Validation of Bakas Caregiving Outcome Scale for brazilian portuguese*

Objective: to analyze the psychometric properties of the adapted version of Bakas Caregiving Outcome Scale for Brazilian Portuguese. Method: this is a cross-sectional methodological study conducted with 151 informal caregivers of people with cerebral vascular accident sequelae enrolled in Family Health Units. To assess reliability, Cronbach’s alpha was used. Construct validity was verified through exploratory factor analysis, confirmatory factor analysis and correlation with measures of instruments that evaluate correlated constructs. Results: Cronbach’s alpha for the total BCOS score was 0.89. Factor and exploratory analysis generated a one-factor structure, which was confirmed by confirmatory factor analysis. Construct validity was supported by the high positive correlations with Negative Affect (r = 0.51) and Negative Experience (r = 0.47) of the Well-being Scale and the Depression Anxiety and Stress Scale -21 (r = 0.53) and negative correlations with Positive Affect (r =-0.47) and Positive Experience (r = -0.17) of the Well-being scale. Conclusion: Bakas Caregiving Outcome Scale shows evidence of satisfactory reliability and validity in family caregivers of cerebral vascular accident survivors.


Introduction
The caregiver is essential to provide the individual with autonomy, independence, inclusion, in the family and social setting, and to avoid hospital readmissions (1) .
However, if he/she is not prepared to care, it may hinder the engagement of healthy behaviors of the patient and delay patient's rehabilitation (2)(3) .
In the case of cerebral vascular accident (CVA)stroke patients, after being discharged, when affected are commonly dependent on the care of others, which can be performed by a professional called a formal caregiver or by an informal caregiver, who is usually a member (1) . This person presents specific and different care needs, such as physical help (moving to the bathroom, to the bed); communication (verbal and nonverbal cues to other family members when the patient has aphasia); support for eating, taking care of their personal hygiene and emotional support (dealing with the destructive behavior caused by the consequences of the disease) (4) .
The many tasks that are attributed to the family caregiver, lack of support, unpreparedness to care, the level of dependence of the patient, the chronicity of the disabling situation, the complexity of the care activities, the worsening of health status and the uncertainty of future causes burden, and this may lead to social isolation, reduction or end of leisure activities, impairment of professional activity, loss of job and lack of time for self-care (5)(6)(7)(8) .
Burden is seen as a multidimensional phenomenon that affects various dimensions of the caregiver's life, which is defined as the subjective perception that results in the impact of one or more of the physical, psychological, social and financial dimensions resulting from an imbalance between demands that are imposed and the resources available to face them, being a continuous process, usually starting with a certain triggering event (9) .
Burden screening is critical for planning psychoeducational and psychotherapeutic interventions to improve the formal support network and caregivers' ability to cope with the situation in order to improve the quality of life (10)(11) .
In Brazil, the use of culturally constructed and adapted scales to assess caregiver burden is still incipient, with Caregiver's Burden Scale (12) , Family Burden Interview Scale (13) , Zarit Burden Interview (14) and Informal Caregiver Burden Assessment Questionnaire (15) .
However, there is no specific tool to measure the caregiver burden of people who had a stroke or in other acute and chronic situations adapted to the Brazilian reality.
Two comprehensive reviews of caregiver burden measures (16)(17) pointed to the Bakas Caregiving Outcomes Scale (BCOS) as one of the broadest to assess burden. Among its strengths, BCOS takes into account positive aspects of care delivery and its consequences, it is brief, has good consistency, moderate correlations with variable criteria and evidence of good content and construct validity (16) .
It was based on the adaptive outcomes of the Lazarus stress and coping model (18) . Provision of care and the new roles are considered stressors, however, the caregiver's assessment of this event is individual and may or may not be perceived as a burden situation.
This means that caregivers may experience similar situations, but perceive them in different ways (19) .  (19) .
BCOS was made in the United States of America (USA) in English and then adapted and validated for other countries such as Turkey (20) and Greece (21) . The use of BCOS has been relevant to practice and research in various areas of health, including nursing, being used, for example, in intervention studies to evaluate the effectiveness of the intervention performed to the caregiver (22) . Due to linguistic and cultural differences, it needs to be translated and cross-culturally adapted for use in Brazil by nurses and other professionals.
Considering the above, the following hypothesis

