Pectus ExcavatumTRANSLATENCT06918392
Field-test and Psychometric Validation of the Pectus Excavatum Evaluation Questionnaire in the Dutch Pectus Excavatum Population
An observational study of Pectus Excavatum, run by Erik de Loos at 1 site in Netherlands.
Trial summary
A questionnaire that can measure disease severity from the patients perspective in patients with pectus excavatum already exists in English (Pectus Excavatum Evaluation Questionnaire; PEEQ). This questionnaire was recently translated into Dutch. Read more about this study
- Who is it for?
- Ages 12 to 18 years
- Conditions the study is for
- Pectus Excavatum
- How many people
- 66 participants
- Where
- 1 siteNetherlands
- Study dates
- 15 Dec 2021to 30 Nov 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 18 years
- All sexes
- No healthy volunteers
- Child, Adult
Study population: Participants will be identified and enrolled during their preoperative visit at the outpatient clinic of Zuyderland Medical Center by a member of the research team.
Who may be able to join
- Eligible participants will be pectus excavatum patients aged 12 to 18 years old who are scheduled for a Nuss procedure. Parents or legal guardians will also be invited to complete the parent section of the PEEQ.
Who cannot join
- Exclusion criteria will be the inability of the patient or their parent/guardian to complete the corresponding section of the questionnaire due to language barriers.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site, 1 recruiting
- Recruiting
Zuyderland Medical Center
Heerlen
Erik R de Loos, 0031 (0)88 4597777, e.deloos@zyuyderland.nl
About this study
A questionnaire that can measure disease severity from the patients perspective in patients with pectus excavatum already exists in English (Pectus Excavatum Evaluation Questionnaire; PEEQ). This questionnaire was recently translated into Dutch. Before this Dutch version can be used, it needs to be tested by a number of patients.
Data will be collected at three moments:
- Preoperatively: The PEEQ will be completed on paper during the outpatient clinic visit.
- Postoperatively: The PEEQ will be completed electronically 2 months post-surgery.
- Test-retest reliability: The PEEQ will be administered electronically at least two weeks after a previous assessment.
- Conditions
- Pectus Excavatum
- Medical subject headings
- Funnel Chest
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Pectus excavatum patients | pectus excavatum patients aged 12 to 18 years old who are scheduled for a Nuss procedure, and their parents or legal guardians. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Structural validity
A Kaiser-Meyer-Olkin (KMO) test and Bartlett's test of sphericity are performed to assess the adequacy of patient sampling before performing further structural tests. Threshold values of ≥ 0.70 in KMO test and p < 0.05 in Bartlett's test of sphericity indicate the suitability of the collected data for factor analysis (6,7). Exploratory factor analysis (EFA), using principal axis factoring and a promax rotation method, will be conducted to identify the underlying factor structure for both the child and parent sections (8,9). These factor structures will later be subjected to confirmatory factor analysis (CFA), using polychoric correlations and robust maximum likelihood estimation, to evaluate the validity of the structures derived from EFA (8,10). Within EFA, the Kaiser criterion (eigenvalue > 1), explained variance (≥50%), and interpretability principle will be applied to determine the number of factors to be retained. Squared multiple correlations are used to compute the communality
Measured: Pre-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Internal consistency
Cronbach's alpha coefficient, a measure of internal consistency, will be calculated for each subscale. A value > .70 indicates sufficient reliability of the questionnaire for application at the group level, while a value > .90 implies suitability for individual assessment
Measured: Pre-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Test-retest reliability
Test-retest reliability for each subscale will be evaluated using a two-way mixed-effects model for the intraclass correlation coefficient (ICC), type (3.1), with 95% confidence intervals reported (CI) (15). The strength of agreement will be interpreted following the guideline provided by Cicchetti (1994) (16): < 0.40 = poor, 0.40-0.59 = fair, 0.60-0.74 = good, 0.75-1.00 = excellent. For individual items, quadratic weighted Cohen's kappa will be calculated along with its 95% to identify problematic items, with interpretation based on the standards proposed by Landis and Koch (1977) (17): <0 = poor, 0.01-0.20 = slight, 0.21-0.40 = fair, 0.41-0.60 = moderate, 0.61-0.80 = substantial, and 0.81-.001 = almost perfect.
Measured: Pre-operative assessment of pectus excavatum evaluation questionnaire OR the 2 months postoperative assessment will be used as a baseline. Another assessment wil be performed minimally 2 weeks after one of the aforementioned assessments.
