Published papers

院内感染制御を適正に行うにあたって、抗methicillin-resistant Staphyrococcus aureus(以下、MRSA)薬および広域抗菌薬等の使用は、届出制等によりその適正使用を推進することが求められている。今回、より効率的かつ確実に特定抗菌薬(抗MRSA薬およびカルバペネム系薬)の使用を管理する目的で、処方オーダリングシステムと連動した特定抗菌薬使用届出システム(以下、本システム)の運用を開始した。本システム導入後では、導入前に比してリネゾリド錠の使用量および長期使用件数が著明に減少し、抗MRSA薬使用金額は年間で約2割減少した。また、本システムは、届出内容を臨床検査値や投与履歴と共に一括表示・外部出力する機能を有している。この機能を活用して、効率的な特定抗菌薬の使用状況把握が可能となった。以上より、本システムの活用は抗菌薬適正使用に有用であることが示唆された。(著者抄録)

Objective: To attain optimal blood concentration rapidly, it is needed to perform initial dose setting appropriately when vancomycin (VCM) used.  In order to design initial dose settings of VCM more currently, we compared the predictive performance of two types of VCM therapeutic drug monitoring (TDM) analysis software retrospectively. Method: We utilized two TDM analysis software, SHIONOGI-VCM-TDM ver.2009 (VCM-TDM) and “Vancomycin MEEK TDM analysis software Ver. 2.0” (MEEK), based on patient’s background. 112 patients who received VCM and performed TDM were analyzed during the period from October 2011 through September 2012 and compared the actual trough level with the predictive trough level.  The predictive performance was evaluated by calculating ME (mean prediction error), MAE (mean absolute prediction error), and RMSE (root mean squared error).  Age, gender, and a renal function were evaluated as patient’s background. Results: VCM-TDM gave good predictive performance for patients overall.  When classified patient’s background complexly (sex, age, and renal function), as for male patients, VCM-TDM showed good predictive performance except for the group over 65 years old and CCr over 85 mL/min.  For female patients, the difference of predictive performance was not accepted by all groups. Conclusion: These results suggest, for male patients, we should use VCM-TDM for initial dose settings except for the group over 65 years old and over CCr 85 mL/min.  For the other patients, we consider that both of software can be used.  These new findings seem to contribute to proper dosage settings of VCM.

Based on the predictive performance in our previous study, we switched the therapeutic drug monitoring (TDM) analysis software for dose setting of vancomycin (VCM) from "Vancomycin MEEK TDM analysis software Ver2.0" (MEEK) to "SHIONOGI-VCM-TDM ver.2009" (VCM-TDM) in January 2015. In the present study, our aim was to validate the effectiveness of the changing VCM TDM analysis software in initial dose setting of VCM. The enrolled patients were divided into two groups, each having 162 patients in total, who received VCM with the initial dose set using MEEK (MEEK group) or VCM-TDM (VCM-TDM group). We compared the rates of attaining the therapeutic range (trough value; 10-20 μg/mL) of serum VCM concentration between the groups. Multivariate logistic regression analysis was performed to confirm that changing the VCM TDM analysis software was an independent factor related to attaining the therapeutic range. Switching the VCM TDM analysis software from MEEK to VCM-TDM improved the rate of attaining the therapeutic range by 21.6% (MEEK group: 42.6% vs. VCM-TDM group: 64.2%, p<0.01). Patient age ≥65 years, concomitant medication (furosemide) and the TDM analysis software used VCM-TDM were considered to be independent factors for attaining the therapeutic range. These results demonstrated the effectiveness of switching the VCM TDM analysis software from MEEK to VCM-TDM for initial dose setting of VCM.