Method
This is a methodological and cross-sectional study that analyzed the validity and reliability of BCOS after its semantic and content adaptation for use in Brazil.
Authorization for the process of cross-cultural adaptation of the scale was obtained from the tool's lead author. the short version with ten items was defined (24) . In the most current version, five items were included, totaling 15 items, measured on a seven-point response scale ("changed for worse" = -3 up to "changed for better" = +3), in which the lower the score, the greater the burden (19) .
For convergent validation, the Depression Anxiety and Stress Scale-21 (DASS -21) was used. The DASS was developed in 1995 (25) and adapted and validated for Brazil in 2014 (26) . The tool has 21 items, which are distributed in three four-point, self-responding Likerttype subscales. Each subscale is composed of seven items designed to evaluate the emotional states of depression, anxiety and stress (26) .
For discriminant validation, we used the BES scale, which was developed in 1980 (27) and validated for  Exploratory factor analysis is used when data behavior is unknown and should be performed whenever an instrument with a new sample is applied.
Confirmatory factor analysis is performed when the factor structure is known and it is intended to confirm this structure by regression-based structural equation modeling. According to Pasquali (23) , to perform construct validation, it is necessary to follow some steps, which he divides into theoretical, empirical and analytical poles.
Prior to EFA, we used the Kaiser-Meyer-Olkin (KMO) measure general sampling suitability and, per item, the Measure of Sampling Adequacy (MAS), whose required score must be greater than or equal to 0.60 for the overall KMO and greater than or equal to 0.50 per item (30) . The results for the general KMO were classified as follows: 0.90 is considered wonderful; 0.80 is meritorious; 0.70 is median; 0.60 is modest; 0.50 is miserable and below that is unacceptable (31) . A hypothesis test was also performed using Bartlett In the first indicator, the score level is required to be above 0.70, while in the second indicator a level above 0.50 is required (30) .
CFA was performed using AMOS GRAFICS 21.0, considering the maximum likelihood method. The following adjustment indicators were considered (33-34) : • χ² (chi-square) -this indicator checks the probability that the theoretical model will fit the data; in this case, the lower the value, the better. As its use in the literature is low, it is more common to consider the ratio in relation to the degree of freedom (χ² / g.l.).
Thus, the maximum value for a proper fit is three; • Comparative Fit Index (CFI) and Tucker-Lewis Index  From the consideration of these criteria, it was decided by the single factor structure, in which the 15 items factor with loads above 0.40, whose factor explains 42.5% and the commonality. What the items have in common with each other ranged from 0.167 to 0.505.
The factor burdens ranged from 0.40 to 0.711 (Table 2).    The factor structure of the BCOS scale for burden was adequate and robust for the evaluation of this construct ( Figure 1).
In the divergent analysis, BCOS was negatively  (Table 4).

Discussion
Burden is a multidetermined phenomenon that occurs when care demands are greater than available resources. BCOS evaluates the burden through changes in the caregiver's life after an acute or chronic event, such as stroke, and, in its original version was reliable and valid to evaluate the construct (19) . Regarding the reliability of the adapted scale, the internal consistency performed by Cronbach's alpha was 0.89, which reveals an internally consistent measurement. This value was similar to the alpha of 0.90 from the original version (19) and also, in another BCOS validation study in caregivers of patients with cancer, alpha was 0.83 (21) . In addition to Cronbach's alpha, these two studies performed the test-retest reliability analysis, which revealed good stability after two weeks.  of the variance represented by the first factor and the factor burdens ranged from 0.41 to 0.78 (19) .
Regarding factor burdens, most items factored above 0.5, a value recommended by the literature (30) , In the most current scale validation studies assessing caregiver burden, such as the Caregiver Burden Inventory (39) and the Informal Caregiver Burden Assessment Questionnaire (15) , similar tests were used, such as Cronbach's Alpha and correlation with other constructs and CFA. However, in both cases, EFC was not used to explore how many existing factors and also the number of indicators in the CFA was lower than this study. In the referred studies, the number of dimensions were different from BCOS, composed respectively by five and seven factors.
Regarding convergent and discriminant validation, from the caregiver role has been associated with mental disorders such as depression, anxiety and stress (40)(41)(42) , which consequently affects well-being and quality of life (43) . A systematic meta-analysis review found that caregivers of stroke patients showed a doubled risk of psychic symptoms compared to the general population, with overall prevalence of 40.2% and 21.4% of depression and anxiety symptoms, respectively (44) .
For this reason, it is important to perform familyspecific nursing interventions during hospital discharge, immediate post-discharge and over time, with psychoeducational therapies, skills training and therapeutic counseling, which will help to reduce anxiety and burden and to have a more favorable outcome. Studies have shown that caregivers' needs are not stable through the different phases after stroke (45) .