Relationship between the Widespread Pain Index and PainMAP software for pain site measurement in patients with widespread pain (2023)

BACKGROUND AND OBJECTIVES:

Identification of the pain site is essential for the treatment of patients with diffuse pain. Various instruments have been developed, including pain drawings, a grid system, and computerized methods. However, it is still unknown if the Generalized Pain Index corresponds to an automated method (painMAP) to quantify the number of painful areas. Therefore, this study aimed to determine the relationship between the pervasive pain index and painMAP software for the measurement of pain location in participants with pervasive pain.

METHOD:

A pre-planned secondary analysis of data collected from 311 patients with musculoskeletal pain was performed. The extended pain index and painMAP software assessed pain sites. Spearman's correlation coefficient investigated the correlation between the generalized pain index and the PainMAP software.

THE RESULTS:

A total of 98 participants with widespread pain were included in this study. Most of the participants were women (67; 83.7%), with a mean age of 57.7±11.5 years, a mean height of 1.6 (0.1) meters, and a mean weight of 73.2 (11 .8) kilograms. Mean pain intensity was 6.7 (2.0) and pain duration was 92.3 (96.3) months. The mean number of pain sites in the generalized pain index was 10.1 (3.7) and in the painMAP software 11.7 (8.8). A weak positive correlation (rho = 0.26, 95% CI 0.45 to 0.04, p = 0.022) was found between the pervasive pain index and painMAP software.

CONCLUSION:

The widespread pain index and painMAP software showed poor correlation for assessment of pain location in participants with widespread pain.

Keywords:
chronic pains; fibromyalgia; Pain management; pain measurement

BACKGROUND AND OBJECTIVES:

Identification of the pain site is an important aspect in the treatment of patients with diffuse pain. Various instruments have been developed, including pain drawings, a grid system, and computerized methods. However, it is still unknown if the pain distribution index matches the automated method (painMAP) to quantify the number of painful areas. Therefore, this study aimed to identify the relationship between pain extension index andwas a MAPto measure painful areas in participants with this pain condition.

METHOD:

A pre-planned secondary analysis of data collected from 311 patients with musculoskeletal pain was performed. Pain spread index iwas a MAPevaluated the areas of pain. Spearman's correlation coefficient was used to investigate the correlation between pain spread index andsofter painMAP.

THE RESULTS:

A total of 98 participants with widespread pain were included in this study. Most of the participants were women (67; 83.7%), with a mean age of 57.7±11.5 years, a mean height of 1.6 (0.1) meters, and a mean weight of 73.2 (11 .8) kilograms. Mean pain intensity was 6.7 (2.0) and pain duration was 92.3 (96.3) months. The mean number of pain areas in the pain spread index was 10.1 (3.7), and insofter painMAPit was 11.7 (8.8). Weak positive correlation (rho=0.26, 95% CI 0.45-0.04, p=0.022) between generalized pain index andwas a MAPIt was found.

CONCLUSION:

Pain spread index iwas a MAPshowed a weak positive correlation for pain area assessment in participants with widespread pain.

