Translation, cross‐cultural adaptation and validation of the “Cardiff wound impact schedule,” a wound‐specific quality of life instrument, to the native Spanish of Mexican patients

Abstract

The aim of this study was to translate into Mexican Spanish, cross‐culturally adapt and validate the wound‐specific quality of life (QoL) instrument Cardiff wound impact schedule (CWIS) for Mexican patients. This instrument went through the full linguistic translation process based on the guidelines of Beaton et al (Beaton DE, Bombardier C, Guillemin F, Ferraz MB, Guidelines for the process of cross‐cultural adaptation of self‐report measures, Spine Phila Pa, 1976, 2000, 318‐391). We included a total of 500 patients with chronic leg ulcers. The expert committee evaluated the Face validity and they agreed unanimously that the instrument was adequate to assess the QoL of these patients, covering all relevant areas presented by them. The content validity index obtained was of 0.95. The construct validity demonstrated moderately significant correlations between related sub‐scales of CWIS and SF‐36 (P = .010 to P < .001). The instrument was able to discriminate between healed and unhealed ulcers. The instrument obtained an overall Cronbach's alpha of .952, corresponding to an excellent internal consistency (.903‐.771 alpha range for domains). The CWIS can be appropriately used to assess the health‐related QoL of Mexican patients with chronic leg ulcers.

1. INTRODUCTION

Chronic wounds like venous ulcers, diabetic foot ulcers, burns, pressure ulcers and arterial ulcers, among other types, are the result of various diseases. Wound healing involves a number of complex processes that can occur over a long period of time, and the treatment may be quite difficult. These chronic wounds provoke additional complications such as lack of mobility, pain, exudate and odour.1, 2, 3, 4, 5 Emotional stress due to fear of recurrence of ulceration, impaired body image, social isolation, increased family tensions, restrictions in employment and repeated bouts of infection and potential life‐long morbidity exaggerates the negative influences of the wounds on these patients.6, 7 These factors report increased depression and less satisfaction with life, and have poorer psychosocial adjustment to illness.8, 9, 10 Due to all of these issues, chronic ulcers affect physical, psychological, social and financial aspects of the individual, leading to poor quality of life (QoL).2, 11, 12, 13

QoL is defined by the World Health Organization (WHO) as an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns. It is a broad ranging concept affected in a complex way by the person's physical health, psychological state, personal beliefs, social relationships and their relationship to salient features of their environment.14, 15

The concept of health‐related quality of life (HRQoL) and its determinants have evolved since the 1980s referring to the impact of health and illness on physical and social functioning and psychological well‐being. It is a complex multidimensional concept that reflects the total impact of health and illness of the individual. HRQoL assesses an individual's physical and psychological well‐being which denotes how a specific disease or intervention has impacted a patient's life.16 Measuring the HRQoL is useful in clinical practice, in research and in assessing quality improvement and assurance allowing the measurement of clinical effectiveness, developing strategies of management, interventions and improving the quality of care of the population to which it is directed.17 For all of this, it is vital that valid, reliable and acceptable tools are available.14, 17

To measure HRQoL, generic tools were devised, such as Short Form Health Survey‐36 (SF‐36),18 EuroQoL five‐dimension questionnaire,13, 19 or Nottingham Health Profile.20 These assess HRQoL in general terms and can be used to create norms, for example, age and gender, and to compare different diseases and conditions. Disease‐specific tools, such as the Cardiff wound impact schedule (CWIS) for lower limb ulcers,21 Wuerzburg wound score (WWS) for chronic arterial or venous leg ulcers,22 Freiburger questionnaire of QoL in venous diseases (FLQA‐w),23 and the Wound‐QoL,24 were designed to detect the impact of the ulcer on patients, and can notice small but clinically relevant differences.7, 14 These instruments can allow health professionals to better understand what it is like to have a wound, the way patients adapt to it on time, and the factors which are related to the QoL. A reliable measurement of HRQoL is relevant for patients as well as clinicians.

The CWIS was developed and validated by the Wound Healing Research Unit in Cardiff at the University of Wales, College of Medicine to investigate the impact of lower leg chronic wounds on HRQoL,21 and has been translated to German, French, American English, Portuguese, Swedish, Canadian, Chinese and Sinhala to spread its use.25, 26, 27, 28

The absence of a specific instrument to assess HRQoL on Spanish‐speaking Mexican patients with leg ulcers has been a limitation for research in Mexico. The authors consider that the CWIS is a useful available instrument that can help to assess the HRQoL in patients with chronic leg ulcers. It is well known that this instrument has substantial evidence of reliability and validity in a variety of populations; as a consequence, the translation, validation and cultural adaptation will allow clinicians to compare their results with international studies.

Therefore, the purpose of this study is to translate, cross‐culturally adapt and validate the CWIS to Mexican Spanish.

2. MATERIALS AND METHODS

This clinical, observational, cross‐sectional study was conducted between 2016 and 2018 in an outpatient wound care clinic in Mexico City. Approved by the Dr Manuel Gea Gonzalez General Hospital Ethics Committee (approval no. 06‐99‐2016). Written informed consent was obtained from 500 patients with chronic wounds of the leg. This study was performed after the authors of the original version of the CWIS, represented by Dr Patricia Price, granted permission to translate, cross‐culturally adapt and validate the instrument to Spanish for Mexico.

2.1. The instrument

The CWIS is a specific self‐report instrument with 47 items assessing HRQoL in patients with chronic wounds of the lower limb. It has three key domains: Physical Symptoms and Daily Living (12 items), Social Life (7 items) and Well‐being (7 items). Physical Symptoms and Daily Living and Social Life assess for both the experience of a given symptom and the associated stress experienced by patients. Each item is scored on a five‐point scale, and these scores are added for each domain. After the integration of domains scores, on the basis of a validated formula, a final score is obtained from 0 to 100; a higher result means a better self‐reported HRQoL. In addition, there are two items measured on a 10‐point scale which assess the overall QoL during the preceding week and the satisfaction with their overall QoL.21

Two instruments were used for data collection: the new version of the CWIS and the SF‐36 as the gold standard (to standardise the study with the previous translations) Patients were asked to answer the questionnaire in order, starting with the CWIS and continuing with the SF‐36. Each patient answered both questionnaires in the clinic waiting room and handed it in to the researcher.

2.2. Characteristics of the patients

Five hundred patients of the Wound and Ostomy Care Center “Dr Manuel Gea González” General Hospital agreed to participate in this study during 2016 to 2018. The inclusion criteria were patients older than 18 years who agreed to participate and who presented with chronic wounds of the lower leg (healed or active) of more than 10 weeks. The exclusion criteria were the following: patients with dementia or any other psychiatric illness that would incapacitate them from answering the questionnaire, and patients that did not speak or write Spanish.

2.3. Translation

The tool was translated and adapted to the culture of Mexican patients based on the guidelines of Beaton et al29 according to the following steps: First, the original English questionnaire was translated into Spanish by two independent translators who are fluent in both languages. Then the two translations were compared and differences were discussed and adjusted with the consensus from both translators, obtaining a second version of the questionnaire. A back‐translation of the consensus version into English was made by a third translator, also fluent in both languages, to ensure that the language is a correct translation of the original. Later, a committee conformed by six healthcare professionals and clinical researchers who were experts in wound management evaluated the second translation based on the comprehension of each item, taking into consideration semantics, cultural language and conceptual equivalencies. This resulted in a third version of the questionnaire. Afterwards, the third version of the questionnaire was tested with 35 patients, who were asked about the perception and interpretation of each item's content. This delivered the final version of the questionnaire.

2.4. Validity of the research instrument

Validity explains how well the collected data covers the actual area of investigation. Validity basically means “measure what is intended to be measured”.30

2.4.1. Face validity

Evaluates whether the instrument appears to measure what it was designed to measure.31 Measured by the expert committee based on the answers of the 35 patients with lower leg chronic wounds, their experience in the management of patients with wounds and their knowledge of the concept of QoL. The expert committee evaluated the relevance of each item to assess the impact of the wound in the patients' life and the adequacy of the instrument to cover all relevant areas in HRQoL of patients with chronic leg ulcers.

2.4.2. Content validity

This type of validity addresses how well the items, developed to operationalise a construct, provide an adequate and representative sample of all the items that might measure the construct of interest. The content validity usually depends on the judgement of experts in the field.32 The expert committee evaluated the relevance and comprehension of each item. This was done by calculating the content validity index (CVI), using ratings of item relevance and clarity by content experts. Members of the expert committee rated each item of the instrument as: 1: not important, 2: slightly important, 3: important, and 4: very important. Items rated 1 or 2 were revised by experts and researchers, according to principles of equivalence and their clinical experience, that way they decided if they were removed from the instrument.28, 30 Items rated 3 and 4 were used for determining the CVI (CVI = Number of items rated 3 + Number of items rated 4 / Total number of items). The minimum level of agreement among experts and researchers was set at 80% (CVI 0.80).

2.4.3. Construct validity

This type of validity is an evidence‐based judgement based on the sum of different studies using a specific measurement. Construct validity's evaluation requires examining the relationship between the measure being evaluated with variables known to be related or theoretically related to the construct measured by the instrument.32 For this purpose, relevant sub‐scales from CWIS and SF‐36 that were based on the study by the original authors of the CWIS Price and Harding21 were used. Two specific sub‐scales were used: mobility and its associated stress (MAS); and pain and its associated stress (PAS) that belong to the scale of physical symptoms and daily living (PSDL).

2.4.4. Discriminant validity

The ability of CWIS to discriminate the HRQoL of patients with healed versus non‐healed ulcers was determined comparing the patient's responses who had their ulcer healed at the time of responding to the instrument versus the patients who still had an active ulcer.

2.5. Internal consistency

Internal consistency gives an estimate of the equivalence of sets of items from the same test. The coefficient of internal consistency provides an estimate of the reliability of measurement and is based on the assumption that items measuring the same construct should correlate. Perhaps the most widely used method for estimating internal consistency reliability is Cronbach's alpha.28, 33 Values of >0.70 are required to demonstrate that items are sufficiently correlated. However, values >0.95 can indicate that the instrument contains too many items that are assessing the same underlying construct. So, it suggests a high level of item redundancy, where essentially the same item is rephrased in several different ways. Statistical analyses were performed with the IBM SPSS Statistics 25 program, considered as P‐value < .05 to be significant.

3. RESULTS

The instrument was tested on 500 patients with chronic wounds of the lower limb, of whom 255 (51%) were women, the mean age was 58.12 years (age range = 71, 18 to 89 years). Among the patients, 231 (46.3%) had venous ulcers, 99 (19%) diabetic foot, 44 (8.8%) traumatic wounds (Table.1).

Table 1.

Characteristics of the patients

Variable	Categories	n	%
Age	<50	142	28.4
	>50	358	71.6
Gender	Female	255	51.0
	Male	245	49.0
Do you live on your own?	Yes	65	13.0
	No	435	70.0
	VU	231	46.3
	AU	14	2.8
	PI	29	5.8
Type of wound	DF	99	19.8
	TU	44	8.8
	Other	82	16.4
Status of wound	Healed	71	14.2
	Nonhealed	429	85.8

Abbreviations: AU: arterial ulcers; DF, diabetic foot; PI, pressure injury; TU, traumatic ulcer; VU, venous ulcers.

3.1. Translation

The expert committee considered semantics, cultural language and conceptual equivalences. The expert committee changed the word “schedule” to the word “Questionnaire,” because “Schedule” has a time connotation. The categorical response options of the Likert‐ type scale related to the Physical Symptoms, Daily Living, and Social Life domains were substituted: Regular replaced Moderate, Enough replaced Quite a Bit, and Much replaced Very. This was done to ensure the correct comprehension of intensity in Mexican Spanish.

