Keywords
Issue: Volume 63 - Issue 10 - October 2017 ISSN 1943-2720
Index: Ostomy Wound Manage. 2017;63(10):16-33. doi: 10.25270/owm.2017.1633
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Abstract
Venous leg ulcers are characterized by a long healing process and repeated cycles of ulceration. A secondary analysis of data from multisite longitudinal studies was conducted to identify risk factors for delayed healing and recurrence of venous leg ulcers for development of risk assessment tools, and a single-site prospective study was performed to assess the new tools’ interrater reliability (IRR).The development of the risk assessment tools was based on results from previous multivariate analyses combined with further risk factors documented in the literature from systematic reviews, randomized controlled trials, and cohort studies with regard to delayed healing and recurrence. The delayed healing tool contained 10 items, including patient demographics, living status, use of high-compression therapy, ulcer area, wound bed tissue type, and percent reduction in ulcer area after 2 weeks. The recurrence tool included 8 items, including history of deep vein thrombosis, duration of previous ulcer, history of previous ulcers, body mass index, living alone, leg elevation, walking, and compression. Using consensus procedures, content validity was established by an advisory group of 21 expert multidisciplinary clinicians and researchers. To determine intraclass correlation (ICC) and IRR, 3 raters assessed 26 patients with an open ulcer and 22 with a healed ulcer. IRR analysis indicated statistically significant agreement for the delayed healing tool (ICC 0.84; 95% confidence interval [CI], 0.70-0.92; P<.001) and the recurrence tool (ICC 0.88; 95% CI, 0.75-0.94; P <.001). The development and reliability results of these risk assessment tools meet the recommendations for evidence-based, reliable tools and may benefit clinicians and patients in the management of venous leg ulcers. Studies to examine the items with low ICC scores and to determine the predictive validity of these tools are warranted.
Introduction
Although approximately 70% of venous ulcers heal within a 24-week period, 30% are unhealed after this time.1 Venous leg ulcers are characterized by repeated cycles of ulceration and recur in 60% to 70% of patients.2 The highest rates of recurrence occur within the first 3 months after healing.3,4 Although the majority of venous leg ulcers recur within 12 months,2,5 these recurrences often occur over decades.6
Comparing studies in the literature on recurrence is difficult due to a lack of a clear or consistent definition of recurrence. However, ongoing monitoring is essential after healing because the underlying venous disease remains.7 In a randomized controlled trial8 (N = 500) and a case series9 with long-term follow-up (N = 97 legs), episodes of recurrence decreased in patients who had undergone surgery for superficial venous reflux and/or perforator surgery in addition to wearing compression. However, surgery is not always an option for patients, particularly in this population where age and comorbidities restrict many patients’ suitability for surgery or where acceptance of surgery may be an issue.8 The long-term and often frequent recurrent nature of the ulcers can lead to uncertainty,10 disappointment, hopelessness, and worry among patients that fear they may never be free of the condition.11 A large obstacle in the treatment of chronic venous leg ulcers is estimating long-term clinical outcomes. Although tools have been developed to assess the severity of a wound and healing progress,12-17 few are specifically for patients with venous leg ulcers that are appropriate for clinicians to assess the risk for delayed healing outcomes, and none were found in the literature with regard to venous leg ulcer recurrence.
Currently, clinician observation indicates practitioners generally utilize their own expert judgment and previous experience to determine whether a wound will be difficult to heal, or once healed, whether it will recur. Five (5) risk assessment tools for delayed healing of venous leg ulcers have been discussed in the literature18-22 and at least 1 has been used in research studies,23,24 but none appear to be widely used in clinical settings to assist the clinician in detecting delayed healing in order to guide appropriate wound management. Skene et al20 concluded from a secondary analysis of 200 participants, where 49% of ulcers healed within 4 months, that the risk factors ulcer area (P <.001), longer duration (P <.001), increased age (P= .002), and deep vein involvement shown on photoplethysmography (P = .006) were significantly related to nonhealing. From these risk factors, a prognostic index was developed to indicate nonhealing within 4 months. Margolis et al22 concluded from a retrospective cohort study of 260 participants, where 56% to 65% of leg ulcers healed within 24 weeks, that the risk factors wound area and wound duration were significantly related to nonhealing; the authors devised a simple prediction rule that was retrospectively and prospectively validated in participants with multilayered limb compression therapy.
