Purpose. Testing a newly developed Swedish version of the Body Image and Relationship Scale (BIRS) for test-retest reliability, convergent validity and inter-item analysis in a Swedish context for breast cancer survivors. Methods. A Swedish BIRS version, translation involving the input of experts and breast cancer survivors, with 41 items (BIRS-S) and the Short Form 36 (SF-36) were sent to a sample of 100 breast cancer survivors, mean age 61.7 years, diagnosed with breast cancer 20-42 months prior to the study. Retest was completed within 2-3 weeks. Results. 71 persons completed both dispatches. Reliability using Cronbach's alpha for the BIRS-S total was satisfactory 0.96 (range 0.87-0.93 for the three subscales). Intra-class correlation for the three subscales ranged between 0.88 to 0.93 revealing test-retest to be satisfactory. Convergent validity between the BIRS-S and SF-36 Physical Composite Score was - 0.68 for BIRS-S total. Convergent validity between the BIRS-S and SF-36 Mental Composite Score was - 0.65 for BIRS-S total. Inter-item analysis revealed the correlation between the original BIRS and the BIRS -S to be 0.98 for all three subscales. The new items correlated with the original BIRS ranging from 0.51 to 0.81 and with the BIRS-S ranging between 0.62 and 0.81. Conclusion. The BIRS-S demonstrates satisfactory test-retest reliability and validity according to the primary hypothesis of a moderate correlation to SF-36. It is not a new scale but an adapted version of the original instrument including specific areas of importance for Swedish breast cancer survivors.
Subject classification (UKÄ)
- Cross-sectional study