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BACKGROUND/OBJECTIVES: Fall accidents may reduce an individual's quality of life and ability to perform the activities of daily life, and may delay recovery from illness. Consequently, medical institutions need to take measures to prevent falls. There are various risk factors for falls, including advanced age, illness and medication effects. Although hyponatremia and hypokalemia have been reported to increase the rate of falls, how they affect falls is not fully understood. SUBJECTS/METHODS: We retrospectively examined 2948 patients, ≥18 years old who had been hospitalized for [greater than or equal to]3 days at Gifu (Japan) Municipal Hospital between May 2012 and April 2013 to determine the effects of hyponatremia and hypokalemia on the risk of falls. After the patients had been divided into fall and non-fall groups, their data were subjected to univariate and multiple regression analysis to identify significant differences. RESULTS: The univariate analysis results revealed significant differences between the groups in terms of age (≥65 years); the presence of hyponatremia, hypokalemia, central nervous system disease, cardiovascular disease and/or peripheral nerve/muscular disease; intake of medications that increase the risk of falls; and increased sedative dosage. The multivariate analysis results revealed significant differences between the groups in terms of the presence of hyponatremia (odds ratio (OR), 1.751; 95% confidence interval (CI), 1.020-3.005), hypokalemia (OR, 2.209;95% CI, 1.280-3.813), central nervous system disease (OR, 2.492;95% CI, 1.629-3.814) and/or age ≥ 65 years (OR, 2.180;95% CI, 1.242-3.826). CONCLUSIONS: The results indicated that the presence of hyponatremia or hypokalemia increases the risk of falls. European Journal of Clinical Nutrition (2015) 69, 205-210; doi: 10.1038/ejcn.2014.195; published online 17 September 2014, INTRODUCTION Reported in up to 70% of all incident reports, falls among hospitalized patients account for the greatest percentage of reported in-hospital incidents. (1) Although the rate of falls varies [...]

Chemotherapy has helped prolong survival in patients with malignant lymphoma, enhancing their quality of life (QOL). Despite the eventual decline in the QOL of patients, the impact of initial chemotherapy remains poorly understood. A prospective patient-reported QOL survey among patients with malignant lymphoma receiving initial chemotherapy was conducted, targeting those treated at Gifu Municipal Hospital (Gifu, Japan) between January 2021 and December 2022. Surveys were conducted pre- and post-chemotherapy based on the EuroQol 5 dimensions. Drug costs were calculated using official prices and analyzed from the cost payer's perspective via cost-utility analysis. Among the 60 patients included in the present study, 28 had diffuse large B-cell lymphoma. Cyclophosphamide, doxorubicin, vincristine, prednisolone ± rituximab therapy was the most common treatment (38 patients) and demonstrated superior cost-effectiveness due to its lowest cost and change in utility value. Initial chemotherapy for patients with malignant lymphoma generally improved the QOL. Clinical trial registration: UMIN000042868 (registered on December 28, 2020)., Competing Interests: The authors declare that they have no competing interests., (Copyright: © 2024 Tanaka et al.)

Objective: In psychiatry, polypharmacy or high psychotropic drug doses increase adverse drug event (ADE) prevalence. However, the full relationship between polypharmacy and ADEs is unclear, and few studies have evaluated dose equivalents for psychotropic drugs for ADEs. Thus, we conducted a retrospective analysis to clarify the effects of polypharmacy and chlorpromazine (CP)-, diazepam (DAP)-, and imipramine- equivalent doses on all ADEs in inpatients., Methods: Psychiatric inpatients in a Japanese hospital from April 1, 2016 to March 31, 2018, were enrolled. ADE severity and causality were assessed. Multiple logistic regression analyses were performed to evaluate ADE risk factors., Results: Among 462 patients analyzed, out of 471 patients enrolled, 145 (31.4%) experienced ADEs. The causality assessment determined that "possible" was 96.5%. The most common ADEs were nervous system disorders (35%). Multiple logistic regression analyses indicated an increase in ADE prevalence with the number of drugs used (≥5; p = 0.026); CP-equivalent dose (p = 0.048); and endocrine, nutritional, and metabolic disorders (p = 0.045). DAP-equivalent dose; infectious and parasitic diseases; and injury, poisoning, and consequences of other external causes decreased ADE prevalence (p = 0.047, 0.022, and 0.021, respectively)., Conclusions: Avoiding polypharmacy in psychiatric inpatients and adjusting drug regimens to safe equivalent doses could reduce ADEs during hospitalization., (© 2024 John Wiley & Sons Ltd.)