Descriptor:
chronic pains; fibromyalgia; Pain management; pain measurement

Health conditions of the musculoskeletal system are a common cause of pain in the general population. Patients with musculoskeletal (DM) pain often have pain in more than one region of the body¹1 Hartvigsen J, Davidsen M, Hestbaek L, Sogaard K, Roos EM. Population patterns of musculoskeletal pain: a latent class analysis using a nationally representative survey based on 4817 Danes. Eur J Pain (United Kingdom). 2013;17(3):452-60.,²2 Carnes D, Parsons S, Ashby D, Breen A, Foster NE, Pincus T, Vogel S, Underwood M. Chronic musculoskeletal pain rarely occurs at one site in the body: results of a UK population-based study. Rheumatology. 2007;46(7):1168-70.. Chronic widespread pain (CWP) can be classified as chronic primary pain (i.e., pain in one or more regions of the body that persists or recurs for more than three months and is associated with significant emotional distress or that cannot be better explained by other chronic pain). pain disorder)³3 Treede RD, Rief W, Barke A, Aziz Q, Bennett MI, Benoliel R, Cohen M, Evers S, Finnerup NB, First MB, Giamberardino MA, Kaasa S, Kosek E, Lavand'homme P, Nicholas M, Perrot S , Scholz J , Schug S , Smith BH , Svensson P , Vlaeyen JWS , Wang SJ . ICD-11 classification records. Insect. 2015;156(6):1003-7.. In the general population, one in 10 adults has CWP⁴4 Mansfield KE, Sim J, Jordan JL, Jordan KP. A systematic review and meta-analysis of the prevalence of widespread chronic pain in the general population. Pain. 2016;157(1):55-63., which represents about 46% of all outpatient consultations in Europe⁵5 Vanhoof J, Declerck K, Geusens P. Prevalence of rheumatic diseases in outpatient rheumatology practice. Ann Rheum Dis. 2002;61(5):453-5.,⁶6 Branco JC, Bannwarth B, Failde I, Abello Carbonell J, Blotman F, Spaeth M, Saraiva F, Nacci F, Thomas E, Caubère JP, Le Lay K, Taieb C, Matucci-Cerinic M. Prevalence of fibromyalgia: a survey in five European countries. Semen Arthritis Rheum. 2010;39(6):448-53. In Brazil, 24% of women had CWP⁷7 Assumpção A, Cavalcante AB, Capela CE, Sauer JF, Chalot SD, Pereira CA, Marques A P. Prevalence of fibromyalgia in a population of low socioeconomic level. BMC musculoskeletal disorder. 2009;10:64.. Multiple pain sites are associated with greater pain intensity.⁸8 Dragioti E, Larsson B, Bernfort L, Levin LÅ, Gerdle B. A cross-sectional study of factors associated with the number of anatomical sites of pain in a real population of general older people: results from the PainS65+ cohort. Resolution of pain J. 2017;10:2009-19.,⁹9 Grimby-Ekman A, Gerdle B, Björk J, Larsson B. Comorbidities, pain intensity, frequency, and duration, daily functioning, and care-seeking in local, regional, and systemic pain: a descriptive population study (SwePain) Epidemiology of Musculoskeletal Disorders BMC Musculoskeletal Disorder. 2015;16(1):1-12., limited activities of daily living²2 Carnes D, Parsons S, Ashby D, Breen A, Foster NE, Pincus T, Vogel S, Underwood M. Chronic musculoskeletal pain rarely occurs at one site in the body: results of a UK population-based study. Rheumatology. 2007;46(7):1168-70., reduced quality of life⁸8 Dragioti E, Larsson B, Bernfort L, Levin LÅ, Gerdle B. A cross-sectional study of factors associated with the number of anatomical sites of pain in a real population of general older people: results from the PainS65+ cohort. Resolution of pain J. 2017;10:2009-19.,⁹9 Grimby-Ekman A, Gerdle B, Björk J, Larsson B. Comorbidities, pain intensity, frequency, and duration, daily functioning, and care-seeking in local, regional, and systemic pain: a descriptive population study (SwePain) Epidemiology of Musculoskeletal Disorders BMC Musculoskeletal Disorder. 2015;16(1):1-12.and poor prognosis regardless of treatment¹⁰10 Kamaleri Y, Natvig B, Ihlebaek CM, Bruusgaard D. Localized or generalized musculoskeletal pain: does it matter? Pain. 2008;138(1):41-6.. Therefore, the identification of patients with widespread pain (WP) is crucial to help clinicians and researchers offer appropriate treatment approaches.

