Declaration of Interests: The authors declare that there are no financial or other relationships that might lead to conflicts of interest.
Original Research Article
Cross-Cultural Adaptation and Validation of the Profile of Chronic Pain: Screen for a Brazilian Population
Article first published online: 21 NOV 2012
Wiley Periodicals, Inc
Volume 14, Issue 1, pages 52–61, January 2013
How to Cite
Caumo, W., Ruehlman, L. S., Karoly, P., Sehn, F., Vidor, L. P., Dall-Ágnol, L., Chassot, M. and Torres, I. L. S. (2013), Cross-Cultural Adaptation and Validation of the Profile of Chronic Pain: Screen for a Brazilian Population. Pain Medicine, 14: 52–61. doi: 10.1111/j.1526-4637.2012.01528.x
Competing Interest Statement: The present research was supported by the following Brazilian agencies: research grant from CNPq (Dr. I. L. S. Torres and Dr. W. Caumo); and assistance administrative support from the Postgraduate Research Group at the Hospital de Clínicas de Porto Alegre. The institution (HCPA, UFRGS) received support from the following governmental Brazilian agencies: FAPERGS; CNPq and CAPES.
Name of department where the work was conducted: Pain and Palliative Care Service at HCPA/UFRGS.
- Issue published online: 15 JAN 2013
- Article first published online: 21 NOV 2012
- Confirmatory Factor Analysis;
- Cross-Cultural Adaptation;
- Factorial Analysis;
- Pain Assessment;
- Profile of Chronic Pain: Screen (PCP:S)
To translate the original English version of the Profile of Chronic Pain: Screen (PCP:S) into Brazilian Portuguese and examine basic psychometric properties of the translated version. We investigated ceiling and floor effects, internal consistency, factor structure, convergent validity, and the ability of the Brazilian PCP:S (B-PCP:S) to discriminate persons with pain who were either employed or not working, or in treatment or not in treatment.
The Brazilian Portuguese version of the Profile of Chronic Pain: Screen (B-PCP:S) was administered to a sample of 414 adults (men = 67). Pain catastrophizing was also assessed. Subsamples with special conditions (working despite pain [N = 116] vs not working due to pain [N = 122], and not receiving treatment for pain [N = 119] vs receiving treatment [N = 119]) were identified to investigate the discriminative properties of B-PCP:S.
For the B-PCP:S, Cronbach's α values were 0.76 (severity), 0.88 (interference), and 0.87 (emotional burden). Confirmatory factor analysis supported the original, English language three-factor structure, with the comparative fit index = 0.93, root mean square error of approximation = 0.075, and normed fit index = 0.93. Significant correlations were found between pain intensity, pain interference, and emotional burden, and a criterion measure of catastrophizing (correlation coefficients ranged from 0.48 to 0.66, P < 0.01). B-PCP:S scores (severity, interference, and emotional burden) were higher in subjects under a doctor's care for pain and in those not working due to pain.
This B-PCP:S version was found to be a reliable instrument, with basic evidence of validity for the evaluation of pain severity, interference, and emotional burden in Brazilian Portuguese adults. The profile of B-PCP:S scores was similar to that observed in the original version.
Prevalence estimates for chronic noncancer pain in the primary care settings range from 5% to 33% . A recent meta-analysis showed that chronic musculoskeletal in a Brazilian sample ranges from 14.1% to 85.5% . In a review of 13 chronic pain studies conducted in various countries around the world, the International Association for the Study of Pain found prevalence rates ranging from 10.1% to 55.2% . The high prevalence of chronic pain observed in Brazil placed it as one of the countries that is most affected by this problem.
Chronic pain is a debilitating condition whose multifaceted nature encompasses physical, psychological, and behavioral characteristics . It is associated with significant suffering, decreased quality of life, higher incidence of absenteeism, and more prevalent symptoms of depression, anxiety, and catastrophic thinking, and differs in important ways from acute pain . Further, the methods used for acute pain screening are insufficient to provide a complete picture of the multidimensional impact of chronic pain upon the lives of those who endure it.