Objective: This study aimed to explore the effectiveness of distributing pocket cards with summaries of key information on appropriate medication usage after the implementation of a structured school-based medication education program for junior high school students in Japan., Methods: A total of 227 3rd-grade high school students participated in the intervention. Students who received the program without the provision of pocket cards in 2022 were included in the comparison group, and students who took the program with the provision of pocket cards in 2023 were included in the intervention group. After propensity score matching, the final sample of N  = 116 comprised n  = 58 comparison group participants and n  = 58 intervention group participants. Questionnaires were administered at baseline, end-of-class, and 3-month follow-up to assess the changes in behavior, attitude, and knowledge scores., Results: The matched intervention group showed significantly lower scores at the 3-month follow-up than the matched comparison group. The results of the multiple linear regression analysis showed that for both groups, only the attitude scores were significantly correlated with the behavior scores. In addition, regardless of the baseline scores, the matched intervention group demonstrated smaller or negative changes in scores at the 3-month follow-up., Conclusion: Overall, the results of this study did not support the effectiveness of distributing pocket cards after in-class intervention. However, the usefulness of medication education intervention was confirmed. These results emphasize the need to explore other supplemental teaching tools to further enhance the impact of structured medication education programs., Competing Interests: TT is currently an Associate Editor. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Sakai, Iguchi, Tachi, Noguchi, Hisamatsu, Katsuno and Teramachi.)

No progress has been made in using remote communication tools for less urgent but equally important health support services, such as preventive medicine and health education. In this study, we developed a remote health support program by pharmacists for community residents and conducted a randomized controlled study on its effectiveness in proper self-medication through pharmacists. People over the age of 20 years who lived in the vicinity of Gifu City, Japan were eligible to participate in this study. Participants were recruited using posters and brochures. This program comprised a lecture, based on the health belief model and behavioral economics, and access to remote health support. The participants were randomly assigned to two groups: the medicine/health class only (control) and the medicine/health class along with the program (intervention) groups. The participants were administered questionnaire surveys immediately before (the first survey) and 2 months after (the second survey) the medicine/health class, which allowed us to compare the changes in the two groups' behavior regarding performing proper self-medication through pharmacists. The percentage of individuals who started consulting pharmacists about self-medication in the intervention group (63.9%, 23/36) was significantly higher than that in the control group (15.2%, 5/33; p < 0.001). The percentage of individuals who started recording information about their self-medication in their medication notebooks in the intervention group (16.7%, 6/36) was significantly higher than that in the control group (0%, 0/33; p = 0.026). We clarified the effectiveness of this program for behavioral changes toward proper self-medication using support from pharmacists.

Polypharmacy exacerbates lower urinary tract symptoms (LUTS). Japan exhibits a higher prevalence of concomitant medication use in drug therapy than other countries. Previous age- and sex-specific reports exist; however, none include patients of all ages. Therefore, this retrospective study determined the impact of polypharmacy and its associated risk factors on LUTS exacerbation in outpatients with urological conditions. We included patients receiving medication who visited the Department of Urology at the Gifu Municipal Hospital (Gifu, Japan) between January, 2018 and December, 2018. The association between LUTS and polypharmacy and the risk factors for LUTS exacerbation were investigated. Patients were categorized into two groups according to their polypharmacy status. We performed propensity score matching and compared the International Prostate Symptom Score (IPSS) between the groups using the unpaired t-test. Multiple logistic regression analysis was performed to examine the risk factors, including "polypharmacy" and "taking multiple anticholinergic medications" for LUTS exacerbation. When comparing the IPSS between the groups, the polypharmacy group was found to have significantly higher scores than the non-polypharmacy group in six items, including "total score" and "storage score." Multiple logistic regression analysis results showed high significance in three items, including "polypharmacy" (odds ratio (OR) = 1.67, 95% confidence interval (CI): 1.03-2.71) and "taking multiple anticholinergic medications" (OR = 8.68, 95% CI: 1.05-71.7). In conclusion, this study revealed that "polypharmacy" and "taking multiple anticholinergic medications" were risk factors for LUTS. Particularly, "polypharmacy" is associated with storage symptom exacerbation. Therefore, eliminating "polypharmacy" and "taking multiple anticholinergic medications" is expected to improve LUTS.

