{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T12:33:06Z","timestamp":1791981186865,"version":"4.4.0"},"reference-count":54,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,12,31]],"date-time":"2020-12-31T00:00:00Z","timestamp":1609372800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004587","name":"Instituto de Salud Carlos III","doi-asserted-by":"publisher","award":["CPII19\/00003"],"award-info":[{"award-number":["CPII19\/00003"]}],"id":[{"id":"10.13039\/501100004587","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000069","name":"National Institute of Arthritis and Musculoskeletal and Skin Diseases","doi-asserted-by":"publisher","award":["U01AR55069-01"],"award-info":[{"award-number":["U01AR55069-01"]}],"id":[{"id":"10.13039\/100000069","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000069","name":"National Institute of Arthritis and Musculoskeletal and Skin Diseases","doi-asserted-by":"publisher","award":["1K01AR064275"],"award-info":[{"award-number":["1K01AR064275"]}],"id":[{"id":"10.13039\/100000069","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Fibromyalgia (FM) is a heterogeneous and complex syndrome; different studies have tried to describe subgroups of FM patients, and a 4-cluster classification based on the Fibromyalgia Impact Questionnaire-Revised (FIQR) has been recently validated. This study aims to cross-validate this classification in a large US sample of FM patients. A pooled sample of 6280 patients was used. First, we computed a hierarchical cluster analysis (HCA) using FIQR scores at item level. Then, a latent profile analysis (LPA) served to confirm the accuracy of the taxonomy. Additionally, a cluster calculator was developed to estimate the predicted subgroup using an ordinal regression analysis. Self-reported clinical measures were used to examine the external validity of the subgroups in part of the sample. The HCA yielded a 4-subgroup distribution, which was confirmed by the LPA. Each cluster represented a different level of severity: \u201cMild\u2013moderate\u201d, \u201cmoderate\u201d, \u201cmoderate\u2013severe\u201d, and \u201csevere\u201d. Significant differences between clusters were observed in most of the clinical measures (e.g., fatigue, sleep problems, anxiety). Interestingly, lower levels of education were associated with higher FM severity. This study corroborates a 4-cluster distribution based on FIQR scores to classify US adults with FM. The classification may have relevant clinical implications for diagnosis and treatment response.<\/jats:p>","DOI":"10.3390\/ijerph18010247","type":"journal-article","created":{"date-parts":[[2020,12,31]],"date-time":"2020-12-31T10:10:37Z","timestamp":1609409437000},"page":"247","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Subgrouping a Large U.S. Sample of Patients with Fibromyalgia Using the Fibromyalgia Impact Questionnaire-Revised"],"prefix":"10.3390","volume":"18","author":[{"given":"Adri\u00e1n","family":"P\u00e9rez-Aranda","sequence":"first","affiliation":[{"name":"Department of Basic, Evolutive and Educational Psychology, Faculty of Psychology, Universitat Aut\u00f2noma de Barcelona, 08193 Cerdanyola del Vall\u00e9s, Spain"},{"name":"AGORA Research Group, Teaching, Research &amp; Innovation Unit, Parc Sanitari Sant Joan de D\u00e9u, 08830 St. Boi de Llobregat, Spain"},{"name":"Institute of Neuropsychiatry and Addictions, Hospital del Mar, 08003 Barcelona, Spain"},{"name":"Centro de Investigaci\u00f3n en Red de Salud Mental, CIBERSAM, 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2810-7670","authenticated-orcid":false,"given":"Albert","family":"Feliu-Soler","sequence":"additional","affiliation":[{"name":"Department of Basic, Evolutive and Educational Psychology, Faculty of Psychology, Universitat Aut\u00f2noma de Barcelona, 08193 Cerdanyola del Vall\u00e9s, Spain"},{"name":"AGORA Research Group, Teaching, Research &amp; Innovation Unit, Parc Sanitari Sant Joan de D\u00e9u, 08830 St. Boi de Llobregat, Spain"},{"name":"Institut de Recerca Sant Joan de D\u00e9u, 08950 Esplugues de Llobregat, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7992-5345","authenticated-orcid":false,"given":"Scott D.","family":"Mist","sequence":"additional","affiliation":[{"name":"Fibromyalgia Research and Treatment Group, Department of Anesthesiology &amp; Perioperative Medicine, Oregon Health &amp; Science University, Portland, OR 97239, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kim D.","family":"Jones","sequence":"additional","affiliation":[{"name":"School of Nursing, Linfield University and School of Medicine, Oregon Health &amp; Science University, Portland, OR 97239, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1690-4130","authenticated-orcid":false,"given":"Yolanda","family":"L\u00f3pez-Del-Hoyo","sequence":"additional","affiliation":[{"name":"Department of Psychology and Sociology, Univesity of Zaragoza, 50001 Zaragoza, Spain"},{"name":"Instituto de Investigaci\u00f3n Sanitaria Arag\u00f3n, 50009 