INTRODUCTION
Urinary incontinence is highly prevalent among older adults and represents a major clinical challenge in both community and institutional care settings [1-3]. The burden is particularly pronounced in frail elderly individuals with mobility limitation, cognitive impairment, and functional dependence, many of whom rely on absorbent diaper-based care as the primary method of urinary management [4, 5]. In long-term care environments, diaper dependence is often unavoidable and results in prolonged moisture exposure, reduced skin aeration, and frequent caregiver interventions.
Diaper-based urinary management is associated with several clinically important complications. Continuous exposure of perineal skin to urine and moisture contributes to incontinence-associated dermatitis, skin maceration, and pressure injury, particularly in individuals with fragile aging skin and impaired mobility [6-9]. These complications may lead to discomfort, secondary infection, delayed wound healing, and increased healthcare utilization. Prevention of moisture-associated skin injury is multifactorial and depends primarily on timely urine removal, skin cleansing, absorbent product changes, moisture control, and barrier protection. Although repositioning is important for pressure injury prevention, it does not directly address all mechanisms of moisture-associated skin damage. Although indwelling urinary catheterization may reduce moisture exposure, catheter use introduces significant risks including catheter-associated urinary tract infection, urethral trauma, reduced mobility, and increased morbidity [10-13]. Consequently, contemporary geriatric care increasingly emphasizes catheter avoidance and promotes development of non-invasive urinary management strategies capable of improving hygiene while minimizing complications.
External urinary collection devices have emerged as potential alternatives to catheterization and diaper-based care. Previous studies suggest that such devices may reduce catheter use and improve patient comfort; however, limitations related to leakage, positioning difficulty, and inconsistent urine capture remain barriers to widespread implementation [14-17]. At the same time, urinary incontinence places a substantial burden on both patients’ quality of life and caregiver workload, further highlighting the need for practical continence management strategies in dependent older adults [18].
Automated suction-based urinary management systems represent a newer technological approach designed to remove voided urine from the perineal area after urination and thereby support cleaner urinary care. Such systems may help reduce prolonged urine exposure and improve workflow efficiency, although they do not replace routine cleansing, skin care, or barrier protection measures. Emerging evidence, including randomized clinical data, supports the feasibility and safety of suction-assisted urinary management technologies in continence care [19]. Nevertheless, real-world evidence regarding usability, safety, and clinical applicability of automated suction devices in highly dependent elderly individuals remains limited.
An additional clinical consideration involves diagnostic reliability of urine specimens obtained in diaper-dependent populations. Accurate diagnosis of urinary tract infection in older adults is often complicated by asymptomatic bacteriuria, specimen contamination, and difficulties obtaining clean urine samples, which may lead to unnecessary antimicrobial therapy and diagnostic uncertainty [20-23]. Prior investigations have demonstrated that urine collection technique significantly affects culture accuracy and urinalysis interpretation, particularly in dependent patients where clean sampling is difficult [24-27].
Accordingly, the present study aimed to evaluate the pilot clinical feasibility of an automated urinary suction device in diaper-dependent older adults. The primary objective was to assess usability, functional performance, and perceived safety. In addition, as a secondary exploratory objective, we examined agreement between device-collected and reference urine specimens to assess the potential diagnostic applicability of this collection approach.
MATERIALS AND METHODS
Study Design and Participants
This study was conducted as a 2-cohort clinical evaluation of an automated urinary suction device in mobility-limited older adults. The primary cohort assessed usability, functional performance, and safety using structured satisfaction questionnaires before and after device implementation. A secondary diagnostic cohort evaluated the microbiologic and biochemical reliability of urine specimens collected using the device through comparison with concurrently obtained reference urine samples processed using standard laboratory methods.
The study was performed in a long-term care hospital setting and included elderly individuals requiring assisted urinary management due to severe mobility limitation or bedridden status.
Eligible participants were older adults with impaired mobility who required caregiver-assisted urinary management. Patients were recruited from a long-term care hospital ward. Inclusion criteria comprised bedridden status or severe functional limitation requiring assisted voiding care. Exclusion criteria included active gross hematuria, inability to use the device due to anatomical constraints, or refusal of consent.
For the usability cohort, participants completed both preuse and postuse assessments after a period of device application. Postuse assessments were performed after the predefined device-use observation period specified in the clinical evaluation protocol. For the diagnostic cohort, paired urine samples were obtained from participants in whom both device-based and conventional urine collection were feasible.
Written informed consent was obtained from all participants or their legally authorized representatives.
Device Description
The automatic urinary suction device evaluated in this study was HYGERA DolBot (HYGERA Networks, Inc., Korea), developed for noncontact urinary management in care-dependent elderly individuals. The system consists of a main control unit, a suction module with a urine collection container, urinary suction tubing, a touchscreen interface, and a remote monitoring application (Fig. 1). The device enables real-time voiding detection, automated urine suction, urine volume measurement, and multiple safety mechanisms, including feces detection, suction pressure overload prevention, and automatic shut-off at maximum container capacity.
