Abstracts

Lower back pain (LBP) is one of the most common health problems found among middle-aged and elderly people¹1 Shi Y, Hooten WM, Roberts RO, Warne DO. Modifiable risk factors for incidence of pain in older adults. Pain. 2010;151(2):366-71. http://dx.doi.org/10.1016/j.pain.2010.07.021
https://doi.org/10.1016/j.pain.2010.07.0... ^,22 Hoy D, Brooks P, Blyth F, Buchbinder R. Best Pract Res Clin Rheumatol. 2010;24(6):769-81. http://dx.doi.org/10.1016/j.berh.2010.10.002
https://doi.org/10.1016/j.berh.2010.10.0... . Evidence suggests that psychosocial factors, in addition to biomechanical factors, may influence pain levels and functional outcome³3 Rudy TE, Weiner DK, Lieber SJ, Slaboda J, Bosto JR. The impact of chronic low back pain on older adults: a comparative study of patients and controls. Pain. 2007;131(3):293-301. http://dx.doi.org/10.1016/j.pain.2007.01.012
https://doi.org/10.1016/j.pain.2007.01.0... ^,44 Quartana PJ, Campbell CM, Edwards RR. Pain catastrophizing: a critical review. Pain catastrophizing: a critical review. Expert Rev Neurother. 2009;9(5):745-58. http://dx.doi.org/10.1586/ERN.09.34
https://doi.org/10.1586/ERN.09.34... .

Psychosocial factors have been suggested as indicators of prognosis or obstacles for recovery from LBP⁵5 Foster NE, Delitto A. Embedding psychosocial perspectives within clinical management of low back pain: integration of psychosocially informed management principles into physical therapist practice-challenges and opportunities. Phys Ther. 2011,91(5):790-803. http://dx.doi.org/10.2522/ptj.20100326
https://doi.org/10.2522/ptj.20100326... ^,66 Linton SJ. Do psychological factors increase the risk for back pain in the general population in both a cross-sectional and prospective analysis? Eur J Pain. 2005,9(4):355-61. http://dx.doi.org/10.1016/j.ejpain.2004.08.002
https://doi.org/10.1016/j.ejpain.2004.08... . There seems to be an interrelation between catastrophizing, pain, kinesiophobia, pain locus of control, depression and disability¹1 Shi Y, Hooten WM, Roberts RO, Warne DO. Modifiable risk factors for incidence of pain in older adults. Pain. 2010;151(2):366-71. http://dx.doi.org/10.1016/j.pain.2010.07.021
https://doi.org/10.1016/j.pain.2010.07.0... ^,22 Hoy D, Brooks P, Blyth F, Buchbinder R. Best Pract Res Clin Rheumatol. 2010;24(6):769-81. http://dx.doi.org/10.1016/j.berh.2010.10.002
https://doi.org/10.1016/j.berh.2010.10.0... ^,33 Rudy TE, Weiner DK, Lieber SJ, Slaboda J, Bosto JR. The impact of chronic low back pain on older adults: a comparative study of patients and controls. Pain. 2007;131(3):293-301. http://dx.doi.org/10.1016/j.pain.2007.01.012
https://doi.org/10.1016/j.pain.2007.01.0... ^,44 Quartana PJ, Campbell CM, Edwards RR. Pain catastrophizing: a critical review. Pain catastrophizing: a critical review. Expert Rev Neurother. 2009;9(5):745-58. http://dx.doi.org/10.1586/ERN.09.34
https://doi.org/10.1586/ERN.09.34... . Among the important psychosocial factors in the etiology and chronicity of lower back pain, pain catastrophizing stands out¹1 Shi Y, Hooten WM, Roberts RO, Warne DO. Modifiable risk factors for incidence of pain in older adults. Pain. 2010;151(2):366-71. http://dx.doi.org/10.1016/j.pain.2010.07.021
https://doi.org/10.1016/j.pain.2010.07.0... ^,22 Hoy D, Brooks P, Blyth F, Buchbinder R. Best Pract Res Clin Rheumatol. 2010;24(6):769-81. http://dx.doi.org/10.1016/j.berh.2010.10.002
https://doi.org/10.1016/j.berh.2010.10.0... ^,77 Sullivan MJ, Bishop SR, Pivik J. The Pain Catastrophizing Scale: development and validation. Psychol Assess. 1995;7(4):524-32. http://dx.doi.org/10.1037/1040-3590.7.4.524
https://doi.org/10.1037/1040-3590.7.4.52... . Pain catastrophizing is defined as a negative and exaggerated response to a given painful stimulus⁷7 Sullivan MJ, Bishop SR, Pivik J. The Pain Catastrophizing Scale: development and validation. Psychol Assess. 1995;7(4):524-32. http://dx.doi.org/10.1037/1040-3590.7.4.524
https://doi.org/10.1037/1040-3590.7.4.52... . There are three dimensions to this construct: rumination, which consists in the inability to inhibit thoughts related to pain; the augmentation of the displeasure of painful situations; and a sense of helplessness, hopelessness or inability to cope with painful situations⁷7 Sullivan MJ, Bishop SR, Pivik J. The Pain Catastrophizing Scale: development and validation. Psychol Assess. 1995;7(4):524-32. http://dx.doi.org/10.1037/1040-3590.7.4.524
https://doi.org/10.1037/1040-3590.7.4.52... .

