Vol. 54 No. 4 October 2017 Journal of Pain and Symptom Management 563 Brief Methodological Report Iranian Brief Pain Inventory: Validation and Application in Elderly People With Cancer Pain Mahtab Alizadeh-Khoei, MPH, PhD, Farshad Sharifi, MD, MPH, PhD, Mohamad Esmaeil Akbari, MD, Reza Fadayevatan, MD, MPH, PhD, and Marjan Haghi, MSN, PhD Gerontology & Geriatric Department (M.A.-K.), Medical School, Tehran University of Medical Sciences, Tehran; Elderly Health Research Center (M.A.-K., F.S.), Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran; Department of Cancer Research Center and Medical School (M.E.A.), Shahid Beheshti University of Medical Sciences, Tehran; and Gerontology Department (R.F., M.H.), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Abstract Context. Cancer is a major health problem in the elderly, and pain is one of the most common symptoms among older patients with cancer. Sufficient pain treatments depend on the accuracy of the pain assessment tool. Objectives. This study aimed to assess the psychometric properties of the Iranian version of the Brief Pain Inventory (BPI-IR) among elderly individuals with cancer. Methods. This validation study was conducted with 368 people aged 60þ years old who were undergoing oncology treatments. The BPI-IR was applied to the elderly participants through face-to-face interviews. Reliability of the BPI-IR was evaluated using Cronbach’s alpha coefficient and intraclass correlation coefficient between test-retest scores. Criterion validity was determined by calculating the Spearman’s correlation coefficient between scores on the BPI-IR and those on the SF-36 physical function, Activities of Daily Living, Instrumental Activities of Daily Living, Center for Epidemiological Studies Depression, Patient Pain Questionnaire, and Symptom Distress Scale. Construct validity of the BPI-IR was evaluated using exploratory factor analyses. Results. Cronbach’s alpha coefficient was calculated to be 0.94, and the intraclass correlation coefficient between twice the BPI-IR scores over two weeks obtained was 0.89. There were moderate-to-high correlations between the BPI-IR and the Patient Pain Questionnaire (r ¼ 0.886), Symptom Distress Scale (r ¼ 0.492), SF-36 physical function (r ¼ 0.554), and Center for Epidemiological Studies Depression (r ¼ 0.608). Two factors were extracted in exploratory factor analyses, and they explained 73.86% of total variance. Conclusion. The BPI-IR is a reliable and valid tool for assessing pain among older adults with cancer. J Pain Symptom Manage 2017;54:563e569. Ó 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved. Key Words Pain measurement, elderly, psychometrics, cancer, Brief Pain Inventory Introduction The incidence of cancer increases in the older population as a vulnerable aged group.1 Elderly patients diagnosed with cancer have many problems like pain.2 Pain management in elderly patients with cancer is one of the main concerns for clinicians.2,3 Cancer pain is underreported in elderly patients due Address correspondence to: Mahtab Alizadeh-Khoei, MPH, PhD, Gerontology & Geriatric Department, Medical School, Tehran University of Medical Sciences, Engelab Street, Ó 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved. to fear of cancer progression.4 It was estimated that 25%e40% of elderly individuals with cancer had daily pain.4 Sufficient pain treatments depend on accurate pain assessment tools.5 Self-reporting is a gold standard method for pain assessment.6 The Brief Pain Inventory (BPI) is short and easy to apply and is the most useful multidimensional tool for pain Poursina Avenue, Tehran, Iran. E-mail: [email protected] yahoo.com Accepted for publication: July 6, 2017. 