Adaptation and validation of the Czech version of the nasal obstruction symptom evaluation scale (NOSE-cz)

Summary

Background: Nasal obstruction is one of the most common symptoms in rhinology. In 2004, Stewart published a very simple instrument of nasal obstruction symptom evaluation (NOSE), which has already been adapted and validated in a number of languages. The aim of this study was to validate the Czech version of the questionnaire (NOSE-cz). Materials and Methods: Two-centre prospective instrument validation study. The psychometric properties (reliability, validity, sensitivity) of the Czech version were assessed in 72 patients undergoing (rhino) septoplasty and 39 asymptomatic controls. Results: Internal consistency (Cronbach’s alpha 0.796 and 0.691 before and after surgery, respectively) and test-retest reliability (Pearson’s test, 0.74; P <0.0001) were very good. The instrument showed excellent discrimination between groups (two sample t-test; P <0.0001) and sensitivity (standardised response mean 2.53). Conclusions: The Czech version of NOSE (NOSE-cz) demonstrated good to excellent psychometric properties and its use is recommended for daily clinical practice and research.

Keywords:

Quality of life – nasal obstruction – validation – NOSE scale – septoplasty

Introduction

Nasal obstruction is one of the most common symptoms in rhinology. At present, objective methods such as rhinomanometry, PNIF, or acoustic rhinometry need to be combined with subjective evaluation as reported by the patient.

Subjective evaluation of nasal breathing is part of a wide range of complex quality of life questionnaires, some of which may be, from the patient‘s point of view, relatively extensive and time consuming, and therefore biased.

In 2004, Stewart et al. published a very simple instrument of nasal obstruction symptom evaluation (NOSE) [1]. This questionnaire contains only five items and has reached rapid popularity, so it has already been adapted and validated in a number of languages [2–7].

Five NOSE questions are scored using a 5-point Likert scale (no problem, very mild problem, moderate problem, fairly bad problem, and severe problem). By multiplying the raw score by 5, a total score is expressed from 0 to 100 (0 means no problems; 100 the most severe problem).

The purpose of this study was to adapt the NOSE questionnaire to the Czech language (NOSE-cz) and to evaluate its psychometric properties so that in addition to the Czech version of SNOT-22 we have another high-quality tool to evaluate sinonasal symptoms.

Materials and methods

Study Populations

A group of 72 patients (43 men, 29 wo­men; mean age 18–67 years) with nasal obstruction were enrolled in the study; they were scheduled to undergo septoplasty or septorhinoplasty in two tertiary centres. All the patients completed a NOSE-cz questionnaire preoperatively and one month after surgery.

The control group consisted of 39 healthy students from the Faculty of Medicine (15 men, 24 women; mean age 22–26 years) who also completed the questionnaire.

Translation and cross-cultural adaptation

General guidelines were followed for the cross-cultural adaptation process of the Czech version of the NOSE survey [2]. Two forward and back translations were made and synthesised into one common translation. A final version of the Czech questionnaire (NOSE-cz) (Fig. 1) for testing was then produced by an expert committee (2 rhinologists familiar with the validation process, a methodologist and a translator).

Methods and statistics

The properties of the questionnaire were tested by determining its reliability, validity and sensitivity.

The internal consistency of the NOSE-cz was evaluated using Cronbach’s alpha coefficient.

Test-retest reliability was tested through Pearson’s coefficient on 21 subject who completed the Czech version of NOSE questionnaire twice with interval 2–3 weeks.

Discriminate validity (the ability of the questionnaire to distinguish between those who suffer from disease and other populations) was tested by comparing patients with the control group. The groups were compared by the two-sample t-test.

Sensitivity (responsiveness) was assessed using the standardised response mean (SRM) coefficient (SRM >0.8 means high sensitivity to change).

Ethical Consideration

The study protocol and informed consent form were approved by the Institutional Ethics Committee and were in accordance with the World Medical Association Declaration of Helsinki. Each patient signed an informed consent to participate in the study.

Results

Results of Cronbach’s alpha were 0.796 and 0.691 before and after surgery, respectively. Values approaching 0.8 and 0.7 indicate very good internal consis­tency of the NOSE-cz questionnaire.