When I graduated from university, my aim was to become a pharmacist capable of recommending prescription medicines to doctors and teaching others to do the same. To achieve this goal, I developed comprehensive curricula incorporating progressive educational tools such as problem-based learning and small group discussions. Subsequently, the effectiveness of these tools and curricula was evaluated, and the findings of these assessments were published in various peer-reviewed journal articles. Consequently, a body of evidence on the most effective ways to recommend prescription medicines to doctors was gradually established. This paper aims to summarize this comprehensive body of research spanning over 43 years, with the objective of highlighting the valuable insights gained thus far, identifying the best practice techniques, and exploring potential avenues for future research.

Introduction: We aimed to compare the safety of lenvatinib as first-line treatment for unresectable hepatocellular carcinoma (HCC) in patients with Child-Pugh A (CP-A) and Child-Pugh B (CP-B) and to determine the adverse events (AEs) that cause dose reduction/interruption of treatment in patients with CP-B., Methods: Sixty-six patients with lenvatinib as a first-line treatment for HCC at Ogaki Municipal Hospital (Ogaki, Japan) between April 2018 and January 2022 were retrospectively evaluated. We analyzed the treatment duration, AEs, and reasons for dose reduction/interruption associated with lenvatinib treatment in patients with CP-A and CP-B HCC., Results: The CP-B group had significantly more cases of grade ≥ 2 fatigue and anorexia than the CP-A group ( p   =  0.045 and p   =  0.042, respectively). Regarding AEs that caused dose reduction/interruption of treatment, the CP-A group had significantly more cases of proteinuria than the CP-B group ( p   =  0.015), whereas the CP-B group had significantly more cases of hand-foot syndrome (HFS) than the CP-A group ( p   =  0.013)., Conclusion: Patients with CP-B have greater difficulty than patients with CP-A in continuing treatment with repeated dose reductions/interruption of treatment due to intolerable grade ≥ 2 AEs (fatigue and anorexia). HFS is more likely to cause dose reduction/interruption of treatment in CP-B than in CP-A unresectable HCC., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Metformin-induced lactic acidosis with acute kidney injury is rare but well known. Here we report a case of a Japanese patient taking metformin who experienced severe acute renal failure accompanied with significantly elevated metformin plasma concentrations and signs of lactic acidosis., Case Presentation: A 60-year-old Japanese man with type II diabetes, who was taking metformin (500 mg three times a day) along with several other medications, visited the emergency department with dizziness, malaise, and oliguria. The initial laboratory test results showed elevated levels of serum creatinine and blood urea nitrogen, although his renal function was normal approximately 2 weeks earlier. His lactate level was raised (4.27 mmol/L), and he was diagnosed with lactic acidosis. Considering the low creatinine clearance and elevated urinary albumin/serum creatinine ratio, urinary N-acetyl-β-D-glucosaminidase level, and β2-microglobulin level, the patient was further diagnosed with AKI (in other words, acute tubular necrosis). A renal biopsy performed on day 3 after admission revealed renal tubular epithelium necrosis, supporting this diagnosis. The patient underwent intermittent hemodialysis until he was discharged on day 13. The metformin concentrations on days 3, 5, and 7 were 8.95, 2.58, and 0.16 μg/mL, respectively, which is significantly higher than the maximal steady-state concentration of metformin at the recommended dosage (approximately 1 μg/mL). The calculated pharmacokinetic parameters of metformin suggested poor renal excretion and a low distribution volume at higher metformin levels. Other possible acute kidney injury-causing factors included dehydration, alcohol consumption, and the use of an angiotensin receptor blocker or SGLT2 inhibitor., Conclusions: This is the first reported case of acute kidney injury possibly caused by high levels of metformin with lactic acidosis in a patient treated with the recommended metformin dose. Thus, the development of metformin-induced acute kidney injury should be considered for patients with several acute kidney injury risk factors who are taking metformin., (© 2023. BioMed Central Ltd., part of Springer Nature.)

