Pulmonary Rehabilitation is widely recognized as an essential component in the integrated care of patients with chronic respiratory disease.1 The impact of this comprehensive intervention can be assessed by patient-centered outcomes, mostly performance-based, and to a certain extent influenced by patients’ perceived efficacy.2

Self-efficacy was defined by Albert Bandura as a personal construct of how successfully one can execute a required behavior to produce a desired outcome.3 According to “Self-efficacy as a unifying theory of behavioral change”, expectations of personal efficacy are based on four sources of information: performance accomplishments (personal mastery experience), vicarious experience (social observation), verbal persuasion (suggestion) and physiological states (emotional arousal and behavioral control).3 Personal mastery is the most powerful factor since it enables self-perception of the capacity to perform a task.4 Although the construct of self-efficacy was originally related to specific situations, recent approaches generalized the concept suggesting that general self-efficacy represents the confidence in one’s ability to deal with different demanding situations.5 Self-efficacy is a key concept in many behavior change frameworks such as the Self-efficacy Theory, the Transtheoretical Model, the Self-determination Theory, the Theory of Planned Behavior, and the Health Belief Model.6

Higher sense of self-efficacy has been found to be positively associated with: better outcomes on mobility, activities of daily living, depression and quality of life in stroke patients7; higher levels of self-care in young adults with type 1 diabetes8; better attendance and improvements in Pulmonary Rehabilitation9; and reduction in sedentary time following Pulmonary Rehabilitation in people with Chronic Obstructive Pulmonary Disease.10

To address adaptive behavior change, Pulmonary Rehabilitation enhances self-efficacy through self-management interventions, developing skills in goal setting, problem solving, decision-making, and taking action in a predefined action plan.1,11 Recent updates highlight the importance of patient’s self-efficacy on long-term adherence to health-enhancing behaviors.1 Evidence by research is that self-efficacy baseline assessment proved to be useful for predicting positive outcomes8 or directing the intervention to patient specific needs,9 maximizing the full benefits of Pulmonary Rehabilitation.

In respiratory clinical practice, self-efficacy has been firstly accessed by the COPD Self-Efficacy Scale, with patients rating on a 5-point Likert scale the amount of confidence in managing breathing difficulties in 34 diverse situations.12 This scale presents a five-factor structure (negative effect, intense emotional arousal, physical exertion, weather/environmental, and behavioral risk factors) and a significant internal consistency (Cronbach's alpha=0.95),11 yet not specific to the Pulmonary Rehabilitation context. For this purpose, Vincent and co-authors proposed the Pulmonary Rehabilitation Adapted Index of Self-Efficacy (PRAISE).2 The PRAISE tool is an adaptation of the General Self-Efficacy Scale (GSE) by Schwarzer and Jerusalem,5 adding 5 new specific items to the previous 10. Araújo and Moura have already validated a Portuguese version of the GSE,13 yet the assessment of such a construct remains to be explored in the Portuguese Pulmonary Rehabilitation setting.

This study aimed to: 1) translate and culturally adapt the PRAISE tool into European Portuguese; 2) evaluate reliability and construct validity of PRAISE in Portuguese respiratory patients.

The validation of the Portuguese version of PRAISE was developed in two phases: 1) translation and cross-cultural adaptation following international recommendations14 and 2) evaluation of reliability and validity according to the Consensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines.15,16

This study presents a Portuguese version of the PRAISE tool as a result of translation and cross-cultural adaptation by an expert committee, including the original author of the instrument, in accordance with international recommendations. Authors provide the Portuguese Version of PRAISE in appendix to enable all Portuguese speaking countries to measure self-efficacy as a patient-centered outcome of Pulmonary Rehabilitation.

As PRAISE measures self-efficacy enabling the clinician to identify important determinants of successful behavior change,1,2 authors applied such an instrument to the diversity of respiratory patients on Pulmonary Rehabilitation. Such heterogeneity may have contributed to different testing results compared with the original PRAISE study applied exclusively to Chronic Obstructive Pulmonary Disease patients.

In this study, the reliability estimated for the Portuguese version of PRAISE was 0.78, slightly lower than the one found in the original version of the scale, 0.95.2 Although one study has shown this to be a two-dimensional scale,20 in the present study four different factors were found, suggesting discriminative self-efficacy qualities.

The first factor included seven items from the GSE related with overall self-efficacy explaining 26.6% of variance. The second factor, explaining 9.7% of variance, included two items, one from each scale, regarding individuals’ belief about their own capacities. The third factor included three specific items from PRAISE, all describing performance accomplishment, explaining 8.7% of variance. Finally, the fourth factor included two items of GSE and one PRAISE item, together focus on rationale for coping, as either a trait or strategy, explaining 7.3% of variance.

Overall, the Portuguese PRAISE version explained 52.3% of the variance. While EFA solutions that account for 60% of the total variance can be considered satisfactory, it is not uncommon to achieve inferior values for multidimensional constructs.18,19 In fact, in this perspective, Bandura elegantly explained how expectations of personal efficacy are dynamic and may vary in magnitude, generality or strength.3 The results also indicate that some items may not be contributing significantly to the measured construct. Nonetheless, considering that the overall factor structure is conceptually plausible, the PRAISE presents itself as a practical and scientifically useful instrument.

The fact that it was a convenience sample with all patients attending Pulmonary Rehabilitation at the same center may be a study limitation. In addition, differences in the rehabilitation program or clinical conditions may have had an effect on how the individuals perceived their self-efficacy in regards to the Pulmonary Rehabilitation program. Hence, future studies should evaluate the reliability and validity of PRAISE for specific patient groups.

Given the lack of evidence published about the original PRAISE factor structure,2 these findings remain to be compared with further studies. The four-factor structure proposed enables future studies of PRAISE construct convergent validity, by a cross-sectional comparison of scores of other Pulmonary Rehabilitation instruments with PRAISE results,16,21 such as those presented by Vincent2 and Song.20 Furthermore, continuing research on longitudinal validity may increase knowledge on clinically important self-efficacy change and PRAISE responsiveness. In fact, some studies already applied PRAISE on a home-based Pulmonary Rehabilitation22 and self-management program,23 but with no differences when compared with traditional care.

The Portuguese version of PRAISE showed adequate psychometric properties with a reliability of 0.78 alpha Chronbach and a validity of 52.3% of explained total variance. This study enables Portuguese clinicians with the instrument to measure self-efficacy as a patient-centered outcome on Pulmonary Rehabilitation, in accordance with international guidelines.

This work was supported by Fundação para a Ciência e Tecnologia (FCT) and Nippon Gases Portugal under the PhD studentship in Industry grant PDE/BDE/127785/2016.

The authors have no conflicts of interest to declare.

Santos C. conceived, planned and executed the study, participated in the multidisciplinary panel of expert judges, analyzed and interpreted data, and wrote and revised the manuscript. Santos A. analyzed and interpreted data, and wrote and revised the manuscript. Santos M. interpreted data, and wrote and revised the manuscript. Rodrigues F. participated in the multidisciplinary panel of expert judges and revised critically the final version of the manuscript for important intellectual content. Bárbara C. revised critically the final version of the manuscript for important intellectual content. All authors have read and approved the manuscript.