The urine collection pathway involves removal of voided urine from the perineal region through a suction interface connected to tubing and a collection container. Because this pathway involves contact with the perineal area and interface components used during routine care, contamination from perineal flora or surrounding materials cannot be fully excluded when interpreting microbiologic findings.
Outcome Measures
Usability, functional performance, and safety were assessed using structured questionnaires administered before and after implementation of the device. The questionnaire utilized a 5-point Likert scale and evaluated 5 predefined domains, including product safety, operation and functional performance, ease of use, infection and skin complication, and overall satis-faction. Both domain-level and item-level analyses were conducted to capture overall usability trends as well as specific functional changes associated with device use. In addition, objective urinary parameters, including mean voided volume per episode and total daily urine output, were recorded during the observation period when feasible to complement subjective usability assessments. Items such as alarm accuracy during urination or defecation and adequacy of urine collection capacity were evaluated as subjective caregiver-reported perceptions of practical performance during routine use, rather than objective engineering validation metrics derived from independent device log analysis. Although most questionnaire items were designed to assess satisfaction, the item “buttock skin infection occurrence” was specifically structured to evaluate the presence of observable skin-related events based on caregiver visual inspection. Therefore, lower scores for this item indicate reduced occurrence rather than decreased satisfaction.
Because the study population consisted largely of mobilitylimited or bedridden older adults who were not always able to reliably assess device handling, urine management workflow, and skin-related care processes directly, the usability questionnaires were completed by bedside caregivers or nursing staff who routinely performed urinary care and observed device use in daily practice. Accordingly, the usability outcomes should be interpreted as caregiver-reported or proxy-reported assessments rather than strict patient-reported outcomes.
For the diagnostic cohort, paired urine specimens were obtained using the automated suction device and conventional reference sampling. Reference urine samples were obtained using standard-of-care clinical sampling methods, including intermittent catheterization or clean-catch urine collection when feasible, depending on patient condition and institutional protocol. The diagnostic analysis was designed as an exploratory secondary assessment to evaluate whether device-collected urine showed basic agreement with reference specimens under real-world care conditions.
Detection-level urine culture agreement was evaluated based on the presence or absence of bacterial growth. Paired results were classified as true positive, true negative, false positive, or false negative. Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were calculated.
Among culture-positive cases, species-level concordance was assessed descriptively. Urine pH values obtained from devicecollected specimens were compared with laboratory measurements. Agreement was evaluated using mean absolute error, root mean square error, and Bland-Altman analysis to assess systematic bias and limits of agreement.
The diagnostic component was intentionally limited to exploratory comparison of culture detectability and pH agreement. We acknowledge that inclusion of broader urinalysis variables would strengthen future diagnostic validation.
Statistical Analysis
Pre- and postuse usability scores were compared using paired statistical testing. Given the small sample size and ordinal nature of Likert-scale data, Wilcoxon signed-rank tests were additionally performed as nonparametric sensitivity analyses. Diagnostic performance metrics were calculated with Wilson 95% confidence intervals. Agreement in urine pH measurements was evaluated using Bland-Altman analysis. A 2-sided P-value <0.05 was considered statistically significant. Statistical analyses were performed using R ver. 4.2.1 (R Foundation for Statistical Computing, Austria).
RESULTS
Seven participants completed both preuse and postuse questionnaires and were included in the analysis. All usability outcomes were based on caregiver-reported questionnaire responses obtained during routine care, and therefore reflect perceived rather than objectively measured performance.
Domain-Level Satisfaction Outcomes
At the domain level, satisfaction scores generally improved following product use (Table 1). Statistically significant increases were observed in operation and functionality (preuse vs. postuse: 2.97±0.52 vs. 3.83±0.18; mean difference, 0.86; P=0.007) and ease of use (2.14±0.48 vs. 3.71±0.39; mean difference, 1.57; P=0.001).
In contrast, scores in the infection/skin complication domain decreased significantly after device use (3.14±0.85 vs. 2.21± 0.39; mean difference, -0.93; P=0.026). Because this domain was specifically designed to assess the occurrence of observable skin-related complications, lower scores indicate reduced perceived occurrence rather than worsening outcomes. Although improvements were observed in product safety (mean difference, 0.90; P=0.156) and overall satisfaction (mean difference, 0.93; P=0.066), these changes did not reach statistical significance.
The proportional distribution of postuse Likert responses across domains is illustrated in Fig. 2. As shown, operation and functionality as well as ease of use demonstrated postuse responses were concentrated in higher satisfaction categories (scores 4–5), whereas the infection/skin complication domain showed a relatively greater proportion of lower satisfaction responses (scores 1–2). Product safety and overall satisfaction domains exhibited more balanced distributions, with responses concentrated in mid-to-high categories. These distributional patterns are consistent with the domain-level statistical comparisons.