This study aimed to identify the risk factors of febrile neutropenia(FN)onset associated with melphalan(L-PAM)therapy. Thirty-nine patients(21 men, 18 women)were administered L-PAM intravenously for multiple myeloma(MM)from April 2011 to February 2022 at the Department of Hematology of Gifu Municipal Hospital. Patients were classified into those with and without FN(Grade 3 or higher), complete blood count and liver function tests were performed immediately before starting therapy. Univariate analysis with Fisher's exact probability test was performed. Factors with p<0.2 were considered as independent variables for multivariate analysis in the multiple logistic regression analysis. A multivariate analysis with 2 independent variables, lactate dehydrogenase(LD)level>222 U/L(upper limit of the facility reference value)and white <3.3×103/μL(lower limit of the facility reference value)from the univariate analysis, and FN onset(Grade 3 or higher)as the dependent variable showed that LD level>222 U/L(odds ratio: 6.33, 95% confidence interval: 1.12-35.8, p=0.037)was a significant factor. In conclusion, patients with LD levels >222 U/L immediately before starting therapy require adequate monitoring for FN onset following L-PAM administration.

Cooperative care between hospitals and community pharmacies is important to safe and effective pharmacotherapy for outpatients. We developed a protocol comprising three agreements about alternative drugs and dosing schedules with the aim of minimizing inquiries about prescriptions to doctors. The protocol was implemented under an agreement between core hospitals in Gifu City and community pharmacy members of the Gifu City Pharmaceutical Association from October 2019. Here, we examined the impact of this protocol on patient waiting time in pharmacies. Before introduction of the protocol, median patient waiting time for questionable prescriptions requiring an inquiry to a doctor was significantly longer than that for prescriptions not requiring an inquiry (23.0 min vs. 10.0 min, p<0.001). After introduction of the protocol, median time for prescriptions which were questionable but nevertheless under the protocol did not require an inquiry to a doctor was significantly reduced compared with those which were questionable and still did require an inquiry (15.0 min vs. 24.0 min, p=0.038). In conclusion, introduction of a protocol aimed at minimizing inquiries about prescriptions to doctors from a community pharmacy was useful in reducing the waiting time of patients, and also likely in decreasing the working times of medical doctors and pharmacists.

Background: Metformin had been recommended as the first-line treatment for type 2 diabetes since 2006 because of its low cost, high efficacy, and potential to reduce cardiovascular events, and thus death. However, dipeptidyl peptidase-4 (DPP-4) inhibitors are the most commonly prescribed first-line agents for patients with type 2 diabetes in Japan. Therefore, it is necessary to clarify the effect of DPP-4 inhibitors on preventing cardiovascular events, taking into consideration the actual prescription of antidiabetic drugs in Japan., Methods: This study examined the effect of DPP-4 inhibitors on preventing cardiovascular events. The Japanese Adverse Drug Event Report (JADER) database, a spontaneous reporting system in Japan, and the Japanese Medical Data Center (JMDC) Claims Database, a Japanese health insurance claims and medical checkup database, were used for the analysis. Metformin was used as the DPP-4 inhibitor comparator. Major cardiovascular events were set as the primary endpoint., Results: In the analysis using the JADER database, a signal of major cardiovascular events was detected with DPP-4 inhibitors (IC: 0.22, 95% confidence interval: 0.03-0.40) but not with metformin. In the analysis using the JMDC Claims Database, the hazard ratio of major cardiovascular events for DPP-4 inhibitors versus metformin was 1.01 (95% CI: 0.84-1.20)., Conclusions: A comprehensive analysis using two different databases in Japan, the JADER and the JMDC Claims Database, showed that DPP-4 inhibitors, which are widely used in Japan, have a non-inferior risk of cardiovascular events compared to metformin, which is used as the first-line drug in the United States and Europe.

