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OMERACT-based fibromyalgia symptom subgroups: an exploratory cluster analysis

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Abstract

Introduction

The aim of this study was to identify subsets of patients with fibromyalgia with similar symptom profiles using the Outcome Measures in Rheumatology (OMERACT) core symptom domains.

Methods

Female patients with a diagnosis of fibromyalgia and currently meeting fibromyalgia research survey criteria completed the Brief Pain Inventory, the 30-item Profile of Mood States, the Medical Outcomes Sleep Scale, the Multidimensional Fatigue Inventory, the Multiple Ability Self-Report Questionnaire, the Fibromyalgia Impact Questionnaire-Revised (FIQ-R) and the Short Form-36 between 1 June 2011 and 31 October 2011. Hierarchical agglomerative clustering was used to identify subgroups of patients with similar symptom profiles. To validate the results from this sample, hierarchical agglomerative clustering was repeated in an external sample of female patients with fibromyalgia with similar inclusion criteria.

Results

A total of 581 females with a mean age of 55.1 (range, 20.1 to 90.2) years were included. A four-cluster solution best fit the data, and each clustering variable differed significantly (P <0.0001) among the four clusters. The four clusters divided the sample into severity levels: Cluster 1 reflects the lowest average levels across all symptoms, and cluster 4 reflects the highest average levels. Clusters 2 and 3 capture moderate symptoms levels. Clusters 2 and 3 differed mainly in profiles of anxiety and depression, with Cluster 2 having lower levels of depression and anxiety than Cluster 3, despite higher levels of pain. The results of the cluster analysis of the external sample (n = 478) looked very similar to those found in the original cluster analysis, except for a slight difference in sleep problems. This was despite having patients in the validation sample who were significantly younger (P <0.0001) and had more severe symptoms (higher FIQ-R total scores (P = 0.0004)).

Conclusions

In our study, we incorporated core OMERACT symptom domains, which allowed for clustering based on a comprehensive symptom profile. Although our exploratory cluster solution needs confirmation in a longitudinal study, this approach could provide a rationale to support the study of individualized clinical evaluation and intervention.

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Abbreviations

BMI:

Body mass index

BPI:

Brief Pain Inventory

FIQ-R:

Revised Fibromyalgia Impact Questionnaire

FM:

Fibromyalgia

GAD-7:

Generalized Anxiety Disorder 7-item scale

MASQ:

Multiple Ability Self-report Questionnaire

MFI:

Multidimensional Fatigue Inventory

MOS-Sleep:

Medical Outcomes Study Sleep Scale

OMERACT:

Outcome Measures in Rheumatology

PHQ-9:

Patient Health Questionnaire

POMS:

Profile of Mood States

SF-36:

36-item Short Form survey

SNRI:

Serotonin norepinephrine reuptake inhibitor

SS:

Symptom severity

SSRI:

Selective serotonin reuptake inhibitor

WPI:

Widespread Pain Index

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Acknowledgements

This study was supported in part by the Center for Translational Science Activities (CTSA) at the Mayo Clinic. This center is funded in part by a grant from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH) (RR024150). The manuscript contents are solely the responsibility of the authors and do not necessarily represent the official views of CTSA, NCRR or NIH. The funders had no role in the study design, data collection and analysis, decision to publish or manuscript preparation. The study data were collected and managed using REDCap electronic data capture tools hosted at the Mayo Clinic. REDCap (Research Electronic Data Capture) is a secure, web-based application designed to support data capture for research studies by providing (1) an intuitive interface for validated data entry, (2) audit trails for tracking data manipulation and export procedures, (3) automated export procedures for seamless data downloads to common statistical packages and (4) procedures for importing data from external sources.

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Authors and Affiliations

  1. Division of General Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, 55902, MN, USA

    Ann Vincent & Mary O Whipple

  2. Division of Biomedical Statistics and Informatics, Mayo Clinic, 200 First Street SW, Rochester, 55902, MN, USA

    Tanya L Hoskin

  3. Chronic Pain and Fatigue Research Center, University of Michigan Health System, 24 Frank Lloyd Wright Drive, Ann Arbor, 48105, MI, USA

    Daniel J Clauw & David A Williams

  4. Division of Medical Oncology, Mayo Clinic, 200 First Street SW, Rochester, 55902, MN, USA

    Debra L Barton

  5. Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, 55902, MN, USA

    Roberto P Benzo

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  1. Ann Vincent
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Correspondence to Ann Vincent.

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Vincent, A., Hoskin, T.L., Whipple, M.O. et al. OMERACT-based fibromyalgia symptom subgroups: an exploratory cluster analysis. Arthritis Res Ther 16, 463 (2014). https://doi.org/10.1186/s13075-014-0463-7

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