Inpatients who had been in close contact with patients with influenza were given oseltamivir [75 mg capsules once daily for adults or 2 mg/kg (maximum of 75 mg) once daily for children] for three days as postexposure prophylaxis (PEP). The index patients with influenza were prescribed a neuraminidase inhibitor and were discharged immediately or transferred to isolation rooms. The protective efficacy of oseltamivir for three days was 93% overall [95% confidence interval (CI) 53-99%; P = 0.023] and 94% for influenza A (95% CI 61-99%; P = 0.017), which is comparable to that of seven- to 10-day regimens of oseltamivir as PEP. (C) 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

We investigated factors affecting the timing of signal detection by comparing variations in reporting time of known and unknown ADRs after initial drug release in the USA. Data on adverse event reactions (AERs) submitted to U.S. FDA was used. Six ADRs associated with 6 drugs (rosuvastatin, aripiprazole, teriparatide, telithromycin, exenatide, varenicline) were investigated: Changes in the proportional reporting ratio, reporting odds ratio, and information component as indexes of signal detection were followed every 3 months after each drugs release, and the time for detection of signals was investigated. The time for the detection of signal to be detected after drug release in the USA was 2-10 months for known ADRs and 19-44 months for unknown ones. The median lag time for known and unknown ADRs was 99.0-122.5 days and 185.5-306.0 days, respectively. When the FDA released advisory information on rare but potentially serious health risks of an unknown ADR, the time lag to report from the onset of ADRs to the FDA was shorter. This study suggested that one factor affecting signal detection time is whether an ADR was known or unknown at release.

Bacteremia is one of the most serious infectious illness resulting from nosocomial infection. Therefore, appropriate antimicrobial chemotherapy should be provided as soon as possible to patients exhibiting symptoms of infectious disease and having positive blood culture results. Antimicrobial stewardship (AS) guidelines were recently released by the Infectious Diseases Society of America. The guidelines recommend "proactive intervention and feedback" as one of the core strategies for implementing optimal antimicrobial drug use to improve patient outcomes in clinical settings. We began using the AS program for optimizing antimicrobial chemotherapy in patients with positive blood culture results. The results of blood cultures and antimicrobial prescriptions for the corresponding patients were daily reviewed by a pharmacist and a physician, members of the infection control team (ICT). If the antimicrobial agents selected were inappropriate, ICT made a recommendation to the attending physicians who prescribed the antibiotics. To evaluate the outcomes of this program, we conducted a single-center, retrospective investigation for near a hundred of patients who underwent intervention by infection-control physician and pharmacist. Resolution of bacteremia (determined by blood culture results) was 96.3% in the group that accepted intervention, whereas only 16.7% of the cases resolved in the group that did not accept intervention. These results strongly suggest the importance of the infection disease-specialist team intervention. This program could become an important method for improving clinical outcomes in patients with bacteremia.

OBJECTIVES: Several publications concerning decision tree (DT) analysis in medical fields have recently demonstrated its usefulness for defining prognostic factors in various diseases. However, there are minimal reports on the predictors of adverse drug reactions. We attempted to use DT analysis to discover combinations of multiple risk factors that would increase the risk of nephrotoxicity associated with vancomycin (VCM). To demonstrate the usefulness of DT analysis, we compared its predictive performance with that of multiple logistic regression analysis. METHOD: A single-centre, retrospective study was conducted at Hokkaido University Hospital. A total of 592 patients, who received intravenous administrations of VCM between November 2011 and April 2016, were enrolled. Nephrotoxicity was defined as an increase in serum creatinine of ≥0.5 mg/dL or a ≥50% increase in serum creatinine from the baseline. Risk factors for VCM nephrotoxicity were extracted from previous reports. In the DT analysis, a chi-squared automatic interaction detection algorithm was constructed. For evaluating the established algorithms, a 10-fold cross validation method was adopted to calculate the misclassification risk of the model. Moreover, to compare the accuracy of the DT analysis, multiple logistic regression analysis was conducted. RESULTS: Eighty-seven (14.7%) patients developed nephrotoxicity. A VCM trough concentration of ≥15.0 mg/L, concomitant medication (vasopressor drugs and furosemide), and a duration of therapy ≥14 days were extracted to build the DT model, in which the patients were divided into 6 subgroups based on variable rates of nephrotoxicity, ranging from 4.6 to 69.6%. The predictive accuracies of the DT and logistic regression models were similar (87.3%, respectively), indicating that they were accurate. CONCLUSION: This study suggests the usefulness of DT models for the evaluation of adverse drug reactions.

