Abstract
BACKGROUND
Pressure ulcers (PUs) are a burden to patients, carers and health-care providers. Specialist mattresses minimise the intensity and duration of pressure on vulnerable skin sites in at-risk patients.
PRIMARY OBJECTIVE
Time to developing a new PU of category ≥ 2 in patients using an alternating pressure mattress (APM) compared with a high-specification foam mattress (HSFM).
DESIGN
A multicentre, Phase III, open, prospective, planned as an adaptive double-triangular group sequential, parallel-group, randomised controlled trial with an a priori sample size of 2954 participants. Randomisation used minimisation (incorporating a random element).
SETTING
The trial was set in 42 secondary and community inpatient facilities in the UK.
PARTICIPANTS
Adult inpatients with evidence of acute illness and at a high risk of PU development.
INTERVENTIONS AND FOLLOW-UP
APM or HSFM - the treatment phase lasted a maximum of 60 days; the final 30 days were post-treatment follow-up.
MAIN OUTCOME MEASURES
Time to event.
RESULTS
From August 2013 to November 2016, 2029 participants were randomised to receive either APM (n = 1016) or HSFM (n = 1013). Primary end point - 30-day final follow-up: of the 2029 participants in the intention-to-treat population, 160 (7.9%) developed a new PU of category ≥ 2. There was insufficient evidence of a difference between groups for time to new PU of category ≥ 2 [Fine and Gray model HR 0.76, 95% confidence interval (CI) 0.56 to 1.04; exact p-value of 0.0890 and 2% absolute difference]. Treatment phase sensitivity analysis: 132 (6.5%) participants developed a new PU of category ≥ 2 between randomisation and end of treatment phase. There was a statistically significant difference in the treatment phase time-to-event sensitivity analysis (Fine and Gray model HR 0.66, 95% CI 0.46 to 0.93; p = 0.0176 and 2.6% absolute difference). Secondary end points - 30-day final follow-up: new PUs of category ≥ 1 developed in 350 (17.2%) participants, with no evidence of a difference between mattress groups in time to PU development, (Fine and Gray model HR 0.83, 95% CI 0.67 to 1.02; p-value = 0.0733 and absolute difference 3.1%). New PUs of category ≥ 3 developed in 32 (1.6%) participants with insufficient evidence of a difference between mattress groups in time to PU development (Fine and Gray model HR 0.81, 95% CI 0.40 to 1.62; p = 0.5530 and absolute difference 0.4%). Of the 145 pre-existing PUs of category 2, 89 (61.4%) healed - there was insufficient evidence of a difference in time to healing (Fine and Gray model HR 1.12, 95% CI 0.74 to 1.68; p = 0.6122 and absolute difference 2.9%). Health economics - the within-trial and long-term analysis showed APM to be cost-effective compared with HSFM; however, the difference in costs models are small and the quality-adjusted life-year gains are very small. There were no safety concerns. Blinded photography substudy - the reliability of central blinded review compared with clinical assessment for PUs of category ≥ 2 was 'very good' (kappa statistic 0.82, prevalence- and bias-adjusted kappa 0.82). Quality-of-life substudy - the Pressure Ulcer Quality of Life - Prevention (PU-QoL-P) instrument meets the established criteria for reliability, construct validity and responsiveness.
LIMITATIONS
A lower than anticipated event rate.
CONCLUSIONS
In acutely ill inpatients who are bedfast/chairfast and/or have a category 1 PU and/or localised skin pain, APMs confer a small treatment phase benefit that is diminished over time. Overall, the APM patient compliance, very low PU incidence rate observed and small differences between mattresses indicate the need for improved indicators for targeting of APMs and individualised decision-making. Decisions should take into account skin status, patient preferences (movement ability and rehabilitation needs) and the presence of factors that may be potentially modifiable through APM allocation, including being completely immobile, having nutritional deficits, lacking capacity and/or having altered skin/category 1 PU.
FUTURE WORK
Explore the relationship between mental capacity, levels of independent movement, repositioning and PU development. Explore 'what works for whom and in what circumstances'.
TRIAL REGISTRATION
Current Controlled Trials ISRCTN01151335.
FUNDING
This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 52. See the NIHR Journals Library website for further project information.
Plain language summary
Pressure ulcers (PUs) are patches of damaged skin, mainly caused by sitting/lying in one position. PUs are graded based on how serious they are, ranging from red patches (category 1) through small skin breaks/blisters (category 2) to serious wounds (category 4). Special mattresses are used to help prevent PUs. This study compared alternating pressure mattresses (APMs) with high-specification foam mattresses (HSFMs), to see which is better at preventing PUs. The study included adults admitted to hospital for acute illness who were at a high risk of developing PUs. Patients were randomly allocated to HSFM or APM. Nurses checked patients’ skin and recorded changes. A total of 132 patients developed at least one new PU of category ≥ 2 before the end of treatment (60 days maximum). Of these, 53 patients were allocated to the APM arm and 79 to the HSFM arm, a difference of 2.6%. This is a small but significant difference. Nurses looked at patients’ skin again 30 days after the patient had stopped using a trial mattress. At this point, 160 patients had at least one new PU (of category ≥ 2). Of these, 70 patients were allocated to the APM arm and 90 to the HSFM arm, a very small difference of 2.0%. Some patients asked to change mattresses; this happened more in the APM group. This study focused on high-risk patients; however, only a small number of people developed PUs, suggesting that prevention is possible with either mattress. Results also suggest that certain groups of patients may benefit more from APMs, for example people who cannot give consent or who have skin redness. When planning prevention and choosing mattresses, professionals and patients need to consider a number of factors, such as comfort, existing PUs and people’s ability to self-care. Further research is recommended to understand what sort of prevention works, for whom and in what circumstances.
Full text of this article can be found in Bookshelf.