Taylor et al21 concluded from a retrospective cohort study of 325 participants in which 78.6% healed by 24 weeks that the risk factors age, ulcer area, gender, and history of a previous leg ulcer were significantly related to nonhealing; from these findings, a complex prognostic index equation was developed and retrospectively validated. Falanga et al19 concluded from a prospective, randomized controlled trial of 177 participants, where 65% of venous ulcers healed within 12 months, that a previous wound bed score based on wound bed appearance, wound exudate, wound duration, and surrounding skin also could be used to predict wound closure. Kulkarni et al18 utilized a randomized controlled trial of 229 participants to determine that the risk factors age, ulcer duration, and venous refill time were significantly related to nonhealing at 24 weeks; they developed an equation based on these factors that was validated in 86 participants, again only in those using high-level compression. Although a few of these tools have been validated, there is no evidence of reliability testing.
These tools may be in limited use because 2 of the tools utilized variables19 and equations21 that would be difficult for many health care professionals to calculate and evaluate without significant time and education. Two (2) other tools used photoplethysmography to determine deep vein involvement20 and venous refill time,18 a test that is mostly beyond the scope of many primary health wound clinics, severely limiting the everyday usability by many clinicians. However, these studies devised scoring systems that identified significant risk factors from their own research or had previously been shown to be significant predictors in the literature. Wound duration was used in 4 of the 5 tools and patient age and wound area in 3 of the 5 tools. Most of these tools have utilized only ulcer-specific variables without consideration of other holistic factors that may influence healing. Identifying a broader range of other potential risk factors could be of assistance in strengthening a tool for use by all clinicians in all settings to improve the ability to predict healing.
Delayed healing and ulcer recurrence are challenges for all practitioners involved in venous leg ulcer management. The lack of risk assessment tools may contribute to the current high levels of health service use for leg ulcers, which has been estimated in a retrospective study25 of 104 participants to include a median of 3 different health disciplines (range 1–8) in the 12 months before admission to a wound specialist clinic. This also may contribute to poor rates of wound healing, because 46% of participants attending a specialist wound clinic were noted to have a wound duration of >6 months and 17% for a year or longer on admission.25 It previously has been identified that any prognostic tool should include clinically relevant patient data that have been tested for inclusion in a risk assessment tool,26 ensure it is easy to calculate the risk assessment score with a small number of items, and not require specialist assessment technology or skills.27 A tool should be able to be used in a timely way to generate a prediction and guide decisions,26 be reliable, and not require undue resources/expense.26,27
The development of venous leg ulcer risk assessment tools for delayed healing and recurrence would be beneficial for clinicians to be able to determine realistic outcomes for their patients and make decisions on adjunctive interventions when standard care may be insufficient to achieve or maintain healing.28 Health care professionals are under increasing pressure to justify their actions in terms of cost-effectiveness and clinical outcomes29; thus, a risk factor profile could be helpful. In addition, a venous ulcer healing predictor also could be of benefit to a health care system, which requires information on the burden of care in order to make decisions on the needs of the population and the allocation of appropriate resources.28
As such, this study aimed to develop tools for predicting the likelihood of delayed healing and recurrence of venous leg ulcers and to assess interrater reliability (IRR) of the tools.
Methods
Developing the risk assessment tools. Previously documented methods for development of a risk assessment tool were utilized18,30,31 and included the results of a literature review on risk factors,32results of analyses on significant predictors of failure to heal or recurrence from previous studies by the authors,33,34 and content validation by consensus of an expert interdisciplinary Wound Advisory Group (WAG).35,36
The WAG was formed to determine face validity37 and assess content validity, as well as to provide expert guidance on the development and testing of the new tools. The development of the risk assessment tool was based on previous multivariate analysis.33,34 Further to this, significant risk factors documented in the literature from systematic reviews, randomized controlled trials, and cohort studies were discussed among the group such as those included in a narrative review published in 2015 of 27 studies.32 The group included 21 multidisciplinary clinicians and researchers from different clinical and organizational settings who had specialist knowledge and expertise in wound healing and/or research and instrument development. The national and international wound care specialists included 3 community nursing managers, 2 nurse practitioners in wound care, 1 clinical nurse consultant, 1 clinical nurse, 4 nurse researchers, 2 podiatrists, 1 dietitian, 1 community care advisor, 2 medical practitioners, and 4 professors in nursing, exercise, and nutrition sciences with many years of combined wound care and research experience. This group also included 5 representatives from a national wound care professional association.