Item-Level Satisfaction Outcomes
Item-level analysis based on the full questionnaire dataset demonstrated heterogeneous but clinically meaningful changes across domains (Table 2). Within the operation and functionality domain, significant improvements were observed in operational convenience (preuse vs. postuse: mean 2.43 vs. 4.00; mean difference, +1.57; P=0.017), alarm accuracy during urination or defecation (+1.14; P=0.030), and adequacy of urine collection capacity (+1.14; P=0.047). Because these measures were obtained via Likert-scale questionnaires, they represent caregiver-perceived performance rather than objective technical validation of device accuracy.
In contrast, no statistically significant changes were noted in suction pad size adequacy or urine overflow prevention. In the ease-of-use domain, the convenience of the urine handling function showed the largest improvement among all items (2.00 vs. 3.86; mean difference, +1.86; P<0.001). Perceived comfort related to urine odor also increased, although this change did not reach statistical significance (P=0.093).
Regarding product safety, all related items demonstrated increasing trends in postuse scores; however, none reached statistical significance. Within the infection/skin complication domain, the item assessing buttock skin infection occurrence showed a significant decrease in score after device use (3.57 vs. 2.14; mean difference, -1.43; P=0.016). As this item specifically evaluated the occurrence of observable skin-related events based on caregiver visual assessment, lower scores indicate reduced perceived occurrence of such complications.
Perceived urinary tract infection occurrence did not change significantly (2.71 vs. 2.29, P=0.200). Taken together, these findings indicate improved usability and functional handling, with a potential reduction in caregiver-perceived skin-related complications, while remaining based on subjective assessment.
Diagnostic Urine Culture and Biochemical Agreement
A total of 12 paired urine samples were included in the diagnostic validation analysis. Given the small sample size, these estimates should be interpreted as preliminary findings from an exploratory pilot analysis rather than definitive measures of diagnostic performance. Reference urine culture identified bacterial growth in 5 cases and no growth in 7 cases. At the detection level, the automated urinary suction device correctly identified bacterial growth in 4 of 5 reference-positive samples and correctly classified all reference-negative samples (Table 3). One false-negative result was observed, and no false-positive results occurred. Sensitivity was 80.0%, specificity was 100.0%, and overall diagnostic accuracy was 91.7%. The positive predictive value was 100.0%, and the negative predictive value was 87.5%.
Species-level concordance among the 5 reference-positive samples is summarized in Table 4. Exact species-level agreement was observed in 2 cases (40.0%). Two cases (40.0%) demonstrated discordant species identification, in which the device detected bacterial growth but identified a different organism than the reference culture. One case (20.0%) represented missed detection, in which the reference specimen showed bacterial growth but the device-based sample showed no growth.
Quantitative comparison of urine pH values demonstrated strong agreement between device-based and reference measurements. The mean reference pH was 5.83, and the mean device-measured pH was 5.88. Eleven of the 12 paired samples demonstrated identical pH values, while one sample showed a +0.5 pH unit difference. However, because preanalytical factors such as time to measurement and exposure to ambient conditions were not independently controlled, these results should be interpreted with caution and considered exploratory.
The mean absolute error was 0.042, the root mean square error was 0.144, and the mean bias (device minus reference) was +0.042, indicating a slight tendency toward higher pH values measured by the device. Bland-Altman analysis demonstrated 95% limits of agreement ranging from -0.241 to +0.325 pH units. Most paired measurements fell within these limits, with minimal systematic bias observed. Accuracy within predefined tolerance thresholds was high, with 91.7% of measurements within ±0.1 pH units and 100% within ±0.5 pH units.
DISCUSSION
The present study evaluated the clinical feasibility of an automated urinary suction device in diaper-dependent older adults and demonstrated improvements in usability and functional performance in this pilot cohort. These findings are clinically meaningful given the high prevalence of diaper-based urinary management among frail elderly individuals and the associated burden of moisture exposure, caregiver workload, and diminished quality of life [1-5, 18]. Importantly, usability outcomes in this study were based on caregiver-reported assessments during routine care and therefore reflect perceived performance rather than objective device metrics. Within this context, significant improvements in operation and functionality and ease of use suggest that the device may facilitate more practical and efficient urinary management in highly dependent patients.
Skin-related outcomes require careful interpretation. In the present study, scores in the infection/skin complication domain decreased significantly after device use. Because this domain assessed the occurrence of skin-related complications, lower scores indicate reduced perceived occurrence of such events.
