Comparison between high and low potency statins in the incidence of open-angle glaucoma: A retrospective cohort study in Japanese working-age population.

Some findings on the association between glaucoma and statins in the Asian population have been reported. We conducted a retrospective cohort study using health insurance claims data maintained by the JMDC Inc., which comprises data on about three million individuals representing 2.4% of the Japanese population. The association between the potency of statins and open-angle glaucoma in Japanese working-age population was examined using a commercially available health insurance claims and enrollment database. We identified 117,036 patients with a prescription of statins between January 1, 2005 and March 31, 2014; 59,535 patients were selected as new statin users. Of these, 49,671 (83%) patients without glaucoma who were prescribed statins for the first time were part of the primary analysis. New users of statin were defined as those with a prescription of statin at the beginning of the study, but without a prescription six months earlier. The cohort comprised 29,435 (59%) and 20,236 (41%) patients with a prescription of high-potency statin (atorvastatin and rosuvastatin) and low-potency statin (pravastatin, fluvastatin, pitavastatin, and simvastatin), respectively. Using Cox proportional hazards regression analysis, hazard ratios (HRs) were estimated for glaucoma adjusted for baseline characteristics. Although some baseline characteristics were not similar between the high-potency and low-potency statin groups, the standardized difference for all covariates was less than 0.1. No associations were found between high-potency statin use and glaucoma (adjusted HR = 1.08; 95% confidence interval, 0.93-1.24) in the primary analyses, using the risk for glaucoma in the low-potency statin group as reference. The risk of glaucoma with individual statin use was not significantly different from that with pravastatin. No significant association was found between high-potency statins and the increased risk of glaucoma in Japanese working-age population. Further studies are needed to examine the association between statins and glaucoma in the elderly population.

Frequency of Clinical Monitoring of Serum Concentrations of Digoxin, Potassium, and Creatinine, and Recording of Electrocardiograms in Digoxin-Treated Patients: A Japanese Claims Database Analysis.

Guidelines for cardiovascular drug therapy recommend monitoring serum digoxin concentration (SDC) in patients receiving digoxin treatment, especially those with renal dysfunction and hypokalemia. However, only a few studies have reported the prevalence of SDC monitoring and laboratory testing in clinical practice. Therefore, the aim of this study was to describe the frequency of SDC monitoring and laboratory testing in digoxin users and to assess the association between SDC monitoring and patient characteristics. We used the Japanese insurance claims data covering approximately 1.7 million patients aged 20-74 years between January 1, 2005 and March 31, 2014. All patients who had at least one prescription for digoxin were included. The frequency of SDC and laboratory tests was calculated and the association between patient characteristics and SDC monitoring was assessed using logistic regression analysis. A total of 98867 prescriptions of digoxin were issued to 3458 patients between 2005 and 2014. The annual mean frequencies of monitoring SDC, serum potassium level and serum creatinine level and of recording electrocardiograms was 16.8, 34.8, 38.7, and 24.1%, respectively. Atrial fibrillation, chronic heart failure, renal diseases, and use of oral anticoagulants were associated with SDC monitoring. We found the frequency of SDC monitoring to be relatively low in Japanese clinical practice.

Drug Prescriptions for Children With ADHD in Japan: A Study Based on Health Insurance Claims Data Between 2005 and 2015.

Objective: The aim of this study is to investigate the trend of prescription drugs for children with ADHD in Japan. Method: Using health insurance claims data of 3,672,951 people between January 2005 and December 2015, we investigated the trend of prescription drugs for 7,856 children with ADHD. Results: After approval in 2007, the proportion of prescriptions for methylphenidate-osmotic-controlled release oral delivery system tablets was 31.4% in 2009 (adjusted odds ratio [AOR] = 2.72; 95% confidence interval [CI] = [2.12, 3.51]) and reached a plateau approximately after 2009 (AOR = 0.96; 95% CI = [0.94, 0.98]). The proportion of prescriptions for atomoxetine increased from 6.1% in 2008 to 21.8% in 2014 (AOR = 1.12; 95% CI = [1.13, 1.18]). The proportion of prescriptions for aripiprazole and ramelteon increased (all trend p < .001). Conclusion: Prescriptions of drugs for children with ADHD have changed. We need to monitor the safety of ADHD medications among children with ADHD.

Positive predictive value of ICD-10 codes for acute myocardial infarction in Japan: a validation study at a single center.