The Pain Catastrophizing Scale (PCS) developed by Sullivan et al.⁷7 Sullivan MJ, Bishop SR, Pivik J. The Pain Catastrophizing Scale: development and validation. Psychol Assess. 1995;7(4):524-32. http://dx.doi.org/10.1037/1040-3590.7.4.524
https://doi.org/10.1037/1040-3590.7.4.52... , obtained good reliability and validity indexes. Sehn et al.⁸8 Sehn F, Chachamovich E, Vidor LP, Dall-Agnol L, Souza ICC, Torres ILS et al. Cross-cultural adaptation and validation of the Brazilian Portuguese version of the pain catastrophizing scale. Pain Medicine. 2012;13(1):1425-35. http://dx.doi.org/10.1111/j.1526-4637.2012.01492.x
https://doi.org/10.1111/j.1526-4637.2012... translated and adapted the PCS for Brazilian individuals with migraines, fibromyalgia and chronic pain. The results showed good validity of the construct and adequate reliability inter-examiners. In spite of that, Hicks and Manal⁹9 Hicks GE, Manal TJ. Psychometric properties of commonly used low back disability questionnaires: are they useful for older adults with low back pain? Pain Med. 2009;10(1):85-94. http://dx.doi.org/10.1111/j.1526-4637.2008.00548.x
https://doi.org/10.1111/j.1526-4637.2008... recommend that, for the safe use of the self-evaluation instruments in clinical or experimental environments, it is necessary to have an adequate process of transcultural adaptation and analysis of the psychometric properties of the instrument through its application on the sample to be used. It is known that instruments applied to young individuals may show different results from those applied to the elderly, in terms of validity and reliability, especially due to the psychosocial and physical peculiarities involved. Despite its impact on public health, LBP is insufficiently understood, especially among the middle-aged and elderly, who are normally excluded from the studies¹⁰10 Preuper HRS, Reneman MF, Boonstra AM, Dijkstra PU, Versteegen GJ, Geertzen JHB et al. Relationship between psychological factors and performance-based and self-evaluationed disability in chronic low back pain. Eur Spine J. 2008;17(11):1448-56. http://dx.doi.org/10.1007/s00586-008-0772-0
https://doi.org/10.1007/s00586-008-0772-... . Furthermore, the biomechanical factors involved in chronic back pain are the most studied, in spite of their multifactorial etiology¹⁰10 Preuper HRS, Reneman MF, Boonstra AM, Dijkstra PU, Versteegen GJ, Geertzen JHB et al. Relationship between psychological factors and performance-based and self-evaluationed disability in chronic low back pain. Eur Spine J. 2008;17(11):1448-56. http://dx.doi.org/10.1007/s00586-008-0772-0
https://doi.org/10.1007/s00586-008-0772-... .

In Brazil, a branch of the study Back Complaints in the Elders – BACE is being developed, including individuals over 55¹¹11 Scheele J, Luijsterburg PAJ, Ferreira ML, Maher CG, Pereira L, Peul WC et al. Back complaints in the elders (BACE); design of cohort studies in primary care: an international consortium. BMC Musculoskelet Disord. 2011;12:193. http://dx.doi.org/10.1186/1471-2474-12-193
https://doi.org/10.1186/1471-2474-12-193... . This study, among other constructs, will evaluate pain catastrophizing through the PCS which requires semantic and conceptual adjustments as well as an analysis of its psychometric properties for use in elderly with lower back pain.

Thus, the objectives of this study are to: proceed with the transcultural adaptation of the Brazilian version of the PCS, evaluate the validity of the construct through Rasch analysis, verify reliability of intra and inter-examiners as well as the convergent validity of pain catastrophizing with the intensity of the pain, locus of pain control, depressive symptoms, self-evaluationed kinesiophobia and disability and physical fitness of the target population.

