ORIGINAL ARTICLE

Validation of brief pain inventory to Brazilianpatients with pain

Karine A. Ferreira & Manoel Jacobsen Teixeira &

Tito R. Mendonza & Charles S. Cleeland

Received: 16 October 2009 /Accepted: 16 February 2010 /Published online: 10 March 2010# Springer-Verlag 2010

AbstractPurpose To validate the Brazilian version of the Brief PainInventory (BPI-B) scale and to determine the optimalcutpoints for mild, moderate, and severe pain based onpatients' rating of their worst pain.Methods One hundred forty-three outpatients with cancerwere recruited in Hospital das Clinicas–University of SaoPaulo, Brazil.Results Confirmatory factor analysis confirmed two underly-ing dimensions, pain severity, and pain interference, withCronbach's α of 0.91 and 0.87, respectively. Convergentvalidity was shown by the correlation observed between theBPI dimensions with the EORTC-QLQ-C30 pain scale andthe McGill Pain Questionnaire. The BPI-B detected signif-icant differences in the two dimensions by disease andperformance status, supporting known-group validity. For

the worst pain, the optimal cutpoints were 4 and 7 (1–4=mild pain, 5–7=moderate, and 8–10=severe).Conclusions Our data show that BPI-B is a brief, useful, andvalid tool for assessing pain and its impact on patient's life.

Keywords Neoplasm . Pain . Pain measurement .

Reproducibility of results . Validation studies

Introduction

Cancer is one of the most prevalent diseases in the world.Most cancer patients had or will have pain during thecourse of their disease [1]. Thus, the regular assessment ofpain is important to early identification and treatment ofcancer.

Pain is one of the most frequent symptoms in patientswith cancer. In Brazil, almost 30% of cancer patients arebeing treated at any one time, and 60–90% of those withadvanced disease have experienced pain [2]. In Braziliancancer centers, from 34.8% to 52.8% of patients havecancer pain, and of them, 14.4–33.3% have referred severepain and 11.6–13.2% moderate pain [3]. Almost 50% ofpatients with cancer pain have received inadequate paintreatment during the course of their treatment [4].

The reasons for such inadequate treatment of pain arenot clear, but some studies have suggested the discrepancybetween patient and physician in judging the severity oftheir patient’s pain and physician underestimation of theirpatient's pain were also predictive of inadequate painmanagement [1, 5, 6]. In addition, patients with uncon-trolled pain were not likely to have a formal assessment orreassessment of their pain or a pain-care order in thenursing notes, or to have been seen by the hospitalspecialist palliative care team [7]. Perhaps, if the healthcare

K. A. Ferreira (*)Instituto do Cancer do Estado de Sao Paulo—ICESP,University of Guarulhos-UnG,R. Coronel Camisão, 409, apto. 72, Butanta,Sao Paulo, SP, Brazil05590-120e-mail: karryi@hotmail.com

K. A. Ferreira :M. J. TeixeiraMultidisciplinary Pain Center, Hospital das Clinicas,School of Medicine, University of São Paulo,São Paulo, Brazil

M. J. TeixeiraDepartment of Neurosurgery, School of Medicine,University of São Paulo,São Paulo, Brazil

T. R. Mendonza : C. S. CleelandDepartment of Symptom Research,UT-M.D. Anderson Cancer Center,Houston, USA

Support Care Cancer (2011) 19:505–511DOI 10.1007/s00520-010-0844-7

providers used a standard self-assessment pain scale, thepatients' pain could be more easily identified and treated.

If cancer-related pain is to be improved, data on theprevalence, severity, and impact on quality of life of painmust be obtained and the effectiveness of various treat-ments documented. A number of instruments have beendeveloped to measure clinical pain, mainly unidimensionalpain measurement tools [8]. However, few pain measure-ment instruments are available in Brazil. Thus, it is veryimportant to make available an instrument that healthcareproviders can use daily to assess the pain of outpatient andinpatients.

Two of the most commonly used multidimensional painscales are the Brief Pain Inventory (BPI) and the McGillPain Questionnaire (MPQ). The MPQ has already beentranslated and validated into Brazilian Portuguese [9, 10].While the MPQ mainly measures the qualities of pain, itdoes not assess how pain interferes with patients’ function-ing. In addition to measuring the intensity and location ofpain and the effectiveness of pain therapy, the BPI alsoevaluates how pain interferes with patient’s functioning.