There are several instruments available to assess the distribution of pain. Pain plotting is one of the strategies most used by health professionals to quantify the distribution of pain.¹¹11 Barbero M, Moresi F, Leoni D, Gatti R, Egloff M, Falla D. Test-retest reliability of pain extent and location using a new method to analyze pain pictures. Eur J Pain. 2015;19(8):1129-38.,¹²12 dos Reis FJJ, de Barros e Silva V, de Lucena RN, Mendes Cardoso BA, Nogueira LC. Pain area measurement: an intra- and inter-examiner reliability study using image analysis software. Practice hurts. 2016;16(1):24-30.. Several studies related to the reliability of measuring the distribution and location of pain have used pain designs.¹³13 Southerst D, Côté P, Stupar M, Stern P, Mior S. Reliability of body pain diagrams in the quantitative measurement of pain distribution and location in patients with musculoskeletal pain: a systematic review. J Physiol Ther Manipulator. 2013;36(7):450-9.,¹⁴14 Ohnmeiss DD. Reproducibility of pain drawings in the population with low back pain. Column. 2000;25(8):980-8.,¹⁵15 Margolis RB, Chibnall JT, Tait RC. Test-retest reliability of the pain design instrument. Pain. 1988;33(1):49-51.,^sixteen16 Beattie PF, Meyers SP, Stratford P, Millard RW, Hollenberg GM. Associations between patient-reported symptoms and anatomical compromise seen on lumbar MRI. Column. 2000;25(7):819-28.,¹⁷17 Triffitt DP. Reproducibility of the pain site diagram. J Musculoskeletal pain. 2002;10(3):83-90.,¹⁸18 Persson AL, Garametsos S, Pedersen J. Computer-assisted assessment of the drawing area of ​​pain: intra- and inter-rater reliability. Resolution of pain J. 2011;4:135-41.,¹⁹19 Corrêa LA, Bittencourt JV, Ferreira A de S, Reis FJJ dos, de Almeida RS, Nogueira LAC. Reliability and concurrent validity of the PainMAP software for the automated quantification of pain patterns on the body map of patients with low back pain. Practice hurts. 2020;20(5):462-70.. The total area of ​​the body surface that hurts and the anatomical location of the pain are commonly measured by clinicians and researchers.¹³13 Southerst D, Côté P, Stupar M, Stern P, Mior S. Reliability of body pain diagrams in the quantitative measurement of pain distribution and location in patients with musculoskeletal pain: a systematic review. J Physiol Ther Manipulator. 2013;36(7):450-9.. networking system²⁰20 Margolis RB, Tait RC, Krause SJ. A classification system for use with patient pain drawings. Pain. 1986;24(1):57-65.and computerized assessment of pain site scores¹¹11 Barbero M, Moresi F, Leoni D, Gatti R, Egloff M, Falla D. Test-retest reliability of pain extent and location using a new method to analyze pain pictures. Eur J Pain. 2015;19(8):1129-38.,¹²12 dos Reis FJJ, de Barros e Silva V, de Lucena RN, Mendes Cardoso BA, Nogueira LC. Pain area measurement: an intra- and inter-examiner reliability study using image analysis software. Practice hurts. 2016;16(1):24-30.,¹⁹19 Corrêa LA, Bittencourt JV, Ferreira A de S, Reis FJJ dos, de Almeida RS, Nogueira LAC. Reliability and concurrent validity of the PainMAP software for the automated quantification of pain patterns on the body map of patients with low back pain. Practice hurts. 2020;20(5):462-70.. Although pain location assessment can be performed with reliable and valid instruments such as ImageJ software¹²12 dos Reis FJJ, de Barros e Silva V, de Lucena RN, Mendes Cardoso BA, Nogueira LC. Pain area measurement: an intra- and inter-examiner reliability study using image analysis software. Practice hurts. 2016;16(1):24-30., it is worth noting that these instruments are challenging for participants and represent a lengthy evaluation for clinicians.

