Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Ataru Igarashi is active.

Publication


Featured researches published by Ataru Igarashi.


American Journal of Geriatric Pharmacotherapy | 2010

Potentially inappropriate medication use in elderly Japanese patients

Manabu Akazawa; Hirohisa Imai; Ataru Igarashi; Kiichiro Tsutani

BACKGROUND Modified Beers criteria for elderly Japanese patients were developed in 2008 by consensus among 9 experts to reflect regional clinical practice and available medications in Japan. Since then, many physicians and pharmacists have expressed interest in obtaining more information about the criteria and alternative drug choices. OBJECTIVE This study examined the incidence, health care utilization, and costs associated with potentially inappropriate medications (PIMs) in elderly patients based on the modified Beers criteria. METHODS A retrospective, observational cohort study was conducted using health insurance claims data in Japan. The study population included elderly patients aged >or=65 years who had at least 2 pharmacy claims in separate months over a 1-year period (April 2006 through March 2007). Use of the PIMs was identified using the modified criteria, and 1-year incidence rates were calculated for the total study population and for subgroups stratified by age and sex. A logistic regression model was used to examine demographic and clinical characteristics associated with PIMs. Health care utilization rates and costs were also analyzed and compared between patients with and without PIMs using generalized linear models. All models included dummy variables indicating age category, female sex, hospitalization, polypharmacy, index month, and number of Elixhauser comorbidities to adjust for potential confounders. RESULTS Among 6628 elderly patients, 71.2% (4721/6628) were female and 62.9% (4167/6628) were aged 65 to 74 years; 43.6% (2889/6628) were prescribed at least one PIM. The most commonly used PIMs were histamine-2 blockers (20.5% [1356/6628]), benzodiazepines (11.4% [756/6628]), and anticholinergics and antihistamines (7.9% [526/6628]). No significant differences in incidence rates were observed based on age or sex. Inpatient service use, polypharmacy, and comorbidities of peptic ulcer, depression, and cardiac arrhythmias were significant predictors of PIM use while controlling for other factors. PIM users had significantly higher hospitalization risk (1.68-fold), more outpatient visit days (1.18-fold), and higher medical costs (33% increase) than did nonusers. CONCLUSIONS In a group of elderly Japanese patients, 43.6% used at least one PIM over a 1-year period in this study. PIM use was associated with greater health care utilization rates and costs.


Cost Effectiveness and Resource Allocation | 2013

WTP for a QALY and health states: More money for severer health states?

Takeru Shiroiwa; Ataru Igarashi; Takashi Fukuda; Shunya Ikeda

BackgroundIn economic evaluation, cost per quality-adjusted life year (QALY) is generally used as an indicator for cost-effectiveness. Although JPY 5 million to 6 million (USD 60, 000 to 75,000) per QALY is frequently referred to as a threshold in Japan, do all QALYs have the same monetary value?MethodsTo examine the relationship between severity of health status and monetary value of a QALY, we obtained willingness to pay (WTP) values for one additional QALY in eight patterns of health states. We randomly sampled approximately 2,400 respondents from an online panel. To avoid misunderstanding, we randomly allocated respondents to one of 16 questionnaires, with 250 responses expected for each pattern. After respondents were asked whether they wanted to purchase the treatment, double-bounded dichotomous choice method was used to obtain WTP values.ResultsThe results clearly show that the WTP per QALY is higher for worse health states than for better health states. The slope was about JPY −1 million per 0.1 utility score increase. The mean and median WTP values per QALY for 16 health states were JPY 5 million, consistent with our previous survey. For respondents who wanted to purchase the treatment, WTP values were significantly correlated with household income.ConclusionThis survey shows that QALY based on the EQ-5D does not necessarily have the same monetary value. The WTP per QALY should range from JPY 2 million (USD 20,000) to JPY 8 million (USD 80,000), corresponding to the severity of health states.


Patient Education and Counseling | 2015

Relationship between health literacy, health information access, health behavior, and health status in Japanese people

Machi Suka; Takeshi Odajima; Masako Okamoto; Masahiko Sumitani; Ataru Igarashi; Hirono Ishikawa; Makiko Kusama; Michiko Yamamoto; Takeo Nakayama; Hiroki Sugimori

OBJECTIVE To examine the relationship between health literacy (HL), health information access, health behavior, and health status in Japanese people. METHODS A questionnaire survey was conducted at six healthcare facilities in Japan. Eligible respondents aged 20-64 years (n=1218) were included. Path analysis with structural equation modeling was performed to test the hypothesis model linking HL to health information access, health behavior, and health status. RESULTS The acceptable fitting model indicated that the pathways linking HL to health status consisted of two indirect paths; one intermediated by health information access and another intermediated by health behavior. Those with higher HL as measured by the 14-item Health Literacy Scale (HLS-14) were significantly more likely to get sufficient health information from multiple sources, less likely to have risky habits of smoking, regular drinking, and lack of exercise, and in turn, more likely to report good self-rated health. CONCLUSION HL was significantly associated with health information access and health behavior in Japanese people. HL may play a key role in health promotion, even in highly educated countries like Japan. PRACTICE IMPLICATIONS In order to enhance the effects of health promotion interventions, health professionals should aim at raising HL levels of their target population groups.