Chronic pain can be defined as continuous or intermittent pain or discomfort that has persisted for 3 months or more, and is associated with the frequent seeking of treatment or the use of analgesic medications [6, 7]. It has been argued that the assessment of chronic pain should gauge the nature of a person's experience in terms of pain severity, pain-related functional interference, and the emotional burden associated with unremitting discomfort [8-10]. To that end, the 15-item Profile of Chronic Pain: Screen (PCP:S)  allows for quick identification of an individual's multidimensional pain experience. The PCP:S comprised a severity scale (four items; possible range 0–32), an interference scale (six items; possible range 0–36), and an emotional burden scale (five items; possible range 0–25) . The importance of these three dimensions (severity, interference, and emotional burden) has recently been underscored by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials , a team of pain experts drawn from academia, government, a self-help organization, and the pharmaceutical industry. It is now understood that chronic pain is a multidimensional experience that incorporates numerous factors related to its assessment and treatment, and that it has been widely underdiagnosed, and consequently undertreated. Thus, the importance of having a reliable assessment instrument to use in different cultures justifies the translation of the PCP:S and the validation of a Brazilian Portuguese version of the PCP:S.
Several assessment instruments target the key dimensions of pain noted above, as well as related aspects of the pain experience and its consequences. Among the most popular assessment devices are the McGill Pain Questionnaire (MPQ) , the West Haven–Yale Multidimensional Pain Inventory (MPI) [14, 15], and a number of specific functional disability assessment devices . While the West Haven–Yale MPI measures the domains of interest and possesses a variety of norms, it is too long for a screen, containing more than 60 questions. The MPQ has strong psychometric properties and normative data but does not measure all three areas of interest. Further, the instructions for completing the MPQ pain adjectives section are complex, and it is recommended that they should be read to patients. However, the 15-item PCP-S has strong psychometric properties, has been used in both clinical and research settings, has national norms, is self-administered in paper and pencil or online format, and takes approximately 5–10 minutes to complete.
Thus, the aim of the present study was to cross-culturally adapt the English version of the PCP:S into Brazilian Portuguese, and to then examine the psychometric properties of the translated instrument. We investigated the ceiling and floor effects, internal consistency, factor structure, and correlations of the Brazilian Portuguese version of the Profile of Chronic Pain: Screen (B-PCP:S) with relevant correlates of chronic pain, such as the level of catastrophizing, an important correlate of dysfunctional chronic pain adaptation . Further, we assessed the ability of the B-PCP:S to discriminate among patients across specific conditions (working vs not working; in treatment vs not in treatment).
The protocol was approved by the local ethics committee of the institution in which the study was developed (Application No. 1005-55—Postgraduate Research Group at Hospital de Clínicas de Porto Alegre). The sample was recruited in a tertiary chronic pain clinic, in which all patients are referred from the primary units. In addition, we also recruited through newspaper advertisements. The inclusion criterion was diagnosis of musculoskeletal pain by physicians with clinical experience in pain treatment. The diagnoses were established using standard protocols for each of one type of pain, that is, the clinical criteria to define myofascial pain syndrome patients were regional pain, normal neurologic examination, presence of trigger points, taut bands, tender points, and pain characterized as “dull,” “achy,” or “deep” . The chronic tensional headache diagnosis was according to the International Headache Society , and the diagnosis of fibromyalgia was given according to the American College of Rheumatology criteria for fibromyalgia . The exclusion criteria were inability to understand Brazilian Portuguese, illiteracy, or inability to come to the hospital for evaluations . The multiple standardized study phases are presented in Figure 1.
