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NCT Number: NCT07344649

Turkish Validation of the Nijmegen Questionnaire in COPD

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.

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Key information

Conditions

COPD Chronic Disease Disease Attributes Lung Diseases Lung Diseases, Obstructive Pathologic Processes Pathological Conditions, Signs and Symptoms Pulmonary Disease, Chronic Obstructive Respiratory Tract Diseases

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Observational

Primary location

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

questionnaires

Other

Administration of validated self-reported questionnaires (Nijmegen Questionnaire, CAT, mMRC, HADS, Dyspnea-12)

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Cahidenur Koçak

CONTACT

[email protected]

0 216 777 8 777

Esra Pehlivan

CONTACT

[email protected]

0 216 777 8 777

Sponsors and collaborators

Lead sponsor

Saglik Bilimleri Universitesi

Other

Registry information

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jan 15, 2026
Registry last updated
Apr 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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