0885-3924/$ - see front matter http://dx.doi.org/10.1016/j.jpainsymman.2017.07.015 564 Alizadeh-Khoei et al. assessment in patients with cancer.7,8 The BPI is a numeric scale that has sensory and reactive dimensions to measure intensity of and interference in pain to apply for both clinicians and researchers.7e9 It has been translated into different languages.7,9e22 One Iranian study reported good reliability of the BPI among young and adult outpatients with any kind of pain in a hospital clinic;23 however, a validated Persian version of the BPI in elderly patients with cancer has not been available until now. The purpose of this study was to evaluate the psychometric properties in terms of construct and concurrent validity of the Iranian BPI (BPI-IR) in older patients with cancer pain and to evaluate the internal consistency and test-retest stability. Methods Participants In this cross-sectional validation study, older participants were selected from a cancer clinic of the Shohadaye Tajrish hospital, Tehran. Inclusion criteria were age $60 years with pathological diagnosis of cancer (primary or metastatic), start of oncology treatments within the past two weeks (among both inpatients and outpatients), presence of cancer-related pain, lack of infection, presence of any analgesic treatment, and experience of at least one episode of pain during the last week. Older patients who had undergone surgery within one month before the interview, were completely bedridden, had severe visual or hearing impairment, had cognitive impairment measured by MinieMental State Evaluation test (<24 score),24,25 and were aphasic were excluded. After approval from the hospital’s ethical committee board, participants were selected by simple random sampling based on medical record codes. Finally, 368 eligible older adults agreed to participate and signed or fingerprinted the consent form. Data Collection This study was conducted from February of 2015 to October of 2016. Participants completed the BPI-IR, a modified version of the functional items of the ShortForm Health Survey (SF-36),26 Katz’s Activities of Daily Living (ADL) scale,27 the Lawton Instrumental ADL (IADL) Scale,28 the Center for Epidemiological Studies Depression (CES-D) Scale,29 the Patient Pain Questionnaire (PPQ) pain experience subscale,30 and two questions from the Symptom Distress Scale (SDS).31 Meanwhile, demographic characteristics, cancer location and stage, treatments, use of medications to relieve pain, and pain status were assessed. Vol. 54 No. 4 October 2017 The BPI-IR asked older patients to rate their pain at its worst in the past week on a scale from 0 to 10. Most of the items were administered by elderly patients themselves according to the user guides,32 although the researchers were allowed to read the items for illiterate older participants and showing hand fingers instead of the Numeric Rating Scale (NRS; 0e10). In clinical trials, the NRS is more reliable in patients with cancer due to ease of understanding and scoring, especially in less-educated people.16,33 Measures The original of BPI was translated into the Farsi language in another study23 before being used in the present study. In the BPI, the NRS (0e10) is used for elderly patients to rate their pain at the time of responding to the questionnaire as worst, least, and average pain for the last week.16 Eleven-point rating scales include four questions on pain intensity with responses ranging from 0 ¼ ‘‘No pain’’ to 10 ¼ ‘‘Pain as bad as you can imagine.’’ The other seven NRS items related to pain interference with function, rated from 0 ¼ ‘‘Does not interfere’’ to 10 ¼ ‘‘Interferes completely,’’14,34 were general activity, mood, walking, working, relationships, sleep, and life enjoyment.8 The BPI has shown high reliability and validity in cancer pain; Cronbach’s alphas are typically over 0.80.14,35 Patients’ health-related quality of life was assessed using the SF-36, including eight domains.26 The Persian version of the SF-36 was validated for use with an Iranian population (Cronbach’s alpha ¼ 0.65).36 In this study, nine items of the SF-36 were used as a modified physical functioning subscale. These items measured how cancer may affect vigorous functions, such as climbing stairs, transferring in and out of bed, running, lifting heavy objects, bending and stooping, climbing one flight of stairs, and walking a block unassisted.37 Katz’s ADL index summarizes overall performance in six functions.27 The Iranian version of Katz’s ADL is a reliable and valid tool for use with elderly patients with cancer with Cronbach’s alpha of 0.923.37 The Lawton IADL scale measures more complex activities than the basic ADL assessed by Katz index.38,28 The Persian version of the Lawton IADL scale has excellent reliability and validity among people with dementia.39 The CES-D scale is commonly used to assess depressive symptoms in patients with cancer during