The BPI is one of the most used instruments around theworld. It was recommended to be included in all chronic-pain clinical trials [11]. The BPI was first developed inEnglish [12] and has been used widely in the United States.This scale has been translated into many different languagessuch as Russian [13], Chinese [14], Italian [15], German[16], Greek [17], Spanish [18], and Japanese [5]. The BPI isa short scale and is easy to understand. However, this scalehas not yet been translated and validated into BrazilianPortuguese. Thus, the purpose of this study was to presentthe Brazilian version of the BPI, to evaluate its psychomet-ric properties among Brazilian patients with cancer pain,and to determine the optimal cutpoints (CP) for mild,moderate, and severe pain based on patients' rating of theirworst pain.

Patients and methods

We performed a cross-sectional study at the Multidisciplin-ary Pain Center of the Hospital das Clinicas, University ofSao Paulo in Sao Paulo, Brazil, after receiving approval bythe institution’s ethics committee. We recruited 143 cancerpatients with pain. They were recruited between June 2004and December 2006.

Eligible patients were required to (1) be an outpatient atthe institution, (2) have a pathologic diagnosis of cancer,(3) be diagnosed by a pain specialist as having only chroniccancer-related pain and no other painful condition, (4) havehad no surgery within the past 30 days, (5) have notreceived radiation therapy or chemotherapy within the past30 days, (6) do not have any infection, and (7) be 18 years

of age or older. If an eligible patient agreed to participate,we obtained written informed consent.

The mean age of the 143 outpatients participating in thestudy was 57.30 (standard deviation [SD] = 13.28, range=27–85), and 61.54% (n=88) of them were women. About53.85% (n=77) had completed at least elementary school.Only 16.78% (n=24) were illiterate, and 23.08% (n=33)had completed high school.

All patients had a pain syndrome resulting from theircancer. The mean time after pain onset was 8.61 months(SD=11.64, median=5.00, range=1–96). About 41% (n=58) of the patients had a diagnosis of breast cancer, 23.78%(n=34) had lung cancer, and 12% had prostate (n=16) orgenitourinary cancer (n=17). The mean time since cancerdiagnosis was 28.79 months (SD=33.13, median=17.50,range=2–168). The majority of the patients had a metasta-sis (65.73%, n=94).

Measurements

Subjects were required to complete the Brazilian version ofthe Brief Pain Inventory (BPI-B), the Brazilian version ofthe McGill Pain Questionnaire, and the European Organi-zation for Research and Treatment of Cancer Quality ofLife-core 30 (EORTC QLQ-c30) questionnaire [19]. Inaddition, the demographic and clinical characteristics andthe performance status were also assessed.

We retrieved data on the patients' diagnosis, diseasestage, and treatment from the hospital medical records.Demographic data were obtained from the patients byinterview. The Karnofsky performance status scale (KPS)was used to assess performance status [20].

Linguistic adaptation

The BPI was translated into Brazilian Portuguese using astandard translation and back-translation procedure. TheEnglish-language items were initially translated into Portu-guese by two native Brazilians who spoke fluent English. Acommittee of bilingually fluent Brazilian pain expertsevaluated and approved these item translations. The itemswere then translated back into English by a bilingualtranslator who had not seen the original English version.The English back-translation and the original versions werecompared. Finally, a Brazilian version of the BPI wasproduced.

The resulting questionnaire was pilot tested amongpatients with cancer and non-cancer pain. On the basis ofthe results from the pilot test, we made further translationrefinements and finalized the tool. The BPI consists of nineitems that are arranged in two dimensions: intensity/severity of pain (sensory dimension, items 3 to 6) andinterference of pain (impact) in the patient's life (reactive

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dimension, items 9a to 9g) [12]. The BPI asks patients torate their pain intensity and the pain interference (withgeneral activities, mood, walking ability, normal work,relationships with others, sleep, and enjoyment of life) in an11-point scale ranging from 0 (no pain/no interference) to10 (as bad as it can be). In addition, it also includes acorporal diagram to assess pain location (item 2), measuresthe percentage of pain relief (item 8), and asks patients todescribe which treatments are being used to control pain.The scores for the two dimensions range from 0 to 10 andare calculated using the mean of the total items. A highscore represents a high pain intensity or pain interference[1, 12].