Zaragoza, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rebeca","family":"Oliv\u00e1n-Ar\u00e9valo","sequence":"additional","affiliation":[{"name":"AGORA Research Group, Teaching, Research &amp; Innovation Unit, Parc Sanitari Sant Joan de D\u00e9u, 08830 St. Boi de Llobregat, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Kratz","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI 48109, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David A.","family":"Williams","sequence":"additional","affiliation":[{"name":"Departments of Anesthesiology, Internal Medicine, Psychiatry, and Psychology, University of Michigan, Ann Arbor, MI 48109, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0750-1599","authenticated-orcid":false,"given":"Juan V.","family":"Luciano","sequence":"additional","affiliation":[{"name":"AGORA Research Group, Teaching, Research &amp; Innovation Unit, Parc Sanitari Sant Joan de D\u00e9u, 08830 St. Boi de Llobregat, Spain"},{"name":"Institut de Recerca Sant Joan de D\u00e9u, 08950 Esplugues de Llobregat, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1002\/art.1780330203","article-title":"The american college of rheumatology 1990 criteria for the classification of fibromyalgia","volume":"33","author":"Wolfe","year":"1990","journal-title":"Arthritis Rheum."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"15022","DOI":"10.1038\/nrdp.2015.22","article-title":"Fibromyalgia","volume":"1","author":"Ablin","year":"2015","journal-title":"Nat. Rev. Dis. Prim."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"R127","DOI":"10.1186\/ar3432","article-title":"Postural control deficits in people with fibromyalgia: A pilot study","volume":"13","author":"Jones","year":"2011","journal-title":"Arthritis Res. Ther."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1097\/PSY.0000000000000161","article-title":"Mood and Anxiety Disorders in Chronic Fatigue Syndrome, Fibromyalgia, and Irritable Bowel Syndrome","volume":"77","author":"Janssens","year":"2015","journal-title":"Psychosom. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"T93","DOI":"10.1016\/j.jpain.2016.06.002","article-title":"Overlapping Chronic Pain Conditions: Implications for Diagnosis and Classification","volume":"17","author":"Maixner","year":"2016","journal-title":"J. Pain"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2388","DOI":"10.1001\/jama.292.19.2388","article-title":"Management of fibromyalgia syndrome","volume":"292","author":"Goldenberg","year":"2004","journal-title":"J. Am. Med. Assoc."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1991","DOI":"10.3899\/jrheum.100104","article-title":"Efficacy of cognitive-behavioral therapies in fibromyalgia syndrome\u2014A systematic review and metaanalysis of randomized controlled trials","volume":"37","author":"Bernardy","year":"2010","journal-title":"J. Rheumatol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"955","DOI":"10.1136\/annrheumdis-2011-201249","article-title":"Comparative efficacy of pharmacological and non-pharmacological interventions in fibromyalgia syndrome: Network meta-analysis","volume":"72","author":"Bernardy","year":"2013","journal-title":"Ann. Rheum. Dis."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/j.pain.2009.05.014","article-title":"Treatment of fibromyalgia syndrome with gabapentin and pregabalin\u2014A meta-analysis of randomized controlled trials","volume":"145","author":"Bernardy","year":"2009","journal-title":"Pain"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2508","DOI":"10.1097\/j.pain.0000000000001655","article-title":"A randomized controlled efficacy trial of mindfulness-based stress reduction compared with an active control group and usual care for fibromyalgia: The EUDAIMON study","volume":"160","author":"McCracken","year":"2019","journal-title":"Pain"},{"key":"ref_11","first-page":"908","article-title":"Clustering a large Spanish sample of patients with fibromyalgia using the FIQR","volume":"160","author":"Calandre","year":"2019","journal-title":"Pain"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"677","DOI":"10.1007\/s10067-011-1912-1","article-title":"Delineating psychological and biomedical profiles in a heterogeneous fibromyalgia population using cluster analysis","volume":"31","author":"Loevinger","year":"2012","journal-title":"Clin. Rheumatol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1007\/s00296-008-0722-5","article-title":"Fibromyalgia subgroups: Profiling distinct subgroups using the Fibromyalgia Impact Questionnaire. A preliminary study","volume":"29","author":"Goffaux","year":"2009","journal-title":"Rheumatol. Int."},{"key":"ref_14","first-page":"728","article-title":"The fibromyalgia impact questionnaire: Development and validation","volume":"18","author":"Burckhardt","year":"1991","journal-title":"J. Rheumatol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1889","DOI":"10.1093\/rheumatology\/ker203","article-title":"Suicide attempts and risk of suicide in patients with fibromyalgia: A survey in Spanish patients","volume":"50","author":"Calandre","year":"2011","journal-title":"Rheumatology"},{"key":"ref_16","first-page":"273","article-title":"Subtypes of patients with fibromyalgia, psychopathological characteristics and quality of life","volume":"39","author":"Keller","year":"2011","journal-title":"Actas Espa\u00f1olas Psiquiatr."