Purpose: The dose-limiting factor of ramucirumab plus docetaxel (RAM + DTX) in patients with non-small cell lung cancer (NSCLC) is febrile neutropenia (FN), which has a high incidence in Asians. This study aimed to evaluate the cost-effectiveness of pegfilgrastim (Peg-G) in patients with NSCLC receiving RAM + DTX in Japan., Methods: We simulated model patients treated with RAM + DTX in Japan and developed a decision-analytical model for patients receiving Peg-G prophylaxis or no primary prophylaxis. The expected cost, quality-adjusted life-year (QALY), and incremental cost-effectiveness ratio (ICER) of each treatment were calculated from the perspective of a Japanese healthcare payer. The willingness-to-pay (WTP) threshold was set at 45,867 United States dollars (USD) (5 million Japanese yen) per QALY gained. The probabilities, utility values, and other costs were obtained from published sources. Deterministic sensitivity analysis (DSA) and probabilistic analysis were conducted to evaluate the effect of each parameter and robustness of the base-case results., Results: The expected cost and QALYs were 20,275 USD and 0.701 for Peg-G prophylaxis and 17,493 USD and 0.672 for no primary prophylaxis, respectively. The ICER was calculated to be 97,519 USD per QALY gained. The results were most sensitive to FN risk with Peg-G. When FN risk with no primary prophylaxis exceeded 51% or the cost of Peg-G was less than 649 USD per injection, the ICER was below the WTP threshold. The probabilistic analysis revealed a 9.1% probability that the ICER was below the WTP threshold., Conclusion: Peg-G is not cost-effective in patients with NSCLC receiving RAM + DTX in Japan., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Olanzapine has been shown to have an additive effect on the three-drug antiemetic therapy consisting of aprepitant, palonosetron, and dexamethasone, in a highly emetogenic cisplatin-containing chemotherapy. Although olanzapine may be more economical than aprepitant or palonosetron, an adequate cost-efficacy analysis has not been conducted., Methods: We conducted a cost-utility analysis to evaluate the cost-effectiveness of olanzapine use in four-drug antiemetic therapy among Japanese patients. We simulated model patients treated with highly emetogenic cisplatin-containing chemotherapy and developed a decision-analytical model of patients receiving triple antiemetic therapy with or without olanzapine in an inpatient setting. The cost and probabilities of each treatment were calculated from the perspective of the Japanese healthcare payer. The probabilities, utility value, and other costs were obtained from published sources. One-way and probabilistic sensitivity analyses were conducted to examine the influence of each parameter on the model and the robustness of a base-case analysis. Threshold analysis was conducted to determine the cost of olanzapine that would make the incremental cost-effectiveness ratio (ICER) equivalent to the threshold ICER). The threshold incremental cost-effectiveness ratio was set at 5 million Japanese Yen (JPY) per quality-adjusted life-year (QALY) gained., Results: The cost was 10,238 JPY in the olanzapine regimen and 9719 JPY in the non-olanzapine regimen. The QALY gained were 0.01065 QALYs and 0.01029 QALYs in the olanzapine and non-olanzapine regimen, respectively. The incremental cost of the olanzapine regimen relative to the non-olanzapine regimen was 519 JPY, and the incremental QALYs were 0.00036 QALY, resulting in an ICER of 1,428,675 JPY per QALY gained. In the one-way sensitivity analysis, the results were most sensitive to the utility value of incomplete control. The probabilistic sensitivity analysis revealed the probability that the ICER was below the willingness-to-pay, and the incremental QALYs was positive was 96.2%. The calculated cost of olanzapine per 5 mg that would make the incremental cost-effectiveness ratio equivalent to the threshold incremental cost-effectiveness ratio was calculated to be 475 JPY., Conclusions: Olanzapine was cost-effective in the four-drug antiemetic therapy for Japanese patients treated with highly emetogenic cisplatin-containing chemotherapy., (© 2022. The Author(s).)

