Yu. E. Balykina

A mathematical model for predicting the development of bacterial resistance based on the relationship between the level of antimicrobial resistance and the volume of antibiotic consumption

OBJECTIVES Infections that are inadequately treated owing to acquired bacterial resistance are a leading cause of mortality. Rates of multidrug-resistant bacteria are rising, resulting in increased antibiotic failures and worsening patient outcomes. Mathematical modelling makes it possible to predict the future spread of bacterial antimicrobial resistance. The aim of this study was to construct a mathematical model that can describe the dependency between the level of antimicrobial resistance and the amount of antibiotic usage. METHODS After reviewing existing mathematical models, a cross-sectional, retrospective study was carried out to collect clinical and microbiological data across 3000 patients for the construction of the mathematical model. Based on these data, a model was developed and tested to determine the dependency between antibiotic usage and resistance. RESULTS Consumption of inhibitor/cephalosporins and fluoroquinolones increases inhibitor/penicillin resistance. Consumption of inhibitor/penicillins increases cephalosporin resistance. Consumption of inhibitor/penicillins increases inhibitor/cephalosporin resistance. CONCLUSIONS It was demonstrated that in some antibiotic-micro-organism pairs, the level of antibiotic usage significantly influences the level of resistance. The model makes it possible to predict the change in resistance and also shows the quantitative effect of antibiotic consumption on the level of bacterial resistance.

Pharmacoeconomic analysis of using typical and atypical antipsychotics in schizophrenia

The aim: to provide a comprehensive pharmacoeconomic evaluation of the maintenance therapy with antipsychotics in outpatients diagnosed with schizophrenia. Materials and methods. The analysis was conducted by two mutually complementary steps: an epidemiological study on outpatients with schizophrenia, and a subsequent pharmacoeconomic modeling. Two medical technologies were evaluated and compared: treatment with classical antipsychotics (kA) and treatment with atypical antipsychotics (AA). For the clinical and economic analysis of these treatments, we used a number of indices derived from our retrospective study of patients’ medical records. The cost-effectiveness analysis, incremental analysis, and «budget impact» analysis were performed taking into account the direct and indirect costs of the treatments. Results. We determined the costs of managing outpatients with schizophrenia from the perspective of the healthcare budget and the social burdens; we also looked into the relevance and effectiveness of the current costs at various time intervals – 6, 12 and 24 months. As shown, the treatment strategies involving AA were more budget-consumptive than the kA treatments. even if the treatments were switched to the reproduced AA (up to 100% replacement), the costs would remain to be higher than those for the kA. The «cost-effectiveness» analysis related to «the proportion of stable patients» for the horizons of 6 and 12 months indicated that the reproduced AA would be more economically effective than the kA. However, when the observation period was increased to 24 months, this economic advantage of AA diminished, and the kA drugs had a lower CeR instead. For the «number of hospitalization-free days per year», the use of AA was more cost-effective only versus the 100% use of reproduced AA at the simulated horizon of 12 months. When the use of 100% reference AA or the combined use of reference + reproduced AA was simulated, the treatment with kA remained more economically effective, regardless of the simulated period. Conclusion. The pharmacoeconomic simulation of the antipsychotic therapy in outpatients with schizophrenia suggests the ways to optimize the treatment. Among them, (a) using AA for the treatment of at least 15.6% of patients (those who are employed); keeping the ≥60% use of kA to ensure the optimal resource-saving effect of the treatment; (b) using reproduced AA at the level of ≥70% (instead of the reference AA similar in efficacy and safety) to keep the treatment economically feasible.

PHARMACOECONOMIC ANALYSIS OF BRENTUXIMAB VEDOTIN THERAPY IN RELAPSED OR REFRACTORY CD30+ SYSTEMIC ANAPLASTIC LARGE CELL LYMPHOMA IN PATIENTS OVER 18 YEARS OF AGE: HEALTH BUDGET IMPACT ANALYSIS

Objectives . To provide a pharmacoeconomic analysis of brentuximab vetodin therapy in relapsed or refractory CD30+ systemic anaplastic large-cell lymphoma in patients over 18 years of age. Methods . Recommendations to carry out a budget impact analysis in theRussian Federation (2016) were used. Results . The analysis covered a period of 3 years. The target population of patients with relapsed or refractory CD30+ systemic anaplastic large cell lymphoma numbered 345 individuals. The results indicate that the introduction of brentuximab vetodin in the List of vital and essential drugs and the Program of state-guaranteed free medical care will not increase the costs of the treatment in patients with relapsed or refractory CD30+ systemic anaplastic large cell lymphoma. Conclusion . The brentuximab vetodin therapy of relapsed or refractory CD30+ systemic anaplastic large cell lymphoma is an economically reasonable and resource-saving medical modality.

ECONOMIC ASSESSMENT OF THE EFFECTIVENESS AND SAFETY OF THE COMMONLY PRACTICED PERIOPERATIVE ANTIBIOTIC PROPHYLAXIS (BASED ON AN EARLIER EPIDEMIOLOGICAL SURVEY OF MULTIDISCIPLINARY HOSPITALS)

A survey conducted in four hospitals located in the city of St. Petersburg revealed that the commonly used perioperative antibiotic prophylaxis (PAP) did not follow (in 88% of cases) the guidelines approved for national clinical practice. Aim . To perform a cost-effectiveness analysis of the commonly practiced PAP among patients with clean, clean-contaminated and contaminated surgical wounds in a multidisciplinary hospital. Materials and methods . The PAP cost-effectiveness analysis was performed using the data from a multicenter epidemiological survey and previously conducted studies. The Markov model was used to compare the effectiveness and safety of the commonly used PAP with that recommended by the clinical practice guidelines. The rate of surgical site infection (SSI) and antibiotic-associated diarrhea (AAD) were chosen for the endpoints. Results . The costs associated with a single case of PAP according to the clinical practice guidelines was 3.5 times less than that associated with the PAP used in the common practice (RUB 4913,67 and 17837,71 respectively). The present analysis demonstrates that the PAP recommended by the clinical practice guidelines was more cost-effective as compared with the commonly practiced PAP. Conclusion . Regular epidemiological monitoring is required to improve effectiveness and safety of the existing PAP practice.

MATHEMATICAL MODEL OF REIMBURSEMENT DECISION MAKING IN RUSSIA. RESULTS OF VIM LIST FOR 2016

Background: In 2014 we firstly analyzed the formalized system (points and expert opinions) of drug inclusion and exclusion into the reimbursement lists in Russian Federation. The liner mathematical model of decision making was developed and adopted. Aim. Update the existing model using the results of reimbursement procedures acting from 2106. Material and methods. The linear models developed and adopted in 2014 were used. In 2015 we included data on 141 drug dossiers. We analyzed the decision of the expert body, chief Ministry of Health expert and the final committee decision. Results. 43 new drugs were included into the reimbursement lists acting from 2016. The model of expert body decision had an error 7,09% (12,4% in 2014). The model of chief Ministry of Health expert decision had an error – 7% (10% in 2014). The above mentioned experts became more experienced in the formalized procedure of decision making. The model of final decision had an error about 42% (35% in 2014). Conclusion. Linear models are working tools for modelling reimbursement system decisions. At the mean time the existing system of decision making needs more formalization.