Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

In this point-prevalence study encompassing 1117 ICUs in 90 countries across 6 continents and involving 13,254 adult patients, we found an overall pressure injury prevalence of 26.6% and an ICU-acquired prevalence of 16.2%. Although the prevalence was highest in low and lower-middle-income economies, our findings suggest that pressure injuries remain a considerable burden for healthcare systems worldwide, and highlight the necessity of additional efforts in patient safety initiatives.

These observational data confirm and reinforce previous findings resulting from meta-analysis [20]. Additionally, they are complementary to findings from systematic reviews aiming at determining risk factors for pressure injuries in ICU patients [12, 24‐26]. These identified a broad range of factors including age, length of ICU stay, diabetes, mechanical ventilation, vasopressor support, hypotension, and cardiovascular disease, and suggest that an interplay of these factors increases the probability of pressure injury development. Our data, albeit resulting from cross-sectional research and thereby only representing the study day, are suggestive for associating pressure injury in ICU with a patient profile characterised by high vulnerability, as evidenced by the following findings. First, the occurrence of pressure injuries was associated with the Braden score, which summarises essential conditions that gradually contribute to a high-risk profile characterised by being bedridden, malnourished, incontinent, and with limited ability to react on or sense pain [22]. These conditions are characteristic for a majority of ICU patients and mirror an overall vulnerability level. Second, older age was independently associated with pressure injury occurrence. The steadily increasing proportion of very old ICU residents constitutes an overt influx of high-risk patients given the accumulation of chronic comorbidities, nutritional deficiencies, immobility, and aging skin [17, 18]. Third, an association was found with organ support (mechanical ventilation and renal replacement therapy), which implies a high severity of acute illness. Finally, this high-vulnerability profile is completed by the finding that patients who resided > 12 days in ICU before the study day had a 7.5-fold increased risk of ICU-acquired pressure injury compared to patients with a short ICU stay (≤ 3 days).

As such, our data suggest that the large majority of factors associated with pressure injury in ICU patients appear to be intrinsic or unmodifiable. This is in line with the unanimous agreement of experts that pressure injuries can be unavoidable in haemodynamically unstable or critically ill/injured individuals [27]. Our findings need validation, preferably in longitudinal studies. Prospective high-resolution data from smaller samples might also identify additional modifiable factors not sought in this study. A hint that these may exist is the lower prevalence reported in Asia where increased awareness may have been prompted by previous large-scale initiatives on this topic. Until such data is generated, the variables we identified can at least be used to flag patients who might benefit from greater vigilance for pressure injuries. Also research into pressure injury pathophysiology and prevention specifically directed towards the heterogeneous ICU population is recommended.

Another factor independently associated with pressure injury was being in a low or middle-low income economy ICU. Limited availability of human and material resources may contribute to this finding, as the mean percentage of gross national income spent on healthcare in these economies is less than half as compared with high-income economies (4.9% versus 10.3%). Additionally, pressure injury prevention might not be a healthcare priority in developing countries.

Manzano and co-workers [28] identified pressure injury as a significant independent predictor of mortality in mechanically ventilated patients (adjusted hazard ratio 1.28; 95% CI 1.003–1.65; p = 0.047). The mortality associated with pressure injuries remains however unclear. As their occurrence often mirrors a generally debilitated condition and high severity of acute illness, an association with mortality seems reasonable. However, our regression analysis demonstrated a gradual increase in mortality with increasing severity of pressure injuries despite adjustment for these covariates. Even though this does not imply causality, this observation calls for clinical concern towards patients presenting with pressure injuries or those at high-risk for developing such complications.

Stage I pressure injuries are generally considered reversible if promptly identified and appropriately managed [13] and, therefore, often excluded from scientific reports [19]. They were nevertheless shown to be prone to deterioration, as in 6 Dutch acute care hospitals where 22.1% worsened to a deeper lesion [29]. In line with several earlier prevalence reports [29], the majority of pressure injuries in our study were of stage I (38.1%). These currently often underreported injuries, however, emerged from our analyses as independently associated with hospital mortality, which calls for considering these lesions as full quality indicators and for the standardized recording of this data in institutional and research reports.

This study has limitations. The cross-sectional design might have resulted in bias toward patients who have long ICU stays [30]. Since the length of stay is associated with pressure injury risk, the reported prevalence might not be representative for the entire ICU population. Our data only represents a snapshot at the study day and cannot account for potentially influencing factors such as staffing levels. Data on pressure injuries on mucosal surfaces have not been collected as these are not staged by the international staging system [4]. Not all geographic regions are well-represented, thus impeding globally generalized results. As pressure injuries might be considered as a result of suboptimal care, fear of criticism or institutional censure may have hampered objective reporting. If so, the actual prevalence might be higher than the rates identified. Accurate assessment of pressure injury staging is challenging and data collectors were not required to be qualified tissue viability experts. Despite our efforts to obtain consistency in reporting using a well-documented data collection procedure and providing a training module, variability and errors in staging may have occurred. Given the scale of the study, it was however not feasible to assess the validity of the data using digital photographs. Nevertheless, the error resulting from our approach will if anything have led to random error in estimations, rather than a systematic error. We were unable to doublecheck the self-reported number of participants who indicated having studied the training module, which may be prone to social desirability bias. As we requested to report the number of ‘nurses’ on the study day, without further definition, we do not know whether assistant-nurses were also reported and included in the calculation of the number of patients-per-nurse. The unexpected association of this variable with pressure injury also needs further exploration. There is a view that Suspected Deep Tissue Injuries should not be included in epidemiological studies because it is unclear how many are actual deep tissue injuries that convert to pressure injuries. Their number was however small and unlikely to have substantial impact, if any, on the estimated prevalence. Finally, our study may be prone to random observer errors as data collectors depended on the reliability of patient files to determine whether a pressure injury was ICU-acquired.

The major strength is that it is the first to present a worldwide picture of the epidemiology of pressure injuries in adult ICU patients and to map a high-risk profile based on a large global sample. It may act as an incentive for tackling this patient safety issue and provide local and regional baseline data for quality improvement programmes. Furthermore, pressure injuries staging was assessed by the gold standard of skin inspection by trained outcome assessors, and the study used a rigorous protocol with clear attention to detail in standardising the data collection process.