The WAG reviewed and discussed the proposed tools’ content and scoring. Responses of the WAG were not quantified; their consensus was obtained by agreement of all the WAG of variables included for content validity.35 It was important to keep the tools simple for use across a variety of settings and to keep the risk assessment tool items to a minimum. As a side note, a “tool within a tool” (eg, a depression screening tool within a risk assessment tool), was deemed not appropriate by the WAG; therefore, it was not included in the final version of the risk assessment tools. However, single-item components of the Pressure Ulcer Scale for Healing (PUSH)38 were included in the final tool. Consensus was reached that all suitable evidence-based items were included and that the response options were appropriate.
Point values for the items in the risk assessment tools identified from the multivariate analyses33,34 were determined utilizing the regression coefficients (β) of significant independent risk factors from the multivariate modeling.27 To ensure a simplified prediction rule and easy computing, the regression coefficients (β) were rounded to the nearest whole number for item point values. Points for additional items were determined by published literature and the WAG. One point was given for any item without published effect size or coefficients.
IRR of the risk assessment tools. IRR was tested using intraclass correlation (ICC) analysis to compare the ratings of 1 nurse practitioner and 2 registered nurses for all items in the risk assessment tool. IRR was computed by comparing the risk assessment tool ratings made by each of the raters when using the risk assessment tool independently (without observation of each other) during the same clinical consultation visit of each patient in the sample. These 3 raters had between 5 and 15 years of clinical and/or research experience with chronic wounds. To avoid unnecessary physical and mental trauma to the patients who participated, only 1 rater performed an ulcer area tracing on each participant utilizing an acetate film tracing; the same rater performed all the tracings . This tracing then was retraced and the area measured and calculated using the Visitrak™ pen planimetry system (Smith and Nephew, North Ryde, New South Wales, Australia) by an additional 2 raters independently. Rater reliability regarding area tracing was assessed utilizing an acetate grid by the same 3 raters on 7 ulcers on a training model, and ICCs were calculated for these assessments.
Sample for IRR. A power analysis determined the required sample for IRR was 30 participants, to be assessed by 3 raters. Sample size calculation was based on 80% power to detect an ICC of 0.8 when the ICC under the null hypothesis is 0.6 using an F-test with a significance level of 0.05.
Patient inclusion/exclusion criteria.
Inclusion criteria. Inclusion criteria stipulated patients must have leg ulcers of primarily venous etiology (defined as a loss of skin on the leg or foot that had been diagnosed as predominantly venous) as diagnosed by the clinician in charge of care (for the risk assessment tool for delayed healing); or a recently healed (within 4 weeks) leg ulcer of primarily venous etiology as diagnosed by the clinician in charge of care (for the risk assessment tool for recurrence), along with an ankle brachial pressure index ≥0.8 and <1.3 in the affected leg. A wound was considered healed when 100% epithelialization of the wound bed was achieved and maintained for at least 2 weeks. A recurrence of a venous leg ulcer was defined as a wound of venous etiology that had recurred on the same leg that had previously been affected by a venous leg ulcer.
Exclusion criteria. Patients with a cognitive impairment, as diagnosed by the clinician assessing the patient, or ulcers with malignancy present were excluded.
The participants were recruited from a community wound healing service where the 3 raters were all available to attend the necessary visits. All consecutive patients who met the inclusion/exclusion criteria were approached for inclusion in the IRR testing of the risk assessment tool between July 2012 and August 2014.
Data collection and assessment.