PharmacoEconomics | 2009

Cost-Utility Analysis of Varenicline, an Oral Smoking-Cessation Drug, in Japan

Ataru Igarashi; Hiroki Takuma; Takashi Fukuda; Kiichiro Tsutani

AbstractObjectives: To conduct a cost-utility analysis of two 12-week smoking-cessation interventions in Japan: smoking-cessation counselling by a physician compared with use of varenicline, an oral smoking-cessation drug, in addition to counselling.Methods: A Markov model was constructed to analyse lifetimemedical costs and QALYs from the perspective of the healthcare payer. The cycle length was 5 years. Both costs and QALYs were discounted at 3% annually. The cohort of smokers was classified by sex and age, and we assumed that smokers started smoking at the age of 20 years and received smoking-cessation therapy at the ages of 30, 40, 50, 60 or 70 years (five separate models were run). The healthcare costs and QALYs were calculated throughout the term until the age of 90 years.In the base-case analysis, success rates of varenicline plus counselling and counselling alone were assumed to be 37.9% and 25.5%, respectively, in male smokers, and 22.2% and 16.1%, respectively, in female smokers, based on a randomized controlled trial conducted in Japan. Both univariate and probabilistic sensitivity analyses were conducted.Results: Prescribed varenicline was shown to be more effective and less costly than smoking-cessation counselling alone. Varenicline would save direct medical costs of Japanese Yen (¥)43 846 (


Value in Health | 2016

Comparison of Value Set Based on DCE and/or TTO Data: Scoring for EQ-5D-5L Health States in Japan

Takeru Shiroiwa; Shunya Ikeda; S. Noto; Ataru Igarashi; Takashi Fukuda; Shinya Saito; Kojiro Shimozuma

US381;


PLOS ONE | 2014

Validity and Reliability of the Japanese Version of the Newest Vital Sign: A Preliminary Study

Takamichi Kogure; Masahiko Sumitani; Machi Suka; Hirono Ishikawa; Takeshi Odajima; Ataru Igarashi; Makiko Kusama; Masako Okamoto; Hiroki Sugimori; Kazuo Kawahara

US1= ¥115; Oct 2007) and generate an increase of 0.094 QALYs in male smokers. In females the incremental costeffectiveness ratio was ¥346 143 per QALY gained. Varenicline is estimated to save ¥23.7 billion (


International Heart Journal | 2016

Comparative Effectiveness of Oral Medications for Pulmonary Arterial Hypertension

Ataru Igarashi; Sachie Inoue; Tomonori Ishii; Kiichiro Tsutani; Hiroshi Watanabe

US206 million) of the medical costs for tobacco-associated diseases for the whole population. Overall savings are ¥9.5 billion. Sensitivity analyses suggested the robustness of the results.Conclusion: As with any data of this nature, there is some uncertainty in the results and further research is warranted. However, based on the results of this pharmacoeconomic evaluation, varenicline, the first non-nicotine, oral treatment developed for smoking cessation, appears to be cost effective andmay contribute to future medical cost savings in Japan.


Journal of Medical Economics | 2016

Cost-effectiveness of direct-acting antiviral regimen ombitasvir/paritaprevir/ritonavir in treatment-naïve and treatment-experienced patients infected with chronic hepatitis C virus genotype 1b in Japan

Suchin Virabhak; Kikuo Yasui; Kiyotaka Yamazaki; Scott Johnson; Dominic Mitchell; Cammy Yuen; Jennifer C. Samp; Ataru Igarashi

