Comparative Evaluation of the Predictive Performances of Three Different Structural Population Pharmacokinetic Models To Predict Future Voriconazole Concentrations.

Bayesian methods for voriconazole therapeutic drug monitoring (TDM) have been reported previously, but there are only sparse reports comparing the accuracy and precision of predictions of published models. Furthermore, the comparative accuracy of linear, mixed linear and nonlinear, or entirely nonlinear models may be of high clinical relevance. In this study, models were coded into individually designed optimum dosing strategies (ID-ODS) with voriconazole concentration data analyzed using inverse Bayesian modeling. The data used were from two independent data sets, patients with proven or suspected invasive fungal infections (n = 57) and hematopoietic stem cell transplant recipients (n = 10). Observed voriconazole concentrations were predicted whereby for each concentration value, the data available to that point were used to predict that value. The mean prediction error (ME) and mean squared prediction error (MSE) and their 95% confidence intervals (95% CI) were calculated to measure absolute bias and precision, while ΔME and ΔMSE and their 95% CI were used to measure relative bias and precision, respectively. A total of 519 voriconazole concentrations were analyzed using three models. MEs (95% CI) were 0.09 (-0.02, 0.22), 0.23 (0.04, 0.42), and 0.35 (0.16 to 0.54) while the MSEs (95% CI) were 2.1 (1.03, 3.17), 4.98 (0.90, 9.06), and 4.97 (-0.54 to 10.48) for the linear, mixed, and nonlinear models, respectively. In conclusion, while simulations with the linear model were found to be slightly more accurate and similarly precise, the small difference in accuracy is likely negligible from the clinical point of view, making all three approaches appropriate for use in a voriconazole TDM program.

Comparison of the accuracy and precision of pharmacokinetic equations to predict free meropenem concentrations in critically ill patients.

Population pharmacokinetic analyses can be applied to predict optimized dosages for individual patients. The aim of this study was to compare the prediction performance of the published population pharmacokinetic models for meropenem in critically ill patients. We coded the published population pharmacokinetic models with covariate relationships into dosing software to predict unbound meropenem concentrations measured in a separate cohort of critically ill patients. The agreements between the observed and predicted concentrations were evaluated with Bland-Altman plots. The absolute and relative bias and precision of the models were determined. The clinical implications of the results were evaluated according to whether dose adjustments were required from the predictions to achieve a meropenem concentration of >2 mg/liter throughout the dosing interval. A total of 157 free meropenem concentrations from 56 patients were analyzed. Eight published population pharmacokinetic models were compared. The models showed an absolute bias in predicting the unbound meropenem concentrations from a mean percent difference (95% confidence interval [CI]) of -108.5% (-119.9% to -97.3%) to 19.9% (7.3% to 32.7%), while absolute precision ranged from -249.1% (-263.4% to -234.8%) to 31.9% (17.6% to 46.2%) and -178.9% (-196.9% to -160.9%) to 175.0% (157.0% to 193.0%). A dose change was required in 44% to 64% of the concentration results. Seven of the eight equations evaluated underpredicted free meropenem concentrations. In conclusion, the overall accuracy of these models supports their inclusion in dosing software and application for individualizing meropenem doses in critically ill patients to increase the likelihood of achievement of optimal antibiotic exposures.

Linguistic and cultural adaptation to the Portuguese language of antimicrobial dose adjustment software.

OBJECTIVE: To adapt an antibiotic dose adjustment software initially developed in English, to Portuguese and to the Brazilian context. METHODS: This was an observational, descriptive study in which the Delphi method was used to establish consensus among specialists from different health areas, with questions addressing the visual and operational aspects of the software. In a second stage, a pilot experimental study was performed with the random comparison of patients for evaluation and adaptation of the software in the real environment of an intensive care unit, where it was compared between patients who used the standardized dose of piperacillin/tazobactam, and those who used an individualized dose adjusted through the software Individually Designed and Optimized Dosing Strategies. RESULTS: Twelve professionals participated in the first round, whose suggestions were forwarded to the software developer for adjustments, and subsequently submitted to the second round. Eight specialists participated in the second round. Indexes of 80% and 90% of concordance were obtained between the judges, characterizing uniformity in the suggestions. Thus, there was modification in the layout of the software for linguistic and cultural adequacy, minimizing errors of understanding and contradictions. In the second stage, 21 patients were included, and there were no differences between doses of piperacillin in the standard dose and adjusted dose Groups. CONCLUSION: The adapted version of the software is safe and reliable for its use in Brazil.