BACKGROUND: In Japan, several large healthcare databases have become available for research since the early 2000's. However, validation studies to examine the accuracy of these databases remain scarce. We conducted a validation study in order to estimate the positive predictive value (PPV) of local or ICD-10 codes for acute myocardial infarction (AMI) in Japanese claims. In particular, we examined whether the PPV differs between claims in the Diagnosis Procedure Combination case mix scheme (DPC claims) and in non-DPC claims. METHODS: We selected a random sample of 200 patients from all patients hospitalized at a large tertiary-care university hospital between January 1, 2009 and December 31, 2011 who had an inpatient claim assigned a local or ICD-10 code for AMI. We used a standardized data abstraction form to collect the relevant information from an electronic medical records system. Abstracted information was then categorized by a single cardiologist as being either definite or not having AMI. RESULTS: In a random sample of 200 patients, the average age was 67.7 years and the proportion of males was 78.0%. The PPV of the local or ICD-10 code for AMI was 82.5% in this sample of 200 patients. Further, of 178 patients who had an ICD-10 code for AMI based on any of the 7 types of condition codes in the DPC claims, the PPV was 89.3%, whereas of the 161 patients who had an ICD-10 code for AMI based on any of 3 major types of condition codes in the DPC claims, the PPV was 93.8%. CONCLUSION: The PPV of the local or ICD-10 code for AMI was high for inpatient claims in Japan. The PPV was even higher for the ICD-10 code for AMI for those patients who received AMI care through the DPC case mix scheme. The current study was conducted in a single center, suggesting that a multi-center study involving different types of hospitals is needed in the future. The accuracy of condition codes for DPC claims in Japan may also be worth examining for conditions other than AMI such as stroke.

The use of anticoagulants in patients with non-valvular atrial fibrillation between 2005 and 2014: A drug utilization study using claims data in Japan.

BACKGROUND: Anticoagulant therapy is recommended in patients with atrial fibrillation (AF) but remains underused. The proper use of anticoagulants has been encouraged in guidelines frequently published over the past two decades. MATERIALS AND METHODS: In this study, we used insurance claims data collected from 2005 to 2014 to investigate the prevalence and incidence of non-valvular AF (NVAF) patients aged 20 to 74 years standardized to the Japanese population in 2012 and subdivided by stroke prevention drug type. We estimated the frequency of coagulation monitoring in patients with incident NVAF undergoing warfarin therapy in 2011 and later. RESULTS: From 2005 to 2014, the standardized prevalence of NVAF increased from 117/100,000 to 278/100,000 and the proportion of anticoagulant users increased from 38.4% to 58.0%, while that of antiplatelet monotherapy decreased from 32.3% to 12.0%. The standardized incidence of NVAF was stable at ~40/100,000 patient-years. The proportion of those patients who started anticoagulant soon after the initial diagnosis increased from 19.9% to 49.1% from 2006 to 2013. Among patients who started warfarin, switchers to DOAC had more frequent coagulation monitoring than non-switchers. CONCLUSION: The use of anticoagulant therapy has gradually increased in patients with NVAF in Japan during the study period from 2005 to 2014.

Epidemiology of psoriasis and palmoplantar pustulosis: a nationwide study using the Japanese national claims database.

OBJECTIVE: The primary objective was to estimate the national prevalence of psoriasis and palmoplantar pustulosis (PPP) in Japan. Secondary objectives were to determine (1) whether psoriasis and PPP disease activity varies by season, and (2) whether disease severity is associated with concurrent diabetes mellitus, hyperlipidaemia and hypertension. SETTINGS: Patients with a psoriasis or PPP diagnosis code between April 2010 and March 2011 were identified using a Japanese national database. PARTICIPANTS: 565 903 patients with psoriasis or PPP were identified. No patient was excluded. PRIMARY AND SECONDARY OUTCOME MEASURES: National prevalence was calculated using census data. We estimated the difference in the proportion of patients who used healthcare services, as a proxy for disease activity, between the hot and cold seasons and the difference in the standardised prevalence of comorbidities between severe and mild disease. The measures were estimated separately for the two broad disease categories of psoriasis and PPP but not in all patients as planned because the two disease categories had major differences. RESULTS: The national prevalence of psoriasis and PPP was 0.34% (95% CI 0.34% to 0.34%) and 0.12% (0.12% to 0.12%), respectively. The difference in the proportion of patients who used healthcare services in the hot compared to the cold season was -0.3% (-0.5% to -0.1%) for psoriasis and 10.0% (9.8% to 10.3%) for PPP. The difference in the standardised prevalence between severe and mild psoriasis was 3.1% (2.7% to 3.4%), 3.2% (2.8% to 3.6%) and 5.1% (4.7% to 5.6%) for concurrent diabetes mellitus, hyperlipidaemia and hypertension, respectively. No significant difference in the prevalence of comorbidity was observed for PPP. CONCLUSIONS: The national prevalence, seasonal variation in disease activity and prevalence of comorbidities in Japanese patients with psoriasis and PPP estimated in this descriptive study may be used as basic information for future studies.