IRR. Data were collected during a participant’s wound treatment clinic visit. Health and medical history questions were first collected from clinical records; if these data were not able to be determined from clinical records, the raters queried the participant directly. Clinical examination and answers to social and preventive strategy questions were collected directly from the patients. For the delayed healing study, the clinician in the clinic removed the participant’s dressings and washed the affected area for participants with open leg ulcers, after which each risk assessment was performed independently at the same clinical consultation visit by 1 nurse practitioner and 2 registered nurses serving as raters. Due to clinic activities and the ability of the raters to attend the clinic at certain times, the raters maintained no consistent or specific order for assessment completion. The risk assessment tools were completed during or immediately following each visit, generating 3 sets of scores for each patient. If physical or emotional discomfort was evident at any point in the study process, the data collection was discontinued.
Data analyses.
IRR. Data on both risk assessment tools were analyzed using the Statistical Package for the Social Sciences (SPSS for Windows, version 19.0; IBM Corp, Armonk, NY) software. The 3 raters for both tools all had been involved in the development of the tools and required no further training on their use. The raters were requested not to exchange information on the variables associated with the risk assessment tools.
ICC. ICC provides a measure of reliability, indicating whether an assessment tool can be used effectively by a variety of health professionals39 by analyzing the degree of concordance or the consistency of the performance of 2 or more observers recording the same responses on the risk assessment tool at the same visit.40 ICC is the standard statistical method for assessing the agreement between 2 or more raters39 and is a measure of the proportion of variance that is attributable to the objects of measurement,41 indicating the degree of agreement between raters. ICC coefficients are categorized between 0 and 1, with 1 indicating total agreement, 0.61 to 0.80 indicating good strength of agreement, and 0.81 to 0.99 indicating very good agreement.40,42 A 1-way random effect analysis of variance model was used where raters were considered random, the risk assessment variables fixed, and confidence intervals (CI) were calculated. ICCs were calculated as average measures because the variables used were average observations of several single observations. A P value <.05 was used to identify statistical significance.
Ethical considerations. This study gained ethical approval from the University Human Research Ethics Committee. All participants were provided with an information package and all participants gave written informed consent.
Results
Development of risk assessment tools. Risk factors for failure to heal and for recurrence were based on results from previous studies by this team using multivariate modeling33,34 in addition to risk factors documented in the literature from systematic reviews, randomized controlled trials, and cohort studies. Risk factors independently and significantly associated with failure to heal a venous leg ulcer by 24 weeks in a previous study33 by this team were patients who lived alone, were not treated with high-level (ie, >30 mm Hg) compression therapy at enrollment to the study, had higher ulcer severity scores (PUSH) at enrollment, and had <25% reduction in ulcer area 2 weeks after initial assessment. Risk factors significantly associated with recurrence of a venous leg ulcer within 12 months after healing in a previous study by this team included history of deep vein thrombosis (DVT), longer duration of previous ulcer, history of more than 1 previous leg ulcer, not elevating legs for at least 30 minutes/day, walking <3 hours/day, and lower levels of self-efficacy.34 These factors all were considered for inclusion in the respective risk assessment tools along with predictors and existing risk factors reported in the literature, such as those reported for delayed healing in a narrative review32 published in 2015 of 27 studies including ulcer duration, previous history of ulceration, venous abnormalities, decreased mobility and/or ankle range of movement, poor nutrition, and increased age; and a survey and retrospective chart review3 of 122 community living patients with a healed venous leg ulcer where risk factors included previous ulcer duration, cardiac disease, low body mass index (BMI), depression, and self-efficacy scores.3 Items were included if they contributed to improved discrimination of the risk assessment tool.
Three (3) teleconferences among the WAG members included 11 to 13 people each time. Email correspondence provided all relevant information in advance of the teleconferences so persons who could not attend the teleconference could provide feedback by email. The teleconferences provided information to the WAG on definitions, findings, potential scoring systems, and items, including questions about format, content, and response choices for each item. The final versions of the risk assessment tools were accepted by all members of the expert WAG as including all important items and that response options were appropriate.
Delayed healing assessment tool. The final risk assessment tool for delayed healing consisted of 8 items including health, medical, and social history items and ulcer characteristics, contributing to a baseline risk assessment score. The items at baseline were age (years), ulcer duration (weeks), history of previous DVT in leg with the ulcer, whether a patient lived alone, whether a patient used an assistive device to ambulate, whether the wound bed had >50% coverage of slough and/or necrotic tissue, ulcer area (cm2), and whether treatment currently involved compression <30 mm Hg. An additional 2 items (making 10 items overall) were added regarding changes in ulcer area and calf circumference to be measured 2 weeks from baseline; the baseline and 2-week scores were combined to determine an overall risk assessment score. The questions are generally yes/no and/or achieved/not achieved, and scores for individual items ranged between 0 and 6. The total risk assessment score for delayed healing ranged from 0 to 13 for the baseline score, 0 to 10 for the 2-week score, and 0 to 23 for the overall risk assessment score. The higher the score, the greater the risk of delayed healing (see Figure 1).
Recurrence assessment tool. The final risk assessment tool for recurrence consisted of 8 items including health, medical, and social variables along with level of preventive activities to determine a risk assessment score. The items were history of previous leg ulcers and history of DVT in the recently healed leg, previous ulcer duration (weeks), BMI <22, whether a patient lives alone, whether patient is ambulating on his/her feet for at least 3 hours/day, elevating legs for 30 minutes/day or more, and whether the patient is wearing compression hosiery Class 2 (20 mm Hg to 30 mm Hg) or higher for at least 5 days/week. The total risk assessment score for recurrence ranged from 0 to 16. The questions are generally yes/no and scores for individual items ranged between 0 and 4 (see Figure 2).
IRR. Due to difficulties in organizing the 3 raters’ availability at the same time as wound clinic appointments for all participants at all appropriate time points, 36 participants were recruited but only 26 had an overall risk assessment score calculated by all 3 raters for the delayed healing risk assessment tool study. In the recurrence risk assessment tool study, 24 participants were recruited and 22 participants had a risk assessment score calculated from all raters. All patients that were approached agreed to be involved.
Delayed healing risk assessment tool IRR. Among the 26 nonhealing risk group participants, 17 (65.4%) were men, the mean age of participants was 66.31 ± 17.47 years, and the median duration of participants’ ulcers at baseline was 18 (range 4–416) weeks. The median area of the ulcers was 2.4 cm2 (range 0.1–23.6 cm2). The mean total risk assessment scores of the 3 raters were 11.35 ± 4.19, 10.58 ± 5.19, and 10.92 ± 5.36, respectively, with an ICC value of 0.84 (95% CI, 0.70-0.92; P <.001). Statistically significant agreement was noted among all raters for all individual item variables, baseline scores (ICC 0.95; 95% CI, 0.90-0.97; P<.001), 2-week scores (ICC 0.62; 95% CI, 0.27-0.82; P = .002), and total risk assessment scores (ICC 0.84; 95% CI, 0.70-0.92; P <.001) (see Table 1).
Statistically significant agreement was obtained among all 3 raters regarding assessment of the ulcer areas; acetate grid tracings of 7 ulcers on a training model achieved an ICC of 1.0 (95% CI, 0.99-1.00; P<.001). This indicated full agreement in reliability among these 3 raters with regard to the measurement of wounds using tracings with acetate grids.
Recurrence risk assessment tool IRR. Among the 22 participants, 14 (63.6%) were men, the mean age was 67.82 ± 11.73 years, and 13 (59.1%) had a history of previous leg ulcers in the same leg as the recently healed ulcer. The median duration of the participants’ recently healed ulcers was 11.0 (range 1–156) weeks. The mean total risk assessment scores of the 3 raters were 5.36 ± 3.22, 5.68 ± 4.34, and 6.23 ± 3.49, respectively, with an ICC value of 0.88 (95% CI, 0.75-0.94; P <.001). A statistically significant agreement was noted among all raters for all individual item variables, the health, medical and social history subtotal (ICC 0.85; 95% CI, 0.72-0.94, P <.001), the preventive subtotal (ICC 0.85; 95% CI, 0.70-0.93; P <.001), and total risk assessment score (ICC 0.88; 95% CI, 0.75-0.94; P <.001) (see Table 2).
