Turkish Validation of the Nijmegen Questionnaire in COPD

April 13, 2026 updated by: ESRA PEHLIVAN, Saglik Bilimleri Universitesi

Dysfunctional breathing is a common and clinically relevant problem in patients with chronic obstructive pulmonary disease (COPD), contributing to increased dyspnea perception, reduced exercise tolerance, and impaired quality of life. The Nijmegen Questionnaire (NQ) is a widely used symptom-based instrument for screening dysfunctional breathing; however, a validated Turkish version for patients with COPD is currently unavailable.

This observational methodological study aims to translate, culturally adapt, and evaluate the validity and reliability of the Turkish version of the Nijmegen Questionnaire (NQ-TR) in individuals with stable COPD.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This single-center observational study will be conducted in patients with clinically stable COPD. The study consists of two main phases: (1) translation and cultural adaptation of the Nijmegen Questionnaire following international guidelines for patient-reported outcome measures, and (2) psychometric evaluation of the Turkish version in a COPD population.

The translation process includes forward translation, reconciliation, back-translation, developer review, cognitive debriefing with patients, and final proofreading. After completion of the linguistic adaptation, the NQ-TR will be administered to eligible participants at baseline and repeated after one week in clinically stable individuals to assess test-retest reliability.

Construct validity will be evaluated using exploratory and confirmatory factor analyses. Convergent validity will be assessed by examining correlations between NQ-TR scores and established clinical measures, including the COPD Assessment Test (CAT), Modified Medical Research Council (mMRC) Dyspnea Scale, Hospital Anxiety and Depression Scale (HADS), and Dyspnea-12 (D-12). Internal consistency, test-retest reliability, and measurement stability will be analyzed.

Study Type

Observational

Enrollment (Estimated)

90

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

The study population consists of adults aged 18 years and older with a confirmed diagnosis of chronic obstructive pulmonary disease (COPD) according to GOLD criteria. Eligible participants are clinically stable patients attending the pulmonology outpatient clinic of a tertiary care hospital, with no acute exacerbation or hospitalization within the previous four weeks. All participants are Turkish-speaking, able to complete self-reported questionnaires, and provide written informed consent.

Description

Inclusion Criteria:

  • Adults aged 18 years and older
  • Diagnosis of COPD confirmed according to GOLD criteria
  • Clinically stable disease (no acute exacerbation or hospitalization within the last 4 weeks)
  • Ability to read and understand Turkish
  • Willingness to participate and provide written informed consent

Exclusion Criteria:

  • Acute COPD exacerbation or respiratory infection within the previous 4 weeks
  • Presence of severe cardiac, neurological, or systemic disease affecting questionnaire responses
  • Coexisting pulmonary conditions such as bronchiectasis, lung cancer, prior pulmonary tuberculosis, pleural disease, or history of lung surgery
  • Moderate to severe cognitive impairment or communication difficulties
  • Severe visual or hearing impairment preventing questionnaire completion
  • Pregnancy
  • Refusal to participate or withdrawal during the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
COPD
Other: Questionnaires
Administration of validated self-reported questionnaires (Nijmegen Questionnaire, CAT, mMRC, HADS, Dyspnea-12)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Turkish version of the Nijmegen Questionnaire (NQ-TR)
Time Frame: Baseline and 1 week
The Nijmegen Questionnaire is a validated self-report instrument used to assess symptoms related to dysfunctional breathing and hyperventilation. It consists of 16 items evaluating the frequency of respiratory and non-respiratory symptoms, with higher total scores indicating greater symptom severity. In this study, the Turkish-validated version of the Nijmegen Questionnaire (NQ-TR) will be used to evaluate dysfunctional breathing symptoms in participants.
Baseline and 1 week

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
COPD Assessment Test (CAT)
Time Frame: Baseline
The COPD Assessment Test (CAT) is a validated, patient-completed questionnaire designed to assess the impact of chronic obstructive pulmonary disease (COPD) on health status. It consists of 8 items covering symptoms, activity limitation, and overall well-being, with total scores ranging from 0 to 40. Higher scores indicate a greater impact of COPD on health status. In this study, the Turkish-validated version of the COPD Assessment Test (CAT) will be used to evaluate disease-related symptom burden and health status in participants with COPD.
Baseline
Modified Medical Research Council (mMRC) Dyspnea Scale
Time Frame: Baseline
The Modified Medical Research Council (mMRC) Dyspnea Scale is a widely used, validated scale for assessing the severity of perceived breathlessness related to physical activity in individuals with chronic respiratory diseases. The scale grades dyspnea from 0 to 4, with higher grades indicating greater functional limitation due to breathlessness. In this study, the Turkish-validated version of the Modified Medical Research Council (mMRC) Dyspnea Scale will be used to assess dyspnea severity in participants.
Baseline
Dyspnea-12 (D-12) Scale
Time Frame: Baseline
The Dyspnea-12 (D-12) Scale is a validated patient-reported outcome measure designed to assess both the physical and affective components of breathlessness. It consists of 12 items, with total scores ranging from 0 to 36, where higher scores indicate greater dyspnea severity. In this study, the Turkish-validated version of the Dyspnea-12 (D-12) Scale will be used to evaluate the multidimensional severity of dyspnea in participants.
Baseline
Hospital Anxiety and Depression Scale (HADS)
Time Frame: Baseline
The Hospital Anxiety and Depression Scale (HADS) is a validated self-report questionnaire designed to assess symptoms of anxiety and depression in individuals with physical health conditions. It consists of 14 items divided into two subscales: anxiety (HADS-A) and depression (HADS-D), each comprising 7 items, with subscale scores ranging from 0 to 21. Higher scores indicate greater psychological distress. In this study, the Turkish-validated version of the Hospital Anxiety and Depression Scale (HADS) will be used to evaluate anxiety and depression levels in participants.
Baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Saglik Bilimleri Universitesi

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 13, 2026

Primary Completion (Estimated)

January 1, 2027

Study Completion (Estimated)

January 1, 2027

Study Registration Dates

First Submitted

January 1, 2026

First Submitted That Met QC Criteria

January 13, 2026

First Posted (Actual)

January 15, 2026

Study Record Updates

Last Update Posted (Actual)

April 15, 2026

Last Update Submitted That Met QC Criteria

April 13, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Nijmegen&TR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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