Stoma formation often exposes patients to short- and long-term complications, such as peristomal skin complications, incidents of leakage and mental distress, which can have negative implications for their quality of life (QoL) (Richbourg et al, 2007; Murken and Bleier, 2019; Goldstine et al, 2019; Jeppesen et al, 2022). Obtaining a secure seal between the pouching system (baseplate and pouch) and peristomal skin is important to reduce the risk of leakage and deterioration of skin health (Colwell, 2022). Peristomal body profiles vary between individuals and may change over time for the individual. The peristomal topography can be flat, turn inward or turn outward, and may have creases or folds that can impact fitting of pouching systems to the body (Colwell et al, 2019). Hence assessment of the peristomal body profile is important for selection of the most favourable pouching system to obtain a secure seal between baseplate and peristomal skin (Colwell, 2022), and use of a peristomal body profile assessment tool has been shown to reduce leakages and increase QoL (Vendelbo et al, 2023).
Approximately one-third of people living with a stoma have an outward peristomal body profile (Martins et al, 2022), and it can be difficult to avoid wrinkles and folds in the baseplate when applying a flat product on curved body shapes (Harris, 2021). Baseplates with a concave contour have been designed to ensure a better fit of the baseplate for people with an outward peristomal body profile (Harris, 2021; Burch, 2023). In a comparative clinical investigation, it was demonstrated that use of a concave two-piece pouching system provided improved body fit on people with outward peristomal body profiles compared with flat pouching systems (Rolfsen et al, 2024). When using the concave pouching system, participants experienced less leakage and improved QoL compared with use of flat pouching systems (Rolfsen et al, 2024).
The primary objective of this product evaluation was to investigate how the use of a one-piece concave pouching system (SenSura® Mio Concave one-piece) affected wear time for people with an outward peristomal body profile and who chose to continue use of the product. Secondary objectives were to evaluate the impact of the concave pouching system on unplanned changes and use of accessories.
Methods
Study design
The product evaluation of the concave pouching system (SenSura Mio Concave one-piece) was conducted from May 2017 to July 2017 in the UK.
The evaluation consisted of two test periods of 14 days ± 3 days each (Figure 1). The first test period was to examine whether participants were able to, and chose to, use the concave pouching system. The second test period was for those who could use the concave pouching system and chose to use it. The criteria for continuing to test period 2 were set to mimic real-world assessment of whether a new stoma product is feasible for the individual. Participants could not continue to test period 2 if:
All participants received a home visit from a research nurse, where participants were informed about the product evaluation and were asked to provide written informed consent to participate in the evaluation. Written consent was the point of inclusion and the research nurse, together with the subject, then filled out a baseline questionnaire, concerning demographics (sex, age, weight, height, type of ostomy and measurement of outward area) and information about the patient's usual flat product. The participants were provided with the concave pouching system and were trained in using the product. The participants then began to use the concave pouching system either at the visit or at the next product change. After the visit, the participants received access to an online questionnaire about use patterns with their usual flat pouching system.
One week after initiation of the product evaluation, participants received a call from the research nurse to ensure compliance and the wellbeing of the individual. None of the answers from the calls were recorded. Two weeks after initiation of the product evaluation, participants received a second call from the research nurse to evaluate whether the participant should continue to the next test period.
At the end of the product evaluation (after 4 weeks), participants received a call from the research nurse to end participation in the evaluation and to remind participants about completing the final online questionnaire about use patterns with the concave pouching system.
Selection of study participants
Potential study participants were found via Coloplast databases and were contacted by either letter, email or phone as first contact. All subjects who were interested, eligible according to the study selection criteria and provided informed written consent were enrolled.
Inclusion criteria
Participants were required to be >18 years, and to have been living with an ileostomy or a colostomy for at least 3 months. Other criteria were that participants should have an outward peristomal body profile (outward area should be 6-30 cm in diameter and at least 2 cm in height and the stoma should be placed on the bulge. Participants had to use a one-piece flat pouching system before enrolment.
Exclusion criteria
People having severe peristomal skin complications (bleeding and/or broken skin) were excluded from participating in the evaluation. People who had received topical steroid treatment in the peristomal skin area or systemic steroid treatment within the past month were also excluded from participating in the evaluation. People were also excluded if they were currently receiving or had received radiotherapy and/or chemotherapy within the past 2 months.
