Antibiotic Consumption in Danish Intensive Care Units, 2013-2023: A Nationwide Study of Temporal Trends

Antibiotics are widely used in intensive care units (ICUs), yet detailed nationwide data on ICU-specific consumption are limited. In 2012, the Danish Health Authority introduced a policy framework to promote prudent antibiotic use. We evaluated national trends in antibiotic consumption across Danish ICUs from 2013 to 2023 considering this initiative.

We conducted a nationwide observational study including all adult ICUs across 29 public hospitals in Denmark. All ICU admissions from January 1, 2013, to December 31, 2023, were included, covering 1,121,639 ICU patient days. Antibiotic consumption was assessed using defined daily doses (DDD) derived from national sales data. No interventions were implemented.

During the study period, a total of 1,624,281 DDD of intravenous antibiotics were administered. Overall antibiotic consumption declined from 1705 to 1348 DDD per 1000 patient days, representing a 21% relative reduction. Marked decreases were observed for fluoroquinolones (-80%), first- and second-generation cephalosporins (-61%), and carbapenems (-34%). Conversely, consumption of penicillins with beta-lactamase inhibitors increased by 139%. Run chart analyses indicated these trends were non-random. Importantly, no deterioration in clinical outcomes was observed. Antibiotic consumption varied widely across ICUs and regions. According to both WHO's AWaRe framework and a modified national classification, 'Watch' antibiotics accounted for the largest share of consumption.

In this nationwide study of Danish ICUs, antibiotic consumption decreased substantially over an 11-year period-driven by reductions in broad-spectrum classes-without evidence of worsening clinical outcomes. These data document a sustained decline in broad-spectrum antibiotic use in Danish intensive-care practice and may provide a benchmark for other high-income healthcare systems.

This inventory of antibiotics consumption in Danish intensive care units demonstrates a recent reduction in broad-spectrum antibiotic ordering which differs from the well-known increase of antibiotics used in health care in general.