Cross-cultural adaptation guidelines were followed as the instructions of Beaten et al. [12] and the World Health Organization (WHO) [13]; forward translation of the original version, expert panel discussion (e.g., oncologists, clinical psychologists, clinician, professor in behavioral sciences, senior lecture in nursing), back-translation, pre-testing, and cognitive interviewing. A preliminary version was developed after reviewing both forward and backward translation by the expert committee. Finally, a modified version of the BC was understood easily; the panel of content experts has ensured the content validity of the scale. Final Sinhalese version of Brief COPE (S-BC) scale [See additional file 1] was developed.
This BC scale has 28- items; contains 14 subscales with only two items on each scale, graded by the four-point Likert scale. The responses to the items were 1= ‘I have not been doing this at all’, 2= ‘I have been doing this a little bit, 3= ‘I have been doing this a medium amount’ and 4= ‘I have been doing this a lot. The higher score of the subscale exhibits more likely the coping methods were used by the respondents. Cronbach’s alpha of original BC was higher than 0.6 for 11 of the 14 subscales. The first eight subscales (16 items) were titled 'adaptive coping strategies, and the other six subscales (12 items) were named 'maladaptive coping strategies'[10]. A higher score indicates a higher adaptive (score ranges from 0-48) and maladaptive coping (score ranges from 0-36). In terms of usage, Carver’s scale has been widely used in different countries and has been shown good psychometric properties [14 - 16].
Internal consistency/reliability of the S-BC was examined using Cronbach's alpha coefficient for an overall score of the S-BC and subscales considering the accepted standard cut-off for internal consistency as 0.60 or above [17]; considered as satisfactory internal consistency.
The test-retest reliability was examined using intra-class correlation coefficient (ICC) using the scores of scales in the first time and second time administrations (administered the same questionnaire after two weeks of first administration among the same 40 cancer patients). Pearson’s correlation coefficient was added to examine test-retest reliability.
Further, Pearson’s correlation coefficient was applied to check the concurrent validity of the S-BC scale and other standards scales (using correlations between the subscales themselves and the total score of the S-BC scale and standards scales). Convergent validity was assessed by item-subscale correlation considering a higher correlation of each item with their respective subscale. In addition, both WHOQOL-BREF and CES-D scales were used to examine convergent and discriminant/divergent validity assumed that participants who have higher coping used to have higher QoL and lower depressive symptoms; all applications were able to confirm the criterion validity of the scale.
Factorial validity of the S-BC was assessed using exploratory factor analysis (EFA). Factor analysis (FA) was performed using principal component analysis (PCA) with Varimax rotation (Kaiser normalization/Kaiser-Meyer – Olkin (KMO)). Bartlett's Test of Sphericity should reach statistical significance (p<0.001) and Commonalities Coefficients should be high (>0.6) [18].
The number of extracted components was determined by the Scree plot, percentage of variance explained by each component, number of Eigenvalues over one (Kaiser-Guttman rule), and consideration of prior psychometric Brief COPE analysis. Items were considered representative of a component if their item loading was ≥0.40 and in the cross-loading items, the factor, which had a higher loading value, was taken the respective factor [19].
A total of 40 cancer patients at the Radiotherapy unit, Oncology ward, Teaching Hospital, Karapitiya (THK) in Southern Sri Lanka were enrolled. Informed written consent was obtained from the patient before the data collection and participation in the study was voluntary. The sample size was considered supposing the correlational coefficient is about 0.45 for the Brief COPE using the subsequent formula N = [(Zα+Zβ)/C] 2 + 3. The calculated sample size was 36 and adding 10% for the non-respondents, the final sample size was 40 [19].
Baseline characteristics of the cancer patients were obtained using an interviewer-administered questionnaire and the diagnosis cards of the patients. Centre for Epidemiological Studies – Depression scale (20 item- CES-D) [20] and the World Health Organization-Quality of Life - Brief scale (26 item- WHOQOL-BREF) [21] were administered along with the newly adopted S-BC scale among 40 cancer patients by the principal investigator. Participants were informed to complete tools; the S-BC, CES-D, and WHOQOL-BREF which were previously validated in the Sri Lankan context.
The CES-D is a 20-item, short and self-report scale, which was originally developed to assess depressive symptomatology in the general population worldwide [20] during the ‘past week’. Each question has 04 responses from 0 (rarely or none of the time) to 3 (most or all of the time). The total score of the CES-D scale ranges from 0 (no depressive symptoms) to 60 (high level of depressive symptoms), where higher scores indicate the presence of more depressive symptomatology. This scale was validated in freely used in Sri Lanka [22].
The WHOQOL-BREF is a 26-item scale comprised of 04 domains; physical, psychological, social, and environmental, and originally developed to measure the QoL [21]. The higher values indicated a higher level of QoL. The scale WHOQOL-BREF has been validated in the Sri Lankan setting and used freely available in many studies [23].
Data analysis was done using SPSS 25.0 (IBM statistics, Inc., Chicago). The level of significance was accepted at p<0.05. Descriptive statistics were used to present baseline characteristics of cancer patients. Correlation coefficient values between 0.10 and 0.29 were considered low, between 0.30 and 0.49 were considered medium, and between 0.50 and 1.00 were considered high and as very strong correlation [19].
Ethical approval was obtained from the Ethics Review Committee of the Faculty of Medicine, University of Ruhuna and permission to recruit patients by healthcare setting. For the scale validation process, permission was obtained from the original authors of Brief COPE.