Impact of changes in the WHO’s 2019 update of DDDs on the measurement of adult hospital antibacterial consumption in Catalonia (Spain), 2008–18
Authors: Grau Santiago , Hernández Sergi , Limón Enric , Calbo Esther , Horcajada Juan P ,   Catalan Infection Control and Antimicrobial Stewardship National Program (VINCat-PROA), Cano Manuel , Canadell Laura , Julián Esther , Gratacós Laura , Carrasco Natàlia , Padulles Ariadna , Quiñones Carles , Campany David , Balet Antònia , Lladó Montse , Gayola Glòria , Frigola Isabel , Ibáñez Ludivina , López Esther , Munell Leonor , Gol Virginia , Barrera Maite , Garriga Ma Rosa , Manso Usúe , Miserachs Núria , Gil Esperanza , Bosacoma Núria , Morón Anisi , Capellà Anna , Curiel Olga , Fuster Mireia , la Valls Camil· , Grañó Marisa , Sagalés Maria , Pascual Begoña , Sardà Silvia , Òdena Eugènia , Terrè Susana , Alemany Pilar , Salvador Pilar , Martí Marta , Martínez Isabel , Fraile Ma José , de Puig Emilia , Navarro Montserrat , Fernández Edurne , Salsé Lidia , Leno Ana Montero , Martínez Virginia Maria , Torrent Josep , Montserrat Magda , González Juan , Enrique-Tarancón Gemma , Carrascosa Montserrat , Domínguez Patricia , Serrais Juan , Ayago Daria , Arranz Teresa , Clopès Anna , Ortí Núria , Guerrera Teresa , Barbadillo Sandra , Brandariz David , Fernández Jordi , Ayestaran Ana , Pascual Oscar , Hidalgo Eduard , Vidal Flotats , Serrano Daniel 
Published: September 2020

Abstract

Objectives
In 2019 the WHO fully adopted new DDD values. The objective of this study is to analyse their impact on the measurement of consumption of antibacterials in hospitals participating in the Catalan Infection Control and Antimicrobial Stewardship National Program (VINCat-PROA) in Catalonia (Spain) between 2008 and 2018.

Methods
The anatomical therapeutic chemical/DDD system was used to monitor adult hospital antibacterial consumption expressed in DDD/100 bed-days. Consumption from 2008 to 2018 was calculated using both pre- and post-update DDD values. Differences were calculated as the percentage variation in DDD/100 bed-days and analysed with Student’s t-test. Simple linear regressions were performed to evaluate the trends in adult antimicrobial consumption over the study period.

Results
The overall consumption according to post-update DDD values decreased by 12.2% (P &lt; 0.001) compared with the pre-update DDD values. Penicillins (−19.6.%; P &lt; 0.001) and carbapenems (−19.0%; P = 0.023) showed the greatest reduction, followed by cephalosporins (−7.7%; P = 0.021) and quinolone antibacterials (−7.7%; P = 0.017). ICU services showed the greatest overall reduction (−13.1%; P &lt; 0.001). From 2008 to 2018 there was a statistically significant decrease in consumption of penicillins and quinolone antibacterials and a statistically significant increase in cephalosporin and carbapenem consumption with both pre- and post-update DDD values. There were no variations in the ranking of consumption between the pre- and post-update DDD values.

Conclusions
The WHO’s updates of DDDs have had a significant impact on the measurement of antibacterial consumption. In our region, they have corrected an overestimation of penicillin and carbapenem consumption amounting to 19%. It is essential to bear these findings in mind for an accurate assessment of temporal trends and benchmarking.