The PCP:S consists of four questions related to pain severity, six questions related to pain's interference with functioning, and five questions related to emotional burden. Two of the pain severity items are presented as numeric rating scales (NRS), with 0 = no pain and 10 = unbearable pain. Two of the items are scored on a 0 (never) to 6 (daily) scale. The PCP:S instructs patients to rate the frequency of any pain, the frequency of severe pain, average pain, and greatest pain intensity over the past 6 months. A pain severity index can be calculated by adding the scores on the pain severity items (four items; possible range 0–30). The six items assessing pain interference on patient function are also presented as NRS scales, with 0 = never interferes to 6 = interferes daily. The interference items ask how often pain interferes with such activities as hobbies, basic self-care, housework, relations with others, personal goals, etc. (six items; possible range 0–36). Emotional burden items ascertain how often pain has caused the person to feel sad or depressed, anxious, angry, isolated, or to experience reduced enjoyment of life, with 0 = never to 5 = extremely often (five items; possible score range 0–25).
The translation into Brazilian Portuguese and cross-cultural adaptation of the original English version of the PCP:S  was carried out in accordance with previously published guidelines [21-23]. Four native Brazilian Portuguese speakers (translators 1–4: T1, T2, T3, T4) carried out independent translations of the PCP:S from English to Brazilian Portuguese. T1 was a professional translator, T2 was a clinical psychiatrist, T3 was a physician with pain specialization, and T4 was a linguist. The forward translations were compared with one another and with the original English version.
Two native English speakers with Brazilian Portuguese as their second language carried out the back-translation of the Brazilian Portuguese version into English. Both back-translators were considered bilingual, according to the definition of Deyo . None of the back-translators were familiar with the subject matter of the questionnaire. A third bilingual person highlighted any conceptual errors or gross inconsistencies in the content of the translated versions in preparation for the expert committee meeting. Ten professionals who work with patients with chronic pain assessed the meaning of the translated questions and the layout of the prefinal version of the B-PCP:S questionnaire.
An expert committee was formed consisting of all of the translators and back-translators, an expert in clinical research methodology, and one clinical research scientist. The task of this expert committee was to ensure semantic and idiomatic equivalence, and experiential and conceptual equivalence (i.e., to address potential issues specific to the cultures examined) between the Brazilian Portuguese and the English versions of the questionnaire. The changes to the B-PCP:S were based on the consensus of members involved in the translation process. We used the principle of translation from the English to the Brazilian version of the B-PCP:S. This principle underscores that sentences in different language versions should have the same meanings and refer to the same underlying concept. Therefore, our goal was to obtain a better idiomatic and conceptual rather than literal equivalence.
Assessment of Psychometric Properties of the Final Version of Portuguese Brazilian Version of B-PCP:S
Four hundred fourteen patients were recruited from the outpatient Pain Clinic and Palliative Care at Clínicas Hospital of Porto Alegre. All subjects were recruited from a convenience sample, and they gave their signed informed consent to participate. Before beginning the interviews, study participants completed a baseline questionnaire that included questions about sociodemographic variables (age, gender, work status due pain, doctor's care to treat pain, marital status, and education), and the Brazilian Pain Catastrophizing Scale (PCS) [25, 26].
Assessment of Pain Catastrophizing
To evaluate convergent validity, we used a version of the PCS adapted for the Brazilian population [25, 26]. It is a self-administered questionnaire consists of 13 items that assess the extent of the patient's catastrophizing thoughts and behaviors. It comprised three subscales: helplessness, magnification, and rumination. The questionnaire is completed in relation to the patient's thoughts and feelings when they are in pain. The total score, which ranges from 0 to 52, is computed by summing all items on the questionnaire .
Floor and ceiling effects were determined in two ways: first, we simply calculated the number of individuals obtaining, respectively, the lowest or highest possible scores on the severity scale (range 0–30), interference scale (range 0–36), and emotional burden scale (range 0–25), where a limit of 15% of patients should not be exceeded [27, 28]; and second, we computed the proportion of individuals obtaining a score within the limits of the minimum detectable change (95% confidence interval [CI]) at the two ends of the scale (Table 2).
Internal consistency reliability was assessed using Cronbach's α (and Cronbach's α if the item deleted) calculated for B-PCP:S severity, interference, and emotional burden of B-PCP:S to compare with the English version.