METHOD

This is a methodological study with a subsample of the longitudinal multicentric international study about low back pain in the elderly – BACE “Back Complaints in the Elders”, in progress¹¹11 Scheele J, Luijsterburg PAJ, Ferreira ML, Maher CG, Pereira L, Peul WC et al. Back complaints in the elders (BACE); design of cohort studies in primary care: an international consortium. BMC Musculoskelet Disord. 2011;12:193. http://dx.doi.org/10.1186/1471-2474-12-193
https://doi.org/10.1186/1471-2474-12-193... . Ethics concern approved (0100.0.203.000-11- UFMG) and all participants signed a consent form.

A total of 131 individuals with acute low back pain but no cognitive impairment participated, recruited in a teaching clinic at Universidade Federal de Minas Gerais through an active screening of people in waiting rooms and by doctor referral.

The inclusion criteria were the same of BACE project: age of 55 or more, LBP of at least six weeks’ duration, without having gone to health services with the same complaint in the past six months or more, characterizing a new back pain crisis¹¹11 Scheele J, Luijsterburg PAJ, Ferreira ML, Maher CG, Pereira L, Peul WC et al. Back complaints in the elders (BACE); design of cohort studies in primary care: an international consortium. BMC Musculoskelet Disord. 2011;12:193. http://dx.doi.org/10.1186/1471-2474-12-193
https://doi.org/10.1186/1471-2474-12-193... ^,1212 Tulder M, Becker A, Bekkering T, Breen A, Real MTG, Hutchinson A et al. European guidelines for the management of acute nonspecific low back pain in primary care. Eur Spine J. 2006;15(2 Suppl):S169-91. http://dx.doi.org/10.1007/s00586-006-1071-2
https://doi.org/10.1007/s00586-006-1071-... .

Excluded from the study were individuals with cognitive alterations detected by the Mini Mental State Examination (MMSE)¹³13 Bertolucci PHF, Brucki SMD, Campacci SR, Juliano Y. O mini-exame do estado mental em uma população geral: impacto da escolaridade. Arq Neuropsiquiatr. 1994;2(1):1-7. and/or some visual or hearing impairment which would prevent the performance of the tests (see more in BACE protocol¹¹11 Scheele J, Luijsterburg PAJ, Ferreira ML, Maher CG, Pereira L, Peul WC et al. Back complaints in the elders (BACE); design of cohort studies in primary care: an international consortium. BMC Musculoskelet Disord. 2011;12:193. http://dx.doi.org/10.1186/1471-2474-12-193
https://doi.org/10.1186/1471-2474-12-193... ).

For the calculation of the sample, we considered an acceptable number of ten individuals for each item contained in the scale (131)¹⁴14 Teixeira-Salmela LF, Magalhães LC, Souza AC, Lima MC, Lima RCM, Goulart F. Adaptação do perfil de saúde de Nottingham: um instrumento simples de avaliação da qualidade de vida. Cad Saúde Pública. 2004;20(4):905-14. http://dx.doi.org/10.1590/S0102-311X2004000400004
https://doi.org/10.1590/S0102-311X200400... .

The instruments used were:

Mini Mental State Examination: for cognitive tracking¹³13 Bertolucci PHF, Brucki SMD, Campacci SR, Juliano Y. O mini-exame do estado mental em uma população geral: impacto da escolaridade. Arq Neuropsiquiatr. 1994;2(1):1-7.. The cutoff points considered were 13 for illiterate individuals, 18 for those with up to 8 years of schooling, and 26 for individuals with over 8 years of schooling¹³13 Bertolucci PHF, Brucki SMD, Campacci SR, Juliano Y. O mini-exame do estado mental em uma população geral: impacto da escolaridade. Arq Neuropsiquiatr. 1994;2(1):1-7..

Sociodemographic questionnaire: age, gender, color/race, marital status, formal education level.

Numerical Pain Scale: to measure intensity of the pain – 11 points, ranging from 0 (absence of pain) to 10 (extreme pain). Scale with good psychometric properties¹⁵15 Williamson A, Hoggart B. Pain: a review of three commonly used pain rating scales. J Clin Nurs. 2005;14(7):798-804. http://dx.doi.org/10.1111/j.1365-2702.2005.01121.x
https://doi.org/10.1111/j.1365-2702.2005... .