the last week.40 The Farsi version of the CES-D-10 was determined as valid and reliable among the Iranian elderly population with Cronbach’s alpha of 0.85.41 The PPQ is a scale with 16 ordinal items that measures the knowledge and experience of pain in patients with cancer, and each subscale can be assessed Vol. 54 No. 4 October 2017 Iranian Brief Pain Inventory 565 as a total score. The experience subscale has seven items that measure pain relief, distress, and pain control.30,42 Cronbach’s alpha for this subscale was reported as 0.84.43 The SDS questionnaire has 13 items that measure 11 symptoms associated with cancer. Two items related to pain were intensity and frequency of pain. Cronbach’s alpha of the total scale was reported as 0.75.44 indicate good correlation between scores on the questionnaires. Exploratory factor analyses with varimax rotation at eigenvalues $1 were used for extraction of factors in the BPI. Percentage of variance was explained by each factor, and factor loading was calculated for each item. Reliability Results Internal reliability and external reliability of the BPI-IR were assessed using a questionnaire administrated two weeks after the first time of evaluation and test-retest analysis. Validity Face validity of the BPI-IR was asked from 10 elderly participants with normal cognition who had at least six years of schooling through a four-point Likert questionnaire regarding items’ clarity and fluency with 0 ¼ the least and 3 ¼ maximum score. The mean $2 for each item indicated clarity and fluency, and face validity of the items was considered sufficient. Content validity was assessed by a group of five experts including an oncologist, nurses, an anesthesiologist, and a gerontologist who reviewed the BPI-IR items’ relevance and coverage, scoring each item on a four-point Likert scale. A score of 3 ¼ complete relevancy and coverage, and a score of 0 ¼ the least. If mean scores for each item were $2, the content validity was considered sufficient. For the factor model of the BPI, correlation of the BPI was determined by two types of scales.12,14 Concurrent validity was evaluated by calculating the Spearman’s rank correlation coefficient in the pain interference subscale by the physical functioning subscale of the SF-36, ADL, IADL, and depression tools. Pain severity was measured by a pain experience subscale of the PPQ and pain-related questions in the SDS tools. Construct validity was evaluated by exploratory factor analysis. Statistical Analysis Descriptive statistics were used for demographic, cancer, and treatment data. For all tests, P < 0.05 was considered statistically significant. Internal reliability and external reliability were assessed by Cronbach’s alpha coefficient and intraclass correlation coefficient (ICC) between test-retest scores for pain severity and pain interference items. Cronbach’s alpha coefficients $0.70 were considered to have acceptable internal consistency. ICC for agreement between test-retest scores $0.80 was considered to indicate very strong external reliability. Spearman’s correlation coefficient $0.70 was considered to The mean age of participants was 67.53 5.81 years, and 36.7% were illiterate or unable to read and write (Table 1). The top cancer diagnosed was gastrointestinal (30.1%). Elderly patients rated more interference with enjoyment of life (Table 2). Reliability High Cronbach’s alpha for the pain severity (0.80) and pain interference subscales (0.95) and the total scale (0.94) demonstrated good internal consistency (Table 3). All corrected item total correlations were Table 1 Demographic and Disease-Related Characteristics (N ¼ 368) Variables Age 60e69 70e79 #80 Marital status Married Single Literacy Literate Illiterate (unable to read and write) Cancer stage 1 or 2 3 or 4 Top five cancer types Gastrointestinal Prostate and bladder Breast Brain Lung Cancer treatments Surgery Radiotherapy Chemotherapy Surgery and chemotherapy Surgery and radiotherapy Radiotherapy and chemotherapy Surgery and radiotherapy and chemotherapy Daily use of analgesics Yes Analgesics use in the past week Yes Pain location Left upper side Left lower side Right upper side Right lower side % Male % Female 58.8 36.7 4.5 74.3 22.9 2.8 93.7 6.3 50.3 49.7 86.8 13.2 76.5 23.5 53.8 46.2 44.4 55.6 19.0 15.7 0.0 5.1 5.7 11.1 1.3 