Psychometric properties of the portuguese version of the Pain Self Efficacy Questionnaire

órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 260 a r t i g o o r i g i n a l p s y c h o m e t r i c p r o p e r t i e s o f t h e p o r t u g u e s e v e r s i o n o f t h e p a i n s e l f -e f f i c a c y q u e s t i o n n a i r e M. Alexandra Ferreira-Valente*,**,***, José L. Pais-Ribeiro*,***, Mark P. Jensen**** *Faculdade de Psicologia e Ciências da Educação da Universidade do Porto, Porto, Portugal; **Fundação para a Ciência e a Tecnologia, Portugal ***Unidade de Investigação em Psicologia e Saúde, ISPA, Lisboa, Portugal ****University of Washington School of Medicine, Seattle, USA. The present study was undertaken with the support of the first author’s FCT PhD grant SFRH/BD/ 40956/2007. the hypothesized directions, supporting its cons - truct validity. Additionally, the confirmatory factor analysis supported a single factor solution, as hypothesized. Conclusions: The findings provide strong support for the reliability and validity of the P-PSEQ. Research is needed to determine the responsivity of the P-PSEQ and to establish the generalizability of the results in other samples of Portuguese patients with chronic pain. Keywords: Pain; Pain Assessment; Intractable Pain; Self-Efficacy. Introduction Biopsychosocial models of chronic pain hypothesize that psychological and social factors play a key role in the adjustment to chronic pain. Pain self- -effi cacy – that is, the belief or confidence in one’s abi lity to engage in a specific behaviour or other action to achieve desired goals despite pain1-4 – has been one of the factors thought to mediate the impact of pain on disability and depression1,5-7. There is strong support for the importance of pain self-efficacy across a broad range of pain populations and conditions, with patients endorsing higher levels of self-efficacy reporting lower levels of pain intensity, disability, depression and anxiety1,4,5,8-14, and higher quality of life and general health12,15. Furthermore, self-efficacy is thought to influence thoughts and feelings, which in turn can affect functioning2,4,16-18. Self-efficacy may also influence the use of pain coping strategies via its effects on readiness to engage in those coping respon - ses4,11,19-21, with patients endorsing lower levels of self-efficacy being more likely to use passive co - ping responses and to catastrophize in response to pain4,19. On the other hand, patients endorsing higher levels of self-efficacy have been shown to Abstract Aims: This study sought to translate and evaluate the psychometric properties of a European Portuguese version of the Pain Self-Efficacy Questionnaire (P-PSEQ), in order to enable its use in clinical and cross-cultural studies. Material and Methods: The Pain Self-Efficacy Questionnaire was translated into European Portuguese and then back-translated into English. A consensus version of the translated version was pre-tested with a pilot sample, followed by cognitive debriefing, resulting in a final version of the measure. A convenience sample of 174 Portuguese adults with chronic musculoskeletal pain completed the Portuguese Pain Self-Efficacy Questionnaire (P-PSEQ) and criterion measures of pain intensity (Numerical Ratings Scale), pain interference (Portuguese Brief Pain Inventory Interference Scale), quality of life and general health (SF-12), and psychological functioning (Hospital Anxiety and Depression Scale). Cronbach’s alpha and composite reliability coefficients were computed as measures of reliability, and confirmatory factor analysis was performed. Pearson correlation coefficients between the P-PSEQ score and the criterion measures were computed to evaluate the construct validity of the scale. Results: The P-PSEQ demonstrated good to excellent reliability (Cronbach’s alpha = 0.88 and Composite reliability = 0.92), and showed moderately strong associations with the criterion measures in órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 261 m. alexandra ferreira-valente e col. use more adaptive coping responses2,11,19,22, even after controlling for demographic and medical status variables11. Given the importance of self-efficacy in the adaptive management of chronic pain, multidisciplinary treatment programs often aim to increase pain self-efficacy as a way to increase patients’ quality of life and enhance positive phy - sical and psychological outcomes in response to treatment. In order to determine the effects of treatment on pain self-efficacy as well as evaluate its potential role in adjustment to pain, a valid and reliable measure of pain self-efficacy is needed. Moreover, translated measures of the construct are needed for cross-cultural research to determine if the same treatments have similar