In the same domains, the patients had difficulty during the pretesting to understand that the same item was interrogated two times, although they were two different questions, one for the presence of the symptom/condition and the other for how stressful it was. Rather than asking the question in a general way and below listing the symptoms/conditions, each item was written as a question. For example, “How stressful is it for you to have difficulty to get out and about?” Or, “Have you experienced difficulty to get out and about during the past week?” “How stressful is it for you to have disturbed sleep?” Or “Have you experienced disturbed sleep during the past week?” In addition, the main question was written in plural: “How stressful have all these experiences been for you?”

The participants had a good understanding of the applied instrument. They asked some questions and gave some suggestions, which were taken into account by the expert committee.

3.2. Validity

3.2.1. Face validity

The expert committee evaluated the relevance of each item and agreed unanimously that the instrument was adequate to assess the QoL of patients with leg ulcers, covering all relevant areas presented by patients.

3.2.2. Content validity

The expert committee evaluated the 47 items of the instrument, having a total of 282 evaluations. Of this, 234 evaluations were considered “very important” (82.98%) and 48 “important” (17.02%). The CVI obtained was of 0.95. There was no need for deletion of items.29, 34

To the question “How would you rate your overall QoL during the past week?” 32% of the patients answered 8; to the question “How satisfied are you with your overall QoL?” 22.4% answered 8. To these two items, Spearman's correlation was applied to find out if there was a relationship between how good their QoL was and how satisfied they were with their QoL. The correlation was positive and significative “QoL during past week” and “How good is your QoL,” a correlation coefficient of r = .738 was obtained and significant (P < .05), a scatter plot was also made to visualise this correlation (Graphic.1).

3.2.3. Construct validity

The correlation between sub‐scales CWIS with sub‐scales SF‐36 are shown in Table 2. The sub‐scale of physical symptoms and daily life (CWIS) significantly correlated with physical functions (SF‐36) r = .386 (P = <.0001). Also, a significant correlation was established between the Mobility sub‐scale and its associated CWIS stress with Physical Functions (SF‐36) (r = .410, P = <.0001). A negative correlation resulted between the pain and associated stress of (PAS) CWIS and Body Pain (SF‐36) r = −.407 (P = <.0001), because the scale directions are different. A significant correlation between Social Life and Social Functions with the sub‐scale Role limitation of SF‐36 was obtained (r = −.115, P = <.0001), assumed a value of r = .497 (P = <.0001). Finally, significant correlations between the CWIS Welfare sub‐scale with the SF‐36 Mental Health sub‐scale (r = .158 (P = <.0001) and with the Role Limitation sub‐scale (SF‐36) r = .348 (P = <.0001).

Table 2.

Correlation between CWIS sub‐scales and SF‐36 sub‐scales

CWIS subscale	SF‐36 subscale	Spearman's r	P
PSDL	PF	.386	<.0001
MAS	PF	.410	<.0001
PAS	BP	−.407	<.0001
SL	SF	−.115	.010
SL	RL	.497	<.0001
WB	MH	.158	<.0001
WB	RL	.348	<.0001

Abbreviations: BP, bodily pain; CWIS, Cardiff wound impact schedule; MAS, mobility and associated stress; MH, mental health; PAS, pain and associated stress; PF, physical functioning; PSDL, physical symptoms and daily living; RL, role limitation; SF, social functioning; SF‐36, short form‐36; SL, social life; WB, well‐being.

3.2.4. Discriminant validity

The authors used independent t test to analyse the scores of the responses to applied the Discriminate Analysis. The three sub‐scales showed differences between the two groups, and all were significant. (Table 3).

Table 3.

