For assessing health-related quality of life in patients with chronic wounds, the Wound-QoL questionnaire has been developed. Two different versions exist: the Wound-QoL-17 and the Wound-QoL-14. For international and cross-cultural comparisons, it is necessary to demonstrate psychometric properties in an international study. Therefore, the aim of this study was to test both questionnaires in a European sample, using item response theory (IRT). Participants were recruited in eight European countries. Item characteristic curves (ICC), item information curves (IIC) and differential item functioning (DIF) were calculated. In both questionnaires, ICCs for most items were well-ordered and sufficiently distinct. For items, in which adjacent response categories were not sufficiently distinct, response options were merged. IICs showed that items on sleep and on pain, on worries as well as on day-to-day and leisure activities had considerably high informational value. In the Wound-QoL-14, the item on social activities showed DIFs regarding the country and age. The same applied for the Wound-QoL-17, in which also the item on stairs showed DIFs regarding age. Our study showed comparable results across both versions of the Wound-QoL. We established a new scoring method, which could be applied in international research projects. For clinical practice, the original scoring can be maintained.
The Wound-QoL assesses the impact of chronic wounds on patients' health-related quality of life (HRQoL). A 17-item and a shortened 14-item version are available. The Wound-QoL-17 has been validated for multiple languages. For the Wound-QoL-14, psychometric properties beyond internal consistency were lacking. We aimed to validate both Wound-QoL versions for international samples representing a broad range of European countries, including countries for which validation data had yet been pending. Patients with chronic wounds of any aetiology or location were recruited in Austria, Lithuania, the Netherlands, Poland, Slovakia, Spain, Switzerland and Ukraine. Psychometric properties were determined for both Wound-QoL versions for the overall sample and, if feasible, country-wise. We included 305 patients (age 68.5 years; 52.8% males). Internal consistency was high in both Wound-QoL-17 (Cronbach's α: 0.820–0.933) and Wound-QoL-14 (0.779–0.925). Test–retest reliability was moderate to good (intraclass correlation coefficient: 0.618–0.808). For Wound-QoL-17 and Wound-QoL-14, convergent validity analyses showed highest correlations with global HRQoL rating (r = 0.765; r = 0.751) and DLQI total score (r = 0.684; r = 0.681). Regarding clinical data, correlations were largest with odour (r = −0.371; r = −0.388) and wound size (r = 0.381; r = 0.383). Country-wise results were similar. Both Wound-QoL versions are valid to assess HRQoL of patients with chronic wounds. Due to its psychometric properties and brevity, the Wound-QoL-14 might be preferrable in clinical practice where time is rare. The availability of various language versions allows for the use of this questionnaire in international studies and in clinical practice when foreign language patients are being treated.