Responsiveness
The responsiveness of the questionnaire will be determined using the construct approach in which preoperative and postoperative scores are compared using a paired t-test or Wilcoxon signed-rank test for skewed data. The effect size will be expressed in Cohen's d and is calculated as the mean difference divided by the standard deviation of the difference. We hypothesize that the total score on the PEEQ and mean scores per subscale improve after surgical correction of the pectus excavatum deformity as demonstrated by the original questionnaire (2,3). Responsiveness of individual items will be evaluated using a paired t-test or Wilcoxon signed-rank test, as appropriate, to guide further item refinement.
Measured: re-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Smallest detectable change
The standard error of measurement (SEM) quantifies the precision of the scores across different time points and is calculated as (18):
SEM = squareroot of MSE
Where:
- Mean square error (MSE) is the error term obtained from repeated measures ANOVA
The SDC represents the minimum change in points a patient must score on the questionnaire over time to ensure the observed change reflects a real change and not a measurement error. The SDC is expressed in points on the PEEQ and will be calculated for the mean scores per subscale, and the total scores of the child's section, parent's section and entire questionnaire. The SDC at a 95% confidence level will be calculated as (18):
SDC = 1.96 x square root of 2 x SEM
Where:
- 1.96 is the z-score corresponding to a 95% confidence level
- square root of 2 x SEM accounts for the error variance from both time points
Measured: Pre-operative assessment of pectus excavatum evaluation questionnaire and two months postoperative assessment. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Secondary outcomes (1)
Floor and ceiling effects
The floor and ceiling effects will be assessed by calculating the proportion of participants scoring the lowest or highest possible scores. Effects are considered substantial if > 15% of the participants score at the extremes for a specific item or subscale (18).
Measured: Pre-operative assessment of pectus excavatum evaluation questionnaire and two months postoperative assessment. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Apr 2025
- Study start15 Dec 2021
- Primary completion30 Nov 2026 (estimated)
- Study completion30 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (20)Papers the sponsor has linked to this study.
- Other trials for Pectus ExcavatumStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 66 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Erik de Loos
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Erik de Loos, Zuyderland Medisch Centrum
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06918392
- Sponsor's protocol ID
- Z2021173
- Acronym
- TRANSLATE
- Status last verified
- Mar 2026
- First submitted
- 24 Mar 2025
- Last updated
- 25 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Publications
Janssen N, Daemen JHT, van Polen EJ, Coorens NA, Jansen YJL, Franssen AJPM, Hulsewe KWE, Vissers YLJ, Haecker FM, Milanez de Campos JR, de Loos ER; Chest Wall International Group Collaborator Group. Pectus Excavatum: Consensus and Controversies in Clinical Practice. Ann Thorac Surg. 2023 Jul;116(1):191-199. doi: 10.1016/j.athoracsur.2023.02.059. Epub 2023 Mar 29.
PubMed 36997016Terwee CB, Bot SD, de Boer MR, van der Windt DA, Knol DL, Dekker J, Bouter LM, de Vet HC. Quality criteria were proposed for measurement properties of health status questionnaires. J Clin Epidemiol. 2007 Jan;60(1):34-42. doi: 10.1016/j.jclinepi.2006.03.012. Epub 2006 Aug 24.
PubMed 17161752Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977 Mar;33(1):159-74.
PubMed 843571Cicchetti D V. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assess. 1994;6:284-90.
Shrout PE, Fleiss JL. Intraclass correlations: uses in assessing rater reliability. Psychol Bull. 1979 Mar;86(2):420-8. doi: 10.1037//0033-2909.86.2.420.
PubMed 18839484Fayers PM. Quality of life : The assessment, analysis, and reporting of patient-reported outcomes. 3rd ed. Chichester: Wiley Blackwell; 2016.
Schreiber JB, Nora A, Stage FK, Barlow EA, King J. Reporting Structural Equation Modeling and Confirmatory Factor Analysis Results: A Review. J Educ Res. 2006;99:323-38
Kline P. An Easy Guide to Factor Analysis. 1st ed. New York: Routledge; 2014.
Pituch KASJ. Applied multivariate statistics for the social sciences: Analyses with SAS and IBM's SPSS. 6th ed. New York: Routledge; 2016.
Holgado-Tello FP, Chacón-Moscoso S, Barbero-García I, Vila-Abad E. Polychoric versus Pearson correlations in exploratory and confirmatory factor analysis of ordinal variables. Qual Quant. 2010;44:153-66.
Osborne JW, Costello AB. Best practices in exploratory factor analysis: four recommendations for getting the most from your analysis. Practical assessment, research and evaluation. 2005;10:1-9.
Brown T. Confirmatory factor analysis for applied research. 2nd ed. New York: Guilford Press; 2015.