effects on outcomes across cultures. The Pain Self-Efficacy Questionnaire (PSEQ)4, which was developed from Bandura’s Social Learning theory2, is the only pain self-efficacy measure developed specifically to assess confidence of patients to engage in a number of activities of daily living, despite pain. The PSEQ was developed to be applicable to patients with all chro - nic pain conditions and to be easy to understand. It assesses self-efficacy regarding a wide range of functions such as household chores, social activities, work, and coping with pain without medication, yet takes less than two minutes to complete. Previous research shows the PSEQ to be reliable and to have both factorial and predictive validity across a number of languages, cultures, and clinical settings4,9,12,14,23-33. Although a Portuguese version of the PSEQ has been developed, it was translated and validated to be used in Brazilian populations14. However, a European Portuguese version of the PSEQ has not yet been translated and validated. A European Portuguese version of the PSEQ that is distinct from the Brazilian Portuguese version is needed because of the cultural and language differences between European Portuguese (as spoken in Portugal) and Brazilian Portuguese. The purpose of this study is to translate and evaluate the psychometric properties of a European Portuguese version of the Pain Self-Efficacy Questionnaire (P-PSEQ), to enable its use in clinical and cross-cultural studies. Based on previous research with the PSEQ in other samples, we hypothesized that: (1) the internal consistency (Cronbach’s alpha) of the P-PSEQ would be good to excellent (above 0.80)34; (2) the predictive validity of the P-PSEQ would be supported via a pattern of significant negative associations with pain intensity (rbetween -0.12 and -0.39)4,5,9,12,14,30 and pain interference (rbetween -0.31 and -0.70)5,9,12,14,30, an - xiety (rbetween -0.49 and -0.56)4,12 and depression (rbetween -0.48 and -0.66)4,9,12,30 and moderate to strong correlations (i.e., 0.30 or larger) with measures of global physical functioning and psychological functioning12; and (3) a factor analysis of the P-PSEQ items would yield one factor that explains a substantial portion of the variance in the items. Materials and Methods Subjects One-hundred and seventy four patients, all over 18 years old, with chronic musculoskeletal pain from seven health care institutions in northern and central Portugal completed the study protocol. Inclusion criteria included: (1) experiencing pain due to a diagnosed musculoskeletal condition for at least 3 months; (2) being at least 18 years old; (3) and being willing to participate in a research. Exclusion criteria included: (1) having a physical or cognitive disability which prevented participation, (2) known/diagnosed severe depression or other severe mental health condition, and (3) pain due to fibromyalgia. As can be seen in Table I, the participants’ ages ranged from 23 to 90 years (M = 59.18, SD = 16.11), 60.2% were married or li - ving with a significant other, 26.3% were either single or divorced/separate and 8.8% of the participants were widowed. The majority of the participants were female (60.2%). Most participants had a history of chronic pain for at least two years (65.3%), and 38.8% reported having had pain for more than 10 years. Measures All participants were asked to provide basic demographic and pain history information (e.g. age, sex, marital status, level of education, professio nal status, duration of pain, pain location and cause of pain). They were also asked to rate their pain intensity at its maximum, minimum and on average during the previous 24hours on a 0 to 10 Numerical Rating Scale (NRS). Research supports the validity of the NRS as a measure of pain intensity35. The Portuguese BPI Pain Interference subscale was used to assess pain interference across seven daily life activities (general activity, mood, walking órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 262 portuguese pain self-efficacy questionnaire -efficacy beliefs. The 10-item scale assesses confidence of patients to engage in a number of activities of daily living despite pain on 0 - 6 numerical rating scales, where 0 = “not at all confident” and 6 = “completely confident”. Higher scores (ranging from 0 to 60) reflect stronger self-efficacy beliefs. Procedure The initial phase of the study involved translating and back-translating the instructions and items of the PSEQ. Through expert discussion, we arrived at a consensus version, and verified that its content assessed the same construct as the ori gi nal. To ensure that the individuals in our population understood the instructions and scale items, we then performed a pre-test of the P-PSEQ in a pilot sample of 15 patients, followed