Proteinuria is a dose-limiting adverse effect of ramucirumab treatment, which is an anti-angiogenic agent that targets the human vascular endothelial growth factor. The predictors of proteinuria have not been completely elucidated and there is currently no consensus. The present study aimed to identify the risk factors for ramucirumab-induced proteinuria and to determine an optimal proteinuria management. A total of 145 patients who received ramucirumab at Ogaki Municipal Hospital (Ogaki, Japan) between September 2015 and March 2021 were retrospectively studied. Multivariate logistic regression analysis was conducted to evaluate the association between the patient baseline characteristics and the development of proteinuria following ramucirumab treatment. Furthermore, the time of proteinuria onset and of the worst qualitative proteinuria were recorded. Proteinuria (>2+) following ramucirumab was independently associated with lung cancer [odd ratio (OR): 0.232, 95% confidence interval (CI): 0.061-0.874; P=0.031] and proteinuria at the start of treatment [qualitative test (+/-); OR: 4.760, 95% CI: 1.360-16.700; P=0.041]. The median time of onset of proteinuria was 56 days (time range, 7-414 days), and the median time when the worst qualitative results were observed was 83 days (time range, 7-442 days). The >2+ proteinuria in the qualitative test was observed in 27 out of the 82 patients with gastric cancer (P=0.041), 8/21 patients with colon cancer (P=0.188), and in 3 out of the 37 patients with lung cancer (P=0.003). The prevalence of proteinuria was low in patients with lung cancer, and proteinuria (>2+) was likely to occur when the proteinuria at the start of ramucirumab was (+/-) by qualitative test. The results from the present study indicated that particular attention should be paid to proteinuria at the start of treatment when monitoring proteinuria as an adverse event of ramucirumab treatment., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2021, Spandidos Publications.)

We performed a study on the ratio of anti-cancer drug purchase costs at municipal hospitals in Aichi using meeting materials from the 2020 Aichi Prefectural Public Hospital Pharmacy Directors' Association. The ratio of anti-cancer drug purchase costs to all drug purchase costs at 17 hospitals was 41.5%(average)and 37.1%(median). In addition, we confirmed a positive correlation between all drug purchase costs and the ratio of anti-cancer drug purchase costs for each hospital(r= 0.537, 95%CI: 0.076-0.809, p=0.026). Furthermore, we conducted a univariate analysis on the background of hospitals where the ratio of anti-cancer drug purchase costs is ≥40%. As a result, we confirmed a significant difference(p<0.05)in the cases where there are more than 500 beds, with the approval of designated cancer hospitals, and with the department of hematology. This study clarified that hospitals with active anti-cancer drug treatment tended to increase drug purchase costs.

Angioedema results from the decreased degradation of vasoactive peptides such as substance P and bradykinin. In this study, we sought to clarify whether dipeptidyl peptidase-4 (DPP-4) and angiotensin-converting enzyme (ACE) inhibitors that suppress the degradation of substance P and bradykinin are involved in angioedema onset. We calculated information coefficients (ICs) by performing a disproportionality analysis to evaluate DPP-4/ACE inhibitor-induced angioedema using the Japanese Adverse Drug Event Report (JADER) database. No angioedema signals were detected for DPP-4 inhibitors; however, a signal was detected for ACE inhibitors (IC: 2.42, 95% confidence interval (CI): 2.19 to 2.65). Of the patients treated with DPP-4 inhibitors, four developed drug-induced angioedema in combination with ACE inhibitors, and all were taking vildagliptin. Signals were detected for enalapril (IC: 2.39, 95% CI: 2.06 to 2.71), imidapril (IC: 2.83, 95% CI: 2.38 to 3.27), lisinopril (IC: 2.28, 95% CI: 1.55 to 3.00), temocapril (IC: 1.35, 95% CI: 0.29 to 2.40), and trandolapril (IC: 1.57, 95% CI: 0.19 to 2.95). Both inhibitors inhibited the degradation of substance P and bradykinin and were thus expected to cause angioedema. However, no signal of angioedema was detected with the DPP-4 inhibitors, in contrast to some ACE inhibitors. This study found that ACE inhibitors and DPP-4 inhibitors, which inhibit the degradation of substance P and bradykinin, tended to have different effects on the onset of angioedema in clinical practice.

