Validation and reliability testing of the BREAST-Q expectations questionnaire in Swedish

Abstract

Knowledge about preoperative expectations and how they affect satisfaction with breast reconstruction are key in improving care. A prerequisite for such studies are methodologically sound ways to define and measure expectations. The aims of this study were to translate and culturally adapt BREAST-Q Expectations for Sweden, and to perform a psychometric evaluation of the questionnaire. A cross-sectional study was performed. BREAST-Q expectations was translated according to current guidelines and sent to all patients on the waiting list for a breast reconstruction in our department. Internal consistency was assessed by Cronbach’s α. Inter-item correlations were calculated, and convergent validity was evaluated using a subjective comparator. Bland–Altman plots were drawn to evaluate test–retest reliability. Floor and ceiling effects were calculated. The questionnaire was sent to 198 patients, of which 129 responded (65%). Internal consistency was acceptable for all domains (Cronbach’s α 0.71–0.85) and all except one inter-item correlations were within the predefined intervals. Bland–Altman plots indicated that the agreement is variable. Ceiling effects were high for most domains. The results of the study support that the Swedish version of BREAST-Q expectations has a good content and face validity and internal consistency. Convergent validity and known-group validation cannot be adequately examined for expectations. Further studies are needed regarding test–retest reliability. High ceiling effects indicate that the instrument cannot discriminate between patients with high expectations and very high expectations. More studies are needed on how we can evaluate if expectations are realistic or not.

Trial registration

ClinicalTrials.gov Identifier NCT04714463, 19 January 2021 Patient and public contribution: All the data were generated directly from patients.

Keywords:

• Breast reconstruction
• patient-reported measures
• expectations
• psychometrics
• validity
• reliability
• health-related quality of life
• plastic surgery
• psycho-oncology

Acknowledgements

We are immensely grateful to the patients for completing the questionnaires. We also thank our colleagues, plastic surgeons Dr Fredrik Brorson, Dr Andri Thorarinsson, Dr Christian Jepsen, and associate professor Mattias Lidén for help in reconciling the two Swedish translations.

Ethical approval

The Swedish Ethical Review Authority reviewed and approved the study (2020-04729). All participants provided written informed consent to participate in the study.

Author contributions

LW made substantial contribution to the conception and design of the study, the analysis and interpretation of the data and drafted the work. AGE made substantial contribution to the analysis and interpretation of the data and revised the work. CL made substantial contribution to the analysis and interpretation of the data and revised the work. EH made substantial contribution to the conception and design of the study, the analysis and interpretation of the data and drafted the work. EH supervised LW. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated and analysed during the current study are not publicly available due to patient confidentiality, but are available from the corresponding author on reasonable request and permissions.

Additional information

Funding

Open access funding provided by University of Gothenburg. The study was funded by grants from The Swedish Cancer Society [21 0279 SCIA-EH], the federal government under the ALF agreement [ALFGBG-724171 and ALFGBG-965161 -EH], The Percy Falk Foundation, Stockholm, Sweden (EH) for research into prostate cancer and breast cancer, and The Swedish Breast Cancer Association (EH). The sources of funding had no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.