by a cognitive debrie - fing. After making final modifications based on the results of the cognitive testing, we invited a sample of patients with chronic musculoskeletal pain to complete all of the study measures. All patients who agreed then signed an informed consent form and were administered the 0-10 NRS, P-BPI Interference Scale, SF-12, HADS and P-PSEQ questionnaires. Data Analysis Means and standard deviations of the study varia - bles were computed for descriptive purposes. Internal consistency of the P-PSEQ was assessed by computing a Cronbach’s alpha. Composite reliability was also computed41,42. Then, to test a hypothesized one-factor model for the P-PSEQ items, we performed a confirmatory factor analysis (CFA). Model quality of fitness was evaluated using the Chi Square (χ2/df), Comparative Fit Index (CFI), Parsimony Comparative Fit Index (PCFI), Goodness of Fit Index (GFI), Parsimony Goodness of Fit Index (PGFI), and Root Mean Square Error of Approximation (RMSEA). The model was considered to have acceptable fit if χ2/df was less than 5 42-44, CFI and GFI higher than 0.842, the PCFI and PGFI we re both higher than 0.642,45,46, the RMSEA was lo - wer than 0.1042,43. The model was considered to ha - ve a good fit it χ2/df was less than 242-44, the CFI and GFI were higher than 0.942, PCFI and PGFI higher than 0.842,45, and the RMSEA was lower than 0.0843. Mo del adjustment was performed, step-by-step, via Modification Indices analysis (higher than 11; p<0.001)42,43 and based on theory. We also used the Expected Cross-Validation Index (ECVI), to compare fit after models’ adjustment, with lower ECVI ability, normal work, relations with other people, sleep, and enjoyment of life) on 0 to 10 numerical rating scales. Research supports the validity and reliability of BPI in several samples, cultures and languages, including European Portuguese36-38. The Portuguese SF-1239 was used as a measure of perceived Physical (Physical Component Summary, PCS) and Mental (Mental Component Summary, MCS) health status, with higher scores (ranging from 0 to 100) indicating better health. The Portuguese version has evidence supporting its reliability and validity39. The Portuguese version of the Hospital Anxiety and Depression Scale (HADS)40 was used to assess psychological functioning. It asks respondents to rate the severity of 14 depressive or anxiety symptoms on 4-point Likert scales, and has shown good reliability and validity40. The possible scores range from 0 to 21. Higher scores reflect higher anxiety or depressive symptomatolo - gy. The Portuguese Pain Self-Efficacy Questionnai - re (P-PSEQ)4was used to assess pain-related selfTable I. Demographic Information Portuguese sample Frequency Mean (%) (SD) Age – 59.18 (16.11) Sex (female participants) 103 (60.2) – Education Level Primary education 76 (44.7) – Incomplete High School 35 (20.6) – High School 27 (15.9) – College 32 (18.9) – Marital Status Single 31 (18.1) – Married/Living with other 103 (60.2) – Divorced 15 (8.8) – Widow 22 (12.9) – Professional Status Employed 68 (39.8) – Unemployed 19 (11.1) – Retired (due to disability) 47 (27.5) – Retired (normal age) 37 (21.6) – Duration of Pain 3 months to 1 year 36 (21.2) – 1 to 2 years 23 (13.5) – 2 to 10 years 45 (26.5) – More than 10 years 66 (38.8) – órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 263 m. alexandra ferreira-valente e col. Results Descriptive information As can be seen in Table II, the study participants reported mild to moderate levels of pain severity (NRS) and pain-related disability (BPI Pain Interference). Mean scores of SF-12 Physical Component Summary and SF-12 Mental Component Summary indicate significant dysfunction in these areas, relative to published norms for healthy individuals39. Overall, the mean scores on the HADS suggested mild levels of anxiety, similar to individuals with a variety of medical disorders, and normal ratings of depressive symptoms40. Finally, the sample was characterized by relatively high le - vels of self-efficacy, on average, according to the cut offs suggested by Tonkin47 (mean > 40), and when compared to normative datasets for patients with chronic pain, as reported by Nicholas and colleagues48 in a study of 6124 patients from across the Australian state of New South Wales. Reliability The P-PSEQ’s internal consistencies (Cronbach’s alphas) in our sample and in previous samples are listed in Table III. The scale shows a very good le - vel of internal consistency in our sample that is consistent with other samples, with an alpha coef - ficient of 0.8834. Values for alpha if single items are deleted are comparable to the overall alpha, sugTable II. Descriptive Statistics Study Variables MinMean (SD) Max Pain Intensity (NRS) Maximum (last 24 hours) 5.70 (2.49) 0-10 Minimum (last 