A confirmatory factor analysis (CFA), with a three-factor model (severity, interference, and emotional burden) as described by Ruehlman and colleagues , was conducted. CFA was utilized to investigate whether the established dimensionality and factor-loading pattern fits data from a new Brazilian sample with chronic pain. M-Plus version 6 was used to analyze the factor structure of B-PCP:S. A weighted least squares estimation procedure was utilized in a factor structure analysis (M-Plus software, Muthén and Muthén, Los Angeles, CA, USA). Each item was assessed based on the factor correlation and t statistic of the parameter estimate. Absolute t values greater than 1.96 were considered significant at the 0.05 level. These items were retained because they were considered important to the model. In addition, the criteria for removing items were factor loadings below 0.5 and greater than 1.0. The M-Plus 6 output was examined for out-of-range values, such as negative variances or factor correlations greater than 1. Any inadmissible results may have been caused by high multicollinearity, by outliers, and/or by flaws in the structural equation modeling program. Correlated error parameters were allowed based on modification indices and logical reasoning. For example, many items for each subscale were similarly worded and measure closely related concepts. One item from each factor was selected as a marker variable. The chi-square significance test is used to determine the degree to which a proposed model fits the data. Indices of fit included the comparative fit index (CFI), the root mean square error of approximation (RMSEA), and the standardized root mean square residual (SRMR). According to recommendations by Hu and Bentler , a model is deemed to show adequate fit when a CFI index greater than 0.95 is observed with an SRMR less than 0.08, or when an RMSEA less than 0.08 is observed in conjunction with an SRMR less than 0.08.
Two approaches to validity assessment were undertaken. The first represents a convergent validity effort in which scores on the B-PCP:S were correlated with another questionnaire that evaluates the aspects related to pain, such as B-PCS, and should result in moderate positive correlation coefficients, not exceeding 0.7. The Pearson correlation was used to compare the relationships between the B-PCP:S severity, interference and emotional burden scales, and catastrophizing as measured by the B-PCS. In the second approach, involving criterion group validity, two multivariate analyses of covariance (MANCOVA) were conducted to determine the extent to which known groups differed in their scores on the B-PCP:S scales.
Finally, a stratified-by-gender analysis was used to assess the correlation between age and education level, and the scores of the dependent variables: B-PCP:S scales (severity, interference, and emotional burden). We employed regression analysis with stepwise forward technique.
Assessment of the B-PCP:S in Pilot Version
After discussing any discrepancies, the four versions were combined into one Brazilian Portuguese version. For Item 6 (an interference item), the original wording focused on “responsibilities” at home, but the translation focuses on “activities” at home as the term “responsibilities” at home is not typically employed by Brazilian Portuguese speakers.
This pilot version of the translated PCP:S was completed by a group of 30 subjects of both genders (N = 15 women) with chronic musculoskeletal pain. They were also interviewed in order to collect qualitative data by exploring what subjects thought was meant by each question and the chosen response. They were also asked for their general comments on the questionnaire. Their mean ± SD of the number of formal schooling was 18.93 ± 3.99, and the mean age was 33.95 ± 10.50. In addition, we assessed their understanding of the questions of the B-PCP:S using 10-cm visual analog scales (0 meaning completely unclear, and 10 cm indicating completely clear). The global mean ± SD of comprehension of the 15 questions of BPI was 8.41 ± 1.90. All the findings were evaluated by the workgroup (to assess face validity), after which two questions were slightly modified to achieve the final Brazilian Portuguese version of the PCP:S.
Assessment of the Final Version of B-PCP:S
Four hundred fourteen patients were recruited from the outpatients of Pain Clinic and Palliative Care at Clinics Hospital of Porto Alegre (N = 347 women) with chronic musculoskeletal pain, with a mean (±SD) on education of 11.03 (±5.43) years and a mean age of 50.23 ± 17.10. In view of the disproportionate number of females in our sample, we analyzed the mean scores for males and females and compared them. We observed statistically significant difference between males and females (Table 1).