Claims-based definition of death in Japanese claims database: validity and implications.

BACKGROUND: For the pending National Claims Database in Japan, researchers will not have access to death information in the enrollment files. We developed and evaluated a claims-based definition of death. METHODOLOGY/PRINCIPAL FINDINGS: We used healthcare claims and enrollment data between January 2005 and August 2009 for 195,193 beneficiaries aged 20 to 74 in 3 private health insurance unions. We developed claims-based definitions of death using discharge or disease status and Charlson comorbidity index (CCI). We calculated sensitivity, specificity and positive predictive values (PPVs) using the enrollment data as a gold standard in the overall population and subgroups divided by demographic and other factors. We also assessed bias and precision in two example studies where an outcome was death. The definition based on the combination of discharge/disease status and CCI provided moderate sensitivity (around 60%) and high specificity (99.99%) and high PPVs (94.8%). In most subgroups, sensitivity of the preferred definition was also around 60% but varied from 28 to 91%. In an example study comparing death rates between two anticancer drug classes, the claims-based definition provided valid and precise hazard ratios (HRs). In another example study comparing two classes of anti-depressants, the HR with the claims-based definition was biased and had lower precision than that with the gold standard definition. CONCLUSIONS/SIGNIFICANCE: The claims-based definitions of death developed in this study had high specificity and PPVs while sensitivity was around 60%. The definitions will be useful in future studies when used with attention to the possible fluctuation of sensitivity in some subpopulations.

Multi-country rapid adverse drug event assessment: the Asian Pharmacoepidemiology Network (AsPEN) antipsychotic and acute hyperglycaemia study.

PURPOSE: To undertake a multi-country study to investigate the risk of acute hyperglycaemia with antipsychotic use. METHODS: Using a distributed network model with a common minimal data set, we performed a prescription sequence symmetry analysis (PSSA) to investigate the risk of acute hyperglycaemia associated with antipsychotic initiation. Incident insulin prescriptions were used as a proxy indicator of acute hyperglycaemia. Participating countries and population datasets included Australia (300,000 persons), Japan I (300,000 persons), Japan II (200,000 persons), Korea (53 million persons) Taiwan (1 million persons), Sweden (9 million persons), USA-Public (87 million persons) and USA-Private (47 million persons). RESULTS: Olanzapine showed a trend towards increased risk in most databases, with a significant association observed in the USA-Public database (Adjusted sequence ratio (ASR) = 1.14; 95% Confidence Interval (CI) 1.10-1.17) and Sweden (ASR = 1.53; 95% CI 1.13-2.06). Null or negative associations were observed for haloperidol, quetiapine and risperidone. CONCLUSION: Acute hyperglycaemia appears to be associated with olanzapine use, however, this effect was only observed in two large databases. Despite different patterns of utilization of both antipsychotics and insulin, PSSA analysis results for individual antipsychotic medicines were qualitatively similar across most countries. PSSA, used in conjunction with existing methods, may provide a simple and timely method further supporting multi-national drug safety monitoring.

The impact in Japan of regulatory action on prescribing of dopamine receptor agonists: analysis of a claims database between 2005 and 2008.