Endpoints and data collection
The primary objective of this product evaluation was to assess the wear time among people with outward peristomal body profiles who chose to use a concave pouching system and had used flat pouching systems before enrolment. The primary endpoint was evaluated with the question: ‘In a typical week, how often do you change your pouching system?’ at baseline (usual flat pouching system) and after 4 weeks' evaluation of the concave pouching system. Participants could choose between pre-defined response options (5 times or more a day; 4 times a day; 3 times a day; 2 times a day; 1 time a day; once every second day; once every third day; once every fourth day; once every fifth day or less).
The secondary objectives of the evaluation were to assess the impact of the concave pouching system on the degree of unplanned changes of the pouching system and the need for accessories among participants choosing to use the concave pouching system. Secondary endpoints were evaluated at baseline and at and after 4 weeks' use of the concave pouching system, with the following questions being reported:
Statistical analysis
No formal sample size calculation was conducted for this evaluation. A sample size of approximately 100 participants was considered suitable to enrol to address the primary objective of the evaluation, with the assumption that approximately 70% would enter test period 2. Statistical analyses were based on participants who provided information to the questionnaire about their usual flat pouching system (n=103) and those who provided information to the questionnaire about the concave pouching system after 4 weeks' use (n=84). Statistical analyses were performed using SAS version 9.4.
Wear time was assessed using an ordinal 9-point scale and analysed with a proportional odds model with subject included as a random effect and with product (usual flat pouching system/concave pouching system) as a fixed effect. The odds ratio (OR) between the usual flat product and concave pouching system as well as the corresponding 95% confidence intervals was estimated, and a test of the hypothesis of no difference in wear time between products (corresponding to an OR equal to 1) was performed. An OR<1 meant shorter wear time for the usual flat product. The analysis of wear time was also performed as subgroup analyses, where the analysis was made by type of stoma (colostomy/ileostomy), as well as by type of stoma product (closed/open pouches).
The endpoints concerning unplanned changes and use of accessories were evaluated dichotomously (Yes/No) and the proportions were compared by chi square tests with a significance level of α=0.05.
Ethical consideration
The product evaluation was carried out in accordance with the Declaration of Helsinki. The product evaluation plan was submitted to an ethics committee in the UK; however, the ethics committee did not consider formal approval necessary for conducting this evaluation, since the concave pouching system used in this product evaluation was already CE-marked in Europe and was used in the product evaluation according to intended use.
All subjects were fully informed about the investigation, both verbally and in writing, and all gave written informed consent to participate in the study. Participation in the study was voluntary and subjects could withdraw from the study at any time. The subjects received a small gift voucher for participation in the study.
Results
Baseline demographics
A total of n=110 participants were enrolled in the study with baseline demographics recorded by study nurses and, of these, 103 participants completed the online questionnaire evaluating use of their usual flat pouching system (Figure 1). A total of 102 participants participated in the second week phone interview. At this phone interview, participants could choose to discontinue the study if they found that the concave pouching system did not suit them (n=2), if their peristomal skin condition had deteriorated (n=3), or if they had not complied with using the concave pouching system (n=10). Hence, 87 participants were included in test period 2, and, of these, 84 completed the online questionnaire evaluating use of the concave pouching system.
The average age of the participants was 65.9 years (SD=10.8, range 31-88) and 77.3% were male (Table 1); 41.8% had an ileostomy, 56.4% a colostomy, and two participants (1.8%) had their type of stoma recorded as ‘unknown’. The size of the outward peristomal area was on average 15.8 cm (SD=5.0; range 4.0-30.0) in diameter and had an average height of 6.2 cm (SD=3.2; range 2.0-16.0).
| Characteristic | Enrolled population n=110 |
|---|---|
| Age in years: mean (SD; range) | 65.9 (10.8; 31−88) |
| Sex females/males: n (%) | 25 (22.7%)/85 (77.3%) |
| Type of stoma: ileostomy; colostomy; unknown (%) | 46 (41.8%); 62 (56.4%); 2 (1.8%) |
| BMI in kg/m2: mean (SD; range) | 29.8 (5.6; 21−53) |
| Outward area | |
| Diameter in cm: mean (SD; range) | 15.8 (5.0; 4.0−30.0) |
| Height in cm: mean (SD; range) | 6.2 (3.2; 2.0−16.0) |
Key: BMI=body mass index; SD=standard deviation
Most participants (n=99, 90.0%) used a pouching system from Coloplast at baseline and the remaining participants used pouching systems from other manufacturers. Most participants used one-piece open/drainable pouches (n=87, 79%) at baseline and the remaining used one-piece closed pouches (n=23, 21%).