BACKGROUND The valuation study of the five-level version of the EuroQol five-dimensional questionnaire (EQ-5D-5L) involved composite time trade-off (cTTO) and a discrete choice experiment (DCE). The DCE scores must be anchored to the quality-of-life scale from 0 (death) to 1 (full health). Nevertheless, the characteristics of the statistical methods used for converting the EQ-5D-5L DCE results by using TTO information are not yet clearly known. OBJECTIVES To present the Japanese DCE value set of the EQ-5D-5L and compare three methods for converting latent DCE values. METHODS The survey sampled the general population at five locations in Japan. 1098 respondents were stratified by age and sex. To obtain and compare the value sets of the EQ-5D-5L, the cTTO and DCE data were analyzed by a linear mixed model and conditional logit, respectively. The DCE scores were converted to the quality-of-life scale by anchoring to the worst state using cTTO, mapping DCE onto cTTO, and a hybrid model. RESULTS The data from 1026 respondents were analyzed. All the coefficients in the cTTO and DCE value sets were consistent throughout all the analyses. Compared with the cTTO algorithm, the mapping and hybrid methods yielded very similar scoring coefficients. The hybrid model results, however, produced a lower root mean square error and fewer health states with errors exceeding 0.05 than did the other models. The DCE anchored to the worst state overestimated the cTTO scores of almost all the health states. CONCLUSIONS Japanese value sets based on DCE were demonstrated. On comparing the observed cTTO scores, we found that the hybrid model was slightly superior to the simpler methods, including the TTO model.


Applied Health Economics and Health Policy | 2016

Cost-Effectiveness Analysis of Smoking Cessation Interventions in Japan Using a Discrete-Event Simulation

Ataru Igarashi; Rei Goto; Kiyomi Suwa; Reiko Yoshikawa; Alexandra J. Ward; Jörgen Moller

Health literacy (HL) refers to the ability to obtain, process, and understand basic health information and services, and is thus needed to make appropriate health decisions. The Newest Vital Sign (NVS) is comprised of 6 questions about an ice cream nutrition label and assesses HL numeracy skills. We developed a Japanese version of the NVS (NVS-J) and evaluated the validity and reliability of the NVS-J in patients with chronic pain. The translation of the original NVS into Japanese was achieved as per the published guidelines. An observational study was subsequently performed to evaluate the validity and reliability of the NVS-J in 43 Japanese patients suffering from chronic pain. Factor analysis with promax rotation, using the Kaiser criterion (eigenvalues ≥1.0), and a scree plot revealed that the main component of the NVS-J consists of three determinative factors, and each factor consists of two NVS-J items. The criterion-related validity of the total NVS-J score was significantly correlated with the total score of Ishikawa et al.s self-rated HL Questionnaire, the clinical global assessment of comprehensive HL level, cognitive function, and the Brinkman index. In addition, Cronbachs coefficient for the total score of the NVS-J was adequate (alpha = 0.72). This study demonstrated that the NVS-J has good validity and reliability. Further, the NVS-J consists of three determinative factors: “basic numeracy ability,” “complex numeracy ability,” and “serious-minded ability.” These three HL abilities comprise a 3-step hierarchical structure. Adequate HL should be promoted in chronic pain patients to enable coping, improve functioning, and increase activities of daily living (ADLs) and quality of life (QOL).


Modern Rheumatology | 2015

Postoperative complications in patients with rheumatoid arthritis using a biological agent - A systematic review and meta-analysis

Hiromu Ito; Masayo Kojima; Keiichiro Nishida; Isao Matsushita; T. Kojima; Takeo Nakayama; Hirahito Endo; Shintaro Hirata; Yuko Kaneko; Yutaka Kawahito; Mitsumasa Kishimoto; Yohei Seto; Naoyuki Kamatani; Kiichiro Tsutani; Ataru Igarashi; Mieko Hasegawa; Nobuyuki Miyasaka; Hisashi Yamanaka

Pulmonary arterial hypertension (PAH) is a disease that imposes a significant burden on patients. Although multiple treatment options for PAH are available, head-to-head comparisons are difficult to conduct. Network meta-analysis (NMA) can be a useful alternative for direct comparison to estimate the relative effectiveness of multiple treatments. The objective of the present study was to conduct a systematic review and NMA to evaluate the relative effectiveness among oral PAH medications.Data collection was performed by searching the Cochrane Central Register of Controlled Trials (CENTRAL) and Ichushi-Web. Randomized controlled trials (RCTs) assessing at least 1 of the following 3 outcome measurements; 6-minute walk distance test (6MWD), WHO functional class (WHOFC), and mean pulmonary artery pressure (mPAP) were included (PROSPERO registration number: CRD42015016557). Outcomes were evaluated by estimating the differences in the mean change from baseline or by estimating the odds ratios. Analyses were performed using WinBUGS 1.4.3.Seven double-blind RCTs were eligible. NMA results showed similar improvements in 6MWD for all medications assessed. Bosentan and sildenafil caused a statistically significant improvement in WHOFC compared to other medications.The relative effectiveness of oral PAH medications could be compared using NMA, which suggested the superiority of bosentan and sildenafil in the improvement of WHOFC.

Collaboration


Dive into the Ataru Igarashi's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Shunya Ikeda

International University of Health and Welfare

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

S. Noto

Niigata University of Health and Welfare

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge