Cardiff Wound Impact Schedule: the development of a condition‐specific questionnaire to assess health‐related quality of life in patients with chronic wounds of the lower limb

Abstract

The purpose of this study was to develop and validate a questionnaire to measure the impact of chronic wounds (leg ulcers and diabetic foot ulcers) on patient health‐related quality of life (HRQoL) and identify areas of patient concern. The Cardiff Wound Impact Schedule (CWIS) was created following a three‐stage process. Stage 1 included a focus group (n = 10) and a series of semi‐structured interviews (n = 13) to generate items for the questionnaire. Stage 2 involved piloting the 28‐item questionnaire on 124 patients (64·5% with leg ulceration and 35·5% with diabetic foot ulceration): data from this stage were analysed using factor analysis. The reliability, validity and reproducibility of the resulting scale were assessed in Stage 3, a 3‐month follow‐up study of 135 patients in which patients completed the CWIS and the SF‐36. Factor analysis identified three domains of HRQoL: physical symptoms and daily living, social life and well‐being. There were no significant differences in scores across the wound types. Internal consistency was good (α = 0·77–0·96) as was reproducibility (P < 0·001). The CWIS was able to discriminate between those with healed ulcers and active ulcers (P < 0·01). Construct validity was demonstrated by strong correlations between related items on CWIS and SF‐36 (P < 0·01–P < 0·0001). The data suggest that CWIS has high internal consistency and the ability to discriminate between health states and good reproducibility. CWIS is a valid tool for studying the impact of chronic wounds of the lower leg on HRQoL. CWIS allows clinicians to identify items of patient concern, which can then be used to negotiate options of care most suited to individual patients.

Introduction

The presence of a chronic non healing wound can result in a profound impact on everyday life. Chronic leg ulceration represents a major health problem for many people over the age of 60, affecting in the region of 0·1–0·3% of the general population, although this figure rises to 2% in complications over the age of 80 (1). Foot complication associated with diabetes mellitus is also a major problem (2); for such individuals, the development of neuropathy can lead to foot wounds that can result in amputation. The presence of foot ulceration is a strong predictor of further foot deterioration, with major impacts on an individual's QoL (3). This article outlines the development of a condition‐specific tool to measure the impact of these two chronic wound types on patients' self‐reported QoL.

The main focus of treatment for patients with chronic wounds is complete healing, with the aim of achieving a healed state as quickly as possible. Even so, patients face the prospect of challenging local and systemic care with frequent dressing changes, episodes of infection, a possible cycle of re‐ulceration and fears of a deteriorating health state. There has also been debate about the existence of a subgroup of patients for whom healing is not a possible outcome (4) but for whom QoL issues remain paramount.

A limited amount of work has already been completed in the investigation of the impact of a chronic wound on health‐related QoL (HRQoL). A number of qualitative studies have been completed that outline the extent of the impact of a wound on everyday living for patients with chronic leg ulceration (5, 6, 7, 8, 9, 10, 11, 12), but there has been less work on diabetes‐related foot problems (13, 14, 15). General health status has also been investigated using generic tools for those with chronic leg ulceration (16, 17, 18, 19, 20) and for those with diabetes‐related foot ulceration (21). In the majority of these studies, those with chronic wounds are reported to experience poorer HRQoL than sex‐ or age‐matched controls.

It is, however, increasingly recognised that such generic measures do not address areas that are salient to specific diseases or health states. Condition‐specific instruments are more likely to be relevant to areas prioritised by the attending clinicians and contain items considered important by the relevant patient group (22, 23). Condition‐specific measures have been developed which relate to venous disease generally (24, 25, 26, 27), to leg ulceration specifically (28) and diabetic peripheral neuropathy (29) or foot ulcer problems (30, 31), but no scale exists that focuses on chronic wounds irrespective of aetiology.

The development of such a scale would allow for the HRQoL of patients with chronic wounds to be more fully understood, leading to possible changes in clinical practice if such a questionnaire were to be fully adopted. One of the concerns about the transformation of HRQoL from a speculative concept to a recognised clinical endpoint is that, to date, the concept has not really been introduced into routine clinical practice (32). This study aimed to produce a questionnaire that would provide both a valid and a reliable form of measuring condition‐specific QoL across a range of wound types and a framework for informing clinicians about specific areas of patient concern that could be used for joint prioritisation of clinical care. The aim was also to develop an instrument sufficiently short and easy to use, so that it could be used in a range of health care settings and in both research and clinical work. This article outlines the development and validation of the Cardiff Wound Impact Schedule (CWIS) for use with patients with chronic wounds. The underlying philosophy behind the development of the tool was the involvement of the patient both in the construction of the instrument and in the weighting of the importance of issues to them as individuals.

Methods

Stage 1: item generation

It is generally agreed that the content of HRQoL instruments should be based directly on the information provided by relevant patients, in terms of both coverage of relevant items and the specific wording of questions (33). A focus group was held, involving 10 patients (three males and seven females, mean age = 74·3 years; SD = 4·9) presenting at a specialist outpatient clinic with chronic non healing wounds that had been present for a minimum of 3 months. The point at which no new themes or ideas emerged from the groups (thematic exhaustion) determined the end of the session. Patients were asked to describe the impact of the wound on their everyday lives, and a list of topics was compiled from the session.

In‐depth semi‐structured interviews with 13 patients (one male and 12 females, mean age = 83·5 years; SD = 3·2) who presented to the same specialist unit were completed. The interviews took place in the patients' homes and lasted about an hour. Patients were asked about their everyday experiences of living with a non healing wound and to identify the aspect of this experience that they found stressful. All interviews were tape‐recorded for subsequent analysis, when common themes were identified using content analysis. A subset of tapes were analysed by a second researcher to minimise bias at this stage (inter‐rater reliability was 93%).

Stage 2: scale generation

The information from Stage 1 was used to compile a 28‐item questionnaire, which was piloted on 50 consecutive consenting patients with chronic wounds attending a specialist outpatient clinic (half with leg ulceration and the others with diabetic foot wounds), none of whom had been involved in Stage 1. The male : female ratio was 23 : 27, with an age range of 34–90 years and a mean age of 65·9 years. Patients completed the questionnaire whilst sitting in the waiting area of the outpatient clinic; those who experienced any visual or writing difficulties were assisted by a researcher. Patients were asked to indicate the extent to which they had experienced a difficulty in relation to the presence of a wound plus the extent to which they found that experience stressful.

In addition, a further 74 patients completed the questionnaire using a postal method. The patients were asked to complete the questions relating to their experiences during the past week and to comment on the wording and layout of the questionnaire. The mean age of this group was 70·4 years (range 48–86·2); 49 were females and 25 were males. Seventy‐five per cent had chronic leg ulceration; the remaining 25% had diabetes‐related foot ulceration. There were no statistical differences in the number of missing items between those who completed the questionnaire at home or at the clinic.

Stage 3: testing reliability and validity

A new version of the questionnaire was developed on the basis of the results from Stage 2. In addition, an overall rating of HRQoL using a 10‐point scale was included, plus a rating of satisfaction with an individual's overall HRQoL.

The validity and reliability of the resulting scale was assessed in a survey of 150 patients attending two specialist wound outpatient clinics. One hundred and thirty‐five patients agreed to participate, giving a 90% response rate. This stage included the completion of the CWIS and the SF‐36 Health Survey Questionnaire (34), plus a clinical indication of the wound state (healed versus non healed): the respondents completed the questionnaires whilst waiting for their clinic appointment. Although half of the patients were asked to complete the SF‐36 first and the other half to complete the CWIS first (to avoid order effects), there is no guarantee that patients complied with these instructions. These data were used to determine the construct validity of the new measure. The mean age of this sample was 65·9 years (range 43–85·5 years), with 55% of the sample males and 45% females. Fifty‐four of the patients had a diabetic foot wound and 81 had chronic leg ulceration, with only 30 of these patients living alone.

In addition, a second copy of the CWIS was given to patients in an envelope to complete within 5–7 days after attending the clinic, together with a stamped, addressed envelope to return the completed questionnaire. These data allowed for the calculation of test–retest reliability of the CWIS to be assessed. Ninety patients returned their second questionnaire, giving a response rate of 66%. The senior clinician responsible for the clinical care of these patients reported no important changes in their health status during this short time period.

Three months (±1 week) later, all 135 patients completed the CWIS at a follow‐up clinic visit. The health status of the patients was assessed by the consultant and classified as ‘wound present’ or ‘wound healed’.

Results

There were no significant differences in the scores of patients, dependent on wound type. This section therefore includes the responses of all patients who participated in the study.

Scale generation

The data from Stage 2 were factor analysed using varimax rotation to determine the factors underlying the scale. The three factors with Eigen values greater than 1·5 were retained; these three factors contained 26 items and explained 51% of the variance. Only two items caused any problems, these were ‘limited contact with family/friends’ and ‘family/friends being overprotective’. These items loaded onto more than one factor. However, given the qualitative comments from earlier stages and the views of the clinician involved, these items were retained within those scales that produced the most meaningful scales. Two items were withdrawn from the scale as they did not load onto any one factor (i.e, ‘changes in appetite’ and ‘I look forward to clinic visits’). This resulted in three scales:

• • Physical symptoms and everyday living (12 items rated for the extent of the problem and associated stress, each on a 5‐point scale): this domain focuses on the impact of symptoms on daily functioning and comfort.
• • Social life (seven items rated for the extent of the problem and associated stress, each on a 5‐point scale): this domain focuses on the individual's ability to get out and about.
• • Well‐being (seven items rated on a 5‐point scale): this domain focuses on the patient's well‐being in relation to the wound, particularly anxieties about outcome.

Examples from each of the subscales are shown in Figure 1 and the factor loadings for the scales are summarised in Table 1.

Figure 1.

Examples of items from each of the subscales of Cardiff Wound Impact Schedule.

Table 1.

Factor analysis: Stage 2 (n = 124)

	Factor 1	Factor 2	Factor 3
Disturbed sleep	0·749	0·108	0·009
Mobility around home	0·721	0·038	0·27
Pain	0·770	0·306	0·123
Discomfort with bandages	0·769	0·118	0·346
Difficulty in everyday tasks	0·743	0·252	0·244
Mobility outside home	0·707	0·063	0·191
Leakage	0·703	0·047	0·384
Odour	0·679	0·214	0·244
Difficulties in bathing	0·574	0·192	0·358
Difficulties with footwear	0·530	0·179	0·127
Time needed to look after the wound	0·566	0·204	0·024
Financial difficulties	0·421	0·249	0·179
Getting out and about	0·207	0·729	0·254
Relying more on others	0·351	0·641	0·032
Enable to enjoy usual social life	0·262	0·638	0·006
Not going out for fear of bumping wound	0·204	0·566	0·024
Limited contact with family and friends	0·137	0·572	0·496
Wanting to withdraw from others	0·055	0·565	0·326
Family/friends being overprotective	0·156	0·470	0·320
Anxious about the wound	0·192	0·144	0·760
Worry about recurrence	0·299	0·286	0·641
Frustration at the time to healing	0·201	0·216	0·629
Appearance of the wound is upsetting	0·239	0·327	0·619
Anxious about bumping the wound	0·264	0·363	0·609
Worry about the impact on family/friends	0·348	0·118	0·544
Confident the wound will heal	0·013	0·261	0·441
Eigen values	9·31	2·27	1·92
% of variance explained	36·26	8·12	6·87

To calculate the scale scores, the items for each scale are summated. For ‘physical symptoms and everyday living’ and ‘social life’, the items are rated for the extent of the experience of the item during the past week and how stressful that experience was on an item‐by‐item basis. This allows the patients to weight the items included in the scale. For example, the experience of ‘disturbed sleep’ may be rated as ‘rarely’ but ‘very stressful’. Thus, the total score includes the patient's perception of the experience and the associated stress. The well‐being scale is scored on a 5‐point Likert scale, with response options from ‘strongly agree’ to ‘strongly disagree’. All three scales are then transformed onto a 0–100 scale, where a high score indicates a positive rating.

Reliability

Internal consistency was calculated using Cronbach's alpha (35), values of which range from 0 to 1. Coefficients above 0·7 are generally regarded as acceptable for psychometric measurements (26). Cronbach's alpha was calculated for the three factors within CWIS. Each of the subscales resulted in an alpha >0·75 [physical symptoms and everyday living (experience alpha = 0·88 and stress alpha = 0·95), social life (experience alpha = 0·96 and stress alpha = 0·93) and well‐being (alpha = 0·77). These findings confirm that the internal consistency is high.

Reproducibility

A specific test–retest component was included within Stage 3 of the development of the questionnaire to confirm that items were answered in a similar way by stable patients within a short time scale (5–7 days). Correlation coefficients for experience of items and their associated stress between the two time points are summarised in Table 2; all are significant at P < 0·001, indicating a high level of reproducibility.

Table 2.

Pearson's correlation coefficients components of Cardiff Wound Impact Schedule on day 1 and 5–7 days later (n = 90)

	Correlation coefficients
	Experience	Associated stress
Physical functioning and everyday living	0·93	0·86
Social functioning	0·93	0·92
Well‐being	0·90	–
Global HRQoL	0·92	–
Satisfaction with HRQoL	0·93	–

Values are significant at P < 0·001. HRQoL, health‐related quality of life.

Discrimination between health states

The ability of CWIS to discriminate between health states (healed versus non healed) was calculated using independent t‐tests to analyse the scores of patients in the 3‐month follow‐up. Those identified as ‘healed’ had consistently higher scores across the three subscales, and differences between the two groups were all significant (Table 3). Although the global ratings for HRQoL were higher for those with a ‘healed wound’, the difference was not significant, but satisfaction with HRQoL was significantly higher for this group (P < 0·01).

Table 3.

Mean scale scores for Cardiff Wound Impact Schedule by clinical assessment of healed status of wound

	Healed (n = 46)	Nonhealed (n = 89)	P‐value
Physical symptoms and everyday living	87·6	71·7	<0·0001
Social life	84·7	76·1	0·025
Well‐being	50·8	38·7	<0·0001
Global HRQoL	7·2	6·9	NS
Satisfaction with HRQoL	7·8	6·7	<0·01

HRQoL, health‐related quality of life; NS, not significant.

Relationship between CWIS and SF‐36

The construct validity was examined by correlating scales in CWIS with relevant scales of SF‐36. Physical symptoms and everyday living total score (CWIS) correlated with physical function (SF‐36) (r = 0·53, P < 0·0001). Specific items on CWIS related to mobility and its associated stress correlated with physical function (SF‐36) at between r = 0·34–0·52 (all items P < 0·0001). Items related to pain and the associated stress (CWIS) correlated with bodily pain (SF‐36) (r = —0·53, P < 0·0001: correlation is negative due to the different direction of the scales). Social life (CWIS) correlated with social functioning (SF‐36) (r = 0·47, P < 0·0001) and role limitation (physical) (r = 0·56, P < 0·0001). Well‐being (CWIS) correlated with mental health (SF‐36) (r = 0·217, P = 0·01) and role limitation (emotional) (SF‐36) (r = 0·332, P < 0·0001).

Discussion

Individuals with chronic non healing wounds may experience a wide range of adverse effects on their everyday lives. Studies to date have either focused on one type of wound (e.g. leg ulceration), have used qualitative methods or generic tools. However, there are a number of aspects of experience of living with a chronic wound that are not addressed by generic instruments. Problems such as leakage and odour are not assessed directly by such instruments, yet can have a profound impact on the patient's life.

The results of this study suggest that the content of the CWIS is appropriate for individuals with chronic wounds, with high internal consistency, the ability to discriminate between health states and good reproducibility. Further studies that confirm the factored scales used in CWIS are currently being undertaken. It is also important to increase the sample size involved in such studies to ensure the representativeness of the items included in the tool, which are currently based on patients from a relatively small geographical area (South Wales).

In addition, the scales correlate well with relevant scales from a well‐validated generic tool (SF‐36). Whilst the correlations are not very strong, the patients involved in this study were all elderly and many had other concomitant disorders of older age (e.g. arthritis). As such, items from CWIS that focus directly on the symptoms of a wound are sensitive to experiences directly attributable to that wound, but the profile may not be matched by responses to items on a generic questionnaire that focus on a general level of functioning. These data support the use of both a generic and a condition‐specific tool for the measurement of HRQoL.

In order for the tool to be useful in clinical trials related to a range of chronic wounds, CWIS needs to isolate the impact of the experiences of a wound from those related to other factors present in this age group. Whilst this is a difficult task, the ability of CWIS to discriminate between different health states indicates that the tool is sensitive to this issue. The profile of scores using CWIS across wound types was similar, with no significant differences in scores dependent on wound type. Further studies which analyse scores related to severity of wound rather than ‘healed’ versus ‘non healed’ need to be completed to maximise the potential for use in clinical trials.

In the area of wound healing, the focus has been on healing as the only measure of success. Many patients with chronic wounds will not heal speedily despite optimum care (4); indeed complete healing may be an unrealistic goal for this subset of patients such that HRQoL becomes a particularly significant part of planning care. Traditionally, the integration of HRQoL issues into clinical care has been done on an informal basis, without the support of well‐defined measurement tools. The use of CWIS in a routine clinical setting is currently under investigation. The ‘stress’ component of the scales gives a useful guide to a clinician of the concerns that a given patient may have at any one time. The stress scale, particularly in relation to physical symptoms and everyday life, can form the basis for patient involvement in clinical decision‐making. This requires the clinician to be sensitive to those aspects of the wound that are most stressful to the individual and use that information to guide clinical decisions or to prioritise information/educational input with the patient. In addition, the well‐being scale allows for clinician–patient communication to focus on the worries of the patient. The long‐term goal is for CWIS to be used routinely as part of clinical assessment and care planning.

The questionnaire was developed with the aim of producing an instrument that could be used with several chronic wound types. The aim was also to develop an instrument sufficiently short and easy to use, so that it could be used in a range of health care settings and in both research and clinical work. The development of such a tool is an essential step if we are to evaluate interventions across a range of wounds, particularly given the necessity for multiprofessional teams to provide comprehensive care for such patients. This article provides evidence of a patient‐centred tool which focuses on the concerns of the individual whilst retaining psychometric integrity. Additional work is now required to evaluate its use in clinical trials and health‐care settings to confirm the current promising data.

Acknowledgements

The authors thank Smith and Nephew Ltd (Medical) for an unrestricted research grant used for the initial stages of this work.