First, a validated desk-based translation process was conducted, followed by a prospective, longitudinal non-interventional validation study in a cohort of patients with chronic wounds of the lower extremities. For the longitudinal study, patients were examined and completed questionnaires at baseline (T1) and after a follow-up period of two to three months (T2).

Patients with leg ulcers of various underlying causes were recruited in the dermatology departments of five Spanish University Hospitals. Inclusion criteria were an active chronic wound of the lower extremity, age ≥ 18 years and the capability to understand and fill in a Spanish questionnaire. Patients were only included after informed consent. The study was approved by the Comité Ético de Investigación Clínica del Hospital General Universitario Gregorio Marañón code “Wound-PRO”, on July 27, 2016. The license holders of the Wound-QoL also agreed on the adaption and validation.

The Wound-QoL questionnaire consists of 17 questions i.e. items. Each item is scored on a five-point Likert scale from 0 = not at all to 4 = very much. The mean rating of all questions results in the global score. Additionally, the three subscales everyday-life, body and psyche were determined in the original version of the Wound-QoL22. Fourth and back-translations of the original German Wound-QoL questionnaire were conducted following international guidance15. Briefly, the original German version was submitted to two Spanish native speakers who independently translated it into Spanish. These two versions were retranslated into German by two further German native speakers. The resulting two German versions were then compared with the original version and a semantic discussion on any deviation was conducted itemwise. This discussion included the original first author of the questionnaire, two physicians and psychologists familiar both with German and Spanish language and a linguist. After refining the Spanish version, a feasibility test was conducted in 10 patients from Spain. The objective of this test was to analyse if the patients feel comfortable with the questionnaire and understand the questions in the same way. We also wanted to find out how long it takes to complete the questionnaire under routine conditions. The questionnaire appeared to show no problems in terms of understanding and feasibility. A content adaption was not necessary. Fig. 1 shows the Spanish version of the Wound-QoL that was used in this validation study.

Figure 1.

Spanish version of the Wound-QoL (translated from the oirignal German version).

(0.68MB).

General patient data on socioeconomic and clinical background were obtained following a specific assessment of the wound condition based on a standard case report

Besides the Spanish version of the Wound-QoL, the following questionnaires were used:

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  EuroQoL five dimensions questionnaire (EQ-5D): a generic instrument reflecting health condition and quality of life in a validated Spanish version23

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  Pain: numerical rating scales (NRS) from 0–1024

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  The three visual analogue scales (VAS) included in the FLQA-w quality of life assessment, a validated, widely used specific quality of life questionnaire for wounds which was translated into Spanish the same way as the WoundQoL (independent translation/backtranslation)25

Due to the lack of recommendations on a priori sample size calculations in validation studies26, the size of the study population was determined based on previous experiences and corresponds to other Wound-QoL validation studies27,28.

Item distribution characteristics such as mean, standard deviation (SD), percentage of items at the lower (floor effects) and the higher end (ceiling effects) were inspected. For internal consistency Cronbach’s alpha was measured. Scores above 0.70 were interpreted as acceptable29. Explorative factor analysis was conducted to test for structural validity. Difference in scores between T1 and T2 were tested using Wilcoxon signed-rank test. To test for responsiveness and convergent validity, the Wound-QoL scores were correlated with the EQ-5D and FLQA-w (Spearman’s correlation). All analyses were conducted using SPSS version 23 (IBM, Armonk, NY, USA).

In the five centres, a total of 115 patients were recruited, including 45 (39.1 %) with venous leg ulcers, four (3.5 %) with mixed leg ulcers and four (3.5 %) with arterial leg ulcers (Table 1). Mean age was 69.5 (SD 14.5) years (median 73, min 28 - max 97), 60.0 % were female. Mean observation time was 9.6 (SD 6.6) weeks. Mean wound size at T1 was 18.9 (SD 36.1) cm², and 1.9 (SD 8.0) cm² at T2 (p < 0.001). Overall, 78 (67.8 %) of the wounds showed complete healing, 110 (95.7 %) an improvement of more than 10 % which was considered relevant.

Mean Wound-QoL at T1 was 1.9 (SD 1.0) and 0.8 (SD 0.9) at T2 (p < 0.001), mean FLQA-w health state concerning the wound was 5.1 (SD 2.7) at T1 and 8.1 (SD 2.1) at T2 (p < 0.001) (Table 2). VAS pain reduced from 4.9 (SD 3.4) to 0.9 (SD 1.7) (p < 0.001).

The Wound-QoL global score in the Spanish version showed high reliability with Cronbach’s alpha > 0.80 in all scales. There were satisfactory distribution characteristics of the global score and the subscales. At T1, 0.9 % had the lowest and the highest possible global score each. At T2, 18.3 % had the lowest possible and 0.9 % the highest possible global score. For the subscales the percentage of patients with the lowest possible score ranged between 2.6 % and 12.2 % at T1 and between 20.9 % and 48.7 % at T2. The percentage of the highest possible score in the subscales was between 7.8 % and 15.7 % at T1 and between 0.9 % and 2.6 % at T2.

In the explorative factor analysis, N = 115 patients who completed the Wound-QoL at T1 visit were included. Three factors with an eigenvalue > 1 were found, explaining 71.0 % of the overall variance. All items loaded on the intended components and the subscales body (items #1 to #5), psyche (items #6 to #10) and everyday-life (items #11 to #16) could be confirmed.

Convergent validity with other instruments (Table 3) and responsiveness were satisfactory (Table 4).

The Wound-QoL was considered a simple and feasible tool by the vast majority of patients. Mean time needed for completely answering was 5.2 (SD 6.4) minutes at T1 and 5.5 (SD 3.6) at T2. Overall, 99.1 % of participants found it easy to understand the questions and 94.7 % stated that the questionnaire suits the personal situation.