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1571","DOI":"10.1007\/s00296-014-3007-1","article-title":"Profiles in fibromyalgia: Algometry, auditory evoked potentials and clinical characterization of different subtypes","volume":"34","year":"2014","journal-title":"Rheumatol. Int."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"R120","DOI":"10.1186\/ar2783","article-title":"The Revised Fibromyalgia Impact Questionnaire (FIQR): Validation and psychometric properties","volume":"11","author":"Bennett","year":"2009","journal-title":"Arthritis Res. Ther."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"279","DOI":"10.2147\/JPR.S100829","article-title":"Identifying the symptom and functional domains in patients with fibromyalgia: Results of a cross-sectional Internet-based survey in Italy","volume":"9","author":"Salaffi","year":"2016","journal-title":"J. Pain Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1016\/j.jpain.2015.02.008","article-title":"Development and initial validation of a brief self-report measure of cognitive dysfunction in fibromyalgia","volume":"16","author":"Kratz","year":"2015","journal-title":"J. Pain"},{"key":"ref_21","first-page":"304","article-title":"Fibromyalgia Impact and Mindfulness Characteristics in 4986 People with Fibromyalgia","volume":"11","author":"Jones","year":"2015","journal-title":"Explor. J. Sci. Health"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1682","DOI":"10.1002\/acr.22034","article-title":"Dimensionality, reliability, and validity of the revised fibromyalgia impact questionnaire in two spanish samples","volume":"65","author":"Luciano","year":"2013","journal-title":"Arthritis Care Res."},{"key":"ref_23","unstructured":"Chapman, C.R., and Loeser, J.D. (1989). Measurement of Pain by Subjective Report. Issues in Pain Measurement, Raven Press."},{"key":"ref_24","first-page":"129","article-title":"Pain assessment: Global use of the Brief Pain Inventory","volume":"23","author":"Cleeland","year":"1994","journal-title":"Ann. Acad. Med. Singap."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1111\/j.1600-0447.1983.tb09716.x","article-title":"The Hospital Anxiety and Depression Scale","volume":"67","author":"Zigmond","year":"1983","journal-title":"Acta Psychiatr. Scand."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"32","DOI":"10.3399\/bjgp08X263794","article-title":"Psychometric comparison of PHQ-9 and HADS for measuring depression severity in primary care","volume":"58","author":"Cameron","year":"2008","journal-title":"Br. J. Gen. Pract."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1080\/01688639408402620","article-title":"Development and Validation of a Multiple Ability Self-Report Questionnaire","volume":"16","author":"Seidenberg","year":"1994","journal-title":"J. Clin. Exp. Neuropsychol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1016\/j.yebeh.2012.11.001","article-title":"Awareness, overestimation, and underestimation of cognitive functions in epilepsy","volume":"26","author":"Giovagnoli","year":"2013","journal-title":"Epilepsy Behav."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/0022-3999(94)00125-O","article-title":"The multidimensional Fatigue Inventory (MFI) psychometric qualities of an instrument to assess fatigue","volume":"39","author":"Smets","year":"1995","journal-title":"J. Psychosom. Res."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Stewart, A., and Ware, J. (1992). Sleep Measures. Measuring Functioning and Well-Being: The Medical Outcomes Study Approach, Duke University Press.","DOI":"10.7249\/CB361"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"S184","DOI":"10.1002\/art.11409","article-title":"Measures of sleep: The Insomnia Severity Index, Medical Outcomes Study (MOS) Sleep Scale, Pittsburgh Sleep Diary (PSD), and Pittsburgh Sleep Quality Index (PSQI)","volume":"49","author":"Smith","year":"2003","journal-title":"Arthritis Rheum."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"81","DOI":"10.2333\/bhmk.29.81","article-title":"Beyond SEM: General latent variable modeling","volume":"29","year":"2002","journal-title":"Behaviormetrika"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Harrell, F.E. (2001). Ordinal Logistic Regression, Springer.","DOI":"10.1007\/978-1-4757-3462-1_13"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"276","DOI":"10.11613\/BM.2012.031","article-title":"Interrater reliability: The kappa statistic","volume":"22","author":"McHugh","year":"2012","journal-title":"Biochem. Med."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1005","DOI":"10.1007\/s00296-007-0403-9","article-title":"The classification of fibromyalgia syndrome","volume":"27","author":"Schneider","year":"2007","journal-title":"Rheumatol. Int."