BACKGROUND: Use of the ergot-derived dopamine receptor agonists (cabergoline and pergolide) is associated with an increased risk of cardiac valvulopathy. Pergolide was withdrawn from the US market in 2007 because of the risk of valvular heart disease, while the European Medicines Agency (EMA) required a reduction in the maximum daily dosage of cabergoline and pergolide from 6 mg/day to 3 mg/day in 2008. In Japan, the package inserts of both drugs were revised in April 2007 to request that physicians conduct periodic ultrasonic cardiography (UCG) examinations for patients taking cabergoline or pergolide. Also, through face-to-face communication with medical representatives of drug companies, physicians were informed that use of cabergoline and pergolide has increased the risk of valvulopathy. However, cabergoline and pergolide have remained in wide use, even following the regulatory actions. OBJECTIVE: The objective of this study was to assess the impact of actions, including the package insert revision in April 2007, to encourage periodic UCG. METHODS: Data on monthly claims (January 2005-October 2008) covering 330 000 patients were obtained from a Japanese database vendor. We selected patients ≥40 years of age with Parkinson's disease. The impact of the regulatory action on the proportion of patients with Parkinson's disease prescribed cabergoline or pergolide was assessed by segmented regression analysis and by a statistical model of the rates of UCG examination in patients taking/not taking cabergoline or pergolide before and after the action. We also compared the use of cabergoline and pergolide before and after the action with that of other antiparkinson drugs. RESULTS: Of 574 patients with Parkinson's disease, the proportion of patients prescribed cabergoline or pergolide did not decrease but rather tended to increase after the action when analysed by segmented regression analysis (p = 0.13). Similarly, the proportion of the prevalent and incident users of cabergoline or pergolide did not change between two 19-month periods before and after the action. The adjusted rates of UCG examination per person-year before and after the action were both 0.02 in those not prescribed cabergoline or pergolide, but 0.02 before the action and 0.09 after the action in those taking either drug. The excess UCG examination rate of cabergoline or pergolide attributable to the action was 0.08 per person-year (95% CI 0.03, 0.11). While 1 of 49 (2%) patients taking cabergoline or pergolide had a UCG up to 19 months before the action, 9 of 36 (25%) patients taking cabergoline or pergolide had a UCG up to 19 months after the action. Annual sales from 2004 to 2008 were 195, 195, 170, 110 and 75 billion yen, respectively, and the number of valvulopathy events, including incompetence of aortic/mitral/tricuspid valves and cardiac valve disease, per annual sales from 2004 to 2008 were estimated at 0.23, 0.03, 0.08, 0.25 and 0.19 per billion yen, respectively. CONCLUSIONS: Following the actions in April 2007, no decrease in the use of cabergoline or pergolide occurred, although more patients administered the drug underwent a UCG. However, those undergoing a UCG represented one-quarter of the total number prescribed cabergoline or pergolide. To mitigate the risk, additional risk management tools such as patient registration may be needed to secure careful clinical examination (including UCG examination, if necessary) for cardiac function.

Resolving a double standard for risk management of thalidomide: an evaluation of two different risk management programmes in Japan.

Thalidomide, once withdrawn because of its teratogenicity, has now been re-launched worldwide. In Japan, thalidomide has been imported by individual doctors since around the year 2000. In October 2008, it was approved for the treatment of multiple myeloma (MM) by the Ministry of Health, Labour and Welfare (MHLW) on the condition that the manufacturer implemented a risk management programme termed the Thalidomide Education and Risk Management System (TERMS). It is likely that the imports of thalidomide will be used off-label to treat diseases other than MM. Thus, the MHLW is also planning to introduce a web-based registration system, referred to as the Safety Management System for Unapproved Drugs (SMUD), for thalidomide imported by individual doctors. To evaluate the difference between TERMS and SMUD and establish a way to resolve the 'double standard' for risk management of thalidomide treatment in Japan. The fraction of patients with disorders other than MM was estimated by the volume of annual imports obtained from the MHLW and records of the imports for patients with MM, other oncological diseases (ODs) and non-ODs in 2007 through a major supplier covering 63% of the total imported thalidomide. The information for TERMS was obtained from web pages of the manufacturer and the MHLW. The components of TERMS were compared with those in SMUD. Provided that the distribution of the indication for thalidomide (MM) in 2007, estimated from the records of imports through the major supplier, is representative of the entire nation, it is estimated that on average 866 patients, including 851 (98.3%) with MM, are using thalidomide on any one day. However, if the major supplier's imports, which account for 63% of the total imports, are not representative of the nation as a whole, possibly only half of the patients treated with thalidomide in Japan have MM. This would be the case in a scenario where the remaining 37% of imports are exclusively used to treat disorders other than MM. TERMS consists of tools for education and registration of patients, and has the potential for real-time intervention. SMUD is a system for registration of patients and exchange of safety information between health professionals, but has some mandatory components that encourage patient registration. TERMS and SMUD are different in nature, and they impose different criteria that doctors and patients should satisfy in order to use thalidomide. To eliminate this double standard, implementation of a single system would be desirable. However, improvement of SMUD may be the second best option by developing tools for patient education, enhancing the potential for real-time intervention and monitoring thalidomide usage by each patient. On average, a total of about 1000 patients are estimated to be using thalidomide on any one day in Japan. It is likely that those patients are placed under one of two different risk management programmes. SMUD should be improved so that all patients are monitored in a way that results in a similar level of risk management.