From Data to Clinical Decisions in Chronic Wound Care: Evaluation of the Interpretability, Minimal Important Difference, and Smallest Detectable Change of the Wound-QoL-14 in a Spanish Population

Abstract

The Wound-QoL-14 questionnaire has proven to be a valid instrument for assessing patients with chronic wounds. However, cutoff scores are not established, and the smallest detectable change and the minimal important difference have not been defined. We aimed to assess the interpretability, smallest detectable change and the minimal important difference of the Wound-QoL-14 questionnaire in a Spanish population with chronic wounds. At baseline, patients responded to a 5-Likert global anchor question about how much their wounds had been a problem, and bands of severity were calculated. At a re-test phase they responded to a 7-Likert anchor question about the severity of the change in wound status, and smallest detectable change and minimal important difference were calculated using a combination of anchor-based and distribution-based methods. At baseline, stratification of 323 patients according to simplified bands of severity (0–0.25/0.26–1.00/1.01–2.00/2.01–3.00/3.01–4) showed a moderate correlation with the global anchor question (polychoric correlation = 0.653), but the level of agreement (41.5%) was poor (Krippendorff's alfa coefficient = 0.609). For 197 re-test patients, the Wound-QoL-14 individual smallest detectable change was lower than the weighted minimal important difference (0.39 vs. 0.53 points, respectively). These findings support the interpretability of the Spanish version of the Wound-QoL-14 questionnaire for clinical and research use.