In Japan, medical costs are increasing annually, and the increase in national medical costs, particularly in the direct cost of managing adverse drug events, is high. An in-depth understanding of these costs is important for their reduction. This study aimed to calculate the direct cost of managing adverse drug events in all ages, including older adults, and that of avoidable adverse drug events in older adults. We conducted a retrospective survey on patients aged 1 year or older who visited Gifu Municipal Hospital in Japan. We investigated and calculated the direct cost of managing adverse drug events and that of avoidable adverse drug events based on the Beers Criteria Japanese version (BCJ) and "Guidelines for medical treatment and its safety in the elderly 2015" (GMTSE-2015) in inpatients and outpatients. Among 6,504 patients, 11.1% visited the hospital or were hospitalized due to adverse drug events. The direct costs per patient with adverse drug events were 21,281 and 22,590 yen (166 and 176 euros as on September 13, 2021) for outpatients, and 853,175 and 874,582 yen (6,648 and 6,815 euros) for inpatients of all ages and older adults, respectively. The direct costs of avoidable adverse drug events per patient using drugs listed in the BCJ and GMTSE-2015 for older adults were 3,212 and 3,341 yen (25 and 26 euros) for outpatients, and 55,548 and 80,246 yen (433 and 625 euros) for inpatients, respectively. In sum, considering both inpatients and outpatients in the whole country, the direct costs of managing adverse drug events were 804.53 billion and 597.19 billion yen (6,269 million and 4,653 million euros) per year for all ages and older ages, respectively. The direct cost of avoidable adverse drug events in older adults was 83.43-258.44 billion yen (650-2,013 million euros) per year. We found that, in Japan, high medical costs are often caused by managing adverse drug events, and that the costs of avoidable adverse drug events in older adults based on the BCJ and GMTSE-2015 account for a substantial proportion of the medical cost. Therefore, by using the BCJ and GMTSE-2015, avoiding adverse drug events and reducing medical costs may be possible., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Katsuno, Tachi, Matsuyama, Sugioka, Aoyama, Osawa, Noguchi, Yasuda, Goto, Mizui and Teramachi.)

Continuous evaluation of drug safety is needed following approval to determine adverse events (AEs) in patient populations with diverse backgrounds. Spontaneous reporting systems are an important source of information for the detection of AEs not identified in clinical trials and for safety assessments that reflect the real-world use of drugs in specific populations and clinical settings. The use of spontaneous reporting systems is expected to detect drug-related AEs early after the launch of a new drug. Spontaneous reporting systems do not contain data on the total number of patients that use a drug; therefore, signal detection by disproportionality analysis, focusing on differences in the ratio of AE reports, is frequently used. In recent years, new analyses have been devised, including signal detection methods focused on the difference in the time to onset of an AE, methods that consider the patient background and those that identify drug-drug interactions. However, unlike commonly used statistics, the results of these analyses are open to misinterpretation if the method and the characteristics of the spontaneous reporting system cannot be evaluated properly. Therefore, this review describes signal detection using data mining, considering traditional methods and the latest knowledge, and their limitations., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The reporting odds ratio (ROR) is easy to calculate, and there have been several examples of its use because of its potential to speed up the detection of drug-drug interaction signals by using the "upward variation of ROR score". However, since the validity of the detection method is unknown, this study followed previous studies to investigate the detection trend. The statistics models (the Ω shrinkage measure and the "upward variation of ROR score") were compared using the verification dataset created from the Japanese Adverse Drug Event Report database (JADER). The drugs registered as "suspect drugs" in the verification dataset were considered as the drugs to be investigated, and the target adverse event in this study was Stevens-Johnson syndrome (SJS), as in previous studies. Of 3924 pairs that reported SJS, the number of positive signals detected by the Ω shrinkage measure and the "upward variation of ROR score" (Model 1, the Susuta Model, and Model 2) was 712, 2112, 1758, and 637, respectively. Furthermore, 1239 positive signals were detected when the Haldane-Anscombe 1/2 correction was applied to Model 2, the statistical model that showed the most conservative detection trend. This result indicated the instability of the positive signal detected in Model 2. The ROR scores based on the frequency-based statistics are easily inflated; thus, the use of the "upward variation of ROR scores" to search for drug-drug interaction signals increases the likelihood of false-positive signal detection. Consequently, the active use of the "upward variation of ROR scores" is not recommended, despite the existence of the Ω shrinkage measure, which shows a conservative detection trend.