Discussion
Risk assessment tool for delayed healing. The 10 variables in the newly developed risk assessment tool for delayed healing (whether patients lived alone, were not treated with high-level compression therapy, ulcer severity [area and tissue type], whether ulcer area decreased <25% in 2 weeks, age, ulcer duration, history of DVT, mobility, and reduction in calf circumference) are easily identifiable and measurable in the clinical area as determined by studies that have previously collected these variables in the clinical area.25,33
Compression therapy and calf circumference reduction items in the risk assessment tool are important with regard to the etiology of a venous leg ulcer. The use of high-level compression therapy has long been identified as the cornerstone of evidence-based management of venous leg ulcers, which includes evidence from an extensive systematic review43 of 22 trials that evaluated compression and concluded high compression (ankle compression 35 mm Hg to 45 mm Hg) was more effective than low compression (ankle compression 15 mm Hg to 25 mm Hg). However, a patient may not commence with treatment in this level of compression for many reasons, such as cost, concordance with recommendations, and lack of training and knowledge by clinical staff.44-46 Previously developed risk assessment tools were limited as being based on data only from participants using high-level compression systems. A level-of-compression question was incorporated into the new tool so all patients with venous leg ulcers across all settings, regardless of type of compression, could be included. The addition of the item addressing calf circumference reduction of ≤2 cm within 2 weeks acknowledges an important potential risk factor in determining early response to treatment and risk of delayed healing in persons with venous disease.
The use of ulcer area and tissue type in the risk assessment tool is supported by evidence in the literature including the current authors’ previous analyses20-22,47,48 along with ulcer area percent reduction also previously reported as a significant risk factor for delayed healing.45,49,50 The 2-week time frame of percent area reduction provides an early marker for the risk assessment tool in this population.
Relatively few studies have concentrated on psychosocial or quality-of-life factors and the risks of delayed healing or recurrence in patients with venous leg ulcers. However, the authors were the first to identify that living alone was independently and significantly associated with failure to heal in a secondary analysis of 318 venous leg ulcers from hospital and community settings.33 In addition, it has been reported that patients who lived alone had a higher incidence of venous leg ulceration,51 and a randomized controlled trial52 (N = 56) demonstrated significant benefits for ulcer healing in patient groups involved in a social model of care,52 an approach based on the Lindsay Leg Club™ model that provides an informal, relaxed environment that is conducive to social interaction and peer support.
Age and ulcer chronicity or duration were included in the risk assessment tool because of consistent findings in the literature across multiple health sites and with large numbers of participants that demonstrated significant associations with delayed healing and consequent inclusion in previously developed risk assessment tools.18-22,53-55 The literature also included 2 randomized controlled trials and 2 cohort studies20,53,56,57 (N = 200 patients and 121 ulcers and N = 153 patients and 32 ulcers, respectively) that found significant relationships between DVT and venous abnormalities with delayed healing (although measurement methods of abnormalities varied). The question of whether a person had a previous DVT in the ulcer leg was deemed the most appropriate venous abnormality question and hence was included in the risk assessment tool.
Despite a lack of consistency in mobility measurement, decreased mobility has been identified as a significant risk factor for delayed healing in a randomized controlled trial58 (N = 40) — specifically, fewer steps per day — and in a prospective cohort study (N = 189) where decreased mobility was considered walking <200 m.59 It was concluded that use of a walking aid was the optimal quantification of mobility for the purpose of a risk assessment tool; it was a quick, easy-to-answer item that would not involve a subjective measure of activity by the patient or the need for equipment and/or staff time in determining other measurements such as ankle range of motion.
Risk assessment tool for recurrence. The 8 variables in the newly developed risk assessment tool for recurrence (previous leg ulcers, history of DVT, duration of previous ulcer, BMI <22, whether the patient lives alone, leg elevation, walking activity, and compression therapy) are also easily identifiable and measurable in the clinical area as determined by studies that have previously collected these variables in the clinical area.34
Based on previous literature and results from data analyses by the authors, history of a previous DVT or deep vein insufficiency and BMI were necessary inclusions in the risk assessment tool because they were found to be significant risk factors for recurrence of venous leg ulcers.5,34 A BMI <22 also has been noted in a large cohort study (N = 4791) to increase the mortality risk in older people.60
A critique of quantitative literature addressing health-related quality of life61 indicated limited mobility can lead to challenges in performing daily activities and pose a significant problem for persons with venous leg ulcers. Decreased mobility and physical activity have been shown in a randomized controlled trial,62 a quasi-experimental study,63 and a literature review64 of 16 studies (N ranging from 49 to 300 community-living participants) to be significant risk factors for recurrence. Guidelines for the prevention of venous leg ulcers65,66 recommend encouragement of mobility and exercise — specifically, a 30-minute daily walk. However, comparison of studies is compromised by a lack of consistency in the measurements of mobility (ie, measuring general mobility, ankle range of motion, or physical activity). The authors identified that walking for at least 3 hours per day, as reported in the Yale Physical Activity Scale,67 was significantly associated with a decreased risk of recurrence34 and offered an easy quantification for use in the risk assessment tool.