|Range of the Scores||Men (N = 67)||Women (N = 347)||P|
|Mean (SD)||Mean (SD)|
|Severity||0–32||18.83 ± 6.67||22.09 ± 5.44||<0.0001|
|Interference||0–36||15.68 ± 9.95||22.07 ± 9.30||<0.0001|
|Emotional burden||0–25||10.52 ± 6.21||15.68 ± 6.93||<0.0001|
|Total B-PCP:S||0–93||45.50 ± 21.19||59.64 ± 18.64||<0.0001|
Distribution of the B-PCP:S Scores
There were no missing data for any item. The distribution of scores is shown in Table 2. The scores ranged from the minimum to the maximum for all 15 items. There is minimal ceiling effect of the highest score possible in the B-PCP:S scales. The ceiling effect is 5.5 for the severity scale, 9.9 for the emotional burden scale, and 8.2 for the interference scale. The floor effect for the lowest possible score was 0.2 for the severity scale and 2.9 for the emotional burden scale.
|Scale||Mean (SD)||Median (Range)||Ceiling Effect (%)||Floor Effect (%)||Skewness||Kurtosis|
|Severity||21.56 ± 5.77||22.00 (19–26)||5.5||0.2||−0.84||0.64|
|Interference||21.05 ± 9.68||22.00 (14–29)||8.2||1.4||−0.19||−0.90|
|Emotional burden||14.76 ± 7.22||16.00 (9–20)||9.9||2.9||−0.27||−0.99|
Internal Consistency Reliability
To assess the internal consistency reliability of the B-PCP:S, Cronbach's α coefficients were computed for the four severity items, six interference items, and five emotional burden items. The alpha coefficient was 0.76 for the severity scale, 0.88 for the interference scale, and 0.87 for the burden emotional scale. The alpha values for the scales if an item was deleted were comparable to the overall alpha coefficient for the scales (Table 3), which indicates that each of the items contributes similarly to the construct it is intended to measure.
|Pain Severity Items (α = 0.76)||Pain Interference Items (α = 0.88)||Burden Emotional Items (α = 0.87)|
|Pain worst||0.76||General activity||0.85||Mood||0.82|
|Pain least||0.66||At home||0.85||Anxiety||0.82|
|Pain average||0.65||Relationship to others||0.85||Angry||0.86|
CFA revealed that all items were significantly related to their specified factors, verifying the hypothesized relationships among the item and latent factors. Figure 2 shows the diagram as well as factor loadings generated for the hypothesized model by Ruehlman and colleagues . The analysis elicited adequate model goodness of fit (Figure 2). Results show consistency in an adequate model fit by all of the goodness-of-fit measures (CFI = 0.93; SRMR = 0.048; RMSEA = 0.075; 95% CI range 0.073, 0.093). Standardized factor loadings are presented in Figure 2. All loadings differed significantly from zero.
Construct validity of the B-PCP:S was further established by examining the pattern of correlations between the total score on the severity, interference, and burden emotional scales, and the criterion measure of catastrophizing. Pearson correlations were performed between the scores on the B-PCP:S scales, and the helplessness, magnification, and rumination subscales, and with the total score of B-PCS (Table 4).
|Severity||rs = 0.56*||rs = 0.48*||rs = 0.51*||rs = 0.58*|
|Interference||rs = 0.59*||rs = 0.50*||rs = 0.54*||rs = 0.57*|
|Emotional burden||rs = 0.63*||rs = 0.53*||rs = 0.50*||rs = 0.61*|
The Brazilian version of B-PCP:S showed evidence of convergent validity (Tables 5 and 6). Similar to the original validation study of the PCP:S , it was expected that individuals who were in treatment for their pain and those who were unable to work due to pain would score higher on pain severity, interference, and/or emotional burden than would subjects who were not in treatment or were able to work, despite their pain. Age served as a covariate in MANCOVA in which the three subscales served as multiple dependent variables. The following groups were compared: 1) working despite pain vs not working due to pain, 2) not receiving treatment for pain vs receiving treatment. Each of the validity MANCOVAs involved subgroups of targeted respondents, that is, those who are in treatment for pain or those who are not working due to their pain. We sought to compare these targeted subgroups to remaining respondents in the sample. However, discrepancies in sample sizes can be problematic for MANCOVA, which becomes less robust to violations of assumptions as these discrepancies increase . To reduce sample size differences among the groups, a subsample of respondents was randomly selected from the larger “comparison” group prior to each analysis so as to achieve equal sample sizes across groups. The sample size for the comparison group was chosen to be equal to that of the target group; the comparison group was then selected at random from the larger sample.