The McGill Pain Questionnaire (MPQ) was translatedinto Brazilian Portuguese by Pimenta and Teixeira in 1996[10]. The long-form McGill Pain Questionnaire includes 78pain descriptors that are arranged in 20 subclasses of wordsthat measure the sensorial-discriminative, affective-motivational, and evaluative-cognitive dimensions of pain[21]. There is a domain called miscellaneous that includesitems that could not be included in the other three domains.Each word from these subclasses has a rank valueindicative of the relative intensity of pain.

In the current study, the long form of the MPQ wasscored according to the rank values of the wordsselected using the Pain Rating Index for the Sensory,Affective, Evaluative, and Miscellaneous groups, as wellas for the Total and number of words chosen (NWC)[21]. In the current study, The BV-LF-MPQ demonstratedinternal consistency when measured by the Cronbach'salpha coefficient for all 20 subgroups of words (Cron-bach's α=0.87) and for sensorial and affective dimensions(Sensorial = 0.73 and Affective = 0.8, respectively). Thereliability was not good for the miscellaneous dimension(Cronbach's α=0.54).

The pain scale of the EORTC QLQ-C30 version 3.0 wasused to assess pain [19]. The QLQ-C30 consists of 30 itemsthat assess health-related quality of life. The pain scaleincluded two items that assess pain intensity (item 9) andpain interference in daily activities (item 19). The scorerange from 0 to 100. A higher score represented a higher(“better”) level of pain and a higher (“worse”) level. In oursample, the EORTC QLQ-C30 showed internal consistencyin functional scales (Cronbach's α=0.74) and symptomscales (Cronbach's α=0.72).

Statistical analysis

The internal consistency reliability of the BPI-B wasevaluated by Cronbach's coefficient alpha. This coefficientwas computed for the interference and severity scales of theBPI. A value of 0.70 or greater was considered adequate forgroup comparisons [22].

Construct validity was determined by confirmatoryfactor analysis (CFA). CFA was conducted using structur-al equation modeling in LISREL version 8.8 for Windows[23]. The hypothesized model was based on the underly-ing structure of the English version of the BPI [1]. Indicesused to evaluate model fit in CFA included the goodness-of-fit index (GFI), normed fit index (NFI), adjustedgoodness-of-fit index (AGFI), non-normed fit index(NNFI), comparative fit index (CFI), normed chi-square(chi-square/degree of freedom), and root-mean-squareerror of approximation (RMSEA). If the models are fit,their GFI, NFI, NNFI, CFI, GFI, and AGFI should behigher than 0.90, the RMSEA lower than 0.10, and thenormed Chi-square lower than five [24].

The Spearman's correlation coefficients were calculatedto assess convergent validity between the BPI-B, MPQ, andQLQ-c30 pain scale.

Known-group validity was evaluated by comparingsubgroups of patients known to differ on clinical variablesusing the Student's t or Mann–Whitney U tests depends ontheir adherence to normal distribution. We hypothesizedthat patients with a higher performance status and withlocal or locoregional disease would report better function-ing and less pain than patients with a lower performancestatus and with metastatic disease.

We also evaluated the possible boundaries, or cutpoints,of the BPI-B for defining mild, moderate, and severe pain,based on patient's ratings of their worst pain. On the basisof other studies that examined different cutpoints [25–28],we tested seven cutpoint models. We created sevendifferent categorical variables that represented seven possi-ble combinations for the cutpoints between 3 and 7 andrelated them to the set of seven interference items (9a to 9g)from the BPI-B using multivariate analysis of variance(MANOVA). The criterion used to determine the bettercutpoints to discriminate between levels of pain severitywas that a MANOVA among pain severity categoriesyielded the largest F ratio for the category effect on theseven interference items as indicated by Pillai's trace, Wilk'slambda, and Hotelling's trace F values.

For all tests, a P value of <0.05 was consideredstatistically significant.

Results

Descriptive analysis

Most of the Brazilian patients filled out the questionnaireduring an interview. The average time to complete theBPI-B was 5 min (range 3–15). Table 1 presents thedescriptive analyses from the Brazilian version of the BPI.Patients rated interference with work as the highest,

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closely followed by general activity, enjoyment of life,and sleep.