17.1 4.6 1.0 15.0 23.2 10.5 5.9 6.8 5.9 32.7 19.0 25.1 9.5 6.1 9.5 8.4 22.3 58.8 65.2 88.7 91.6 35.3 23.1 31.2 10.4 35.0 22.0 34.5 8.5 566 Alizadeh-Khoei et al. Vol. 54 No. 4 October 2017 Table 2 Descriptive Statistics Study Variables and Correlations With the BPI-IR (N ¼ 368) Variables Pain intensity Pain worst Pain least Pain average Pain now Pain interference General activity Mood Walking ability Normal work Relationship Sleep Enjoyment of life SF-36 Physical Function ADL IADL CES-D PPQ SDS Mean SD 6.76 1.30 4.83 2.17 2.415 1.970 1.983 2.378 3.32 2.91 3.35 3.59 3.29 2.98 3.90 33.55 6.98 8.76 20.95 26.52 3.5 2.848 2.908 3.001 2.919 2.707 2.730 2.981 8.20 2.45 3.89 6.24 12.88 2.19 Correlation With Pain Intensity Correlation With Pain Interference 0.554a 0.228b 0.304b 0.608a 0.886a 0.492b BPI-IR ¼ Iranian version of the Brief Pain Inventory; ADL ¼ Activities of Daily Living; IADL ¼ Instrumental Activities of Daily Living; CES-D ¼ Center for Epidemiological Studies Depression; PPQ ¼ Patient Pain Questionnaire; SDS ¼ Symptom Distress Scale. a P < 0.01. b P < 0.05. more than 0.2,17 indicating that no item should be revised or excluded. Regarding values of ‘‘alpha if item deleted,’’ which were less than the subscale alpha, it was not necessary to remove any items. The ICC between test-retest obtained was 0.89, showing acceptable stability in both pain intensity (0.91) and pain interference (0.87). Validity Spearman’s correlation coefficient between the BPI-IR pain interference subscale scores with ADL and IADL was weak but statistically significant (r ¼ 0.228, r ¼ 0.304, P < 0.05). The correlation coefficient of the BPI-IR interference subscale was moderate with the SF-36 physical function subscale (r ¼ 0.554, P < 0.01) and high with the CES-D (r ¼ 0.608). Generally, pain interference items were correlated with the physical function and depression (Table 2). Meanwhile, the BPI-IR intensity score had high correlation with the pain experience subscale of the PPQ (r ¼ 0.886, P < 0.01) and moderate correlation with the pain-related questions of the SDS (r ¼ 0.492, P < 0.05). The possibility to perform factor analyses was examined by the Kaiser-Meyer-Olkin measure of sampling adequacy (0.91) and Bartlett’s test of sphericity (c2 ¼ 3856.453, P < 0.05), which attained significance. Based on the rule that meaningful factors should be associated with eigenvalues greater than 1.0, a two-factor solution is appropriate (Table 3). The two-dimensional structure of the BPI-IR was confirmed by scree plot (Fig. 1). In Table 3, pain interference items were highly correlated with Factor I, and pain severity items had high correlation with Factor II. Table 3 Validity and Reliability Analyses of the BPI-IR Factor Loading Variable Pain severity Pain worst Pain least Pain average Pain now Pain interference General activity Mood Walking ability Normal work Relationship Sleep Enjoyment of life Internal Consistency Factor I Factor II Corrected Item Total Correlation Alpha if Item Deleted 0.143 0.277 0.228 0.399 0.763 0.663 0.859 0.719 0.543 0.548 0.745 0.673 0.798 0.788 0.701 0.729 0.858 0.804 0.861 0.906 0.835 0.709 0.883 0.327 0.274 0.198 0.246 0.317 0.424 0.232 0.884 0.796 0.829 0.907 0.853 0.754 0.875 0.943 0.951 0.948 0.941 0.946 0.954 0.944 Cronbach’s Alpha 0.805 0.954 Vol. 54 No. 4 October 2017 Iranian Brief Pain Inventory Fig. 1. Scree plot of the eigenvalues of BPI-IR factors. BPI-IR ¼ Iranian version of the Brief Pain Inventory. These two factors explained 73.86% total variance of the BPI-IR while the first factor explained 47.58% variance, and second factor explained 26.28% (Table 4). Discussion We conclude that the BPI-IR is a valid and reliable cancer pain assessment tool in Iranian elderly with excellent internal consistency and external reliability. The BPI-IR has two factors (pain severity and pain interference). Acceptable criterion validity was observed with a high correlation between the BPI-IR score and other criteria: functional items of the SF-36, Katz’s ADL scale, the Lawton IADL scale, the CES-D, the PPQ pain experience subscale, and painrelated questions of the SDS. Many studies conducted on the validity of the BPI in different languages presented the BPI as a valid and reliable scale to assess cancer pain.7,12,17 Supporting the validity of the BPI-IR are the