Pain locus of control scale: to classify the perception of pain control. The components are: internal, chance, doctors and health professionals, and others. The adapted version shows good applicability and reliability¹⁶16 Araújo LG, Lima DMF, Sampaio RF, Pereira LSM. Pain Locus of control scale: adaptation and reliability for elderly. Rev Bras Fisioter. 2010;14(5):438-45. http://dx.doi.org/10.1590/S1413-35552010000500014
https://doi.org/10.1590/S1413-3555201000... .

Center for Epidemiological Studies – Depression (CES-D): valid and reliable instrument for tracking symptoms of depression or vulnerability to depression in old age¹⁷17 Batistoni SS, Neri AL, Cupertino APFB. Validity of the Center for Epidemiological Studies Depression Scale among Brazilian elderly. Rev Saúde Pública. 2007;41(4):598-605. http://dx.doi.org/10.1590/S0034-89102007000400014
https://doi.org/10.1590/S0034-8910200700... .

Tampa Kinesiophobia Scale: to measure the fear of movement. Consists of 17 questions and shows good applicability to individuals with back pain¹⁸18 Siqueira FB, Teixeira-Salmela LF, Magalhães LC. Analysis of the psychometric properties of the Brazilian version the tampa scale for kinesiophobia. Acta Ortop Bras. 2007;15(1):19-24. http://dx.doi.org/10.1590/S1413-78522007000100004
https://doi.org/10.1590/S1413-7852200700... .

Roland Morris Disability Questionnaire: instrument validated for Brazil, with 24 items about self-evaluationed disability due to back pain¹⁹19 Nusbaum L, Natour J, Ferraz M, Goldenberg J. Translation, adaptation and validation of the Roland-Morris questionnaire – Brazil Roland-Morris. Braz J Med Biol Res. 2001;34(2):203-10. http://dx.doi.org/10.1590/S0100-879X2001000200007
https://doi.org/10.1590/S0100-879X200100... .

Short Performance Physical Battery: valid and reliable instrument for evaluation of balance, gait speed, strength of lower limbs²⁰20 Nakano MM. Versão brasileira da Short Physical Performance Battery – SPPB: adaptação cultural e estudo da confiabilidade. [dissertação]. Campinas: Faculdade de Educação, Universidade Estadual de Campinas; 2007..

The adaptation procedures followed those proposed by Herdman et al.²¹21 Herdman M, Fox-Rushby J, Badia X. A model of equivalence in the cultural adaptation oh HRQoL instruments: the universalist approach. Qual Life Res. 1998;7(4):323-35. http://dx.doi.org/10.1023/A:1024985930536
https://doi.org/10.1023/A:1024985930536... . According to them, conceptual equivalence ooccurs when they present the same idea; items equivalence refers to the adjustment of the elements in the original scale to represent the concept in question in the language in which the tool is to be applied; semantics equivalence is to transfer the meaning from one language to the other; operational equivalence is relative to the possibility of using a similar format of questionnaire, instructions, manner of application and metrics equivalence is to verify if the different versions reach similar levels in terms of validity and reliability²¹21 Herdman M, Fox-Rushby J, Badia X. A model of equivalence in the cultural adaptation oh HRQoL instruments: the universalist approach. Qual Life Res. 1998;7(4):323-35. http://dx.doi.org/10.1023/A:1024985930536
https://doi.org/10.1023/A:1024985930536... .

The semantic adaptation of the PCS followed four phases as proposed by Beaton et al.²²22 Beaton DE, Bombardier C, Guillemin F, Ferraz MB. Guidelines for the process of cross-cultural adaptation of self-evaluation measures. Spine. 2000;25(24):3186-91. It consists in: (1) Translation into Portuguese by two independent translators; (2) Synthesis for a final version; (3) Back translation by two independent back translations; and (4) Expert committee formed to define the adjusted version. Details about the process are described below.

Statistical analysis

A descriptive analysis was carried out to characterize the profile of the sampling along all variables of the study.

The Kolmogorov Smirnov test was performed to verify the hypothesis of distribution normality of variable for the analysis of convergent validity.

The analysis of convergent validity between the PCS and other outcomes evaluated was performed with the Spearman Correlation Coefficient (r). The Quadratic Weighted Kappa Coefficient (Kp), considering the total number of agreements and disagreements inter and intra examiners, was used for the reliability analysis. To allow comparison with other studies, the Intraclass Correlation Coefficient (ICC) was also used²³23 Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74.. All statistical tests were set at a significance of α = 0.05. The Vassarstats^® software was used for the Quadratic Weighted Kappa Coefficient and the other analyses were conducted using the Statistical Package for Social Sciences (SPSS 17.0, Chicago, IL, USA).

