The following is a summary of the article “Trends in ICU mortality and underlying risk over three decades among mechanically ventilated patients. A group-level analysis of cohorts from infection prevention studies,” published in the July 2023 issue of Critical Care by Hurley et al.

Researchers conducted a cohort study to examine changes in ICU mortality and the risk for mechanically ventilated (MV) patients over three decades, focusing on adjusted analysis for shifting patient risk.

They analyzed data from 147 randomized concurrent control trials (RCCT) and 63 observational studies, primarily listing 13 Cochrane reviews and 4 systematic reviews involving ICU patients, with over 50% receiving more than 24 hrs of MV and with available mortality data. ICU mortality (before day 21) and late mortality (after day 21) rates, along with group-mean age and group-mean APACHE II scores, were extracted. Five meta-regression models were used, adjusting for variables such as publication year, age, APACHE II scores, study intervention type, & other group parameters.

The results showed 210 studies published from 1985 to 2021, and 169 were included in systematic reviews. The mean mortality incidence increased by <1% point per decade (P=0.43). The group-mean APACHE II score increased by 1.83 points (95% CI: 0.51-3.15), and the group-mean age increased by 3.9 years (95% CI: 1.1-6.7). A significant decline in mortality was observed only when adjusting for both group-mean age & group-mean APACHE II score. There was paradoxically a five-point increase in mortality incidence across all models, compared to the benchmark, in concurrent control groups in decontamination studies.

The conclusion was that mortality incidence in ICU infection prevention studies remains low, with APACHE II scores indicating increasing patient age and disease severity despite low mortality among control groups.

Source: annalsofintensivecare.springeropen.com/articles/10.1186/s13613-023-01159-0