Only minimal information exists regarding the treatment outcomes of patients suffering from methicillin-resistant Staphylococcus aureus (MRSA) bacteremia treated with teicoplanin (TEIC) when the TEIC minimum inhibitory concentration (MIC) is close to the upper limit of the "susceptibility range" according to the Clinical Laboratory Standards Institute (CLSI). We investigated the outcome of TEIC-treated patients in MRSA bacteremia, focusing on TEIC MIC against MRSA. A retrospective cohort study was conducted on patients with MRSA bacteremia. TEIC treatment failure was defined as any of the following: (1) all-cause 60-day mortality, (2) persistent bacteremia until the end of TEIC treatment, or (3) 30-day recurrence of MRSA bacteremia. Nineteen patients were enrolled, of whom 15 exhibited TEIC MICs ≤2 μg/mL and the remaining 4 exhibited >2 μg/mL. The rate of treatment failure and all-cause 60-day mortality in patients with MIC >2 μg/mL were significantly higher than those in patients with MIC ≤2 μg/mL [4 patients (100%) versus 4 patients (26.7%) (p=0.018) and 4 patients (100%) versus 2 patients (13.3%) (p=0.004), respectively]. Three of four patients (75%) with MIC >2 μg/mL had persistent bacteremia, which was quantitatively higher than in patients with MIC ≤2 μg/mL (1 of 7 patients, 14.3%). Our finding suggests that TEIC MIC >2 μg/mL may be related to poor treatment outcome in MRSA bacteremia, and that TEIC should not be used in this case.

Purpose: The development of surgical site infection (SSI) after biliary reconstruction is highly influenced by the presence of preoperative bacteria in the bile juice. We selected vancomycin and piperacillin/tazobactam (VCM + PIPC/TAZ) as perioperative prophylactic antibiotics for patients undergoing pancreaticoduodenectomy. This study aimed to retrospectively analyze the effectiveness of VCM + PIPC/TAZ compared to cefmetazole. Methods: Seventy-two patients who underwent pancreaticoduodenectomy between April 2015 and March 2017 at our department were evaluated. Forty patients were administered cefmetazole as the perioperative prophylactic antibiotic, and 32 were administered VCM + PIPC/TAZ. The intraoperative VCM blood concentration (incision, biliary reconstruction, and wound closure) was measured during surgery to confirm the hemodynamics. Results: The frequency of SSIs was significantly lower in the VCM + PIPC/TAZ group (8/32 patients) than in the cefmetazole group (20/40 patients, P = 0.031). Postoperatively, significantly fewer patients in the VCM + PIPC/TAZ group (4/32 patients) required ≥ 15 days of additional antibiotic administration compared to those in the cefmetazole group (14/40 patients, P = 0.033). Six of 32 patients in the VCM + PIPC/TAZ group showed redneck syndrome symptoms. There was no significant difference in the VCM blood concentration between patients with and without SSIs. Conclusions: The use of VCM + PIPC/TAZ can reduce the incidence of SSI after pancreaticoduodenectomy and also reduce the need for the additional administration of antibiotics for ≥ 15 days after surgery.

Therapeutic drug monitoring for voriconazole, an antifungal agent, is essential for maximizing efficacy and preventing toxicity. The aim of this study was to elucidate the optimal maintenance dose of voriconazole in patients with severe liver cirrhosis (Child-Pugh class C) by reviewing the plasma trough concentrations obtained by therapeutic drug monitoring and daily doses of voriconazole. We retrospectively evaluated 6 patients with Child-Pugh class C cirrhosis who received oral voriconazole treatment and were liver transplant recipients or were awaiting liver transplantation. We compared their voriconazole trough concentrations and daily maintenance doses to those of patients who did not have liver cirrhosis (n=56). We found that plasma voriconazole trough concentrations in all patients with Child-Pugh class C were almost within therapeutic range, and the median plasma trough concentration at steady state was not significantly different from that of patients who did not have liver cirrhosis. In addition, the median daily maintenance dose of voriconazole was significantly lower (2.13 mg/kg/d) than that of the control patients (6.27 mg/kg/d), suggesting that trough voriconazole concentrations are elevated in Child-Pugh class C patients. Thus, we conclude that oral voriconazole maintenance doses in patients with Child-Pugh class C should be reduced to approximately one-third that of patients with normal liver function, with the follow-up dose adjusted by therapeutic drug monitoring.