The instruments chosen by clinicians and researchers to assess the location of pain must be simple, light, fast, and inexpensive. In this sense, the generalized pain index (WPI) was designed to assess the distribution of pain according to the number of body parts with reported pain. The WPI is a list of self-reported pain consisting of 19 body parts.²¹21 Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Häuser W, Katz RL, Mease PJ, Russell AS, Russell IJ, Walitt B. 2016 Reviews of two diagnostic criteria for fibromyalgia 2010/2011. Semen Arthritis Rheum. 2016;46(3):319-29.and demonstrated good construct and criterion validity among young patients with painful conditions.²²22 Dudeney J, Law EF, Meyyappan A, Palermo TM, Rabbitts JA. Evaluation of the psychometric properties of the Generalized Pain Index and the Symptom Severity Scale in young people with painful conditions. Can J Bull. 2019;3(1):137-47.. The WPI is a clear, well-organized and inexpensive instrument compared to the Regional Pain Scale.²³23 Wolfe F. Extension and diagnosis of pain: development and validation of a regional pain scale in 12,799 patients with rheumatic disease. J Rheumatol. 2003;30(2):369-78.and the Pain Self-Assessment Scale²⁴24 Salaffi F, Sarzi-Puttini P, Girolimetti R, Gasparini S, Atzeni F, Grassi W. Development and validation of self-reported fibromyalgia assessment status: a disease-specific composite measure to assess treatment effect. Arthritis Res Ther. 2009;11(4):1-12.determine the places of pain. WPI has been used in patients with chronic pain²⁵25 Wasserman RA, Brummett CM, Goesling J, Tsodikov A, Hassett AL. Characteristics of chronic pain patients taking opioids who report persistently high-intensity pain. Reg Anesth Dolor Med. 2014;39(1):13-7.,²⁶26 Walters JL, Baxter K, Chapman H, Jackson T, Sethuramachandran A, Couldridge M, Joshi HR, Kundra P, Liu X, Nair D, Sullivan B, Shotwell MS, Jense RJ, Kassebaum NJ, McQueen KAK. Chronic pain and associated factors in India and Nepal: a pilot study of the Vanderbilt Global Pain Survey. Analgesic Anesth. 2017;125(5):1616-26., surgical specimens²⁷27 Brummett CM, Urquhart AG, Hassett AL, Tsodikov A, Hallstrom BR, Wood NI, Williams DA, Clauw DJ. Fibromyalgia characteristics independently predict worse long-term analgesic outcomes after total knee and hip arthroplasty. Rheumatoid arthritis. 2015;67(5):1386-94.and youth with painful conditions²²22 Dudeney J, Law EF, Meyyappan A, Palermo TM, Rabbitts JA. Evaluation of the psychometric properties of the Generalized Pain Index and the Symptom Severity Scale in young people with painful conditions. Can J Bull. 2019;3(1):137-47..

However, the WPI can be confusing for participants who are not used to instrument terminology for body site, and a body diagram is likely to help the participant visualize pain sites. On the other hand, painMAP software was developed to quantify the number of pain sites and areas, with excellent inter- and intra-rater reliability in patients with low back pain.¹⁹19 Corrêa LA, Bittencourt JV, Ferreira A de S, Reis FJJ dos, de Almeida RS, Nogueira LAC. Reliability and concurrent validity of the PainMAP software for the automated quantification of pain patterns on the body map of patients with low back pain. Practice hurts. 2020;20(5):462-70.. No study has evaluated the correlation between the WPI and a computerized method for the evaluation of painful sites. Therefore, this study aimed to identify the relationship between the WPI and the painMAP software for measuring pain sites in participants with WP. This study hypothesized that painMAP would be positively correlated with the WPI for measuring pain location in WP participants.

In this study, a pre-planned secondary analysis of data collected from a previous study of the same group was carried out.²⁸28 Bittencourt JV, Bezerra MC, Pina MR, Reis FJJ, de Sá Ferreira A, Nogueira LAC. Use of painDETECT to differentiate musculoskeletal pain phenotypes. Arch physiotherapist. 2022;12(1):1-8.. The current study is a cross-sectional study following the STRengthening the Reporting of Observational Studies in Epidemiology (STROBE) requirements.²⁹29 Von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke J P. Statement on Strengthening Reporting of Observational Studies in Epidemiology (STROBE): Guidelines for Reporting Observational Studies. Brochure of the World Health Organization. 2007;85(11):867-72.. Likewise, the original research was cross-sectional and followed the STROBE criteria.²⁹29 Von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke J P. Statement on Strengthening Reporting of Observational Studies in Epidemiology (STROBE): Guidelines for Reporting Observational Studies. Brochure of the World Health Organization. 2007;85(11):867-72.. The original study enrolled 311 participants with PM to compare pain characteristics classified by the painDETECT questionnaire as nociceptive, vague pain, and neuropathic-type symptoms.²⁸28 Bittencourt JV, Bezerra MC, Pina MR, Reis FJJ, de Sá Ferreira A, Nogueira LAC. Use of painDETECT to differentiate musculoskeletal pain phenotypes. Arch physiotherapist. 2022;12(1):1-8.. The original study included participants with PM (over 18 years of age), with acute pain (pain lasting less than three months), and chronic pain (pain lasting more than three months). PM is defined as pain perceived in a part of the body that originates in muscles, ligaments, bones, or joints. The original study excluded participants who had undergone spinal surgery, pregnant women, patients diagnosed with rheumatology in the acute inflammatory phase, tumors, illiterate, or those who could not complete the self-assessment questionnaires.