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1002\/art.24163","article-title":"Toward the identification of symptom patterns in people with fibromyalgia","volume":"61","author":"Wilson","year":"2009","journal-title":"Arthritis Care Res."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1186\/s13075-014-0463-7","article-title":"OMERACT-based fibromyalgia symptom subgroups: An exploratory cluster analysis","volume":"16","author":"Vincent","year":"2014","journal-title":"Arthritis Res. Ther."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"R9","DOI":"10.1186\/ar1863","article-title":"Heterogeneity of psychophysiological stress responses in fibromyalgia syndrome patients","volume":"8","author":"Thieme","year":"2005","journal-title":"Arthritis Res. Ther."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1002\/2327-6924.12270","article-title":"Heterogeneity in fibromyalgia based upon cognitive and physical performance and psychological symptomology","volume":"28","author":"Follick","year":"2016","journal-title":"J. Am. Assoc. Nurse Pract."},{"key":"ref_40","first-page":"26","article-title":"Subgroups of fibromyalgia patients using the 1990 American College of Rheumatology criteria and the modified 2010 preliminary diagnostic criteria: The al-\u00e1ndalus project","volume":"34","year":"2016","journal-title":"Clin. Exp. Rheumatol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1002\/ejp.935","article-title":"Identifying fibromyalgia subgroups using cluster analysis: Relationships with clinical variables","volume":"21","author":"Yim","year":"2017","journal-title":"Eur. J. Pain"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"233","DOI":"10.3109\/03009749309095129","article-title":"Fibromyalgia in the adult danish population: I. A prevalence study","volume":"22","author":"Prescott","year":"1993","journal-title":"Scand. J. Rheumatol."},{"key":"ref_43","first-page":"140","article-title":"The prevalence of fibromyalgia in women aged 20\u201364 in Turkey","volume":"34","author":"Topbas","year":"2005","journal-title":"Scand. J. Rheumatol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1136\/bmj.303.6796.216","article-title":"Prevalence of primary fibromyalgia in the Finnish population","volume":"303","author":"Makela","year":"1991","journal-title":"Br. Med. J."},{"key":"ref_45","first-page":"1","article-title":"Prevalence of fibromyalgia in a low socioeconomic status population","volume":"10","author":"Cavalcante","year":"2009","journal-title":"BMC Musculoskelet. Disord."},{"key":"ref_46","first-page":"1043","article-title":"Demographic characteristics, clinical findings and functional status in patients with fibromyalgia syndrome","volume":"68","author":"Demirbag","year":"2018","journal-title":"J. Pak. Med. Assoc."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/1471-2474-7-4","article-title":"Major depression, fibromyalgia and labour force participation: A population-based cross-sectional study","volume":"7","author":"Kassam","year":"2006","journal-title":"BMC Musculoskelet. Disord."},{"key":"ref_48","first-page":"417","article-title":"Work stress and incidence of newly diagnosed fibromyalgia: Prospective cohort study","volume":"57","author":"Virtanen","year":"2004","journal-title":"J. Psychosom. Res."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1071\/AH15047","article-title":"Health service utilisation by people living with chronic non-cancer pain: Findings from the Pain and Opioids in Treatment (POINT) study","volume":"40","author":"Nielsen","year":"2016","journal-title":"Aust. Health Rev."},{"key":"ref_50","first-page":"1255","article-title":"Pain, disability, and phyisical funcitoning in subgroups of patients with fibromyalgia","volume":"23","author":"Turk","year":"1996","journal-title":"J. Rheumatol."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2916","DOI":"10.1002\/art.11272","article-title":"Subgrouping of Fibromyalgia Patients on the Basis of Pressure-Pain Thresholds and Psychological Factors","volume":"48","author":"Giesecke","year":"2003","journal-title":"Arthritis Rheum."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.jpsychores.2012.04.002","article-title":"The Hospital Anxiety and Depression Scale (HADS) is dead, but like Elvis, there will still be citings","volume":"73","author":"Coyne","year":"2012","journal-title":"J. Sychosomatic Res."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1002\/art.38905","article-title":"The prevalence of fibromyalgia in the general population: A comparison of the American College of Rheumatology 1990, 2010, and modified 2010 classification criteria","volume":"67","author":"Jones","year":"2015","journal-title":"Arthritis Rheum."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"e290","DOI":"10.2196\/jmir.7071","article-title":"The Use of Facebook in Recruiting Participants for Health Research Purposes: A Systematic Review","volume":"19","author":"Whitaker","year":"2017","journal-title":"J. Med. 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