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DUMAS : Behavioral Approach to Appropriate Antimicrobial Prescribing in Hospitals: The Dutch Unique Method for Antimicrobial Stewardship (DUMAS) Participatory Intervention Study.

DUMAS : Behavioral Approach to Appropriate Antimicrobial Prescribing in Hospitals: The Dutch Unique Method for Antimicrobial Stewardship (DUMAS) Participatory Intervention Study.



 2017年5月 JAMA Intern Med に報告された、オランダのASP研究。




 Inappropriate antimicrobial prescribing leads to antimicrobial resistance and suboptimal clinical outcomes. Changing antimicrobial prescribing is a complex behavioral process that is not often taken into account in antimicrobial stewardship programs. 



To examine whether an antimicrobial stewardship approach grounded in behavioral theory and focusing on preserving prescriber autonomy and participation is effective in improving appropriateness of antimicrobial prescribing in hospitals. 



The Dutch Unique Method for Antimicrobial Stewardship (DUMAS) study was a prospective, stepped-wedge, participatory intervention study performed from October 1, 2011, through December 31, 2015. Outcomes were measured during a baseline period of 16 months and an intervention period of 12 months. The study was performed at 7 clinical departments (2 medical, 3 surgical, and 2 pediatric) in a tertiary care medical center and a general teaching hospital in the Netherlands. Physicians prescribing systemic antimicrobial drugs for any indication for patients admitted to the participating departments during the study period were included in the study. 



We offered prescribers a free choice of how to improve their antimicrobial prescribing. Prescribers were stimulated to choose interventions with higher potential for success based on a root cause analysis of inappropriate prescribing. 



Appropriateness of antimicrobial prescriptions was determined using a validated approach based on guideline adherence and motivated guideline deviation and measured with repeated point prevalence surveys (6 per year). Appropriateness judgment was masked for the study period. Antimicrobial consumption was extracted from pharmacy records and measured as days of therapy per admission. We used linear and logistic mixed-model regression analysis to model outcomes over time.



A total of 1121 patient cases with 700 antimicrobial prescriptions were assessed during the baseline period and 882 patient cases with 531 antimicrobial prescriptions during the intervention period. The mean antimicrobial appropriateness increased from 64.1% at intervention start to 77.4% at 12-month follow-up (+13.3%; relative risk, 1.17; 95% CI, 1.04-1.27), without a change in slope. No decrease in antimicrobial consumption was found. 



Use of a behavioral approach preserving prescriber autonomy resulted in an increase in antimicrobial appropriateness sustained for at least 12 months. The approach is inexpensive and could be easily transferable to various health care environments.


Intervention Approach

Figure 1 summarizes the intervention approach.

The approach was performed for each department separately and started with a plenary introduction and discussion with department physicians.

Participation was voluntary for each department and physician.

Department members were stimulated to choose interventions with higher potential for success based on the root cause analysis, which would result in one set of interventions per department.

Intervention choice was not predefined, was free, and was only restricted by practical feasibility.

Essential to the approach was the appointment of 1 or more antibiotic ambassadors chosen by their peers, which defined the start of the intervention period.

We also informed nurses from each department of the baseline results.

The ambassador team contained at least 1 medical specialist per department, but participation of junior physicians, nurses, and quality-of-care personnel was encouraged.

Department ambassadors were asked to represent their department during subsequent intervention discussions, to champion good antibiotic policy and the chosen interventions,3,29 and to help develop and implement the interventions. Support and in- volvement of study personnel with each department’s intervention approach were determined by the preferences of the antibiotic ambassador(s) and limited to a maximum of 12 months after the start of the intervention period.

Fig and Tab






A, Antimicrobial appropriateness relative to the start of the intervention phase and logistic mixed-model regression analysis. Mean antimicrobial appropriateness increased 13.3%, from 64.1% at intervention start to 77.4% at 12-month follow-up.

B, Antimicrobial consumption in days of therapy per admission relative to the start of the intervention phase and logistic mixed-model regression analysis. Points represent results from the point prevalence surveys; lines, predicted means from the regression analysis; and shaded area, 95% CIs around these predicted means. RR indicates relative risk.




Limitations and Strengths


First, prescribers’ awareness of being monitored could have led to a change in behavior (Hawthorne effect). Because they were informed of the study before the start of the baseline measurements, this could have led to di- minished intervention effects. Of importance, the department received even more attention from the research team during the start of the intervention phase; thus, the Hawthorne effect would then be even bigger. However, this behavioral phenomenon (ie, personal attention for commitment leads to be- havioral change) is in fact a feature not a bug of the interven- tion approach mechanism.


Second, the stepped-wedge enrollment order was non- randomized because the approach was dependent on practical circumstances, such as department preferences, room in the educational roster, or availability of department heads and opinion leaders. We believed that adapting to these circum- stances superseded the advantages of randomization, especially because this adaption will also be necessary when implementing our approach in practice. Still, although we found no evidence of this, departments could have stalled their participation in the study until they improved their antibiotic prescribing on their own just before intervention start.


Third, the earlier validation study of the antimicrobial appropriateness method was limited to prescriptions for adult patients. However, there was no procedural difference with the method used for the assessment of pediatric prescriptions.


Fourth, execution of our approach in one pediatric department was less fluent, with delayed implementation of some interventions. This was caused by time constraints of the antibiotic ambassador and the department’s extensive size. The local effect of the approach on appropriateness mirrored this (eTable 2 in the Supplement), perhaps reflecting the importance of the ambassador on the effect.


Fifth, the Dutch health care system differs from other systems, which may limit generalizability. However, our results were achieved regardless of specialists’ payment structure because we included both salaried (hospital 1) and self- employed specialists (hospital 2).


Sixth, a potential weakness of a stepped-wedge design is contamination of the intervention; thus, information or ef- fects of departments in the intervention period could have influenced departments still in the baseline period. Although this effect cannot be excluded, to our knowledge, there were no physicians who transferred between participating departments in this period.




JAMA Intに掲載された事は素晴らしい。