This study excluded 213 participants with MP without WP and had a final sample of 98 patients with WP. The original study was approved by the Research Ethics Committee of the Federal Institute of Rio de Janeiro (number: 02228818.0.3001.5258) following the Declaration of Helsinki for research in humans. All patients met the eligibility criteria and signed an Informed Consent Form (TCLE) prior to study procedures.

study participants

Consecutive participants with WP (over 18 years of age) from two physiotherapy clinics (Hospital Universitário Gaffrée e Guinle and Centro Universitário Augusto Motta), two private clinics and one multidisciplinary rehabilitation clinic (Centro de Reabilitação de Cabo Frio) in the state of Rio de Janeiro, Brazil, were included when they sought treatment between March and September 2019. The study included participants with WP (n = 98). Of these, 18 participants were excluded because they colored the area with red and blue pencils (n=11), only with blue pencils (n=2), because they did not respect the limits of the body diagram (n=1) or because the sites of pain were not recognized by the painMAP software (n=4).

Thus, 80 participants with WP were included. Although the term "pervasive pain" is widely used²¹21 Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Häuser W, Katz RL, Mease PJ, Russell AS, Russell IJ, Walitt B. 2016 Reviews of two diagnostic criteria for fibromyalgia 2010/2011. Semen Arthritis Rheum. 2016;46(3):319-29., this study selected W P, following the recent classification of chronic pain for the International Classification of Diseases (ICD-11)³⁰30 Treede RD, Rief W, Barke A, Aziz Q, Bennett MI, Benoliel R, Cohen M, Evers S, Finnerup NB, First MB, Giamberardino MA, Kaasa S, Korwisi B, Kosek E, Lavender P, Nicholas M, Perrot [ PubMed ] [ Cross Ref ] Scholz S, Scholz J, Schug S, Smith BH, Svensson P, Vlaeyen JWS, Wang SJ. Chronic pain as a symptom or disease: the IASP classification of chronic pain for the International Classification of Diseases (ICD-11). Pain. 2019;160(1):19-2. Widespread pain was defined when the participant reported pain in at least 4 of 5 regions (upper left and right, lower left and right, and axial) on the WPI. Pain in the jaw, chest, and abdomen are not included in the definition of WP²¹21 Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Häuser W, Katz RL, Mease PJ, Russell AS, Russell IJ, Walitt B. 2016 Reviews of two diagnostic criteria for fibromyalgia 2010/2011. Semen Arthritis Rheum. 2016;46(3):319-29.. Participants who had undergone spinal surgery in the last year, pregnant women, participants with rheumatological diagnoses in the acute inflammatory phase, with tumors, people who were illiterate or who were unable to complete the self-examination questionnaires were excluded from the study.

procedures

Participants were referred for an initial evaluation of the medical history and physical examination. WPI assessed weaknesses at the time of the assessment. After that, the examiner calculated the number of painful sites and areas using the painMAP software.