The version of the tool adjusted for acute low back pain was submitted to a Rasch analysis, which allows the calibration of the difficulty of the items and the skill level of the individuals in a single continuum¹⁴14 Teixeira-Salmela LF, Magalhães LC, Souza AC, Lima MC, Lima RCM, Goulart F. Adaptação do perfil de saúde de Nottingham: um instrumento simples de avaliação da qualidade de vida. Cad Saúde Pública. 2004;20(4):905-14. http://dx.doi.org/10.1590/S0102-311X2004000400004
https://doi.org/10.1590/S0102-311X200400... ^,2424 Bond TG, Fox CM. Applying the rasch model: fundamental measurement in the human sciences. New Jersey: LawrenceErlbaum; 2001.. The basic assumption of the Rasch analysis, in the case of this study, is that, the higher the level of pain catastrophizing by the person, the greater their probability of getting higher scores in all the items of the scale (which reflect less or more catastrophizing)²⁴24 Bond TG, Fox CM. Applying the rasch model: fundamental measurement in the human sciences. New Jersey: LawrenceErlbaum; 2001.. The analysis of the PCS was carried out using the program Winsteps 3.74.0, which calculates values such as MnSq (goodness-of-fit), in the formats infit and outfit, and the value “t” associated with this estimate, which indicate if the ratio between the level of catastrophizing of the individual and the difficulty of the item meet the assumptions of the model. Reasonable values to show the suitability of the items are: MnSq = 1 ± 0.3, with associated value of t = ± 2 (). So, we chose Rasch analysis because its main contribution is related to the dependency relationship between the individual’s ability and the probability of certain responses. Moreover, the map Rasch facilitates visual analysis of the distribution of individuals in relation to items. Further details about the Rasch analysis are described in Bond and Fox²⁴24 Bond TG, Fox CM. Applying the rasch model: fundamental measurement in the human sciences. New Jersey: LawrenceErlbaum; 2001..

RESULTS

Characterization of the sample

A total of 131 individuals participated in this study, with ages ranging between 55 and 85. The other sociodemographic data are shown in Table 1.

Phases of the adaptation procedure

Evaluation of the equivalence between concepts and items

The review of the literature showed the universality of the expression of pain catastrophizing, leading one to assume a conceptual equivalence, showing that the construct has the same conception in both English and Brazilian Portuguese. Likewise, we found that the elements contained in the scale are pertinent in any country or culture, representing an equivalence of items.

Evaluation of semantic equivalence

The semantic adaptation of the PCS for use in a population of middle-aged and elderly people with acute lower back pain consisted of four phases, described in Figure 1.

Evaluation of operational equivalence

It was recommended that the PCS be applied in the form of an interview, by trained examiners following standardized instructions, instead of a self evaluation, as proposed in the original version. The expert committee deemed that, since a large portion of the individuals among whom the scale was to be applied had low and/or heterogeneous schooling levels, the assisted application would avoid errors in interpretation. In order to check on the adjustments made by this committee, the scale was applied to 30 individuals²⁴24 Bond TG, Fox CM. Applying the rasch model: fundamental measurement in the human sciences. New Jersey: LawrenceErlbaum; 2001.. These were shortly thereafter interviewed to verify their understanding. The pre-test showed a good comprehension on the part of the respondents and there was no need to return to the expert committee to make changes in the questions (^appendix CATASTROPHIZING PAIN SCALE – ADJUSTED VERSION ). Another 101 individuals were evaluated for the other analyses.

Evaluation of the measurement equivalence

After obtaining the minimum score necessary in the MMSE, the individuals were interviewed and submitted to the functional tests during one day. After 7 to 10 days, the PCS was applied again by the same examiner to check on the intraexaminer reliability. For the analysis of the inter-examiner reliability, the same instrument was applied to the same individual by two different examiners on the same day. The validity of the construct and the convergence were evaluated and are described below.

Analysis of the validity of the construct

The result of the Rasch analysis is shown in Table 2, which breaks down the calibration or difficulty values of the items, MnSq (Infit and Outfit) and t. Of the 13 items of the PCS, only one (item 11 – “When I am in pain, I keep thinking how much I want the pain to stop”) did not fit into the expectations of the model.