This finding suggests that caregiver-observed skin-related complications may have decreased during device use. This observation is consistent with the proposed mechanism of suction-based urinary management, which removes voided urine from the perineal area and may reduce prolonged moisture exposure. However, it is important to emphasize that the device does not replace routine skin care measures, including cleansing, repositioning, and barrier protection, which remain essential components of moisture-associated skin damage prevention.
Despite this potentially favorable signal, interpretation should remain cautious because the study relied on subjective caregiver observation and did not include objective dermatologic endpoints such as validated incontinence-associated dermatitis scores or clinician-based skin assessments. Therefore, the magnitude and clinical significance of this effect cannot be definitively established in the present pilot study.
Caregiver burden represents another critical aspect of diaperbased continence management. Frequent diaper changes, repositioning, and skin care interventions are time-consuming and physically demanding, particularly in long-term care environments. The observed improvements in operational convenience and urine handling suggest that automated suction technology may reduce manual caregiving demands and improve workflow efficiency, although this effect was not directly quantified in this study. The findings also support the ongoing shift toward noninvasive urinary management strategies aimed at minimizing indwelling catheter use. Catheterization is associated with infection risk, mobility restriction, and healthcare costs, prompting efforts to reduce unnecessary catheter placement [10-13]. External urinary devices have been proposed as alternatives; however, leakage and inconsistent urine capture remain recognized limitations [14-17]. In this context, suction-based systems may offer an alternative approach by actively removing urine after voiding, although their performance remains dependent on appropriate positioning and caregiver-assisted application.
Proper positioning represents a critical factor for optimal device function. In this study, device placement was performed by trained caregivers according to standardized instructions; however, positioning stability, frequency of repositioning, and malposition-related failure or leakage were not systematically recorded. Suboptimal positioning may lead to reduced suction efficiency, incomplete urine capture, or leakage, representing an important source of performance variability in real-world settings.
These findings highlight the importance of caregiver training and suggest that future studies should incorporate objective monitoring of positioning stability and its relationship to device performance and failure events.
An additional exploratory component of this study was the evaluation of diagnostic agreement of device-collected urine samples. At the detection level, the device demonstrated acceptable agreement with reference samples in this small cohort; however, species-level concordance was limited (40.0%), indicating insufficient microbiologic reliability for organism-level identification. This discrepancy is likely attributable to contamination or variability inherent to the urine collection pathway, which involves contact with the perineal environment and external interfaces prior to sample collection. Accordingly, the present findings do not support the use of device-collected urine as a reliable method for organism-level microbiologic diagnosis. The device should not be used for clinical decisionmaking based on culture results obtained through this method. Instead, device-based sampling may have limited utility in exploratory or preliminary screening contexts, but requires further validation under controlled conditions.
This observation is clinically relevant because diagnostic uncertainty related to asymptomatic bacteriuria and contaminated urine specimens is common in frail elderly populations and may lead to inappropriate antimicrobial prescribing [20-23]. Previous studies have highlighted the influence of urine sampling technique on culture accuracy and urinalysis interpretation [24-27]. Routine urinalysis parameters were assessed in a subset of samples; however, no consistent or clinically meaningful findings were observed, and therefore these data were not included in the final analysis. Urine pH measurements demonstrated close agreement between device-collected and reference samples. However, these findings should be interpreted cautiously, as key preanalytical variables (e.g., time to analysis and environmental exposure) were not controlled, and therefore should be regarded as exploratory rather than confirmatory.
The present study also contributes to the evolving evidence base supporting suction-assisted urinary management technologies. While prior research has demonstrated favorable safety and patient-reported outcomes with suction-based systems, the current study provides additional real-world data demonstrating usability benefits in highly dependent elderly individuals alongside exploratory findings regarding diagnostic specimen characteristics [19].
Several limitations should be acknowledged. First, the study was conducted in a small sample and should be considered a pilot feasibility study. Second, usability outcomes were based on subjective caregiver-reported measures, which may introduce reporting bias. Third, objective clinical endpoints including dermatologic outcomes, infection incidence, and device performance metrics were not assessed. Fourth, the diagnostic analysis was limited in sample size and may have been influenced by contamination or methodological variability in urine collection.
Overall, automated urinary suction technology may represent a promising non-invasive urinary management strategy for diaper-dependent older adults, with potential to improve caregiving workflow and hygiene, while the diagnostic applicability of device-collected urine remains exploratory and should not be used for organism-level clinical decision-making based on current evidence.
In conclusion, the automated urinary suction device improved usability and functional performance in mobility-limited older adults and may facilitate more practical urinary management in dependent care settings. Skin-related findings suggest a potential reduction in caregiver-perceived complications; however, these observations remain preliminary and require confirmation through objective dermatologic evaluation. The diagnostic applicability of device-collected urine remains exploratory and should be interpreted with caution pending further validation. Clinical application should be limited to supportive urinary management rather than diagnostic use until further validation is available.
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