Wear time
Participants evaluated how often they changed their usual flat pouching system in a typical week at baseline and how often they had changed the concave pouching system within a week at the final evaluation. Most participants reported that they changed both their usual flat product and the concave pouching system between two times a day and once every second day (79.6% vs 76.2%, respectively) (Table 2). There was no significant difference between the wear time of the concave pouching system and participants' usual flat product (OR 0.620 95%CI (0.302; 1.275), P=0.191). Furthermore, no significant differences in wear time between the usual flat product and the concave pouching system were identified when segmenting participants by stoma type or product type (closed and open pouches).
| Usual flat pouching system (n=103) | Concave pouching system (n=84) | |
|---|---|---|
| Q. In a typical week, how often do you change your usual/concave pouching system? | ||
| 5 times or more a day | 1 (1.0%) | 1 (1.2%) |
| 4 times a day | 2 (1.9%) | 2 (2.4%) |
| 3 times a day | 12 (11.7%) | 7 (8.3%) |
| 2 times a day | 20 (19.4%) | 15 (17.9%) |
| 1 time a day | 40 (38.8%) | 30 (35.7%) |
| Once every second day | 22 (21.4%) | 19 (22.6%) |
| Once every third day | 5 (4.9%) | 8 (9.5%) |
| Once every fourth day | 1 (1.0%) | 1 (1.2%) |
| Once every fifth day or less | 0 (0.0%) | 1 (1.2%) |
Unplanned changes
In a typical week, n=44 (52.4%) of the participants reported having no unplanned changes of their concave pouching system, compared with n=38 (36.9%) of the participants reporting this when using their usual flat product (P=0.034) (Table 3). A few participants reported having several unplanned changes per day. Leakage underneath or outside the baseplate was the most common reason for unplanned changes when using their usual flat product (40 out of 65; 61.5%) and the concave pouching system (20 out of 40; 50.0%).
| Usual flat pouching system (n=103) | Concave pouching system (n=84) | P-value | |
|---|---|---|---|
| Q. In a typical week, how often do you experience unplanned changes? | |||
| No unplanned changes | 38 (36.9%) | 44 (52.4%) | P=0.034 |
| 5 times or more a day | 1 (1.0%) | 1 (1.2%) | |
| 4 times a day | 1 (1.0%) | 0 (0.0%) | |
| 3 times a day | 4 (3.9%) | 3 (3.6%) | |
| 2 times a day | 4 (3.9%) | 2 (2.4%) | |
| 1 time a day | 5 (4.9%) | 4 (4.8%) | |
| Once every second day | 11 (10.7%) | 2 (2.4%) | |
| Once every third day | 5 (4.9%) | 4 (4.8%) | |
| Once every fourth day | 7 (6.8%) | 6 (7.1%) | |
| Once every fifth day or less | 27 (26.2%) | 18 (21.4%) | |
| Q. What is the typical cause of the majority of the unplanned changes you experienced? | |||
| (n=65) | (n=40) | ||
| Ballooning (ie the bag fills with air) | 3 (4.6%) | 3 (7.5%) | |
| Leakage | 40 (61.5%) | 20 (50.0%) | |
| Pancaking | 14 (21.5%) | 7 (17.5%) | |
| Skin irritation | 2 (3.1%) | 3 (7.5%) | |
| Other | 6 (9.2%) | 7 (17.5%) | |
Accessories
Significantly more participants used accessories together with their usual flat pouching system (72 out of 103; 69.9%) compared with the concave pouching system (35 out of 84; 41.7%) (P=0.0001) (Table 4). Significantly fewer participants used adhesive remover, tape, rings/seals, powder, cleansing spray/wipes and deodorant with the concave pouching system than with their usual flat pouching system.