The item which represents the highest level of catastrophizing (greatest number of people answering 0), was item 7 – “When I am in pain, I keep thinking of other painful events (situations)”, and the item with the lowest level of catastrophizing was number 11 – “When I am in pain, I keep thinking of how much I want the pain to stop”. The separation index among individuals was 2.95 and among the items, 4.69.

In Figure 2, the center line represents the continuum of catastrophizing, defined by the items organized hierarchically to the right and by the level of expression of the catastrophizing of the participants on the left. On the upper left, one can see the presence of a participant with a higher level of catastrophizing. On the bottom, one observes, likewise, a participant with a lower level of catastrophizing. One can also observe that most of them are aligned with moderate to high levels of catastrophizing. As expected, few individuals are located in the upper and lower part of the continuum, with no ceiling or floor effect being found. Most were distributed in the middle third of the continuum, characterizing a moderate level of catastrophizing. The analysis of the score patterns indicates that the option “not at all” was used in 18% of the replies, “light” in 14%, “moderate” in 24%, “intense” in 17% and “always” in 27%.

Reliability

For the reliability analysis, the sampling considered was of 50 individuals. After 7 to 10 days, the PCS was applied again by the same examiner to check on the intraexaminer reliability. For the analysis of the inter-examiner reliability, the same instrument was applied to the same individual by two different examiners on the same day. The result of the intraexaminer reliability was Kp = 0.80 ± 0.01 (95%CI = 0.77 - 0.82) and the ICC was 0.88 (95%CI = 0.87 - 0.90). The interexaminer reliability was Kp = 0.75 ± 0.01 (95%CI = 0.72 - 0.78) and ICC = 0.77 (95%CI = 0.73 - 0.80).

Convergent validity

The correlations between pain catastrophizing and the other constructs evaluated are shown in Table 3.

DISCUSSION

The adjusted version of the PCS was validated for elderly Brazilians with acute lower back pain and presented psychometric characteristics equivalent to the other versions⁸8 Sehn F, Chachamovich E, Vidor LP, Dall-Agnol L, Souza ICC, Torres ILS et al. Cross-cultural adaptation and validation of the Brazilian Portuguese version of the pain catastrophizing scale. Pain Medicine. 2012;13(1):1425-35. http://dx.doi.org/10.1111/j.1526-4637.2012.01492.x
https://doi.org/10.1111/j.1526-4637.2012... ^,2525 Fernandes L, Storheim K, Lochting I, Grotle M. Cross-cultural adaptation and validation of the Norwegian pain catastrophizing scale in patients with low back pain. BMC Musculoskeletal Disord. 2012;13:111-20. http://dx.doi.org/10.1186/1471-2474-13-111
https://doi.org/10.1186/1471-2474-13-111... ^,2626 Yap JC, Lau J, Chen P, Gin T, Wong T, Phil M et al. Validation of the Chinese Pain Catastrophizing Scale (HK-PCS) in patients with chronic pain. Pain Med. 2008;9(2):186-95. http://dx.doi.org/10.1111/j.1526-4637.2007.00307.x
https://doi.org/10.1111/j.1526-4637.2007... .

With regard to the sample characteristics, the constitution was mainly feminine (92.3%). Considering that the sample was random at the health center, this corroborates the trend towards feminization of aging and quest for health care²⁷27 Gomes R, Nascimento EF, Araújo FC. Por que os homens buscam menos os serviços de saúde do que as mulheres? As explicações de homens com baixa escolaridade e homens com ensino superior. Cad Saúde Pública. 2007;23(3):565-74. http://dx.doi.org/10.1590/S0102-311X2007000300015
https://doi.org/10.1590/S0102-311X200700... . The representation of taking care of one’s self as a woman’s task, the issues related to work, the difficulty of access to health services and the lack of units specifically focused on men’s health, are some of the reasons given by the individuals to explain the lower demand for health services²⁷27 Gomes R, Nascimento EF, Araújo FC. Por que os homens buscam menos os serviços de saúde do que as mulheres? As explicações de homens com baixa escolaridade e homens com ensino superior. Cad Saúde Pública. 2007;23(3):565-74. http://dx.doi.org/10.1590/S0102-311X2007000300015
https://doi.org/10.1590/S0102-311X200700... .

