The study was evaluated and approved by the Research Ethics Board at our center (reference PIC-82-19) complying with the local laws on Biomedical Research (Ley 14/2007, de 3 de julio, de Investigación Biomédica). All legal guardians or patients older than 18 years provided written informed consent according to our center’s policy. Children aged 12 to 17 years also provided written assent.
The PEEQ is a tool designed by a psychologist and a group of PE clinical experts  in Norfolk, Virginia. It consists of both preoperative and postoperative telephone questionnaires, with versions for patients and parents. It includes questions related to body image and also to physical activities. Answers are given using a Likert-type scale from 1 to 4, reflecting the extent or frequency of a particular experience. Higher values on the response scale indicate a less desirable experience (e.g., 4 very unhappy and 1 very happy).
The questionnaire is divided in two parts: the first part is for patients and the second one for parents. The patient’s preoperative part of the questionnaire consists of 15 items; the postoperative part consists of 17 items. Items 1-14 are equal in both pre-surgical and post-surgical; the other items differ. There are a total of 18 different questions in the patient’s part. The parents’ part consists of 16 items; there is only a slight difference in one item (item 13) that was considered irrelevant for the analysis.
Process of adaptation of the PEEQ into Catalan and European Spanish
Principles of good practice for the translation and cultural adaptation process for PRO were followed according to the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) recommendations .
Permission was obtained from Dr. RE Kelly, one of the PEEQ developers. He provided the original version of PEEQ and allowed us to transform the telephonic original version into a written questionnaire.
- Step 2: Forward translation.
Selected forward translators were native speakers of both target languages and had an advanced knowledge of English. One of them is a professional translator; the other two are pediatric surgeons —one has special dedication to PE patients and the other is a senior pediatric surgeon with previous experience in PRO translation .
A document including our written adaptation of the PEEQ original version and an explanation of the tool and the goals of our study was prepared and delivered to translators. Following the ISPOR recommendations, we stressed that the translation should be conceptual rather than literal. Common language was also recommended, so that patients and parents having diverse educational level could easily understand the questions and responses.
Each translator developed a Catalan and a European Spanish version of the PEEQ.
Reconciliation of the three forward translations into a single one in each language was performed in a meeting between the forward translators and the thoracic pediatric surgeon of our department. Agreement of the main word and sentence construction was recorded for each item of the questionnaire. An item was considered discordant if all the 3 versions were different in any of both parts of the translation (key-word or sentence construction).
- Step 4: Back translation.
A native English speaker was the back translator for each target language (Catalan and European Spanish). They are both medical doctors. A document including the reconciled version, an explanation of the tool and the goals of the study, was delivered to each translator. Again, we stressed that the translation should be conceptual rather than literal and that common language was recommended.
- Step 5: Back translation review.
A revision of the back translations against the original English version was performed in a meeting of two of the forward translators and the thoracic pediatric surgeon of the department. For each item, we recorded changes in the wording or in sentence construction in the back translations compared to the original source. Discrepancies between the original version and the back translations were identified and an improved version was developed for each language. Despite differences with the original source were detected; we only changed the forward version in case of significant meaning alteration.
Comparison between our new Catalan and European Spanish versions and the original English version was performed to guarantee conceptual equivalence between the source language and the target language versions. Formulation of questions was also unified at this point. The forward translators and the thoracic pediatric surgeon of the department amended this issue in the back-translation review meeting.
- Step 7: Cognitive debriefing.
In order to ensure that the translation was comprehensible to the patient population, a cognitive debriefing was performed on 10 patients for each language. Patients aged 8 to 21 years were selected from the thoracic outpatient agenda between April and September 2019. Five patients who had undergone Nuss procedure and five untreated patients were selected for each language. The main researcher approached potential participants, explained them and their parents the purpose of the study and invited them to participate. After informed consent, patients and parents were asked to answer the questionnaires and express for each item whether they understood the entire sentence and every word. Sentences in which patients or parents required any clarification were considered difficult to understand, age, gender and treatment of PE of the participants were recorded.
- Step 8: Review of the results of cognitive debriefing and finalization.
The results of the cognitive debriefing were reviewed and sentences that were not easily understood by the patients or their parents were checked in a meeting between two of the forward translators and the thoracic pediatric surgeon of the department. The necessary modifications were done to improve the final versions.
Two other pediatric surgeons of our department proofread the final versions.
A final report was done including a description of all translation and cultural adaptation decisions.