|Under Doctor's Care for Pain ([N = 116] Female 97/Male 19)||Not under Doctor's Care for Pain ([N = 122] Female 101/Male 21)||F|
Significant omnibus tests were followed with univariate analyses of covariance to examine group differences for each dependent variable. As shown in Tables 5 and 6, both omnibus tests across the two MANCOVAs were significant, indicating that, in each analysis, each pair of groups differed significantly on the set of scales of the B-PCP:S. In addition, all univariate follow-up tests were significant, indicating, in each case, that the groups differed significantly on each of the three scales of our instrument in accordance with our predictions.
|Not Working Due to Pain ([N = 119] Female 102/Male 17)||Working Despite Pain ([N = 119] Female = 102/Male 17)||F|
Table 5 demonstrates that those under doctor's care for pain have significantly higher scores than those not under a doctor's care for pain on each one of B-PCP:S scales (severity, interference, and emotional burden).
Table 6 indicates that those not working due to pain have significantly higher scores than those who were working despite their pain in each one of B-PCP:S scales (severity, interference, and emotional burden).
Finally, the association between gender, age, education level, and each one of B-PCP:S scales—severity, interference, and emotional burden—was analyzed by regression analysis in a forward stepwise model. The factor was the gender. In males, only the variable number of years of schooling was retained in the model with the dependent variable severity with β coefficient −0.36 (95% CI; −0.73 to −0.16; P = 0.002). Age and schooling were not retained in the model. Interference and emotional burden were not associated with the covariates age and schooling. For females, when the dependent variable was severity, the β coefficient for schooling was −0.17 (95% CI; −0.28 to −0.06; P = 0.002) and 0.13 (95% CI; 0.008 to 0.23; P = 0.01) for age. When the dependent variable was emotional burden, the β coefficient for schooling was −0.18 (95% CI; −0.37 to −0.10; P = 0.001). Interference was not associated either with age or with schooling.
The goal of the present research was to translate the PCP:S to a Brazilian Portuguese version, and to evaluate and verify basic psychometric properties. The process of translating and back-translating the English PCP:S to Brazilian Portuguese version was carried out strictly in accordance with established guidelines , and with the assistance of a diverse panel of experts as well as persons with pain. This process yielded a Brazilian Portuguese version that is semantically equivalent to the English-language PCP:S, while reflecting cultural variations. Thus, the current version can be used without major difficulty in Portuguese-speaking populations. Further, minimal respondent burden was observed, with a completion time of approximately 5–10 minutes.
Having established a Brazilian Portuguese version of the PCP:S, we examined a number of basic psychometric properties. Minimal floor and ceiling effects were revealed using the traditional approach to analyzing such effects. Further, the scales demonstrate adequate variation in range of scores, that is, the scores did not show large concentration near upper or lower limits. Kurtosis and skewness tests suggested a normality of the distribution of scores, which support the use of parametric statistical analysis. Overall, the B-PCP:S showed satisfactory psychometric properties. The test for internal consistency, Cronbach's α, indicates that the participants showed adequate consistency in their responses (see Table 3) and were similar to alpha coefficients obtained in previous study .
CFA of the B-PCP:S using a variety of different goodness-of-fit measures suggested an adequate model fit. The Brazilian translation shows satisfactory goodness of fit with three factors, consistent with the model suggested by Ruehlman and colleagues . Overall, the items contained in each of the three scales should, therefore, remain as proposed by Ruehlman and colleagues . Our CFA suggests that it is possible to maintain the original structure scale items in the refined Brazilian translation of the B-PCP:S.