outcome measures

The WPI is a self-reported list of regions of pain consisting of 19 body parts, and participants are asked to mark the areas where they have felt pain in the past week. Each marked area is worth 1 point. The final score varies between zero and 19 points. The American College of Rheumatology criteria recognize a participant as having WP when the participant reports pain in at least 4 of 5 regions (upper left and right, lower left and right, and axial) on the WPI. Pain in the jaw, chest, and abdomen are not included in the definition of WP²¹21 Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Häuser W, Katz RL, Mease PJ, Russell AS, Russell IJ, Walitt B. 2016 Reviews of two diagnostic criteria for fibromyalgia 2010/2011. Semen Arthritis Rheum. 2016;46(3):319-29.. The psychometric assessment of the WPI demonstrated good construct and criterion validity among young patients with painful conditions.²²22 Dudeney J, Law EF, Meyyappan A, Palermo TM, Rabbitts JA. Evaluation of the psychometric properties of the Generalized Pain Index and the Symptom Severity Scale in young people with painful conditions. Can J Bull. 2019;3(1):137-47..

PainMAP software is an automated image processing tool for quantifying the number of pain sites and areas from pain drawings on digitized body maps. painMAP software processes scanned body graphics into image calibration and object detection without user intervention¹⁹19 Corrêa LA, Bittencourt JV, Ferreira A de S, Reis FJJ dos, de Almeida RS, Nogueira LAC. Reliability and concurrent validity of the PainMAP software for the automated quantification of pain patterns on the body map of patients with low back pain. Practice hurts. 2020;20(5):462-70.. The body diagram consisted of a 10 x 10 cm printed image (head-to-toe distance: 6.7 cm) containing two views (front and back), as shown in the figure.Photo 1.

Participants were asked to identify painful areas on a body map using a red pen during the clinical assessment (Figure 2). Pain drawings were excluded from the study if the participant did not complete the body area correctly (ie, colored the area with red and blue pencils or only blue pencils or did not respect the boundaries of the body charts). The validity of the shaded pain and exclusion points was assessed by an examiner (JVB) with four years of professional experience in the treatment of patients with MP. For pragmatic evaluation, all body diagrams were photographed once by a single examiner (JVB) using a smartphone (Motorola G5). For offline analysis, all scanned images were stored as JPEG files (resolution set to 72 DPI).

Sample's size calculation

Sample size calculations assumed a two-sided correlation test, a type I error rate of 0.05 (5%), and a power of 95%, taking painful sites as the unit of analysis. In addition, a minimum Pearson correlation coefficient of 0.4 between the WPI and painMAP pain site software was selected to determine a sufficient sample size. Therefore, a total of 75 WP participants were required. Ninety-eight WP participants were recruited, assuming possible loss of data. The sample size was calculatedFirstin G*Power software version 3.1.9.4 (Heinrich Heine University, Düsseldorf, Germany).

statistic analysis

The demographic (age, sex, weight, and height) and clinical (pain intensity and duration) variables of the study participants were summarized descriptively. Paired samples t-tests were used to compare the mean differences between the WPI and painMAP software. Categorical variables are presented in absolute frequency and sample proportion, and continuous variables in mean value and standard deviation (SD). For continuous variables, the normal distribution of results was confirmed using the Shapiro-Wilk test.

Due to the non-normal distribution of the data, Spearman's correlation was used. Spearman's correlations (rho) evaluated the relationship between WPI and the painMAP software. Rho < 0.30 was interpreted as weak correlation, 0.30 to 0.60 as moderate correlation, and ≥ 0.60 as good correlation.³¹31 Fleiss JL. Planning and analysis of clinical trials. John Wiley and sons; 2011. 432 pp.. Outliers were excluded using the ROUT method with Q = 1.0%³²32 Motulsky HJ, Brown RE. Outlier detection in data fitting with nonlinear regression: a new method based on robust nonlinear regression and a false discovery rate. BMC Bioinformatics. 2006;7(1):1-20.. Statistical evidence for the significance level was defined as less than 5% for all analyses. Statistical analysis was performed using JASP (version 0.16.1) and Prism for Macintosh, version 8 (GraphPad Software Inc., San Diego, CA).