Construct validity

A confirmatory factor analysis (CFA) was used to deter-mine the adjustment of the BPI-B factors identified in theEnglish version: pain interference (reactive dimension) and

pain severity/intensity (sensory dimension). The hypothe-sized model is presented in Fig. 1. The independent modelthat tests the hypothesis that all variables are uncorrelatedwas rejected in BPI-B model, normed χ2=1.83, P=0.00.The BPI-B model with two dimensions (pain severity andpain impact/interference) showed a good fit to data: GFI=0.82, CFI=0.95, NFI=0.91, NNFI=0.94 and RMSEA=0.11 (CI95%=0.072–0.15).

Fig. 1 Confirmatory factoranalysis for the Brief PainInventory-B

Variables Mean Median SD Cronbach's α if item deleted

Severity items (pain) 0.91a

Least 4.13 4.00 3.09 0.87

Average 2.43 2.00 2.52 0.85

Now 4.79 5.00 2.54 0.87

Worst 7.08 7.00 2.62 0.92

Interference items 0.87a

General activity 6.87 8.00 3.25 0.83

Mood 4.96 6.00 3.81 0.87

Walking ability 5.08 5.50 3.54 0.84

Normal work 7.03 8.00 3.34 0.84

Relationships with others 3.32 2.00 3.63 0.86

Sleep 5.15 6.00 3.88 0.86

Enjoyment of life 5.98 8.00 3.93 0.84

Table 1 Descriptive analyses ofthe BPI items and reliabilityanalysis

a Cronbach's alpha of the component

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Reliability

The reliability of the BPI-B was evaluated by the internalconsistency (Cronbach's α Coefficient). We separatelycalculated coefficient alpha for the pain severity items andthe pain interference items. Cronbach's alpha coefficientresults are presented in Table 1. The internal consistency forthe pain severity dimension was 0.91 and for the paininterference dimension was 0.87. Table 1 also shows thatthe values for Cronbach's α Coefficients if items weredeleted were comparable to the overall alpha value of eachof the two dimensions, and thus each of the itemscontributes to the underlying constructs.

Convergent validity

As expected, positive and moderate to strong correlationswere obtained among the pain interference dimension, painseverity dimension, MPQ- PRI, MPQ-NWC; the PRI ofeach MPQ dimension (sensory, affective, and evaluative)ranged from 0.38 to 0.90 (Table 2).

Both dimensions (pain severity and pain interference)showed a strong correlation with the QLQ-C30 pain scale,which measures frequency of pain and pain interference indaily activities.

Known-group validity

Known-group validity was examined by comparing thetotal score of pain severity and pain interference dimen-sions, stratified by poor (<70) and high (≥70) KPS. Resultsindicated that patients with poor performance status hadgreater pain severity than those with high performancestatus (6.20, SD=2.62 vs. 4.32, SD=2.34, P=0.000) andmore severe pain-related interference (6.96, SD=2.27 vs.4.95, SD=2.66, P=0.007).

The total score of pain severity and pain interference wasalso able to differentiate patients according to disease status.Those patients with metastatic disease had higher pain severitythan patients with local or regional disease (5.26, SD=2.57 vs.4.28, SD=2.39, P=0.042) and higher pain-related interference(6.04, SD=2.75 vs. 4.20, SD=1.94, P=0.012).

Table 2 Significant (p<0.05) Spearman's correlation coefficients for the correlation between BPI-B domains, MPQ scores, and QLQ-c30 pain scale

MPQ score: PRI MPQ score: NWC PRI sensory PRI affective PRI evaluative QLQ-c30 pain scale

Pain severity (BPI) 0.65 0.90 0.57 0.38 0.61 0.94

Pain interference (BPI) 0.80 0.70 0.66 0.60 0.71 0.82

MPQ score: PRI 1.00 0.95 0.93 0.77 0.72 0.76

MPQ score: NWC 0.95 1.00 0.87 0.76 0.62 0.90

PRI: sensory 0.93 0.87 1.00 0.54 0.58 0.64

PRI: affective 0.77 0.76 0.54 1.00 0.51 0.53

PRI: evaluative 0.72 0.62 0.58 0.51 1.00 0.76

PRI: miscellaneous 0.71 0.68 0.54 0.50 0.51 0.49

QLQ-c30 pain scale 0.76 0.90 0.64 0.53 0.76 1.00

MPQ McGill Pain Questionnaire, BPI-B Brazilian version of the Brief Pain Inventory, PRI pain rating index, NWC number of words chosen