The convergent validity of B-PCP:S was examined by investigating the strength of the relationship between the B-PCP:S scales and the scores for other pain-related aspects, such as catastrophic thinking. The correlation coefficients for these relationships ranged from 0.48 to 0.71 (see Table 4). This represents moderate agreement, which confirms that the B-PCP:S assesses a different construct, and it can thus be considered suitable as part of a multidimensional battery of assessments in chronic patients. The fact that most of the correlation coefficients were higher than 0.5 allows us to infer that this translated scale measures a comparable concept, a criterion usually considered satisfactory for establishing construct validity .
The B-PCP:S version of severity, interference, and emotional burden scales showed criterion-group validity to differentiate between subgroups. This finding indicates the capability of all three scales to discriminate in the comparison involving 1) individuals under doctor care for pain vs not under doctor care for pain, and 2) not working due to pain vs working despite pain. In sum, these findings provide evidence to support the validity of B-PCP:S. This result is similar to the findings from a previous study involving chronic pain patients recruited from primary care . Establishing the validity of an instrument is an intensive process. The data obtained herein provide a solid foundation from which to explore validity in more depth. For example, it would be useful to evaluate the predictive validity of the tool as well as its sensitivity to change in conjunction with treatment.
Gender differences are not uncommon in research in the area of chronic pain . In the present study, for both males and females, years of schooling were associated with scores on the severity scale. However, in females, age was correlated with severity and schooling with emotional burden. Future research will need to examine this complex network of relationships more carefully, and in particular to evaluate these associations over time. In general, the explanation for gender differences in pain has been proposed to be partially attributed to biological factors (hormones, brain-derived neurotrophic factor, etc.)  and psychosocial factors. In addition, cultural factors may influence gender differences in attitudes and health behavior .
The study is limited by the nonrandom selection of patients from an outpatient pain clinic. Selection bias was possible, and it is uncertain whether these findings can be extrapolated to chronic pain patients from different settings, such as inpatients, those receiving care from their family physician, or those who are not receiving any treatment for their pain. However, it is noteworthy that our results are consistent with findings observed in the original English language version, which involved a variety of development samples, including primary care, community, and a representative national sample . Future research could evaluate the utility of the instrument in a variety of clinical settings.
In summary, this study demonstrates that the original English version of the PCP:S successfully adapted to Portuguese as methodologically demonstrated herein. B-PCP:S constitutes a reliable research instrument for evaluating severity, interference, and emotional burden related to pain. It can be conveniently used to assess health status as it is completed both easily and quickly. Chronic pain is a consistent predictor of poor outcomes and warrants attention in treatment; it might be useful to incorporate additional outcome measures into a standardized assessment battery. This study provides evidence for the validity and reliability of the B-PCP:S. Our results have demonstrated that the psychometric properties of the B-PCP:S were satisfactory. Also, the B-PCP:S showed good discriminative properties. The B-PCP:S represents a valuable tool for use in scientific studies and in clinical setting involving patients with chronic pain in Portuguese-speaking countries. Future studies should investigate whether the B-PCP:S is sufficiently sensitive to detect a meaningful clinical change in chronic pain conditions over time, before and after a treatment, and its predictive properties of interventions effect.
We would like to express our appreciation to Linda S. Ruehlman and Paul Karoly for their permission to use the Profile of Chronic Pain: Screen.
- 2Prevalence of chronic musculoskeletal disorders in elderly Brazilians: A systematic review of the literature. BMC Musculoskelet Disord 2012;29:13–82., , , .
- 3Prevalence of chronic pain: An overview. Edmonton: Alberta Heritage Foundation for Medical Research, Health Technology Assessment; 2002;1–60., .
- 14Assessment of the psychosocial context of the experience of chronic pain. In: Turk DC , Melzack R , eds. Handbook of Pain Assessment. New York: Guilford; 2001:362–385., .
- 16Physical and occupational therapy assessment approaches. In: Turk DC , Melzack R , eds. Handbook of Pain Assessment (2nd ed.). New York: Guilford; 2001:204–224., .
- 19Society HCSotIH. The international classification of headache disorders. Cephalalgia 2004;24:1–160.
- 30Using Multivariate Statistics, 4th edition. Needham Heights, MA: Allyn & Bacon; 2001., .