Participant characteristics

Eight participants with WP were included in this study, 67 (83.7%) women, mean age 57.7 (11.5) years, mean body height 1.6 (0.1) meters, mean weight 73.2 ( 11.8) kg, average body mass index 27.6 ( 6.8) kg/m². More than half (56.9%) of WP participants indicated elementary school as their highest level of education, 20.2% indicated secondary school, and 18.9% indicated higher education. Regarding the characteristics of pain, the mean pain intensity at that time was 6.7 (2.3) out of 10, the highest pain level in the last 4 weeks was 8.3 (2.0). out of 10, the average pain level in the previous 4 weeks was 7.3 ( 2.0) out of 10, and the duration of pain was 92.4 (96.3) months. In addition, 71 (88.7%) participants with WP were classified as having chronic WP, 6 (7.5%) were classified as having acute WP, and 3 (3.7%) did not report pain duration.

The results of the analysis of pain sites reported by WP participants revealed that the mean number of pain sites on the WPI was 10.2 (3.7); the most pronounced regions in WPI were: upper back (81.2%), lower back (81.2%), right shoulder (81.2%), neck (73.7%), flank right (68.7%), left side (66.2%), left leg (63.7%), right leg (62.5%) and left and right hand (53.7%). Data from the painMAP software showed that the mean number of pain zones marked by the participants was 11.7 (8.8) and the mean area of ​​pain in the painMAP software was 0.8 (1.1). In addition, a paired samples t-test showed that there was no significant difference between the average pain sites assessed on the WPI 10.2 (3.7) and the average pain sites observed on the painMAP software were 11.7 (8.8) (W = 1316,500; z = −0.758, p = 0.449) (tabla 1).

Spearman's correlation coefficient analysis showed a weak positive correlation between the WPI and the painMAP pain localization software in participants with WP (rho = 0.26, 95% CI 0.45 to 0.04, p = 0.022) (figure 3).

This study showed a relationship between the number of pain sites in WPI and the painMAP software in patients with W P. When comparing the two instruments in terms of mean pain sites, similar results were found for both the WPI software and the painMAP software. painMAP. However, the results of this study revealed a weak correlation between WPI and the painMAP software for the number of pain sites. Pain drawings are often used in clinical practice to clarify the number of pain sites. Although it is necessary to determine the number of pain sites, healthcare providers should consider other relevant information when treating patients with WP. For example, the painMAP software can provide a total area of ​​pain that cannot be found on a simple pain drawing.

In terms of strengths and limitations, this study is the first to evaluate the relationship between the WPI and computerized pain localization methods in patients with WP. Second, painMAP software is more detailed compared to WPI (for example, while WPI recognizes only the upper left arm region, painMAP software can identify some regions on the left arm, such as anterior and posterior, medial, and lateral , proximal and distal). ) . Third, downloadable automated software (ie painMAP) can facilitate clinical use. In addition, the painMAP software is a user-friendly feature and does not require user involvement for image processing/analysis, an expert, and does not require much training to review the image.

Regarding the limitations of the study, the main one is that there is no gold standard instrument to identify the location of pain. Second, the clinical diagnosis of the included patients was not controlled and may influence the response at the pain site. Furthermore, caution is needed when generalizing the results because the results of this research need to be tested in different populations. Therefore, more studies are needed that include samples from more patients with other conditions. Finally, precise instructions are needed to properly guide participants in completing the body map, as the painMAP software may incorrectly account for colored areas (eg, outside the body map).

The findings of this study showed a weak correlation between the two methods, which is in contrast to a previous study that reported a strong correlation between similar measures of pain.³³33 Wallace MS, North J, Grigsby EJ, Kapural L, Sanapati MR, Smith SG, Willoughby C, McIntyre PJ, Cohen SP, Rosenthal RM, Ahmed S, Vallejo R, Ahadian FM, Yearwood TL, Burton AW, Frankoski EJ, Shetake J, Lin S, Hershey B, Rogers B, Mekel-Bobrov N. An integrated quantitative index to measure chronic pain at multiple sites: the multiple area pain (MAP) study. Pain medicine. 2018;19(7):1425-35.. Another study showed that a greater number of pain sites on the WPI was associated with a greater number of pain sites on the body diagram (r = 0.57, p < 0.001) in young patients with pain conditions.²²22 Dudeney J, Law EF, Meyyappan A, Palermo TM, Rabbitts JA. Evaluation of the psychometric properties of the Generalized Pain Index and the Symptom Severity Scale in young people with painful conditions. Can J Bull. 2019;3(1):137-47.. Likewise, there is a strong correlation between the painMAP software and the ImageJ software for the number of pain sites (R²=0.985) and pain area domains (R²=0.952) in the body maps of patients with low back pain.¹⁹19 Corrêa LA, Bittencourt JV, Ferreira A de S, Reis FJJ dos, de Almeida RS, Nogueira LAC. Reliability and concurrent validity of the PainMAP software for the automated quantification of pain patterns on the body map of patients with low back pain. Practice hurts. 2020;20(5):462-70..