Of the 13 items of the PCS, only one (item 11 – “When I am in pain, I keep thinking of how much I want the pain to stop”) did not reflect the expectations of the model, which was considered acceptable, according to the assumptions of the Rasch analysis. This item presents a more complex grammatical construction, which may have contributed to misunderstanding by some individuals. Upon examining the scores for this item, we found an unexpected reply given only by three individuals. One of the elderly, a 61 year old woman, was not in pain at the moment of evaluation, which may have led to a memory bias and inconsistency in the reply, as reported by Maric et al.²⁸28 Maric A, Banozic A, Cosic A, Kraljevic S, Sapunar D, Puljak L. Validation of the Croatian Pain Catastrophizing Scale through a study on the influence of medical education on pain catastrophizing. Periodicum Biologorum. 2011;113(2):171-5.. Furthermore, the three elderly women in question were aged 61, 68 and 76, with a low schooling level, which may have contributed to their difficulty in understanding this more complex item, as reported by Teixeira-Salmela et al.¹⁴14 Teixeira-Salmela LF, Magalhães LC, Souza AC, Lima MC, Lima RCM, Goulart F. Adaptação do perfil de saúde de Nottingham: um instrumento simples de avaliação da qualidade de vida. Cad Saúde Pública. 2004;20(4):905-14. http://dx.doi.org/10.1590/S0102-311X2004000400004
https://doi.org/10.1590/S0102-311X200400... .

The indexes of separation of items and of individuals showed that the scale is able to divide the people into approximately three levels of catastrophizing (low, medium and high), as described by Fernandes et al.²⁵25 Fernandes L, Storheim K, Lochting I, Grotle M. Cross-cultural adaptation and validation of the Norwegian pain catastrophizing scale in patients with low back pain. BMC Musculoskeletal Disord. 2012;13:111-20. http://dx.doi.org/10.1186/1471-2474-13-111
https://doi.org/10.1186/1471-2474-13-111... and five levels of expression of catastrophizing.

The calibration of the items (0.95) and the individuals (0.91) indicated stability and good internal consistency, which means that the answers of the individuals were also quite reliable, and as a result the measures can be reproduced in subsequent applications²³23 Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74..

The average level of pain catastrophizing was 29.2 (± 13.1) points, corroborating the results of other versions²⁶26 Yap JC, Lau J, Chen P, Gin T, Wong T, Phil M et al. Validation of the Chinese Pain Catastrophizing Scale (HK-PCS) in patients with chronic pain. Pain Med. 2008;9(2):186-95. http://dx.doi.org/10.1111/j.1526-4637.2007.00307.x
https://doi.org/10.1111/j.1526-4637.2007... ^,2929 Meyer K, Sprott H, Mannion AF. Cross-cultural adaptation, reliability, and validity of the German version of the Pain Catastrophizing Scale. J Psychosom Res. 2008;64(5):469-78. http://dx.doi.org/10.1016/j.jpsychores.2007.12.004
https://doi.org/10.1016/j.jpsychores.200... and going against those of Fernandes et al.²⁵25 Fernandes L, Storheim K, Lochting I, Grotle M. Cross-cultural adaptation and validation of the Norwegian pain catastrophizing scale in patients with low back pain. BMC Musculoskeletal Disord. 2012;13:111-20. http://dx.doi.org/10.1186/1471-2474-13-111
https://doi.org/10.1186/1471-2474-13-111... . In this study, the average level was 14 points, but the population was of young adults with subacute lower back pain, which may have led to different results. We wish to point out that we did not find any analysis study of the psychometric properties of the PCS for other populations with samplings of elderly with acute lower back pain, especially Rasch analysis, thus making it difficult to compare the data.

The expectation of the Rasch model is for there to be a rising order in the use of the scores, which did not happen, generating a small distortion in the use of category 3 (intense), which seems to be more difficult to be used than categories 2 (moderate) and 4 (always). It was expected that the percentage of “always” answers would be lower than 27%, remaining at 17% or less. One of the hypotheses is that the individuals found it more familiar and easier to answer “always” than “intense”, especially for those who had fewer years of formal education, true for most of the respondents. Another hypothesis is that the participants were in doubt because the answers “intense” and “always” are two different categories of words: the first refers to intensity, and the second to frequency. In the study of Meyer et al.²⁹29 Meyer K, Sprott H, Mannion AF. Cross-cultural adaptation, reliability, and validity of the German version of the Pain Catastrophizing Scale. J Psychosom Res. 2008;64(5):469-78. http://dx.doi.org/10.1016/j.jpsychores.2007.12.004
https://doi.org/10.1016/j.jpsychores.200... of adaptation of the PCS to German, this observation was also made and the option of answers was altered. In spite of this, in the present study, in a discussion of the expert committee, they did not believe it necessary to make any changes in the options of the answers, other than a simple translation, since the original scale had already been developed and applied that way. During the Rasch analysis, an attempt was made to group the “intense” and “always” categories, seeking to improve the behavior of the scale, but this procedure did not modify the distortion pattern in the use of the score categories. Future studies will probably verify if the change of the name of the category will result in a lesser distortion in the use of the categories and a better quality of the metrics.