similarity of the factor structure of the BPI-IR with other validated language versions of the BPI7,8,12 and excellent internal consistency. Exploratory factor analysis indicates that the BPI-IR is composed of two factors similar to the original BPI8 and other language versions.11e14,16 Although much evidence found a two-factor structure for the BPI, few studies exhibited a three-factor structure including pain severity, activity interference, and mood interference.10,19,45 This difference may be due to changes in the conceptual meaning of items during translation.19 567 To our knowledge, there is no valid and reliable version of the BPI for use with geriatric patients with cancer. Mirzamani et al. found the Iranian version of the BPI to be reliable with Cronbach’s alphas of 0.89 for the interference subscale and 0.88 for the severity subscale in a hospital clinic;23 however, the study by Mirzamani et al. was about any age group (until 70 years old) and any types of pain. Considering that the BPI was initially developed to assess cancer pain,8 being original pain research among Iranian elderly with cancer is the strength of our study. Despite these differences, both studies found the Persian BPI to be a valid and reliable tool. Measures of pain interference were correlated with physical functioning, depression, and mood.9,33 Pain interference especially is a predictor of patients’ quality of life.9 In a Portuguese study, patients with more pain interference and higher levels of pain intensity had worse physical functioning and more depression.9 Older patients with cancer face functional limitations in ADL performance37,46 due to daily pain.4,47 The BPI-IR interference subscale is a measure to assess the impact of pain on function.12 In this study, the BPI was correlated with quality of life and performance status. Functional limitations were caused by pain effects on quality of life in the Norwegian version of BPI.19 We observed pain interference to be more correlated with the SF-36 physical function subscale, which was similar to the finding of Greek15 and Malaysian17 studies. Pain interference was correlated with bodily pain in the SF-36 in a German study.22 Severe pain in patients with cancer is more related to depression.48e50 In the present study, correlation between depression and the BPI-IR was assessed for concurrent validity and showed a strong correlation in the pain interference subscale. In a Korean study, higher depression scores were observed in patients with cancer with more pain.33 The original BPI can be used as a self-administered questionnaire just for highly educated adult patients,17,18 except in Vietnamese and Chinese patients.13,51 For the BPI-IR among elderly illiterate individuals, participants were asked by interviewers by showing hand fingers as a symbol of numbers on a 0e10 scale to describe pain severity. We used this method, as with the NRS, due to simplicity46 and better applicability among illiterate older participants. Table 4 Eigenvalue of Components and Percentage of Variance Explained by Each Factor Initial Eigenvalues Rotation Sums of Squared Loadings Component Total % of Variance Cumulative % Total % of Variance Cumulative % 1 2 6.769 1.356 61.538 12.326 61.538 73.864 5.234 2.891 47.580 26.284 47.580 73.864 568 Alizadeh-Khoei et al. Regarding limitations, this used a cross-sectional design that is not representative of the Iranian older cancer population, although it should be pointed out that this is the first study to look at the geriatric cancer pain validity of the BPI. Furthermore, we did not use the BPI for longitudinal evaluation and, therefore, cannot offer conclusions about the sensitivity of the BPI to changes in the analgesics. We also did not determine a cutoff point for the BPI-IR. Moreover, we did not calculate the pain management index for our patients as the adequacy of the analgesic therapy.8,17,23 Conclusions Validity and reliability of the BPI-IR was comparable to the original version for cancer pain in terms of structure and psychometric properties. The BPI-IR has two factors in which pain interference items could measure cancer pain’s impact on elderly function. Applying the BPI-IR is easy and brief to complete for assessing pain severity and interference. 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