Furthermore, the reliability value of the test and the test-retest, expressed as the Pearson test, of 0.74 (P <0.0001) demonstrates a high correlation between the two questionnaires completed by the same patient 2–3 weeks apart.

The mean of the total score of the questionnaire for patients and healthy controls was 58.75 (SD 19.91) and 14.54 (SD 13.99), respectively. This significant difference (P <0.0001) shows the excellent ability of the questionnaire to distinguish patients with nasal obstruction.

In terms of sensitivity, expressed by the SRM coefficient, the questionnaire recorded significant improvement in postoperative nasal breathing, which would be expected in a correctly compiled health-related QoL questionnaire. The mean of the total score of the questionnaire for patients before and after surgery was 58.75 (SD 19.91) and 10.76 (SD 9.88), respectively. The SRM coefficient for the difference in the total score before and after surgery was 2.53.

Discussion

The Nasal Obstruction Symptom Evaluation Scale (NOSE), developed by Stewart et al. in 2004 has become very popular among rhinologists and has been adapted into many languages, including Greek, Spanish, French, Italian and Polish [3–8]. In the present study, the psychometric properties of the Czech version are evaluated. All previously translated and validated language versions proved that NOSE is a very good indicator of nasal obstruction and is able to distinguish between the disease-affected and the normal population. This relatively short and feasible instrument can also detect change after medical intervention.

The internal consistency expressed by Cronbach’s a of NOSE-cz was similar to the original version (0.79 and 0.78, respectively) and comparable to other adaptations. Furthermore, the reliability value of the test-retest, expressed as Pearson’s coefficient, of 0.74 indicates a high correlation between the two questionnaires completed by the same patient 2–3 weeks apart and also demonstrates that the Czech version is stable and reproducible over time [1, 3–8].

Compared with the control group, similarly to other language versions, NOSE-cz has shown good discriminatory validity, which confirms the instrument’s ability to measure nasal obstruction and detect the presence or absence of disease [3, 6, 8].

The mean of the total score of the questionnaire for patients before and after surgery was 58.75 and 10.76, respectively. In terms of sensitivity, expressed by the SRM coefficient, the questionnaire recorded significant improvement in postoperative nasal breathing, which would be expected in a correctly constructed QoL questionnaire. This result is consistent with the review published by Rhee et al. who compared the decrease in NOSE scores in patients before and after (septo) rhinoplasty with or without concomitant turbinate surgery. In this study, the authors also noted that in no study did the NOSE score drop below 30 points and suggested that a change of at least 30 points may be considered a clinically significant measure of surgical success [9].

The study has several limitations. The controls were students of the medical faculty, so the control group was not selected to match patients according to sex and age. However, van Zilj et al. found no relation between NOSE and gender and concluded that the influence of gender should be minimal [6]. Another limitation could be the fact that the study was carried out in two tertiary centres, so there is potential patient selection bias. However, Larrosa et al. include both regional and tertiary centres and have demonstrated comparable results [3]. Finally, there might be one more argument that there was no correlation with some of the ‚objective‘ methods for the evaluation of nasal obstruction. However, it is generally accepted that subjective perception of nasal breathing is a complex phenomenon not always correlating with the results obtained by rhinomanometry or PNIF measurement and objectively measurable values represent only one possible view on this issue. Therefore, we believe that these limitations do not compromise the results obtained in the validation of NOSE-cz.

Conclusion

In conclusion, the study showed that the Czech version of the NOSE questionnaire is also a valid tool to assess nasal obstruction and the effectiveness of surgical treatment. The use of NOSE-cz can be recommended as a brief but reliable tool for clinical practice and research.

Conflict of interest

The authors declare that they have no conflicts of interest.

ORCID authors

Z. Hornáčková ORCID 0000-0002-7552-7590,

L. Otruba ORCID 0000-0002-1043-5775,

J. Fuksa ORCID 0000-0003-3845-2945,

P. Schalek ORCID 0000-0003-2740-6177.

Submitted: 15. 9. 2021

Accepted: 27. 10. 2021

Petr Schalek, MD, PhD

Department of Otorhinolaryngology 3^rd Faculty of Medicine, Charles University, and UHKV

Šrobárova 50

100 34 Prague 10

petr.schalek@fnkv.cz