The intra and inter examiner reliabilities were considered through the weighted Kappa Coefficient as substantial, and by the Intraclass Correlation Coefficient as high, thus corroborating previous results²⁶26 Yap JC, Lau J, Chen P, Gin T, Wong T, Phil M et al. Validation of the Chinese Pain Catastrophizing Scale (HK-PCS) in patients with chronic pain. Pain Med. 2008;9(2):186-95. http://dx.doi.org/10.1111/j.1526-4637.2007.00307.x
https://doi.org/10.1111/j.1526-4637.2007... ^,2929 Meyer K, Sprott H, Mannion AF. Cross-cultural adaptation, reliability, and validity of the German version of the Pain Catastrophizing Scale. J Psychosom Res. 2008;64(5):469-78. http://dx.doi.org/10.1016/j.jpsychores.2007.12.004
https://doi.org/10.1016/j.jpsychores.200... . These results support the replicability of the Brazilian version of the adjusted PCS.

Pain catastrophizing correlated with all evaluated constructs, except control of locus of internal pain and among doctors and health professionals, corroborating previous results²⁶26 Yap JC, Lau J, Chen P, Gin T, Wong T, Phil M et al. Validation of the Chinese Pain Catastrophizing Scale (HK-PCS) in patients with chronic pain. Pain Med. 2008;9(2):186-95. http://dx.doi.org/10.1111/j.1526-4637.2007.00307.x
https://doi.org/10.1111/j.1526-4637.2007... ^,2929 Meyer K, Sprott H, Mannion AF. Cross-cultural adaptation, reliability, and validity of the German version of the Pain Catastrophizing Scale. J Psychosom Res. 2008;64(5):469-78. http://dx.doi.org/10.1016/j.jpsychores.2007.12.004
https://doi.org/10.1016/j.jpsychores.200... (Table 2). The correlations were considered moderate and weak, showing that, although the constructs are close, they are not redundant. According to Vlaeyen et al.³⁰30 Vlaeyen JWS, Kole-Snijders AMJ, Rotteveel AM, Ruesnik R, Heuts PHTG. The role of fear of movement/(re)injury in pain disability. J Occupat Rehabilit. 1995;5(4):235-52. http://dx.doi.org/10.1007/BF02109988
https://doi.org/10.1007/BF02109988... , the individuals who catastrophize their pain tend to have more kinesiophobia and greater disability⁷7 Sullivan MJ, Bishop SR, Pivik J. The Pain Catastrophizing Scale: development and validation. Psychol Assess. 1995;7(4):524-32. http://dx.doi.org/10.1037/1040-3590.7.4.524
https://doi.org/10.1037/1040-3590.7.4.52... . When they are depressed and disabled, the chances of heightened catastrophization are greater, generating a vicious cycle⁷7 Sullivan MJ, Bishop SR, Pivik J. The Pain Catastrophizing Scale: development and validation. Psychol Assess. 1995;7(4):524-32. http://dx.doi.org/10.1037/1040-3590.7.4.524
https://doi.org/10.1037/1040-3590.7.4.52... .

In conclusion, the results showed that the version of Pain Catastrophizing Scale ajusted for the middle-aged and elderly population with acute low back pain presented a good understanding of the items by the respondents and presented adequate psychometric properties.

Analyzing the erratic pattern of item 11, it is recommended that, in future studies, the behavior of this item be monitored to check if the problems observed in this study will persist in other population groups. Should this occur, it is necessary to consider the possibility of revision, replacement or exclusion. One should also monitor the use of the score categories to see if there is any need to adjust the name in the option of “intense” score.

It is important to point out the importance of the option of applying this sort of tool by an examiner and not on a self-evaluation basis, for most of the current population of elderly who seek medical care at the health clinics present a low level of formal education, which can interfere in the interpretation of the questions, compromising the reliability of the responses.

It is recommended that the interviewer reinforce the initial instructions assuring that the individuals understand the question, avoiding inconsistencies in the responses. Furthermore, in subsequent studies, the PCS-B should be applied on other types of samplings so that the clinimetric validity and quality of the tool is better investigated and expanded.

 CATASTROPHIZING PAIN SCALE – ADJUSTED VERSION

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