Linezolid (LZD), an antimicrobial agent against methicillin-resistant Staphylococcus aureus, demonstrates good bone and joint penetration, and is used for prosthetic bone and joint infections. Recently, we observed vomiting in several patients administered LZD. However, there are few reports on the incidence rate of, and risk factors for, LZD-induced nausea and vomiting. In this study, we aimed to verify the relationship between LZD administration and vomiting. Patients administered LZD at the Department of Orthopedic Surgery of Hokkaido University Hospital between November 2008 and December 2017 were enrolled in the study. The primary endpoint was the comparison of the vomiting rate between patients administered LZD (LZD group) and those administered other antibiotics (non-LZD group). For the secondary endpoint, to verify the risk factors of vomiting, a univariate logistic regression analysis was performed. In total, 130 patients were included in this study; 77 patients in the LZD group, and 53 in the non-LZD group. Vomiting occurred in 18 patients in the LZD group and 4 patients in the non-LZD group (23.4% and 7.5%, respectively); this was significantly higher in the LZD group. In the univariate logistic regression analysis, LZD administration, gender (female), age ≥65 years, renal impairment (creatinine clearance <60 mL/min) and concomitant use of rifampicin were extracted as potential risk factors of vomiting. The results of this study reveal a possible relationship between LZD administration and vomiting.

OBJECTIVES: In our previous study, we built a risk prediction model of vancomycin (VCM)-associated nephrotoxicity using decision tree (DT) analysis. However, this has several limitations in clinical applications. Our objective here was to construct a clinically applicable risk prediction model to be used at the time of initial therapeutic drug monitoring (TDM), in patients with uncomplicated infections. METHOD: A retrospective study was conducted at Hokkaido University Hospital. Subjects that had received VCM were extracted between November 2011 and April 2017. Nephrotoxicity was defined as an increase in serum creatinine of 0.5 mg/dL or 50% or higher from baseline. The additional inclusion criteria in this study were as follows: (1) the target trough level of VCM was set to 10 to 15 mg/L, and (2) the duration of therapy was 7 to 14 days. Patients were assumed to have uncomplicated infections. Risk factors for nephrotoxicity were evaluated, which could be extracted at the initial TDM. In the DT analysis, a chi-squared automatic interaction detection algorithm was constructed. RESULTS: A total of 402 patients were enrolled, and 56 (13.9%) patients developed nephrotoxicity. In the DT analysis, concomitant medications (furosemide, piperacillin-tazobactam, and vasopressor drugs) and an initial VCM trough concentration ≥ 15.0 mg/L were extracted as predictive variables by which patients were divided into six subgroups. The incidence of nephrotoxicity was 5.2% to 70.0%, with subgroups classified as low to high risk of nephrotoxicity. The accuracy of DT model was favourable (87.1%). CONCLUSION: We propose that the DT model built in this study is applicable to clinical practice.

下顎埋伏智歯抜歯術においてセフカペンピボキシル(CFPN-PI)またはアモキシシリン(AMPC)の予防投与を受けた患者の手術部位感染(SSI)発生率を比較した。解析対象となったのはCFPN-PI群129例(男性50例、女性79例、中央値24.0歳)、AMPC群164例(男性75例、女性89例、中央値25.0歳)であった。SSI発生率はCFPN-PI群において11.6%(15/129)、AMPC群において2.4%(4/164)であり、CFPN-PI群のSSI発生率は有意に高かった。次いで、SSI発生に影響する要因分析を行った。単変量解析において抗菌薬(CFPN-PIの使用)、性別(女性)、術後入院、手術難易度、反対側下顎埋伏智歯抜歯の有無、Pell-Gregory分類がP≦0.2となり、これらを多変量解析における解析対象因子として抽出した。解析対象因子のvariance inflation factorはいずれも4未満であり多重共線性はみられなかった。多変量解析の結果、抗菌薬(CFPN-PIの使用)および術後入院がそれぞれオッズ比5.61、4.66を示し、SSIに影響する独立因子として抽出された。