Elevating legs at or above the level of the heart for at least 30 minutes/day was found to be significantly associated with a decreased risk of recurrence of venous leg ulcers in longitudinal studies.34 Similarly, a quasi-experimental study63 of 49 community-residing participants indicated persons who spent time with their legs elevated each day were significantly less likely to have their ulcers recur, and elevating legs when resting or immobile has been recommended in guidelines on venous leg ulcers to assist in the control of edema.7,65,66 Abu-Own et al68 concluded from a cohort study of 30 participants (15 with chronic venous insufficiency and 15 without chronic venous insufficiency) that limb elevation enhanced the microcirculatory flow velocity in skin of patients with chronic venous insufficiency.
A systematic literature review69 of 4 randomized controlled trials (N = 979) concluded compression therapy is the primary conservative strategy for preventing the recurrence of venous leg ulcers. This systematic review reported high compression lowers recurrence rates when compared to moderate compression; however, rates of patient intolerance in relation to compression can be high because of issues related to cost, difficulties with application, and comfort.4,69 Guidelines on venous leg ulcer recurrence recommend compression with at least 18 mm Hg to 40 mm Hg or the highest level able to be tolerated once the venous leg ulcer is healed.7,66 The study by Finlayson et al3 of 122 community-living participants concluded that for every additional day/week participants wore Class 2 or 3 compression hosiery, the odds of recurrence were almost halved (OR 0.53; 95% CI, 0.34-0.81); therefore, this variable was included in the new risk assessment tool.
Similar to delayed healing in venous leg ulcers, investigation of psychosocial or quality of life factors and the risk of recurrence in patients with venous leg ulcer in the literature is scant. However, 1 case-controlled study51 of 113 participants found patients who live alone have a higher incidence of venous leg ulceration. The Lindsay Leg Club® social model of care ensures management of wounds in a social atmosphere where patients are not discharged upon healing; instead, the focus is on continuing to attend clinics to participate in social and health promoting activities. This approach has been extremely successful in removing the stigma of leg ulceration for sufferers and has resulted in many encouraging benefits, including improved compliance with treatments and positive healing outcomes.52,70 Low recurrence rates in these clubs also support the rationale of patient empowerment and the synergistic effect of ongoing health promotion and education in a supportive social environment.70 Although the reasons for a higher risk of recurrence in persons who live alone are unknown, it is important to acknowledge this factor in the risk assessment tool as well as the need for further research in addressing these patients’ clinical needs.
IRR. A high level of IRR is an essential requirement of a risk assessment tool, because clinical practice risk assessment tools are used by many different members of the health care team at different points of time where they would be devalued by high degrees of error among users.71 IRR results on these venous leg ulcer tools indicate good agreement between raters. The majority of the ICC indices (0.6–1.0) obtained for the comparison between raters for individual items in the risk assessment tool confirmed the reliability of the tool with statistical significance (P <.05).
Implications for Practice
Healing venous leg ulcers and preventing recurrence are priorities for all health professionals working in wound care. Early availability of information on the risk of delayed healing or recurrence could contribute to improved outcomes for patients and hospital systems. Clinical credibility was ensured in these tools; the tool components were based on evidence from studies across a variety of settings and endorsed by an expert WAG. The tools also may assist in the estimation of health care costs.