Models Mild Moderate Severe F-statistics in MANOVA

Pillai's trace Wilk's lambda Hotelling's trace

Rank F Rank F Rank F

CP 4,7 1–4 5–7 8–10 1 2.68 1 3.01 1 3.35

CP 5,7 1–5 6–7 8–10 1 2.68 2 2.92 3 3.17

CP 3,6 1–3 4–6 7–10 3 2.55 3 2.89 2 3.23

CP 4,6 1–4 5–6 7–10 4 2.36 4 2.66 4 2.94

CP 3,5 1–3 4–5 6–10 5 2.10 6 2.31 6 2.52

CP 5,6 1–5 6 7–10 6 2.08 5 2.35 5 2.62

CP 4,5 1–4 5 6–10 7 1.86 7 2.06 7 2.26

Table 3 Results of the multi-variate analysis of variance todetermine optimal cutpointsusing worst pain intensity andthe interference items fromBPI-B

CP cutpoint

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Defining pain severity categories

To determine the optimal cutpoints for mild, moderate, andsevere pain based on patient's ratings of worst pain intensity,we performed a MANOVA test. Based on the seveninterference items from the BPI for worst pain, the cutpointsof 4 for moderate and 8 for severe (Model 1, CP 4,7) was theoptimal combination, as it has the highest criterion ratio inthe Pillai's trace (F value=2.68), Wilk's lambda (F value=3.01), and Hotelling's trace (F value=3.35). The second bestcutpoint was model 2 (CP 5, 7) (Table 3).

Discussion

Based on our findings, we conclude that the BPI-B is avalid and reliable measurement to assess pain in Brazilianpatients with cancer.

The construct validity of BPI-B performed in otherstudies was supported by the confirmatory factor analysisand convergent validity. The number of dimensionsidentified from previous psychometric tests was two orthree. In most studies, two factors have been identified:pain severity and pain interference [12, 13, 15]. These samefactors were also confirmed in the current study. In ourstudy, the model with two dimensions showed a good fit fora two dimension model: pain severity and pain interference/impact. For the Norwegian [29] and Hindi [30] version ofBPI, three factors were identified: pain severity, activityinterference, and mood interference.

In the current study the CFA showed the validity of thetwo-factor model suggested by other BPI validation studies[12, 13, 15].

The BPI-B is really actually measuring the painconstruct, since it showed a moderate to strong correlationwith valid pain questionnaires such as the McGill PainQuestionnaire (MPQ) and EORTC-QLQ-C30 Pain Scale.

The Cronbach's alpha coefficients for both the severityand interference items were high. They were similar tothose identified in other BPI validation studies [13, 15, 31].These values exceed 0.7, a typical standard for acceptablescale stability.

This study also attempted to determine the optimalcutpoints for mild, moderate, and severe pain based onpatients’ rating of worst pain in this patient group. Usingthe methods described by Serlin and colleagues [25], ourresults provide additional confirmation that the limitbetween mild and moderate levels of pain is at a 4 in an11-point numeric rating scale. This limit was also observedin the Russian BPI validation study with cancer patients[13], among patients with cancer-related bone pain [28],and in patients with osteoarthritis of the knee [32].However, this study did not confirm the limit between

moderate and severe pain previously reported by Serlin andcolleagues [25]. According to Serlin et al. [25], the optimalcutpoint between moderate and severe pain was at 6. Thus,patients with pain equal or higher than seven should beconsidered as having severe pain. This cutpoint was alsoobserved among patients with cancer pain in Russia [13]and patients experiencing postoperative pain followingcoronary artery bypass surgery [33]. In the present study,the cutpoint between moderate and severe pain was at 7,with a rating of 7 being in the moderate category and arating of >7 being in the severe category. This somecutpoint was observed by Paul and colleagues in patientswith cancer pain due to bone metastasis [28].

These differences in cutpoints between moderate andsevere pain need confirmation in larger samples than theone used in the current study. Pain is multidimensional andcan be influenced by cultural aspects [34]. Thus, thedisparity between cutpoints for severe pain could beexplained by the cultural difference between multi-national samples. In addition, our sample included onlyoutpatients with chronic pain. In the Serlin [25] and theRussian BPI [13] validation studies, were included inpa-tients and outpatients with probable acute and chronic pain.

