and negative predictive values of the discrimination criteria for physician-diagnosed asthma were estimated and compared with those estimated from discrimination criteria based solely on ICD-10 codes. RESULTS: The new discrimination criteria had a high positive predictive value (PPV) of 86.0%, which was significantly higher than the PPV for the criteria defined solely by the ICD-10 codes (61.5%) (P < 0.01). The negative predictive values for both criteria were 100%. Allergic rhinitis and chronic cough were frequently misclassified as asthma using the discrimination criteria based solely on ICD-10 codes but were more likely to be appropriately classified using our proposed criteria. CONCLUSIONS: Our proposed criteria adequately identified asthma subjects using health insurance claims data in Japan with a high PPV. Further studies are needed for external validation of these criteria.

Current Status of Catheter Ablation for Atrial Fibrillation in Japan.

Catheter ablation for atrial fibrillation (AF) has been an established and frequently utilized approach in a variety of clinical settings. Nevertheless, real-world data about the clinical course of AF patients after initial catheter ablation remain limited, and these are mainly derived from particular registries or selected high-volume centers.In this study, we used health check-ups and insurance claims database from a Japanese insurance organization. The study population was comprised of 1777 patients who underwent catheter ablation for AF before June 2016. During the 3-year follow-up period, 396 (22.3%) patients underwent at least one repeated AF ablation, while 74 (4.2%) underwent two or more repeated ablations. In multivariate Cox regression analysis, longer time after AF diagnosis (7-11 months and ≥12 months versus 1-6 months) (HR, 1.05; 95% CI, 1.01-1.08 and HR, 1.04; 95% CI 1.02-1.07) was independently associated with repeated ablation. The discontinuation rates of OACs and AADs after the first ablation were 26.7% and 63.0% at 3 months and 75.2% and 89.1% at 1 year after the initial ablation, respectively. The former was independently associated with shorter time after AF diagnosis and lower diastolic blood pressure, whereas the latter was independently associated with older age, smaller CHADS2 score, and shorter time after AF diagnosis.We presented real-world data regarding the clinical course of young Japanese AF patients after initial catheter ablation based on a claims database in Japan.

Effects of the concentration of digestive surgical operations in regional Japan.

PURPOSE: The purpose of this study was to investigate the relationship between the concentration of digestive system surgery and outcomes at a regional level in Japan, using time-series data. METHODS: We used nationwide data from 2008 to 2013, and analyzed the ten most common surgical procedures. The unit of analysis was secondary medical areas (SMAs), which cover several municipalities and provide medical services for common diseases. The concentration of surgery in these areas was measured using the Herfindahl-Hirschman Index (HHI) and the relationship between the concentration of surgery and length of stay in hospital (LOS) was analyzed, in accordance with surgical difficulty. RESULTS: There was a downward trend in both the HHI and LOS from 2008 to 2013. SMAs showing an upward trend in the HHI (increased concentration) were associated with a greater reduction in LOS than those showing a downward trend for eight surgical procedures. For three easy surgical procedures, increased concentration of surgery was significantly associated with a reduction in LOS. After adjustment for trends in the aging population and the surgical volume in 2008, an increasing concentration for three easy surgical procedures was significantly related to a reduction in the LOS. CONCLUSION: Concentrating relatively easy surgical procedures at a regional level may be associated with a reduction in LOS.

Development of algorithms for identifying patients with Crohn's disease in the Japanese health insurance claims database.

BACKGROUND: Real-world big data studies using health insurance claims databases require extraction algorithms to accurately identify target population and outcome. However, no algorithm for Crohn's disease (CD) has yet been validated. In this study we aim to develop an algorithm for identifying CD using the claims data of the insurance system. METHODS: A single-center retrospective study to develop a CD extraction algorithm from insurance claims data was conducted. Patients visiting the Kitasato University Kitasato Institute Hospital between January 2015-February 2019 were enrolled, and data were extracted according to inclusion criteria combining the Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) diagnosis codes with or without prescription or surgical codes. Hundred cases that met each inclusion criterion were randomly sampled and positive predictive values (PPVs) were calculated according to the diagnosis in the medical chart. Of all cases, 20% were reviewed in duplicate, and the inter-observer agreement (Kappa) was also calculated. RESULTS: From the 82,898 enrolled, 255 cases were extracted by diagnosis code alone, 197 by the combination of diagnosis and prescription codes, and 197 by the combination of diagnosis codes and prescription or surgical codes. The PPV for confirmed CD cases was 83% by diagnosis codes alone, but improved to 97% by combining with prescription codes. The inter-observer agreement was 0.9903. CONCLUSIONS: Single ICD-code alone was insufficient to define CD; however, the algorithm that combined diagnosis codes with prescription codes indicated a sufficiently high PPV and will enable outcome-based research on CD using the Japanese claims database.

Current status of oral anticoagulant adherence in Japanese patients with atrial fibrillation: A claims database analysis.

BACKGROUND: Direct oral anticoagulants (DOACs) are widely used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). We investigated the adherence of DOACs for years known to be associated with the effectiveness in Japanese NVAF patients, using a claim database. METHOD: We performed a retrospective evaluation of NVAF patients in a claims database in Japan, who initiated dabigatran, rivaroxaban, and apixaban between April 2011 and June 2016. Drug persistence was assessed by Kaplan-Meier method for the initially-prescribed DOAC and all DOACs including switched ones. Proportion of days covered (PDC) was also evaluated in patients with persistent prescription and compared among DOACs. RESULTS: In the total of 671 patients, rivaroxaban (47%) was more prescribed than dabigatran (28%) and apixaban (25%). Drug persistence at 3 years was higher in rivaroxaban (69%) than dabigatran (57%) and apixaban (67%). Including switching to other DOACs, persistence of DOACs was 72% at 3 years without significant differences between index-DOACs. In multivariate Cox regression analysis, absence of hypertension, and prior history of cancer were significantly associated with the drug discontinuation of all DOACs. The mean PDC was ~ 95% and the frequency of high-adherent patients (PDC ≥0.80) was more than 90%, which similarly persisted at 3 years and showed no significant differences between index DOACs. CONCLUSION: In a real-world Japanese claim data analysis, about 70% of patients under DOAC showed persistence with anticoagulation therapy at 3 years. High adherence to DOACs assessed by PDC (over 90%) persisted to 3 years regardless of the types of DOACs.