| Usual flat pouching system (n=103) | Concave pouching system (n=84) | P-value | |
|---|---|---|---|
| Q. Do you use accessories with your usual flat/concave pouching system? | |||
| Yes | 72 (69.9%) | 35 (41.7%) | 0.0001*** |
| No | 31 (30.1%) | 49 (58.3%) | |
| Q. If you use any accessories, which do you use? | |||
| Adhesive remover (spray/wipes) | 57 (55.3%) | 26 (31.0%) | 0.0008*** |
| Skin barrier (spray/wipes/cream) | 35 (34.0%) | 19 (22.6%) | 0.0881 |
| Tape | 19 (18.4%) | 2 (2.4%) | 0.0005*** |
| Rings/seals | 26 (25.2%) | 10 (11.9%) | 0.0214* |
| Belts | 9 (8.7%) | 6 (7.1%) | 0.6896 |
| Paste | 4 (3.9%) | 3 (3.6%) | 0.9110 |
| Powder | 14 (13.6%) | 3 (3.6%) | 0.0177* |
| Cleansing spray/wipes | 22 (21.4%) | 8 (9.5%) | 0.0283* |
| Deodorant | 13 (12.6%) | 3 (3.6%) | 0.0278* |
| Lubricant | 12 (11.7%) | 6 (7.1%) | 0.2985 |
| Other accessories | 6 (5.8%) | 1 (1.2%) | 0.0968 |
Discussion
This product evaluation was designed to evaluate use patterns with a one-piece concave pouching system in people with an outward peristomal body profile, who chose to use the product. Wear time of the one-piece concave pouching system was similar to the wear time reported when using their usual flat pouching system, with most participants changing pouching system between two times a day and once every second day. The reported frequency of change in the product evaluation is similar to that reported in a large multinational study (Claessens et al, 2015) and within the national guidelines for prescribing stoma care products in the UK (PrescQIPP, 2015; Association of Stoma Care Nurses, 2016). Comparable wear times were also observed between corresponding two-piece concave- and flat pouching systems with the average wear time being approximately 50 hours for the baseplates (Rolfsen et al, 2024). Many people with a stoma establish regular change routines, and even during periods with leakage issues outside the baseplate approximately half the users do not change their usage pattern of pouching systems (de Fries Jensen et al, 2023), suggesting that it can be difficult to alter established change routines. A consensus statement stated that it was considered a central goal to extend wear time of baseplates and that use of convex products can extend wear time (Hoeflok et al, 2017). Extensions of wear times with convex pouching systems have been reported in few clinical investigations (Kruse and Størling, 2015; Evans and White, 2020), however, with the average extension in wear time being in hours and not days (Kruse and Størling, 2015), and it could be hypothesised that the current evaluation did not capture change frequency in enough detail.
Even though no difference in wear time between product types was observed in the present study, significantly fewer participants reported having unplanned changes of their concave pouching system compared with their usual flat pouching system, with the main reason for this difference being related to leakage. Indeed, we previously showed that use of a two-piece concave pouching system in people with an outward peristomal body profile resulted in less leakage underneath the baseplate and in fewer episodes where faecal output progressed outside the baseplate, soiling clothes or bed sheets (Rolfsen et al, 2024). People with a stoma who struggle with leakage incidents and worry about leakage use more accessories to mitigate the risk of future incidents (Jeppesen et al, 2022; de Fries Jensen et al, 2023). The proportion of participants using accessories in the present study fell from 69.9% when using their usual flat pouching system to 41.7% when using the concave pouching system. For example, significantly fewer participants used tape and rings/seals for leakage protection with the concave versus flat pouching system. Reducing the use of accessories could potentially lead to cost savings for the healthcare system.
Suboptimal fit between the baseplate and peristomal skin is a common reason for leakage (Vendelbo et al, 2023), and stoma care nurses have rated body profiles and incorrect product usage as key reasons for experiencing leakage (Down et al, 2021). Leakage of stomal effluent can have psychological implications and also increase the risk of experiencing peristomal skin complications (Voegeli et al, 2020; Jeppesen et al, 2022; Rolls et al, 2022). Choice of baseplate contour for a specific body profile is important to obtain a secure seal between baseplate and peristomal skin, and use of a body assessment tool for selection of appropriately fitting pouching systems has been shown to significantly reduce the number of leakages and improve QoL (Vendelbo et al, 2023). The authors recommend that nurses caring for people with an outward peristomal body profile consider use of baseplates with a concave contour designed for people with an outward peristomal body profile to ensure a better fit between baseplate and peristomal skin, reducing the risk of leakage, unplanned product changes and use of accessories.
Strengths and limitations
The aim of this evaluation was to investigate wear time, unplanned changes and use of accessories by participants who could and chose to use a concave pouching system. To achieve this, we compared these metrics for the concave pouching system against the participants' usual flat pouching systems. Therefore, the participants were first asked to try the concave pouching system in a 2-week screening period to allow participants to get used to the concave pouching system and evaluate if it was a product they would continue to use in the second evaluation period and if assessed appropriate to do so by the research nurse. This design was chosen because the purpose of the product evaluation was to observe how the concave pouching system would perform in the real world when used by people who chose to use it. The weakness of this evaluation design was that it introduced a positive bias for the concave pouching system, because only participants who could use and wanted to use the concave pouching system evaluated the performance of the product.
Conclusion
Selecting the right stoma-care product can be challenging but it is very important to obtain a secure seal between peristomal skin and baseplate. For people with an outward peristomal body profile, use of a concave pouching system led to fewer unplanned changes of pouching systems, and less use of accessories compared with use of flat pouching systems.