24 hours) 2.97 (2.25) 0-9 Average Pain 4.59 (2.18) 0-10 Pain Interference (P-BPI) 4.03 (2.44) 0-9 Physical Component 39.07 (23.51) 0-100 Summary (SF-12) Mental Component 57.02 (20.39) 10-100 Summary (SF-12) Anxiety (HADS-A) 7.58 (3.91) 1-20 Depression (HADS-D) 6.07 (3.87) 0-17 Self Efficacy (P-PSEQ) 40.83 (11.31) 6-60 Note: NRS = Numerical Rating Scale of pain intensity; P-BPI = Portuguese Brief Pain Inventory – Interference scale; HADS-A = Hospital Anxiety and Depression Scale – Anxiety scale; HADS-D = Hospital Anxiety and Depression Scale – Depression scale; P-PSEQ = Portuguese Pain Self-Efficacy Questionnaire. Table III. Reliability Analyses of Brief Pain Inventory Interference Scale P-PSEQ Total scale or item Our sample Australia4Brazil14 China12 Iran9 Cronbach's Alpha P-PSEQ Total scale 0.88 0.92 0.90 0.93 0.92 Cronbach's Alpha if item deleted (Item Total Correlation) P-PSEQ Items Item 1 0.87 (0.48) - (0.70) - (0.79) 0.92 (0.72) – Item 2 0.86 (0.56) - (0.72) - (0.73) 0.92 (0.71) – Item 3 0.86 (0.61) - (0.71) - (0.67) 0.92 (0.66) – Item 4 0.85 (0.70) - (0.83) - (0.71) 0.92 (0.66) – Item 5 0.86 (0.61) - (0.74) - (0.76) 0.92 (0.71) – Item 6 0.85 (0.67) - (0.79) - (0.77) 0.92 (0.81) – Item 7 0.88 (0.43) - (0.67) - (0.50) 0.93 (0.62) – Item 8 0.86 (0.62) - (0.79) - (0.82) 0.92 (0.80) – Item 9 0.85 (0.72) - (0.84) - (0.80) 0.92 (0.78) – Item 10 0.86 (0.63) - (0.84) - (0.79) 0.92 (0.75) – Note: P-PSEQ = Portuguese Pain Self-Efficacy Questionnaire reflecting better fit. Finally, Pearson correlation coefficients between the P-PSEQ score (or scores) and the criterion measures were computed to evaluate the construct validity of the scale. Statistical ana - lyses were performed using software PASW Statistics (v.18, SPSS Inc. Chicago, IL) and AMOS (v.18, SPSS Inc. Chicago, IL). órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 264 portuguese pain self-efficacy questionnaire gesting that no item detracts from the reliability of the measure. Additionally, the Composite Reliabi - lity coefficient41,42 of 0.92 indicates excellent reliability34,41,42,49. Factor Analysis A factor analysis of the PSEQ in the original scale development sample resulted in a single factor that accounted for 59% of the variance. This result has been replicated in other samples of patients from Brazil14 and China12. We used a confirmatory factor analysis, using maximum likelihood to estimate model parameters, to determine the fit of a single factor model. Four of the seven combined fit indices for the CFA supported a one-factor solution with acceptable fit. However, the fitness quality of the one-factor solution appeared somewhat limi ted in our sample [χ2(35) = 155.58 (p<0.001); χ2/df = 4.44; CFI = 0.83; PCFI = 0.65; GFI = 0.84; PGFI = 0.54; RMSEA = 0.14 (p<0.001); ECVI = 1.15] (Figure 1). Inspection of P-PSEQ items suggests that some items have very similar content, which could potentially explain the reduced fitness levels for the one-factor solution. For example, Item 2 (“I can do most household chores (e.g. tidying-up, washing dishes, etc.), despite the pain”) and Item 5 (“I can do some form of work, despite the pain. (“work” includes housework, paid and unpaid work)”) appear to assess a very similar domain, as do Item 8 (“I can still accomplish most of my goals in life, des pite the pain”) and Item 9 (“I can live a normal lifestyle, despite the pain”). Based on an inspection of the modification indexes, specific error terms Fi gu re 1. Confirmatory Factor Analysis: Initial Model χ2(35) = 155.58 (p<0.001); χ2/df = 4.44; CFI = 0.83; PCFI = 0.65; GFI = 0.84; PGFI = 0.54; RMSEA = 0.14 (p<0.001); ECVI = 1.15 Fi gu re 2. Confirmatory Factor Analysis: Final Model χ2(33) = 66.95 (p<0.001); χ2/df = 2.03; CFI = 0.95; PCFI = 0.70; GFI = 0.93; PGFI = 0.56; RMSEA = 0.08 (p=0.05); ECVI = 0.65 órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 265 m. alexandra ferreira-valente e col. were correlated sequentially, which resulted in a new model (Figure 2) that maintained all the items of the original P-PSEQ. After taking into account the error term correlations, the combined fit indices for the CFA, support the one factor solution hypothesized [χ2(33) = 66.95 (p<0.001); χ2/df = 2.03; CFI = 0.95; PCFI = 0.70; GFI = 0.93; PGFI = 0.56; RMSEA = 0.08 (p=0.05); ECVI = 0.65], with six of the seven combined fit indices for the CFA supporting this solutions, with acceptable to good fit. This new model revealed a goodness of fit significantly hi gher than the initial model [χ2(33) = 66.95 (p < 0.001), and ECVI conside - rably different: 1.15 vs. 0.65]. Correlational Analysis Table IV presents the Pearson correlation coefficients computed between the P-PSEQ score and the criterion variables. As hypothesized, statistically significant negative associations were found between the