ガンシクロビル(GCV)による血小板減少症の発現因子を従来の手法であるロジスティック回帰分析を用いて探索した。さらに、2種の決定木(DT)分析アルゴリズムを用いて血小板減少症発現割合の推定モデルを構築し、そのモデルの妥当性について検討した。GCVの点滴静注製剤の投与を受けた患者386例を対象とした。血小板減少症の発現は12.2%(386例中47例)に認められ、多変量解析において白血球数7000cells/mm3未満、血小板数101000cells/mm3未満、総ビリルビン値0.8mg/dL以上が血小板減少症発現に影響する独立因子として抽出された。CHAID法で構築したDTモデルでは、ツリーは3段階、六つのサブグループに分枝し、五つのリスク因子が抽出された。また、CRT法で構築したモデルでは、ツリーは3段階、七つのサブグループに分枝し、五つのリスク因子が抽出された。ロジスティック回帰モデルならびにCHAID法で構築されたDTモデルの精度は87.8%、CRT法で構築されたDTモデルの精度は88.3%であった。

腎機能低下患者におけるバンコマイシン(VCM)初回負荷投与の安全性は十分に検証されていない。そこで今回、腎機能低下患者に対するVCM初回負荷投与の安全性を明らかにするために、単施設(n=1489)後ろ向き観察研究を実施した。初回負荷投与実施群(n=86)と非実施群(n=206)では、腎機能障害発現割合に有意差は認めなかった。(初回負荷投与実施群:非実施群=6.98%:9.71%、P=0.46)ベースラインの腎機能別でも同様の結果であった。また、VCMの初回トラフ値(中央値)はいずれの群も推奨濃度範囲内であり、両群間に有意差はなかった。多変量ロジスティック回帰分析で腎機能障害発現の危険因子として、投与日数9日以上、フロセミド、ピペラシリン・タゾバクタムの併用、ICU入室、初回トラフ値12.2μg/mL以上が抽出され、初回負荷投与の実施は抽出されなかった。以上より、VCMの初回負荷投与は腎機能低下患者に対しても安全に行える可能性が示唆された。(著者抄録)

WHAT IS KNOWN AND OBJECTIVE: Haematological toxicities such as neutropaenia are a common side effect of ganciclovir (GCV); however, risk factors for GCV-induced neutropaenia have not been well established. Decision tree (DT) analysis is a typical technique of data mining consisting of a flow chart-like framework that shows various outcomes from a series of decisions. By following the flow chart, users can estimate combinations of risk factors that may increase the probability of certain events. In our previous study, we demonstrated the usefulness of this approach in the evaluation of adverse drug reactions. Therefore, we aimed to construct a risk prediction model of GCV-induced neutropaenia including severity grade. METHODS: We performed a retrospective study at the Hokkaido University Hospital and enrolled patients who received GCV between April 2008 and March 2018. Neutropaenia was defined as an absolute neutrophil count (ANC) <1500 cells/mm3 and a decrease to <75% relative to baseline. We classified the patients who developed neutropaenia in three groups (Grades 2-4) based on the National Cancer Institute-Common Terminology Criteria for Adverse Events. Data collection was achieved through the retrieval of medical records. We employed a chi-squared automatic interaction detection algorithm to construct the DT model and compared the accuracies to the logistic regression model (a conventional statistical method) to evaluate the established model. RESULTS AND DISCUSSION: In total, 396 adult patients were included in the study; 61 (15.4%) developed neutropaenia. Three predictive factors (hematopoietic stem cell transplantation, baseline ANC <3854 cells/mm3 and duration of therapy ≥15 days) were extracted using the DT analysis to produce five subgroups, the incidence of neutropaenia ranged between 1.7% and 52.8%. In each subgroup, patients who developed neutropaenia were categorized based on the severity. The accuracies of each model were the same (84.6%), which indicated precision. WHAT IS NEW AND CONCLUSION: We successfully built a risk prediction model of GCV-induced neutropaenia including severity grade. This model is expected to assist decision-making in the clinical setting.