Linguistic and cultural adaptation to the Portuguese language of antimicrobial dose adjustment software / Adaptação linguística e cultural para a língua portuguesa de um software para ajuste de dose de antimicrobianos

ABSTRACT Objective To adapt an antibiotic dose adjustment software initially developed in English, to Portuguese and to the Brazilian context. Methods This was an observational, descriptive study in which the Delphi method was used to establish consensus among specialists from different health areas, with questions addressing the visual and operational aspects of the software. In a second stage, a pilot experimental study was performed with the random comparison of patients for evaluation and adaptation of the software in the real environment of an intensive care unit, where it was compared between patients who used the standardized dose of piperacillin/tazobactam, and those who used an individualized dose adjusted through the software Individually Designed and Optimized Dosing Strategies. Results Twelve professionals participated in the first round, whose suggestions were forwarded to the software developer for adjustments, and subsequently submitted to the second round. Eight specialists participated in the second round. Indexes of 80% and 90% of concordance were obtained between the judges, characterizing uniformity in the suggestions. Thus, there was modification in the layout of the software for linguistic and cultural adequacy, minimizing errors of understanding and contradictions. In the second stage, 21 patients were included, and there were no differences between doses of piperacillin in the standard dose and adjusted dose Groups. Conclusion The adapted version of the software is safe and reliable for its use in Brazil.

RESUMO Objetivo Adaptar um software de ajuste de dose de antibióticos inicialmente elaborado em língua inglesa para o português e a conjuntura brasileira. Métodos Trata-se de estudo observacional, descritivo, em que foi utilizado o método Delphi para estabelecer consenso entre especialistas de diferentes áreas da saúde, com perguntas que abordaram os aspectos visuais e operacionais do software. Em uma segunda etapa, foi realizado um estudo piloto, experimental, com alocação aleatória dos pacientes, para avaliação e adaptação do software em ambiente real de uma unidade de tratamento intensivo, onde foram comparadas diferenças entre pacientes que utilizaram dose padronizada usual de piperacilina/tazobactam, e os que utilizaram a dose individualizada ajustada por meio do software Individually Designed Optimum Dosing Strategies. Resultados Participaram da primeira rodada 12 profissionais cujas sugestões foram encaminhadas ao desenvolvedor do software para adequação e ajustes, e posteriormente submetidas à segunda rodada. Oito especialistas participaram da segunda rodada. Foram obtidos índices de 80% e 90% de concordância entre os juízes, caracterizando uniformidade nas sugestões. Dessa forma, houve modificação no layout do software para adequação linguística e cultural, minimizando erros de entendimento e contradições. Na segunda etapa, foram incluídos 21 pacientes, e não houve diferenças entre doses de piperacilina nos grupos dose padronizada e dose ajustada. Conclusão A versão adaptada do software é segura e confiável para seu uso no Brasil.

Investigation of the marked and long-standing spatial inhomogeneity of the Hungarian suicide rate: a spatial regression approach.

BACKGROUND: In the last century Hungary had astonishingly high suicide rates characterized by marked regional within-country inequalities, a spatial pattern which has been quite stable over time. AIMS: To explain the above phenomenon at the level of micro-regions (n=175) in the period between 2005 and 2011. METHODS: Our dependent variable was the age and gender standardized mortality ratio (SMR) for suicide while explanatory variables were factors which are supposed to influence suicide risk, such as measures of religious and political integration, travel time accessibility of psychiatric services, alcohol consumption, unemployment and disability pensionery. When applying the ordinary least squared regression model, the residuals were found to be spatially autocorrelated, which indicates the violation of the assumption on the independence of error terms and - accordingly - the necessity of application of a spatial autoregressive (SAR) model to handle this problem. According to our calculations the SARlag model was a better way (versus the SARerr model) of addressing the problem of spatial autocorrelation, furthermore its substantive meaning is more convenient. RESULTS: SMR was significantly associated with the "political integration" variable in a negative and with "lack of religious integration" and "disability pensionery" variables in a positive manner. Associations were not significant for the remaining explanatory variables. LIMITATIONS: Several important psychiatric variables were not available at the level of micro-regions. We conducted our analysis on aggregate data. CONCLUSION: Our results may draw attention to the relevance and abiding validity of the classic Durkheimian suicide risk factors - such as lack of social integration - apropos of the spatial pattern of Hungarian suicides.