self-efficacy score and pain intensity [ranging between -0.27 and -0.32, p < 0.01], pain interference [r = -0.41, p < 0.01], anxiety [r = -0.39, p < 0.01] and depression [r = -0.55, p < 0.01]. Moreover, a statistically significant positive association was found between the P-PSEQ score and the SF-12 Physical Health score [r = 0.51, p < 0.01] and SF-12 Mental Health score [r = 0.46, p < 0.01]. All of the significant associations were in the hypothesized directions and showed magnitudes that were within the anticipated ranges, with the exception of anxie - ty, which was slightly lower than expected, although even for this criterion a moderate association with self-efficacy in the hypothesized direction was found. Discussion Consistent with previous findings for other versions of the PSEQ, our results provide strong support for the reliability and validity of the Portuguese PSEQ. Its internal consistency (Cronbach’s alpha) is greater than 0.80, indicating good reliability. Moreover, its Composite Reliability coefficient of 0.92 indicates excellent reliability34,41,42,49. These values are similar to those found in the origi nal scale develop - ment sample and other transla ted versions of the measure4,9,12,14. In addition, the results of a confirmatory factor analysis support a one factor solution41-46,50 and provides further support for a high level of internal consistency. The correlation coefficients between P-PSEQ scale score and criterion measures are consistent with those found in previous studies4,9,12,14,30, and support the validity of the P-PSEQ. Consistent with previous research1,4,5,8-14, our findings support the importance of self-efficacy as a predictor of adjustment to chronic pain, given its significant associations with pain intensity, phy - sical and psychological functioning (pain interfe - rence, anxiety and depression), as well as with glo - bal quality of life and general health12,15. As a group, the findings from the current and pre vious studies suggest that the concept and effects of pain self-efficacy are similar across cultures, in line with the findings available for the effects of self-efficacy beliefs on performance17,51. There are a number of study limitations that should be considered when interpreting the fin - dings. First, we employed a cross-sectional correlational design. As a result, we were unable to exa - mine the test-retest stability of the P-PSEQ. Also, such a design does not allow for an evaluation of the causal effects of self-efficacy on functioning. Further research is needed to study the stability of P-PSEQ score over time, as well as to determine the potential beneficial effects of interventions that increase pain self-efficacy beliefs. Second, the study sample was one of convenience. We were not able to determine how representative the sample is of Table IV. Correlations with Measures of Pain Intensity, Physical Dysfunction and Psychological Functioning Self-Efficacy Scale (P-PSEQ) Pain Intensity (NRS) Maximum (last 24 hours) -0.27** Minimum (last 24 hours) -0.32** Average Pain -0.28** Pain Interference (P-BPI) -0.41** Physical Functioning (SF-12, PCS) 0.51** Mental Health (SF-12, MCS) 0.46** Anxiety (HADS-A) -0.39** Depression (HADS-D) -0.55** **p < 0.01 Note: P-PSEQ = Portuguese Pain Self-Efficacy Questionnaire; NRS = Numerical Rating Scale of pain intensity; P-BPI = Portuguese Brief Pain Inventory – Interference scale; HADS-A = Hospital Anxiety and Depression Scale – Anxiety scale; HADS-D = Hospital Anxiety and Depression Scale – Depression scale órgão oficial da sociedade portuguesa de reumatologia - a c ta r e u m at o l p o r t.2011;36:260-267 266 portuguese pain self-efficacy questionnaire the population of patients in Portugal with chro - nic musculoskeletal pain. Research is therefore needed to help establish the generalizability of the findings. Third, we did not administer other measures of self-efficacy to help establish the convergent validity of the P-PSEQ. Additional research is needed to help determine the extent of overlap between the P-PSEQ and other pain self-efficacy measures. Nevertheless, our findings provide support for the reliability and validity of the Portuguese PSEQ, and suggest that the measure may be useful for understanding the importance of the self-efficacy concept to pain and adjustment to pain in Portuguese patients with chronic pain, as well as for cross-cultural research examining similarities and differences in the role that self-efficacy plays in patients from Portugal and patients from other countries and cultures. Acknowledgments M. Alexandra Ferreira-Valente has received PhD grant SFRH/BD/ 40956/2007 in the past year from the Portuguese Foundation for Science and Technology. Correspondence to M. 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