The health condition studied (ie, WP) may have influenced the findings of this study due to the nature of the large number of painful sites reported by each participant. Presumably, more localized pain (eg knee osteoarthritis) may show a stronger correlation between the instruments (WPI and pain-MAP software). Also, both devices measure painful regions, but in a different way. For example, a body region tagged in WPI may have more than one tag in the PainMAP software. Also, WPI does not show options for specific areas like wrist, ankle, and foot. Therefore, categorization of pain location using the WPI is likely to miss information and underestimate pain assessment in WP patients.

Evidence suggests that patients with chronic pain may have a distorted body image (ie they tend to perceive the area of ​​the body that hurts as enlarged or reduced).³⁴34 Senkowski D, Heinz A. Chronic pain and distorted body image: implications for multisensory feedback interventions. Neurosci Biobehav Rev. 2016;69:252-9.,³⁵35 Moseley GL. Distorted body image in complex regional pain syndrome. Neurology. 2005;65(5):773.,³⁶36 Moseley GL. I can not find! Distorted body image and tactile dysfunction in patients with chronic low back pain. Pain. 2008;140(1):239-43.,³⁷37 Lewis JS, Kersten P, McCabe CS, McPherson KM, Blake DR. Body perception disorder: contribution to pain in complex regional pain syndrome (CRPS). Pain. 2007;133(1-3):111-9.. Body image was negatively associated with pain intensity in men with chronic pain (ie, rheumatoid arthritis and low back pain).³⁸38 Rzeszutek M, Oniszczenko W, Schier K, Biernat-Kałuża E, Gasik R. Gender differences in trauma symptoms, body image, and pain intensity in a Polish sample of chronic pain patients. Psychological Health Med. 2016;21(7):827-35.. Chronic LBP patients had a more negative body image than subacute LBP patients and healthy control subjects.³⁹39 Levenig CG, Kellmann M, Kleinert J, Belz J, Hesselmann T, Hasenbring MI. Body image is more negative in chronic low back pain patients than in subacute low back pain patients and healthy control groups. Scan JPanel. 2019;19(1):147-56.. Furthermore, patients with chronic WP reported significantly more comorbidities and psychosomatic symptoms than patients with local chronic low back pain.⁴⁰40 Viniol A, Jegan N, Leonhardt C, Brugger M, Strauch K, Barth J, Baum E, Becker A. Differences between patients with chronic generalized pain and chronic local low back pain in primary care: a comparative cross-sectional analysis. BMC musculoskeletal disorder. 2013;14:351.common type of CLP, in primary health care institutions. METHODS: Fifty-eight German general practitioners (general practitioners. Presumably, patients with chronic pain conditions have different impairments that can alter the pattern of body pain.

Clinicians should be aware of the use of other computational methods that can provide valuable information beyond the number of pain sites. Future research should evaluate the relationship between different approaches to assess the location and area of ​​pain. Pain measures have been widely used in WP, but many aspects of the measurement properties can be improved. For example, measures of pain intensity have low or very low quality evidence for content validity in patients with low back pain, and there is no instrument with superior measurement properties.⁴¹41 Chiarotto A, Maxwell LJ, Ostelo RW, Boers M, Tugwell P, Terwee CB. Measurement properties of the visual analogue scale, numerical rating scale, and pain intensity subscale of the Brief Pain Inventory in patients with low back pain: a systematic review. Dor J. 2019;20(3):245-63..

The WPI and painMAP software showed a weak correlation in the evaluation of the number of painful sites in patients with WP.