The present study has some limitations in that we did notevaluate the BPI's test–retest reliability and responsiveness.However, we did observe that the BPI-B was able todifferentiate between patients with low and high perfor-mance status and with local and advanced disease. We canimply that if we use the BPI-B to assess the effectiveness ofsome interventions to treat pain, the BPI-B will be able toidentify changes in pain intensity and interference. BPIidentified changes in pain severity in some studies thatevaluated pharmacological [35] and non-pharmacologicalinterventions [36, 37] to treat pain.

In conclusion, we can say that the BPI-B is a useful andreliable tool to assess pain in Brazilian cancer patients. Wehope this instrument can help researchers and clinicians toassess pain, select interventions, and evaluate their effec-tiveness. Thus, the use of this tool will be able to improvepatients' pain treatment and quality of life.

Acknowledgements The authors would like to thank the physicians,nurses, and physical therapists from the Hospital das Clinicas, Schoolof Medicine, University of Sao Paulo, who helped us to enroll patientsin our study.

Conflict of interest statement None declared.

References

1. Cleeland CS, Gonin R, Hatfield AK, Edmonson JH, Blum RH,Stewart JA et al (1994) Pain and its treatment in outpatients withmetastatic cancer. N Engl J Med 330(9):592–596

510 Support Care Cancer (2011) 19:505–511

2. Instituto Nacional de Cancer Brasil (2001) Cuidados paliativosoncológicos: controle da dor. Rio de Janeiro: INCA-MS

3. Ferreira KASL (2008) Dor e qualidade de vida relacionada àsaúde de pacientes com câncer: influência das citocinas pró-inflamatórias TNF-α, IL-6, IL-8 e IL-1β. Universidade de SãoPaulo, São Paulo

4. Ferreira KASL, Kimura M, Teixeira MJ, eds (2006) Impact ofadequacy of pain treatment on quality of life of cancer patients.2006 International Society for Quality of Life Research meeting -ISOQOL; Lisboa: Quality of Life Research Journal. A-90.Abstract #1280

5. Uki J, Mendoza T, Cleeland CS, Nakamura Y, Takeda F (1998) Abrief cancer pain assessment tool in Japanese: the utility of theJapanese Brief Pain Inventory—BPI-J. J Pain Symptom Manage16(6):364–373

6. Larue F, Colleau S, Brasseur L, Cleeland C (1995) Multicentrestudy of cancer pain and its treatment in France. BMJ 310(6986):1034–1037

7. Menzies K, Murray J, Wilcock A (2000) Audit of cancer painmanagement in a cancer centre. Int J Palliat Nurs 6(9):443–447

8. Caraceni A, Brunelli C, Martini C, Zecca E, De Conno F (2005)Cancer pain assessment in clinical trials. A review of the literature(1999–2002). J Pain Symptom Manage 29(5):507–519

9. Varoli FK, Pedrazzi V (2006) Adapted version of the McGill painquestionnaire to Brazilian Portuguese. Braz Dent J 17(4):328–335

10. Pimenta CAdM, Teixeira MJ (1996) Questionário de dor McGill:proposta de adaptação para a língua portuguesa. Revista da Escolade Enfermagem da USP 30(3):473–483

11. Turk DC, Dworkin RH, Allen RR, Bellamy N, Brandenburg N,Carr DB et al (2003) Core outcome domains for chronic painclinical trials: IMMPACT recommendations. Pain 106(3):337–345

12. Cleeland C, Ryan K (1994) Pain assessment: global use of theBrief Pain Inventory. Ann Acad Med Singapore 23(2):129–138

13. Kalyadina SA, Ionova TI, Ivanova MO, Uspenskaya OS,Kishtovich AV, Mendoza TR et al (2008) Russian brief paininventory: validation and application in cancer pain. J PainSymptom Manage 35(1):95–102

14. Wang XS, Hao XS, Wang Y, Guo H, Jiang YQ, Mendoza TR et al(2004) Validation study of the Chinese version of the BriefFatigue Inventory (BFI-C). J Pain Symptom Manage 27(4):322–332

15. Caraceni A, Mendoza TR, Mencaglia E, Baratella C, Edwards K,Forjaz MJ et al (1996) A validation study of an Italian version ofthe Brief Pain Inventory (Breve Questionario per la Valutazionedel Dolore). Pain 65(1):87–92

16. Radbruch L, Loick G, Kiencke P, Lindena G, Sabatowski R,Grond S et al (1999) Validation of the German version of the BriefPain Inventory. J Pain Symptom Manage 18(3):180–187