Hoelzle JB, J. Meyer G. Exploratory Factor Analysis: Basics and Beyond. In: Handbook of Psychology, 2nd ed. New York: Wiley; 2012.
Watkins MW. Exploratory Factor Analysis: A Guide to Best Practice. Journal of Black Psychology. 2018;44:219-46.
Mokkink L, Prinsen C, Patrick D, et al. COSMIN Study Design checklist for Patient-reported outcome measurement instruments. 2019. Available online: https://www.cosmin.nl/wp-content/uploads/COSMIN-study-designing-checklist_final.pdf.
Study at a glance
From the registry record, last updated by the sponsor on 25 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Field-test and Psychometric Validation of the Pectus Excavatum Evaluation Questionnaire in the Dutch Pectus Excavatum Population
- ClinicalTrials.gov ID
- NCT06918392
- Acronym / sponsor ID
- TRANSLATE / Z2021173
- Conditions
- Pectus Excavatum
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 66 participants (estimated)
- Lead sponsor
- Erik de LoosUniversity, hospital or other
- Study start
- 15 Dec 2021 (actual)
- Primary completion
- 30 Nov 2026 (estimated)
- Study completion
- 30 Nov 2026 (estimated)
- First posted
- 9 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A questionnaire that can measure disease severity from the patients perspective in patients with pectus excavatum already exists in English (Pectus Excavatum Evaluation Questionnaire; PEEQ). This questionnaire was recently translated into Dutch. Before this Dutch version can be used, it needs to be tested by a number of patients.
Data will be collected at three moments:
- Preoperatively: The PEEQ will be completed on paper during the outpatient clinic visit.
- Postoperatively: The PEEQ will be completed electronically 2 months post-surgery.
- Test-retest reliability: The PEEQ will be administered electronically at least two weeks after a previous assessment.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Pectus excavatum patients | – | –pectus excavatum patients aged 12 to 18 years old who are scheduled for a Nuss procedure, and their parents or legal guardians. |
Who may qualify
- Ages
- 12 to 18 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
- Study population
- Participants will be identified and enrolled during their preoperative visit at the outpatient clinic of Zuyderland Medical Center by a member of the research team.
Key inclusion criteria (1 listed)
- Eligible participants will be pectus excavatum patients aged 12 to 18 years old who are scheduled for a Nuss procedure. Parents or legal guardians will also be invited to complete the parent section of the PEEQ.
Key exclusion criteria (1 listed)
- Exclusion criteria will be the inability of the patient or their parent/guardian to complete the corresponding section of the questionnaire due to language barriers.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Structural validity
Time frame: Pre-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
A Kaiser-Meyer-Olkin (KMO) test and Bartlett's test of sphericity are performed to assess the adequacy of patient sampling before performing further structural tests. Threshold values of ≥ 0.70 in KMO test and p < 0.05 in Bartlett's test of sphericity indicate the suitability of the collected data for factor analysis (6,7). Exploratory factor analysis (EFA), using principal axis factoring and a promax rotation method, will be conducted to identify the underlying factor structure for both the child and parent sections (8,9). These factor structures will later be subjected to confirmatory factor analysis (CFA), using polychoric correlations and robust maximum likelihood estimation, to evaluate the validity of the structures derived from EFA (8,10). Within EFA, the Kaiser criterion (eigenvalue > 1), explained variance (≥50%), and interpretability principle will be applied to determine the number of factors to be retained. Squared multiple correlations are used to compute the communality
Internal consistency
Time frame: Pre-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Cronbach's alpha coefficient, a measure of internal consistency, will be calculated for each subscale. A value > .70 indicates sufficient reliability of the questionnaire for application at the group level, while a value > .90 implies suitability for individual assessment
Test-retest reliability
Time frame: Pre-operative assessment of pectus excavatum evaluation questionnaire OR the 2 months postoperative assessment will be used as a baseline. Another assessment wil be performed minimally 2 weeks after one of the aforementioned assessments.
Test-retest reliability for each subscale will be evaluated using a two-way mixed-effects model for the intraclass correlation coefficient (ICC), type (3.1), with 95% confidence intervals reported (CI) (15). The strength of agreement will be interpreted following the guideline provided by Cicchetti (1994) (16): < 0.40 = poor, 0.40-0.59 = fair, 0.60-0.74 = good, 0.75-1.00 = excellent. For individual items, quadratic weighted Cohen's kappa will be calculated along with its 95% to identify problematic items, with interpretation based on the standards proposed by Landis and Koch (1977) (17): <0 = poor, 0.01-0.20 = slight, 0.21-0.40 = fair, 0.41-0.60 = moderate, 0.61-0.80 = substantial, and 0.81-.001 = almost perfect.