Mean scale scores for instrument by clinical assessment of healed status of wound

CWIS subscale	Healed (71)	Nonhealed (429)	p‐value
PSDL	87.69	80.19	.003
SL	10.23	12.66	.011
WB	19.45	16.95	.001

Abbreviations: CWIS, Cardiff Wound Impact Schedule; PSDL, physical symptoms and daily living; SF, social functioning; WB, well‐being.

3.3. Reliability

And last but not least, the instrument obtained an overall Cronbach's alpha of 0.952, corresponding to an excellent internal consistency. Well‐being domain 0.771 Cronbach's alpha considered acceptable, PSDL domain 0.830 Cronbach's alpha and Social Life domain of 0.903 Cronbach's alpha, both considered as good. Pain associated Stress Cronbach = .895 and it was good (Table 4).

Table 4.

Cronbach's alpha coefficient values for the Spanish for Mexico version of the Cardiff wound impact schedule

Sections	Cronbach α
General	.952
SL	.903
WB	.771
PSDL	.830
PAS	.895

Abbreviations: PAS, pain and associated stress; PSDL, physical symptoms and daily living; SL, social life; WB, well‐being.

The final cross‐culturally adapted, Mexican Spanish version of the CWIS for assessing HRQoL in patients with chronic leg ulcers was named Cardiff wound impact schedule‐Mexican Spanish (CWIS‐MS).

4. DISCUSSION

Chronic ulcers, whatever the aetiology, have a negative effect in HRQoL of patients.35 The negative state of mind in which patients find themselves interferes with the attachment to treatment in long term, which gets worse with time. An improvement in the HRQoL results in a better adherence to the therapy that is indicated.36 Thus, it is vital to have availability of reliable and acceptable tools.14

In addition, the assessment of HRQoL in patients with chronic leg ulcers, may contribute to the development of management strategies and interventions for improving quality of care for these patients. The CWIS is a specific disease HRQoL that has substantial evidence of reliability and validity in a variety of populations. Using this is more cost‐effective than starting from zero to develop and validate a new instrument,32 and allow us to compare the results with international studies.

As well as other translations and validation of CWIS, the expert committee established by unanimity that the CWIS‐S had face validity for measuring HRQoL in patients with chronic wounds.35, 37 The CWIS‐S also showed good content validity obtaining a CVI of 0.95 according to the ratings of chronic wounds experts. This is in accordance with the findings given by the original instrument, as well as other versions of this measure.38 The construct validity demonstrated that the correlations between sub‐scales CWIS and sub‐scales SF‐36 are significative. We evaluated the construct as the original study which showed moderate to strong correlations.21 The analysis showed an acceptable construct validation between the two instruments.

In terms of internal consistency, the CWIS‐S proved to have an overall Cronbach's alpha of 0.952, which indicates excellent internal consistency. In the same way, it showed acceptable and very good Cronbach scores α = .771 to .903 for the domains. Well‐being domain showed a low internal consistency, Cronbach α = .771; however, this value is considered acceptable. Similar result to the original instrument (alpha range, .770‐.960), and those obtained in validation studies of the CWIS conducted in Canada (alpha range, .562‐.809), Sweden (alpha range, .690‐.920), China (alpha range, .789‐.915) and Portugal (alpha range .805‐.956).21, 26, 27, 28, 37, 38

5. CONCLUSIONS

The translated, cross‐culturally adapted and validated CWIS‐MS showed satisfactory face validity, content validity and construct validity, and an excellent internal consistency, making it an adequate instrument to assess the HRQoL of Mexican patients with wounds of the lower limb.

Lozano‐Platonoff A, Contreras‐Ruiz J, Dominguez‐Cherit J, Cardenas‐Sanchez A, Alvarez‐Rivero V, Martínez‐Regalado JA. Translation, cross‐cultural adaptation and validation of the “Cardiff wound impact schedule,” a wound‐specific quality of life instrument, to the native Spanish of Mexican patients. Int Wound J. 2020;17:167–173. 10.1111/iwj.13253