Pressure injury incidence density in an Italian NICU: a 7-year interrupted time series analysis

To describe the incidence density of pressure injuries (PIs) in neonatal intensive care unit patients and their temporal trends over a seven-year period. The secondary aim was to describe the incidence density of medical device-related pressure injuries.

A retrospective interrupted time-series analysis was undertaken using routinely collected surveillance data from a 30-bed tertiary-level neonatal intensive care unit in Northern Italy between 2018 and 2024. PI incidence density (events per 1000 patient-days) was calculated annually and monthly.

Overall, 121 PIs were identified in 83 neonates, corresponding to an overall incidence density of 2.46 events per 1000 patient-days. Annual incidence density declined from 4.80 in 2018 to 1.08 per 1000 patient-days in 2024. Interrupted time series analysis identified an immediate 62.2% reduction in incidence density at the January 2020 breakpoint (incidence rate ratio: 0.378; 95% confidence interval: 0.148-0.963; p=0.044), with no significant changes in temporal trend before or after the breakpoint. Most injuries (93.4%) were related to use of medical devices, predominantly associated with non-invasive respiratory support and monitoring devices, and the head and face were the most frequently affected anatomical sites.

The incidence density of pressure injuries decreased substantially during the study period, but medical device-related pressure injuries remained the predominant type of injury in the neonatal intensive care unit. Routine surveillance may facilitate the early identification of unexpected changes in reported incidence density, prompting timely evaluation of whether these reflect genuine improvements in patient outcomes or changes in clinical attention and reporting practices.