Responsiveness
Time frame: re-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
The responsiveness of the questionnaire will be determined using the construct approach in which preoperative and postoperative scores are compared using a paired t-test or Wilcoxon signed-rank test for skewed data. The effect size will be expressed in Cohen's d and is calculated as the mean difference divided by the standard deviation of the difference. We hypothesize that the total score on the PEEQ and mean scores per subscale improve after surgical correction of the pectus excavatum deformity as demonstrated by the original questionnaire (2,3). Responsiveness of individual items will be evaluated using a paired t-test or Wilcoxon signed-rank test, as appropriate, to guide further item refinement.
Smallest detectable change
Time frame: Pre-operative assessment of pectus excavatum evaluation questionnaire and two months postoperative assessment. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
The standard error of measurement (SEM) quantifies the precision of the scores across different time points and is calculated as (18): SEM = squareroot of MSE Where: · Mean square error (MSE) is the error term obtained from repeated measures ANOVA The SDC represents the minimum change in points a patient must score on the questionnaire over time to ensure the observed change reflects a real change and not a measurement error. The SDC is expressed in points on the PEEQ and will be calculated for the mean scores per subscale, and the total scores of the child's section, parent's section and entire questionnaire. The SDC at a 95% confidence level will be calculated as (18): SDC = 1.96 x square root of 2 x SEM Where: * 1.96 is the z-score corresponding to a 95% confidence level * square root of 2 x SEM accounts for the error variance from both time points
1 secondary outcome
Floor and ceiling effects
Time frame: Pre-operative assessment of pectus excavatum evaluation questionnaire and two months postoperative assessment. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Mar 2026.
- Background: PubMed 36997016Janssen N, Daemen JHT, van Polen EJ, Coorens NA, Jansen YJL, Franssen AJPM, Hulsewe KWE, Vissers YLJ, Haecker FM, Milanez de Campos JR, de Loos ER; Chest Wall International Group Collaborator Group. Pectus Excavatum: Consensus and Controversies in Clinical Practice. Ann Thorac Surg. 2023 Jul;116(1):191-199. doi: 10.1016/j.athoracsur.2023.02.059. Epub 2023 Mar 29.
- Background: PubMed 17161752Terwee CB, Bot SD, de Boer MR, van der Windt DA, Knol DL, Dekker J, Bouter LM, de Vet HC. Quality criteria were proposed for measurement properties of health status questionnaires. J Clin Epidemiol. 2007 Jan;60(1):34-42. doi: 10.1016/j.jclinepi.2006.03.012. Epub 2006 Aug 24.
- Background: PubMed 843571Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977 Mar;33(1):159-74.
- BackgroundCicchetti D V. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assess. 1994;6:284-90.
- Background: PubMed 18839484Shrout PE, Fleiss JL. Intraclass correlations: uses in assessing rater reliability. Psychol Bull. 1979 Mar;86(2):420-8. doi: 10.1037//0033-2909.86.2.420.
- BackgroundFayers PM. Quality of life : The assessment, analysis, and reporting of patient-reported outcomes. 3rd ed. Chichester: Wiley Blackwell; 2016.
- BackgroundSchreiber JB, Nora A, Stage FK, Barlow EA, King J. Reporting Structural Equation Modeling and Confirmatory Factor Analysis Results: A Review. J Educ Res. 2006;99:323-38
- BackgroundKline P. An Easy Guide to Factor Analysis. 1st ed. New York: Routledge; 2014.
- BackgroundPituch KASJ. Applied multivariate statistics for the social sciences: Analyses with SAS and IBM's SPSS. 6th ed. New York: Routledge; 2016.
- BackgroundHolgado-Tello FP, Chacón-Moscoso S, Barbero-García I, Vila-Abad E. Polychoric versus Pearson correlations in exploratory and confirmatory factor analysis of ordinal variables. Qual Quant. 2010;44:153-66.
- BackgroundOsborne JW, Costello AB. Best practices in exploratory factor analysis: four recommendations for getting the most from your analysis. Practical assessment, research and evaluation. 2005;10:1-9.
- BackgroundBrown T. Confirmatory factor analysis for applied research. 2nd ed. New York: Guilford Press; 2015.
- Individual participant dataSharing planned: Yes
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Pectus Excavatum, run by Erik de Loos at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 25 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Erik R de Loos, MD, PhD (+3188 459 9719, e.deloos@zuyderland.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Structural validity (time frame: Pre-operative assessment of pectus excavatum evaluation questionnaire at the outpatient clinic visit. Minimum score of this questionnaire is 22, maximum score is 88, a higher score indicates a lower disease-related quality of life.). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06918392, which also lists 20 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Mar 2026.