Although these risk assessment tools can provide data to guide decisions for ongoing care of the patient (eg, when to refer for specialist care, include adjunctive treatment, and individually tailor interventions to improve healing and delay recurrence), it is also important that clinicians use reliable and valid instruments to ensure credibility and usefulness for evidence-based practice72 and to support accurate and effective decisions about patient care. The authors intend to validate these risk assessment tools in prospective cohorts of patients from different health facilities and across different countries to ensure the tools are valid in identifying the risk of delayed healing and/or recurrence and to provide evidence to facilitate use of the tools in clinical decision making internationally. Validation studies will assist in determining recommendations with regard to timing of completion of the risk assessment tools (ie, once only or at multiple time points) and to develop cutoff points to indicate if patients are at low, moderate, or high risk. An additional benefit is that instruments to assess the risk of delayed healing wounds and/or recurrence could help enhance communication among clinicians by defining a common language and standardizing assessment characteristics.73
Limitations
The risk factors included were limited to those identified from studies by the authors, evidence found in the literature, and expert opinion. Other factors that have not been well investigated may be identified and provide items for an even more reliable scoring system. Further research also is required to identify why some variables, such as living alone, are producing poorer wound healing outcomes.
Although a power analysis determined a sample size of 30 was required for IRR, this study was only able to achieve 26 and 22 participants for each of the risk assessment tools. This was due to difficulties in the availability of the 3 raters. Further testing of reliability would be beneficial. The 3 variables on the risk assessment tool that were less reproducible (ICC <0.8) (ie, treatment compression level and calf reduction on the delayed healing tool and BMI on the recurrence tool) require further evaluation, modification, and clarification to improve reliability. The differences in ratings could have resulted from a misunderstanding of the compression and BMI question, with the less than symbol (<) often appearing to be misunderstood and mistakenly answered as <30 mm Hg although the compression type had been documented as a type which was higher than 30 mm Hg. The use of words rather than symbols may assist with clarifying this. Measurement of the calf circumference was less reliable between the 3 raters due to slightly differing measurements between raters, and the measurement of circumference reduction often was close to the 2-cm cutoff. Further research is required to determine whether this measurement can be achieved more accurately.
Conclusion
A secondary analysis of data from multisite longitudinal studies aimed to develop and a single site prospective study assessed the IRR of risk assessment tools for delayed healing and recurrence of venous leg ulcers. This has resulted in the development of 2 risk assessment tools for use in patients with chronic venous insufficiency. Both were found to have good IRR. These tools are not resource-intensive and provide a quick, easy way to identify persons at high risk of delayed healing or recurrence of a venous leg ulcer. Questions use plain language with simple responses and incur little or no expense to complete in a variety of settings.
The results of the IRR indicate the risk assessment tools for delayed healing and recurrence of venous leg ulcers (ICC 0.6–1.0; P <.05) meet recommendations for reliable tools that may benefit clinicians, patients, and the health care system. Providing the tools have sufficient predictive validity, the risk assessment tools may help health professionals be more confident in recognizing the necessity for early additional interventions in high-risk patients with venous leg ulcers.
Acknowledgement
The first author acknowledges the support of Queensland University of Technology; parts of this study were undertaken in partial fulfillment of a Doctor of Philosophy. The authors acknowledge and thank the members of the expert WAG for their contributions and all of the staff and participants at Queensland University of Technology’s Wound Healing Community Outreach Service who were involved in the reliability study.
Disclosure
This study was supported by the Wound Management Innovation Cooperative Research Centre (established and supported under the Australian government’s Cooperative Research Centres Program) and partially supported by a Queensland University of Technology Faculty of Health Masters Scholarship, a National Health & Medical Research Council Primary Health Care Postgraduate Research Scholarship, an Australian College of Nursing Margaret Y Winning Queensland Nursing Scholarship.
Affiliations
Dr. Parker is a lecturer and researcher, Faculty of Health, Institute of Health & Biomedical Innovation, Queensland University of Technology; and affiliated with the Wound Management Innovation Cooperative Research Centre, Kelvin Grove, QLD, Australia. Dr. Finlayson is a research fellow, Faculty of Health, Institute of Health & Biomedical Innovation, Queensland University of Technology; and affiliated with the Wound Management Innovation Cooperative Research Centre. Professor Edwards is Assistant Dean (International and Engagement) and researcher, Faculty of Health, Institute of Health & Biomedical Innovation, Queensland University of Technology; and leads the Clinical Application Program of the Wound Management Innovation Cooperative Research Centre.
Correspondence
Please address correspondence to: Christina Parker, RN, PhD, School of Nursing, Queensland University of Technology, Victoria Park Rd, Kelvin Grove, QLD 4059; email: 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。.