17. Mystakidou K, Mendoza T, Tsilika E, Befon S, Parpa E, Bellos Get al (2001) Greek brief pain inventory: validation and utility incancer pain. Oncology 60(1):35–42

18. Badia X, Muriel C, Gracia A, Nunez-Olarte JM, Perulero N,Galvez R et al (2003) Validation of the Spanish version of theBrief Pain Inventory in patients with oncological pain. Med Clin(Barc) 120(2):52–59

19. Aaronson N, Ahmedzai S, Bergman B, Bullinger M, Cull A, DuezN et al (1993) The European Organization for Research andTreatment of Cancer QLQ-C30: a quality-of-life instrument for

use in international clinical trials in oncology. J Natl Cancer Inst85(5):365–376

20. Karnofsky DA, Abelmann WH, Craver LF, Burchenal JH (1948)The use of nitrogen mustard in the palliative treatment of cancer.Cancer 1(4):634–656

21. Melzack R (1975) The McGill Pain Questionnaire: majorproperties and scoring methods. Pain 1(3):277–299

22. Cronbach LJ (1951) Coefficient alpha and the internal structure oftests. Psychometrika 16(3):297–334

23. Jöreskog KG, Sörbom D. LISREL 8.80 for Windows [ComputerSoftware] Lincolnwood, IL: Scientific Software International, Inc.2006

24. Hair J, Anderson R, Tatham R, Black W (1998) Multivariate dataanalysis, 5th edn. Prentice-Hall, Englewood Cliffs

25. Serlin R, Mendoza T, Nakamura Y, Edwards K, Cleeland C(1995) When is cancer pain mild, moderate or severe? Gradingpain severity by its interference with function. Pain 61(2):277–284

26. Palos GR, Mendoza TR, Mobley GM, Cantor SB, Cleeland CS(2006) Asking the community about cutpoints used to describemild, moderate, and severe pain. J Pain 7(1):49–56

27. Dihle A, Helseth S, Paul SM, Miaskowski C (2006) Theexploration of the establishment of cutpoints to categorize theseverity of acute postoperative pain. Clin J Pain 22(7):617–624

28. Paul S, Zelman D, Smith M, Miaskowski C (2005) Categorizingthe severity of cancer pain: further exploration of the establish-ment of cutpoints. Pain 113(1–2):37–44

29. Klepstad P, Loge JH, Borchgrevink PC, Mendoza TR, CleelandCS, Kaasa S (2002) The Norwegian brief pain inventoryquestionnaire: translation and validation in cancer pain patients.J Pain Symptom Manage 24(5):517–525

30. Saxena A, Mendoza T, Cleeland CS (1999) The assessment ofcancer pain in north India: the validation of the Hindi Brief PainInventory—BPI-H. J Pain Symptom Manage 17(1):27–41

31. Ger LP, Ho ST, Sun WZ, Wang MS, Cleeland CS (1999)Validation of the Brief Pain Inventory in a Taiwanese population.J Pain Symptom Manage 18(5):316–322

32. Kapstad H, Hanestad BR, Langeland N, Rustoen T, Stavem K(2008) Cutpoints for mild, moderate and severe pain in patientswith osteoarthritis of the hip or knee ready for joint replacementsurgery. BMC Musculoskelet Disord 9:55

33. Mendoza TR, Chen C, Brugger A, Hubbard R, Snabes M, PalmerSN et al (2004) The utility and validity of the modified Brief PainInventory in a multiple-dose postoperative analgesic trial. Clin JPain 20(5):357–362

34. Blaylock J (1968) The psychological and cultural influences onthe reaction to pain. Nurs Forum 7(3):262–274

35. Hanna M, Thipphawong J, Study G (2008) A randomized,double-blind comparison of OROS hydromorphone andcontrolled-release morphine for the control of chronic cancerpain. BMC Palliat Care 7(1):17

36. Kutner JS, Smith MC, Corbin L, Hemphill L, Benton K, MellisBK et al (2008) Massage therapy versus simple touch to improvepain and mood in patients with advanced cancer: a randomizedtrial. Ann Intern Med 149(6):369–379

37. Carrafiello G, Lagana D, Ianniello A, Nicotera P, Fontana F,Dizonno M et al (2009) Radiofrequency thermal ablation for paincontrol in patients with single painful bone metastasis fromhepatocellular carcinoma. Eur J Radiol 71:363–368

Support Care Cancer (2011) 19:505–511 511